fix: stop background session checks and loading flicker

# Conflicts:
#	crates/worker-runtime/src/worker_backend.rs
#	openapi/server-api.json
#	web/workspace/src/lib/generated/companion-api.ts
#	web/workspace/src/lib/generated/repository-api.ts
#	web/workspace/src/lib/generated/runtime-api.ts
#	web/workspace/src/lib/generated/ticket-api.ts
#	web/workspace/src/lib/generated/worker-launch-api.ts

Cargo.lock

@@ -5266,6 +5266,7 @@ dependencies = [
  "thiserror 2.0.18",
  "tokio",
  "tracing",
+ "uuid",
  "workdir",
 ]
 
@@ -6705,6 +6706,7 @@ dependencies = [
 name = "yoi-e2e"
 version = "0.0.0"
 dependencies = [
+ "chrono",
  "libc",
  "reqwest",
  "serde",
@@ -6714,6 +6716,7 @@ dependencies = [
  "tempfile",
  "webauthn-authenticator-rs",
  "webauthn-rs-proto",
+ "yoi-workspace-server",
 ]
 
 [[package]]

crates/client/src/backend_runtime.rs

@@ -908,6 +908,7 @@ mod tests {
             workdir_attachments: Vec::new(),
             feature_connections: Default::default(),
             control_operation_id: None,
+            execution_grant: None,
         };
 
         let response = create_backend_worker_with_client(&target, &create, &api)

crates/client/src/workspace_product.rs

@@ -567,6 +567,7 @@ impl BackendWorkspaceProductClient {
             workdir_attachments: Vec::new(),
             feature_connections: Default::default(),
             control_operation_id: None,
+            execution_grant: None,
         };
         let workspace_id = self.workspace_id.clone();
         let response: BrowserCreateWorkerResponse = self.generated(move |client| async move {

crates/fs-operation/src/local.rs

@@ -200,6 +200,7 @@ fn run_read_with_limits(
         total_lines,
         content_hash: content_hasher.finalize().into(),
         truncated: end < total_lines || byte_truncated,
+        byte_truncated,
     })
 }
 
@@ -885,6 +886,34 @@ mod bounded_read_tests {
         assert!(error.to_string().contains("exceeds provider limit 4096"));
     }
 
+    #[test]
+    fn bounded_read_distinguishes_utf8_byte_cut_from_complete_line_continuation() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().canonicalize().unwrap();
+        fs::write(root.join("text"), "雪雪needle\nnext").unwrap();
+        for (offset, max_bytes, bytes, more, cut) in [
+            (0, 5, "雪", true, true),
+            (0, 64, "雪雪needle\n", true, false),
+            (1, 64, "next", false, false),
+        ] {
+            let result = run_read_bounded(
+                &root,
+                ReadRequest {
+                    path: FsPath::new("text").unwrap(),
+                    offset,
+                    limit: 1,
+                    max_bytes,
+                },
+                &RootAccess(root.clone()),
+                BoundedReadLimits::new(1024, 64).unwrap(),
+            )
+            .unwrap();
+            assert_eq!(result.bytes, bytes.as_bytes());
+            assert_eq!(result.truncated, more);
+            assert_eq!(result.byte_truncated, cut);
+        }
+    }
+
     #[test]
     fn bounded_read_caps_retained_response_independently_of_request() {
         let temp = tempfile::tempdir().unwrap();
@@ -907,6 +936,7 @@ mod bounded_read_tests {
         assert_eq!(result.bytes, b"alpha");
         assert_eq!(result.total_lines, 3);
         assert!(result.truncated);
+        assert!(result.byte_truncated);
     }
 }
 

crates/fs-operation/src/operation.rs

@@ -204,7 +204,11 @@ pub struct ReadResult {
     #[schemars(range(min = 0, max = 9_007_199_254_740_991_usize))]
     pub total_lines: usize,
     pub content_hash: ContentHash,
+    /// More source lines remain, or the selected window exceeded the response byte budget.
     pub truncated: bool,
+    /// The selected line window was cut by its byte budget, possibly within a line.
+    /// Line-based cursors must not treat such a window as completely scanned.
+    pub byte_truncated: bool,
 }
 
 /// Binary-safe byte range read with an optional whole-file version fence.

crates/protocol/src/lib.rs

@@ -408,7 +408,7 @@ pub enum Method {
 /// Transport is fire-and-forget; receivers must tolerate out-of-order
 /// delivery (e.g. `TurnEnded` arriving after `ShutDown` for the same
 /// child Worker).
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
 #[serde(tag = "kind", rename_all = "snake_case")]
@@ -982,6 +982,17 @@ pub enum SessionEntryProvenance {
     LegacyUnknown,
 }
 
+/// Public use decisions contain no Feature identity or private payload. Absence
+/// denotes the older projection contract, not permission to expose System input.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
+#[serde(deny_unknown_fields)]
+pub struct SessionEntryUsePolicy {
+    pub observation_readable: bool,
+    pub memory_evidence: bool,
+}
+
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
@@ -994,6 +1005,8 @@ pub struct SessionSnapshotEntry {
     pub provenance: SessionEntryProvenance,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub derived_from: Vec<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub use_policy: Option<SessionEntryUsePolicy>,
     #[serde(flatten)]
     pub data: SessionSnapshotEntryData,
 }
@@ -1180,12 +1193,10 @@ pub enum Event {
     },
     /// One agent-injected system item committed to history.
     ///
-    /// Carries the JSON form of `session_store::SystemItem`. Covers
-    /// `Method::Notify` echoes, child-Worker lifecycle events from
-    /// `Method::WorkerEvent`, `@<path>` resolution payloads, and any future
-    /// Clients dispatch on the `kind` tag for typed rendering instead
-    /// of parsing free-text prefixes like `[Notification] …` or
-    /// `[File: …]`.
+    /// Carries the allowlisted JSON form of `session_store::PublicSystemItem`,
+    /// not the storage record. Its descriptive `kind` is independent from the
+    /// typed `presentation` used for notification, reminder, or context rendering.
+    /// Private Feature payloads and prompt provenance are never event data.
     ///
     /// One event per `LogEntry::AnnotatedSystemItem` commit. Disk-side and
     /// wire-side are 1:1.
@@ -2621,6 +2632,7 @@ mod tests {
             session: SessionSnapshot {
                 pending_submissions: PendingSubmissionsSnapshot::default(),
                 entries: vec![SessionSnapshotEntry {
+                    use_policy: None,
                     entry_id: "entry-1".into(),
                     timestamp: 1,
                     provenance: SessionEntryProvenance::HumanInput,

crates/protocol/src/typescript.rs

@@ -17,12 +17,12 @@ use crate::{
     PasteArtifactRef, PendingSubmissionSummary, PendingSubmissionsSnapshot, Permission,
     ReasoningConfig, RewindSummary, RunFailureKind, RunResult, RunResumeSource, RunYieldReason,
     ScopeRule, Segment, SessionContentPart, SessionConversationTurn, SessionEntryProvenance,
-    SessionHistoryLineageBoundary, SessionHistoryPage, SessionMessageRole, SessionSnapshot,
-    SessionSnapshotEntry, SessionSnapshotEntryData, SessionToolAttachment, SubmissionDisposition,
-    SymlinkPolicy, ToolResultDisposition, TurnResult, UploadedFileAvailability, UploadedFileRef,
-    WorkerBusyState, WorkerCommandAcknowledgement, WorkerCommandDisposition, WorkerCommandEnvelope,
-    WorkerCommandKind, WorkerEvent, WorkerMaintenanceState, WorkerRunState, WorkerState,
-    WorkerStateSnapshot, WorkerStatus,
+    SessionEntryUsePolicy, SessionHistoryLineageBoundary, SessionHistoryPage, SessionMessageRole,
+    SessionSnapshot, SessionSnapshotEntry, SessionSnapshotEntryData, SessionToolAttachment,
+    SubmissionDisposition, SymlinkPolicy, ToolResultDisposition, TurnResult,
+    UploadedFileAvailability, UploadedFileRef, WorkerBusyState, WorkerCommandAcknowledgement,
+    WorkerCommandDisposition, WorkerCommandEnvelope, WorkerCommandKind, WorkerEvent,
+    WorkerMaintenanceState, WorkerRunState, WorkerState, WorkerStateSnapshot, WorkerStatus,
     subscription::{
         EventSubscriptionSelector, MAX_CORRELATION_ID_BYTES, MAX_REJECTION_MESSAGE_BYTES,
         MAX_RESOURCE_ID_BYTES, MAX_SUBSCRIPTION_COLLECTION_ITEMS,
@@ -117,6 +117,7 @@ pub fn generated_protocol_types() -> String {
     push_decl::<InFlightCompaction>(&cfg, &mut output);
     push_decl::<InFlightSnapshot>(&cfg, &mut output);
     push_decl::<SessionEntryProvenance>(&cfg, &mut output);
+    push_decl::<SessionEntryUsePolicy>(&cfg, &mut output);
     push_decl::<SessionMessageRole>(&cfg, &mut output);
     push_decl::<SessionContentPart>(&cfg, &mut output);
     push_decl::<SessionToolAttachment>(&cfg, &mut output);

crates/runtime-api/src/lib.rs

@@ -518,9 +518,10 @@ pub struct WorkerRestorePreparation {
     pub workspace_api: Option<WorkspaceApiRef>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub workdir_attachments: Option<Vec<LogicalWorkdirAttachment>>,
+    /// Retained in saved Restore intents; Restore does not apply Repository access.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub repository_access: Vec<WorkingDirectoryRepositoryAccessRequest>,
-    /// Read-only references resolved by Workspace only after this operation owns admission.
+    /// Retained references from saved resource preparation, not Restore prerequisites.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub repository_access_workdirs: Vec<RepositoryAccessWorkdirReference>,
 }
@@ -1140,8 +1141,36 @@ pub struct SubjectReleaseResponse {
     pub state: SubjectReleaseState,
 }
 
+/// Irreversibly fence an unpublished failed Subject create. Exact retries must retain
+/// all four fields; this is distinct from releasing an existing Subject Controller.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+#[serde(deny_unknown_fields)]
+pub struct SubjectCreateRecoveryRequest {
+    pub workspace_id: String,
+    pub worker_id: WorkerId,
+    pub create_fingerprint: String,
+    pub operation_id: String,
+}
+
+/// Durable admission-fence proof plus freshly confirmed execution absence.
+/// An error (including a lost response) is never evidence of absence.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+#[serde(deny_unknown_fields)]
+pub struct SubjectCreateRecoveryResponse {
+    pub workspace_id: String,
+    pub worker_id: WorkerId,
+    pub create_fingerprint: String,
+    pub operation_id: String,
+}
+
 #[api(reqwest, axum)]
 pub trait RuntimeApi {
+    #[post("/v1/subject-create-recovery", status = 200, error_status = 400)]
+    async fn recover_subject_create(
+        &self,
+        #[body] request: SubjectCreateRecoveryRequest,
+    ) -> Result<SubjectCreateRecoveryResponse, RuntimeApiError>;
+
     #[post("/v1/subject-release", status = 200, error_status = 400)]
     async fn subject_release(
         &self,
@@ -1675,6 +1704,18 @@ mod tests {
         ) -> Result<SessionMaterialPinResponse, RuntimeApiError> {
             Err(test_error(501))
         }
+        async fn recover_subject_create(
+            &self,
+            request: SubjectCreateRecoveryRequest,
+        ) -> Result<SubjectCreateRecoveryResponse, RuntimeApiError> {
+            Ok(SubjectCreateRecoveryResponse {
+                workspace_id: request.workspace_id,
+                worker_id: request.worker_id,
+                create_fingerprint: request.create_fingerprint,
+                operation_id: request.operation_id,
+            })
+        }
+
         async fn subject_release(
             &self,
             _request: SubjectReleaseRequest,
@@ -1820,6 +1861,21 @@ mod tests {
             .build()
             .unwrap();
 
+        let recovery = SubjectCreateRecoveryRequest {
+            workspace_id: "workspace-a".into(),
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "failed-create-fingerprint".into(),
+            operation_id: "recovery-1".into(),
+        };
+        let response = client
+            .recover_subject_create(recovery.clone())
+            .await
+            .unwrap();
+        assert_eq!(response.workspace_id, recovery.workspace_id);
+        assert_eq!(response.worker_id, recovery.worker_id);
+        assert_eq!(response.create_fingerprint, recovery.create_fingerprint);
+        assert_eq!(response.operation_id, recovery.operation_id);
+
         let summary = client.runtime_summary().await.unwrap();
         assert_eq!(summary.runtime.display_name.as_deref(), Some("round-trip"));
         let workers = client

crates/server-api/src/authorization.rs

@@ -0,0 +1,475 @@
+//! Neutral explicit-allow authorization contracts. Resource containment never crosses kinds.
+//!
+//! # Trusted Feature boundary
+//!
+//! A Profile requests execution configuration, not authority. The Worker asks the
+//! Host for each enabled Feature's exact activation name before initialization,
+//! then trusted Feature code asks for each protected operation and its semantic
+//! resource before access or effects. `ticket` on [`PermissionResource::Feature`]
+//! activates Ticket; it implies neither `ticket.create` nor any future operation.
+//! `ticket.create` on a Workspace permits creation there but cannot activate the
+//! Feature. There are no wildcard permissions or implicit dotted-name inheritance.
+//!
+//! Identity is absent from the authorization request intentionally: the Host
+//! authenticates the bound Runtime/Worker and resolves current source permissions,
+//! body ownership and any per-Worker execution grant. A shared client, Profile,
+//! remembered receipt or caller-supplied Subject claim is not authority. Features
+//! depend on this contract, never on a particular Subject policy implementation.
+//!
+//! Supported cooperative boundaries are Feature activation, ordinary Worker
+//! delegation, Ticket creation (Tool/native WIP/typed service), Workdir filesystem
+//! read/write and whole-attachment command execution, and scoped result notify.
+//! Workdir providers still enforce resolved paths, traversal, capability, Ticket
+//! and provider ceilings. The returned scope is for provider narrowing, not a
+//! transferable credential. Scoped checkout/overlap operations are refused until
+//! their complete access semantics are adapted. Other Feature operations retain
+//! their existing owner checks; they do not automatically acquire this operation
+//! policy. Missing calls are trusted Feature bugs, not interception by a universal
+//! Tool executor or protection against malicious Feature code. Connection tests
+//! must exercise each exposed surface, assert a genuine permitted effect and
+//! assert zero downstream calls on denial, including revocation and provider denial.
+//!
+//! # Delegation callers and recovery
+//!
+//! Callers such as a chat Feature supply explicit operation/resource selections
+//! and retain the same public operation ID and full request after an unknown
+//! result. Normal Profile/Worker allocation and control/resource grants are reused;
+//! there is no Subject Worker registry. Effective grants bind immutable Profile
+//! resolution, the reserved Worker and source assignment. Permission replacement
+//! invalidates existing children rather than refreshing them. Body replacement,
+//! retirement and restore must recheck current authority; historical result lookup
+//! is not new execution permission. Cancellation acceptance is distinct from
+//! terminal confirmation and does not undo completed effects.
+//!
+//! A child receives no Subject body identity, singleton, whole Memory or public
+//! conversation-post authority. `worker.result` is explicit notify authority to a
+//! named origin Worker, not arbitrary control or publication. Chat delivery and
+//! conversation correlation belong to the caller integration, not this contract.
+//! Unset existing Subject policies deny new Subject execution/delegation; ordinary
+//! non-Subject Workers explicitly retain existing Backend/provider contracts.
+//! Standalone non-Workspace activation compatibility grants no Workspace operation.
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+pub const MAX_SCOPED_PERMISSIONS: usize = 256;
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]
+pub enum PermissionResource {
+    Feature,
+    Workspace {
+        workspace_id: String,
+    },
+    Workdir {
+        working_directory_id: String,
+        path: String,
+        recursive: bool,
+    },
+    Worker {
+        runtime_id: String,
+        worker_id: String,
+    },
+}
+
+// Serde's internally tagged unit variants ignore extra fields even with deny_unknown_fields.
+// A struct-shaped wire variant preserves the public unit variant while rejecting those claims.
+impl<'de> Deserialize<'de> for PermissionResource {
+    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        #[derive(Deserialize)]
+        #[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]
+        enum Wire {
+            Feature {},
+            Workspace {
+                workspace_id: String,
+            },
+            Workdir {
+                working_directory_id: String,
+                path: String,
+                recursive: bool,
+            },
+            Worker {
+                runtime_id: String,
+                worker_id: String,
+            },
+        }
+        Ok(match Wire::deserialize(deserializer)? {
+            Wire::Feature {} => Self::Feature,
+            Wire::Workspace { workspace_id } => Self::Workspace { workspace_id },
+            Wire::Workdir {
+                working_directory_id,
+                path,
+                recursive,
+            } => Self::Workdir {
+                working_directory_id,
+                path,
+                recursive,
+            },
+            Wire::Worker {
+                runtime_id,
+                worker_id,
+            } => Self::Worker {
+                runtime_id,
+                worker_id,
+            },
+        })
+    }
+}
+
+impl PermissionResource {
+    pub fn validate(&self) -> Result<(), String> {
+        match self {
+            Self::Feature => Ok(()),
+            Self::Workspace { workspace_id } => validate_authorization_identifier(workspace_id),
+            Self::Workdir {
+                working_directory_id,
+                path,
+                ..
+            } => {
+                validate_authorization_identifier(working_directory_id)?;
+                validate_relative_permission_path(path)
+            }
+            Self::Worker {
+                runtime_id,
+                worker_id,
+            } => {
+                validate_authorization_identifier(runtime_id)?;
+                validate_authorization_identifier(worker_id)
+            }
+        }
+    }
+
+    pub fn covers(&self, other: &Self) -> bool {
+        if self.validate().is_err() || other.validate().is_err() {
+            return false;
+        }
+        match (self, other) {
+            (Self::Feature, Self::Feature) => true,
+            (Self::Workspace { workspace_id: a }, Self::Workspace { workspace_id: b }) => a == b,
+            (
+                Self::Worker {
+                    runtime_id: ar,
+                    worker_id: aw,
+                },
+                Self::Worker {
+                    runtime_id: br,
+                    worker_id: bw,
+                },
+            ) => ar == br && aw == bw,
+            (
+                Self::Workdir {
+                    working_directory_id: a,
+                    path: ap,
+                    recursive: ar,
+                },
+                Self::Workdir {
+                    working_directory_id: b,
+                    path: bp,
+                    recursive: br,
+                },
+            ) => {
+                a == b
+                    && if *ar {
+                        ap == "."
+                            || ap == bp
+                            || bp
+                                .strip_prefix(ap)
+                                .is_some_and(|tail| tail.starts_with('/'))
+                    } else {
+                        ap == bp && !br
+                    }
+            }
+            _ => false,
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct ScopedPermission {
+    pub operation: String,
+    pub resource: PermissionResource,
+}
+
+impl ScopedPermission {
+    pub fn validate(&self) -> Result<(), String> {
+        validate_operation_name(&self.operation)?;
+        self.resource.validate()?;
+        if matches!(self.resource, PermissionResource::Feature) && self.operation.contains('.') {
+            return Err("Feature resources authorize activation names only, not operations".into());
+        }
+        Ok(())
+    }
+
+    pub fn covers(&self, other: &Self) -> bool {
+        self.validate().is_ok()
+            && other.validate().is_ok()
+            && self.operation == other.operation
+            && self.resource.covers(&other.resource)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct SubjectPermissions {
+    pub change_id: String,
+    pub execution: Vec<ScopedPermission>,
+    pub delegation: Vec<ScopedPermission>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct SubjectPermissionsUpdate {
+    pub operation_id: String,
+    pub expected_change_id: Option<String>,
+    pub execution: Vec<ScopedPermission>,
+    pub delegation: Vec<ScopedPermission>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct WorkerExecutionGrant {
+    pub subject_id: String,
+    pub origin_runtime_id: String,
+    pub origin_worker_id: String,
+    pub source_change_id: String,
+    pub runtime_id: String,
+    pub worker_id: String,
+    pub profile: String,
+    pub profile_digest: String,
+    pub permissions: Vec<ScopedPermission>,
+    pub redelegation: Vec<ScopedPermission>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct WorkerDelegationRequest {
+    pub permissions: Vec<ScopedPermission>,
+    pub redelegation: Vec<ScopedPermission>,
+}
+
+impl WorkerDelegationRequest {
+    pub fn validate(&self) -> Result<(), String> {
+        validate_scoped_permissions(&self.permissions)?;
+        validate_scoped_permissions(&self.redelegation)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct OperationAuthorizationRequest {
+    pub operation: String,
+    pub resource: PermissionResource,
+}
+
+impl OperationAuthorizationRequest {
+    pub fn validate(&self) -> Result<(), String> {
+        ScopedPermission {
+            operation: self.operation.clone(),
+            resource: self.resource.clone(),
+        }
+        .validate()
+    }
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct OperationAuthorizationResponse {
+    /// Matching granted scope for provider-resolved checks, not a credential.
+    /// `None` identifies the explicit non-Subject legacy authorization path.
+    #[serde(default)]
+    pub scope: Option<PermissionResource>,
+}
+
+pub fn validate_operation_name(value: &str) -> Result<(), String> {
+    if value.is_empty()
+        || value.len() > 256
+        || !value.split('.').all(|part| {
+            !part.is_empty()
+                && part
+                    .bytes()
+                    .all(|b| b.is_ascii_alphanumeric() || b == b'_' || b == b'-')
+        })
+    {
+        return Err(
+            "permission operation must be an exact, nonempty dot-separated name (no wildcards)"
+                .into(),
+        );
+    }
+    Ok(())
+}
+
+pub fn validate_scoped_permissions(permissions: &[ScopedPermission]) -> Result<(), String> {
+    if permissions.len() > MAX_SCOPED_PERMISSIONS {
+        return Err("too many scoped permissions".into());
+    }
+    for permission in permissions {
+        permission.validate()?;
+    }
+    Ok(())
+}
+
+pub fn validate_authorization_identifier(value: &str) -> Result<(), String> {
+    if value.is_empty()
+        || value.len() > 256
+        || value.trim() != value
+        || value.chars().any(|c| c.is_control() || c == '*')
+    {
+        return Err("authorization identity must be nonempty, bounded and exact".into());
+    }
+    Ok(())
+}
+
+/// Paths are already-normalized lexical paths, not host filesystem paths. The Host must
+/// still enforce symlink/provider boundaries; lexical containment grants no filesystem access.
+pub fn validate_relative_permission_path(path: &str) -> Result<(), String> {
+    if path == "." {
+        return Ok(());
+    }
+    if path.is_empty()
+        || path.len() > 4096
+        || path.contains(['\\', ':'])
+        || path.chars().any(char::is_control)
+        || path
+            .split('/')
+            .any(|part| part.is_empty() || part == "." || part == "..")
+    {
+        return Err("permission path must be a normalized relative path without escape".into());
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn workdir(path: &str, recursive: bool) -> PermissionResource {
+        PermissionResource::Workdir {
+            working_directory_id: "wd".into(),
+            path: path.into(),
+            recursive,
+        }
+    }
+
+    #[test]
+    fn lexical_containment_rejects_escape_and_respects_component_and_recursion_boundaries() {
+        for path in [
+            "",
+            "/src",
+            "../src",
+            "src/../secret",
+            "src/./a",
+            "src//a",
+            "src/",
+            "C:/src",
+            "src\\a",
+        ] {
+            assert!(workdir(path, true).validate().is_err(), "{path}");
+        }
+        let root = workdir(".", true);
+        let src = workdir("src", true);
+        assert!(root.covers(&src));
+        assert!(src.covers(&workdir("src/a", true)));
+        assert!(!src.covers(&workdir("src-other", false)));
+        assert!(!workdir("src", false).covers(&src));
+        assert!(workdir("src", false).covers(&workdir("src", false)));
+        assert!(!workdir("src", false).covers(&workdir("src/a", false)));
+        assert!(!src.covers(&PermissionResource::Workdir {
+            working_directory_id: "other".into(),
+            path: "src".into(),
+            recursive: false
+        }));
+    }
+
+    #[test]
+    fn operation_hierarchy_never_implies_inheritance_or_feature_activation() {
+        for name in [
+            "",
+            "*",
+            "ticket.*",
+            ".ticket",
+            "ticket.",
+            "ticket..read",
+            "ticket read",
+        ] {
+            assert!(validate_operation_name(name).is_err(), "{name}");
+        }
+        let activation = ScopedPermission {
+            operation: "ticket".into(),
+            resource: PermissionResource::Feature,
+        };
+        let create = ScopedPermission {
+            operation: "ticket.create".into(),
+            resource: PermissionResource::Workspace {
+                workspace_id: "ws".into(),
+            },
+        };
+        let parent_name = ScopedPermission {
+            operation: "ticket".into(),
+            resource: create.resource.clone(),
+        };
+        assert!(!parent_name.covers(&create));
+        assert!(!create.covers(&parent_name));
+        assert!(!activation.covers(&create));
+        assert!(!create.covers(&activation));
+        assert!(
+            ScopedPermission {
+                operation: "ticket.create".into(),
+                resource: PermissionResource::Feature
+            }
+            .validate()
+            .is_err()
+        );
+        assert!(
+            !PermissionResource::Workspace {
+                workspace_id: "ws".into()
+            }
+            .covers(&workdir(".", true))
+        );
+    }
+
+    #[test]
+    fn wire_contract_rejects_self_claimed_identity_and_unknown_fields() {
+        let request = serde_json::json!({"permissions":[],"redelegation":[],"subject_id":"forged"});
+        assert!(serde_json::from_value::<WorkerDelegationRequest>(request).is_err());
+        let resource: PermissionResource =
+            serde_json::from_value(serde_json::json!({"kind":"feature"})).unwrap();
+        assert_eq!(resource, PermissionResource::Feature);
+        assert!(
+            serde_json::from_value::<PermissionResource>(
+                serde_json::json!({"kind":"feature","workspace_id":"ws"})
+            )
+            .is_err()
+        );
+    }
+
+    #[test]
+    fn authorization_response_carries_matching_scope_and_defaults_legacy_absence() {
+        let legacy: OperationAuthorizationResponse =
+            serde_json::from_value(serde_json::json!({})).unwrap();
+        assert_eq!(legacy.scope, None);
+        assert_eq!(
+            serde_json::to_value(legacy).unwrap(),
+            serde_json::json!({"scope":null})
+        );
+        let granted = OperationAuthorizationResponse {
+            scope: Some(workdir("src", true)),
+        };
+        let wire = serde_json::to_value(&granted).unwrap();
+        assert_eq!(
+            wire,
+            serde_json::json!({"scope":{"kind":"workdir","working_directory_id":"wd","path":"src","recursive":true}})
+        );
+        assert_eq!(
+            serde_json::from_value::<OperationAuthorizationResponse>(wire).unwrap(),
+            granted
+        );
+    }
+}

crates/server-api/src/drive.rs

@@ -134,6 +134,14 @@ pub enum DriveEntryKind {
     File,
 }
 
+/// Current caller's advisory publication ceiling, never a grant or execution credential.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct DriveCapabilities {
+    pub write: bool,
+}
+
 /// Metadata only: content is returned through bounded text or binary routes.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
@@ -491,6 +499,7 @@ impl api_macros::HttpRequestError for DriveApiError {
 
 impl api_macros::openapi::OpenApiSchema for DriveApiError {}
 impl api_macros::openapi::OpenApiSchema for DriveEntry {}
+impl api_macros::openapi::OpenApiSchema for DriveCapabilities {}
 impl api_macros::openapi::OpenApiSchema for DriveEntryQuery {}
 impl api_macros::openapi::OpenApiSchema for DriveListQuery {}
 impl api_macros::openapi::OpenApiSchema for DriveSearchQuery {}
@@ -518,6 +527,7 @@ pub fn drive_api_typescript() -> String {
         DriveEntryRef::decl(&config),
         DriveEntryKind::decl(&config),
         DriveEntry::decl(&config),
+        DriveCapabilities::decl(&config),
         DriveEntryQuery::decl(&config),
         DriveListQuery::decl(&config),
         DriveSearchQuery::decl(&config),

crates/server-api/src/lib.rs

@@ -6,6 +6,7 @@ use api_macros::api;
 pub use api_macros::axum as server_support;
 pub use api_macros::reqwest as client_support;
 pub use api_macros::{ApiContract, BinaryBody, HttpMethod, TransportMetadata, WebSocketOperation};
+pub mod authorization;
 mod drive;
 mod notification;
 pub use notification::*;
@@ -23,6 +24,34 @@ use webauthn_rs_proto::{
 };
 pub use workspace_config::*;
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct SubjectPermissionsResponse {
+    pub permissions: Option<authorization::SubjectPermissions>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct SubjectPermissionsMutationResponse {
+    pub permissions: authorization::SubjectPermissions,
+    /// New operations are already fenced. These are cancellation requests and
+    /// Backend command cleanup evidence, not proof that a Runtime turn stopped.
+    pub interruptions: Vec<SubjectPermissionInterruption>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct SubjectPermissionInterruption {
+    pub runtime_id: String,
+    pub worker_id: String,
+    pub cancellation_accepted: bool,
+    pub backend_command_sessions_closed: bool,
+    pub diagnostics: Vec<String>,
+}
+
 #[allow(dead_code)]
 #[derive(JsonSchema)]
 struct ServerJsonSafeU64(#[schemars(range(min = 0, max = 9_007_199_254_740_991_u64))] u64);
@@ -168,6 +197,11 @@ macro_rules! impl_openapi_schema {
 }
 
 impl_openapi_schema!(
+    SubjectPermissionsResponse,
+    SubjectPermissionsMutationResponse,
+    SubjectPermissionInterruption,
+    authorization::SubjectPermissions,
+    authorization::SubjectPermissionsUpdate,
     AuthBootstrapUserRequest,
     AuthPublicConfig,
     HostingSettings,
@@ -1298,6 +1332,51 @@ pub trait ServerApi {
         #[body] request: MemoryConsolidateStagingRequest,
     ) -> Result<MemoryConsolidationResponse, RepositoryApiError>;
 
+    #[post(
+        "/api/w/{workspace_id}/authorization/check",
+        status = 200,
+        error_status = 400,
+        additional_error_statuses = [401, 403, 404, 409, 500],
+        openapi = false,
+    )]
+    async fn operation_authorize(
+        &self,
+        #[extension] context: ServerRequestContext,
+        #[path] workspace_id: String,
+        #[body] request: authorization::OperationAuthorizationRequest,
+    ) -> Result<authorization::OperationAuthorizationResponse, RepositoryApiError>;
+
+    #[get(
+        "/api/w/{workspace_id}/subjektiv/subjects/{subject_id}/permissions",
+        status = 200,
+        error_status = 400,
+        additional_error_statuses = [401, 403, 404, 500],
+        bearer_auth = true,
+        browser_auth = true,
+    )]
+    async fn subjektiv_subject_permissions_get(
+        &self,
+        #[extension] context: ServerRequestContext,
+        #[path] workspace_id: String,
+        #[path] subject_id: String,
+    ) -> Result<SubjectPermissionsResponse, RepositoryApiError>;
+
+    #[post(
+        "/api/w/{workspace_id}/subjektiv/subjects/{subject_id}/permissions",
+        status = 200,
+        error_status = 400,
+        additional_error_statuses = [401, 403, 404, 409, 500],
+        bearer_auth = true,
+        browser_auth = true,
+    )]
+    async fn subjektiv_subject_permissions_set(
+        &self,
+        #[extension] context: ServerRequestContext,
+        #[path] workspace_id: String,
+        #[path] subject_id: String,
+        #[body] request: authorization::SubjectPermissionsUpdate,
+    ) -> Result<SubjectPermissionsMutationResponse, RepositoryApiError>;
+
     #[post(
         "/api/w/{workspace_id}/subjektiv/subjects",
         status = 201,
@@ -2762,6 +2841,12 @@ pub trait ServerApi {
         #[extension] context: ServerRequestContext,
         #[path] workspace_id: String,
     ) -> Result<DriveEntry, DriveApiError>;
+    #[get("/api/w/{workspace_id}/drive/capabilities", status = 200, error_status = 400, additional_error_statuses = [401,403,404,409,413,503], bearer_auth = true, browser_auth = true)]
+    async fn drive_capabilities(
+        &self,
+        #[extension] context: ServerRequestContext,
+        #[path] workspace_id: String,
+    ) -> Result<DriveCapabilities, DriveApiError>;
     #[get("/api/w/{workspace_id}/drive/metadata", status = 200, error_status = 400, additional_error_statuses = [401,403,404,409,413,503], bearer_auth = true, browser_auth = true)]
     async fn drive_metadata(
         &self,
@@ -4025,6 +4110,17 @@ impl RequestActor {
 #[serde(deny_unknown_fields)]
 pub struct WhoamiResponse {
     pub actor: Option<RequestActor>,
+    pub session: BrowserSessionState,
+}
+
+/// Browser navigation evidence, not an authorization grant or a generic 401 classification.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]
+pub enum BrowserSessionState {
+    Anonymous {},
+    Authenticated { expires_at: Option<String> },
+    Expired {},
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
@@ -10428,6 +10524,10 @@ pub struct CreateWorkspaceWorkerRequest {
     /// Backend idempotency key used only for authenticated Worker-owned spawn/control.
     #[serde(default)]
     pub control_operation_id: Option<String>,
+    /// Requested least-authority child permissions. Host derives the origin; this
+    /// input cannot assert Subject identity or create a body/singleton attachment.
+    #[serde(default)]
+    pub execution_grant: Option<authorization::WorkerDelegationRequest>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
@@ -11533,6 +11633,7 @@ pub fn auth_api_typescript() -> String {
         ActorAuthMethod::decl(&config),
         AuthenticatedUser::decl(&config),
         RequestActor::decl(&config),
+        BrowserSessionState::decl(&config),
         WhoamiResponse::decl(&config),
         AuthBootstrapUserRequest::decl(&config),
         AuthUserResponse::decl(&config),
@@ -12929,6 +13030,7 @@ mod tests {
             workdir_attachments: Vec::new(),
             feature_connections: Default::default(),
             control_operation_id: None,
+            execution_grant: None,
         })
         .unwrap();
         assert_eq!(
@@ -12943,6 +13045,7 @@ mod tests {
                 "workdir_attachments": [],
                 "feature_connections": {},
                 "control_operation_id": null,
+                "execution_grant": null,
             })
         );
     }
@@ -13961,7 +14064,8 @@ mod tests {
                 "handle": "hare",
                 "display_name": "Hare",
                 "auth_method": "browser_session"
-            }
+            },
+            "session": { "kind": "authenticated", "expires_at": "2026-10-20T00:00:00Z" }
         });
         let decoded = serde_json::from_value::<WhoamiResponse>(whoami.clone())
             .expect("server whoami fixture should match shared DTO");
@@ -14143,11 +14247,36 @@ mod tests {
 
         let unexpected_field = serde_json::json!({
             "actor": null,
+            "session": { "kind": "anonymous" },
             "access_token": "must-not-be-accepted"
         });
         assert!(serde_json::from_value::<WhoamiResponse>(unexpected_field).is_err());
     }
 
+    #[test]
+    fn whoami_session_json_distinguishes_anonymous_expired_and_token_auth() {
+        for session in [
+            serde_json::json!({"kind":"anonymous"}),
+            serde_json::json!({"kind":"expired"}),
+            serde_json::json!({"kind":"authenticated", "expires_at":null}),
+        ] {
+            let value = serde_json::json!({"actor":null, "session":session});
+            let response: WhoamiResponse = serde_json::from_value(value.clone()).unwrap();
+            assert_eq!(serde_json::to_value(response).unwrap(), value);
+        }
+        for session in [
+            serde_json::json!({"kind":"unknown"}),
+            serde_json::json!({"kind":"expired", "expires_at":null}),
+        ] {
+            assert!(
+                serde_json::from_value::<WhoamiResponse>(
+                    serde_json::json!({"actor":null, "session":session})
+                )
+                .is_err()
+            );
+        }
+    }
+
     #[test]
     fn device_login_debug_output_redacts_secret_material() {
         let start = DeviceLoginStartResponse {
@@ -14532,6 +14661,7 @@ mod openapi_artifact_tests {
         // identity, or a one-use Reviewer capability. They remain generated Rust client/Axum
         // operations, but must not appear as unauthenticated operations in the public OpenAPI.
         const SIGNED_INTERNAL: &[&str] = &[
+            "operation_authorize",
             "current_worker_workspace_config_get",
             "current_worker_workspace_config_attach",
             "current_worker_workspace_config_observe",

crates/session-store/src/fs_store.rs

@@ -361,6 +361,7 @@ impl Store for FsStore {
         segment_id: SegmentId,
         entry: &LogEntry,
     ) -> Result<(), StoreError> {
+        entry.validate_input_metadata()?;
         let _retention = self.retention().lock_live(session_id)?;
         let line = serde_json::to_string(entry)?;
         self.append_line(&self.log_path(session_id, segment_id), &line)
@@ -448,6 +449,9 @@ impl Store for FsStore {
         segment_id: SegmentId,
         entries: &[LogEntry],
     ) -> Result<(), StoreError> {
+        for entry in entries {
+            entry.validate_input_metadata()?;
+        }
         let _retention = self.retention().lock_live(session_id)?;
         let path = self.log_path(session_id, segment_id);
         if let Some(parent) = path.parent() {

crates/session-store/src/history.rs

@@ -67,6 +67,10 @@ pub enum LoggedSessionHistoryOrigin {
     ToolOutput {
         worker: LoggedWorkerSubject,
     },
+    /// Descriptive producer identity; use policies live in separate metadata.
+    Provided {
+        producer: String,
+    },
     /// Host-produced opening context summary; not auto-read or TaskStore material.
     CompactionSummary,
     /// Frozen Host Journal reference, never independent observation evidence.
@@ -81,19 +85,32 @@ pub struct LoggedHistoryDerivation {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct LoggedSessionHistoryMetadata {
     pub entry_id: LoggedSessionHistoryEntryId,
     pub origin: LoggedSessionHistoryOrigin,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub derivation: Option<LoggedHistoryDerivation>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub input_metadata: Option<crate::HistoryInputMetadata>,
 }
 
 impl LoggedSessionHistoryMetadata {
+    pub(crate) fn validate_input_metadata(&self) -> Result<(), crate::InputMetadataError> {
+        if matches!(self.origin, LoggedSessionHistoryOrigin::Provided { .. })
+            && self.input_metadata.is_none()
+        {
+            return Err(crate::InputMetadataError::MissingMetadata);
+        }
+        Ok(())
+    }
+
     pub fn legacy_unknown() -> Self {
         Self {
             entry_id: LoggedSessionHistoryEntryId::new(),
             origin: LoggedSessionHistoryOrigin::LegacyUnknown,
             derivation: None,
+            input_metadata: None,
         }
     }
 }
@@ -101,20 +118,146 @@ impl LoggedSessionHistoryMetadata {
 /// Persisted item and metadata are one value so transforms cannot reorder or
 /// truncate one without the other.
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(try_from = "HistoryEntryWire")]
 pub struct LoggedHistoryEntry {
     pub item: LoggedItem,
     pub metadata: LoggedSessionHistoryMetadata,
 }
 
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct HistoryEntryWire {
+    item: LoggedItem,
+    metadata: LoggedSessionHistoryMetadata,
+}
+
+impl TryFrom<HistoryEntryWire> for LoggedHistoryEntry {
+    type Error = crate::InputMetadataError;
+
+    fn try_from(wire: HistoryEntryWire) -> Result<Self, Self::Error> {
+        let entry = Self {
+            item: wire.item,
+            metadata: wire.metadata,
+        };
+        entry.validate_input_metadata()?;
+        Ok(entry)
+    }
+}
+
+impl LoggedHistoryEntry {
+    pub fn validate_input_metadata(&self) -> Result<(), crate::InputMetadataError> {
+        self.metadata.validate_input_metadata()?;
+        if let Some(input) = &self.metadata.input_metadata {
+            match &self.item {
+                LoggedItem::Message {
+                    role: crate::LoggedRole::System,
+                    content,
+                } => {
+                    let [crate::LoggedContentPart::Text { text }] = content.as_slice() else {
+                        return Err(crate::InputMetadataError::InconsistentRecord);
+                    };
+                    if text.len() > crate::input_metadata::MAX_SYSTEM_INPUT_BYTES {
+                        return Err(crate::InputMetadataError::ResourceLimit);
+                    }
+                }
+                // Other logical roles may carry use policy, but cannot masquerade
+                // as the System-only public/payload extension contract.
+                _ if input.feature_payload().is_some() || input.public_item().is_some() => {
+                    return Err(crate::InputMetadataError::InconsistentRecord);
+                }
+                _ => {}
+            }
+        }
+        Ok(())
+    }
+}
+
 /// Typed system-item history record. The typed system event remains available
 /// to client replay while its model-visible projection carries the same stable
 /// metadata used by live history.
 #[derive(Clone, Debug, Serialize, Deserialize)]
+#[serde(try_from = "SystemEntryWire")]
 pub struct LoggedSystemHistoryEntry {
     pub item: crate::SystemItem,
     pub metadata: LoggedSessionHistoryMetadata,
 }
 
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct SystemEntryWire {
+    item: crate::SystemItem,
+    metadata: LoggedSessionHistoryMetadata,
+}
+
+impl TryFrom<SystemEntryWire> for LoggedSystemHistoryEntry {
+    type Error = crate::InputMetadataError;
+
+    fn try_from(wire: SystemEntryWire) -> Result<Self, Self::Error> {
+        let entry = Self {
+            item: wire.item,
+            metadata: wire.metadata,
+        };
+        entry.validate_input_metadata()?;
+        Ok(entry)
+    }
+}
+
+impl LoggedSystemHistoryEntry {
+    pub fn from_input(
+        origin: LoggedSessionHistoryOrigin,
+        derivation: Option<LoggedHistoryDerivation>,
+        input: crate::SystemInputEnvelope,
+    ) -> Self {
+        let (body, input_metadata) = input.into_parts();
+        Self {
+            item: crate::SystemItem::Input { body },
+            metadata: LoggedSessionHistoryMetadata {
+                entry_id: LoggedSessionHistoryEntryId::new(),
+                origin,
+                derivation,
+                input_metadata: Some(input_metadata),
+            },
+        }
+    }
+
+    pub fn validate_input_metadata(&self) -> Result<(), crate::InputMetadataError> {
+        self.metadata.validate_input_metadata()?;
+        match (&self.item, &self.metadata.input_metadata) {
+            (crate::SystemItem::Input { body }, Some(_)) => {
+                if body.len() > crate::input_metadata::MAX_SYSTEM_INPUT_BYTES {
+                    return Err(crate::InputMetadataError::ResourceLimit);
+                }
+            }
+            (crate::SystemItem::Input { .. }, None) => {
+                return Err(crate::InputMetadataError::MissingMetadata);
+            }
+            (_, Some(_)) => return Err(crate::InputMetadataError::InconsistentRecord),
+            (_, None) => {}
+        }
+        Ok(())
+    }
+
+    pub fn to_history_entry(&self) -> LoggedHistoryEntry {
+        LoggedHistoryEntry {
+            item: self.item.to_history_item().into(),
+            metadata: self.metadata.clone(),
+        }
+    }
+
+    pub fn public_item(&self) -> crate::PublicSystemItem {
+        if matches!(self.item, crate::SystemItem::Input { .. }) {
+            return self
+                .metadata
+                .input_metadata
+                .as_ref()
+                .and_then(crate::HistoryInputMetadata::public_item)
+                .cloned()
+                .unwrap_or_else(|| self.item.public_item());
+        }
+        self.item.public_item()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -132,6 +275,7 @@ mod tests {
                 }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId::new(),
                 origin: LoggedSessionHistoryOrigin::HumanInput {
                     account_id: "account-1".into(),
@@ -150,6 +294,64 @@ mod tests {
         );
     }
 
+    #[test]
+    fn external_system_records_reject_missing_policy_role_mismatch_and_overlimit_body() {
+        let valid = serde_json::json!({
+            "item": { "kind": "input", "body": "context" },
+            "metadata": {
+                "entry_id": "stable-entry", "origin": { "kind": "provided", "producer": "owner" },
+                "input_metadata": { "usage": {
+                    "recording_material": "exclude", "memory_evidence": "exclude",
+                    "observation": "hidden", "compaction": "reference_input"
+                } }
+            }
+        });
+        let restored: LoggedSystemHistoryEntry = serde_json::from_value(valid.clone()).unwrap();
+        let flat = serde_json::to_value(restored.to_history_entry()).unwrap();
+        assert!(serde_json::from_value::<LoggedHistoryEntry>(flat.clone()).is_ok());
+        for generic in [true, false] {
+            let wire = if generic { &valid } else { &flat };
+            let decode = |wire| {
+                if generic {
+                    serde_json::from_value::<LoggedSystemHistoryEntry>(wire).is_err()
+                } else {
+                    serde_json::from_value::<LoggedHistoryEntry>(wire).is_err()
+                }
+            };
+            let mut missing = wire.clone();
+            missing["metadata"]
+                .as_object_mut()
+                .unwrap()
+                .remove("input_metadata");
+            assert!(decode(missing));
+            let mut absent_policy = wire.clone();
+            absent_policy["metadata"]["input_metadata"]
+                .as_object_mut()
+                .unwrap()
+                .remove("usage");
+            assert!(decode(absent_policy));
+            let mut invalid_role = wire.clone();
+            invalid_role["item"] =
+                serde_json::to_value(LoggedItem::from(agen::Item::user_message("not system")))
+                    .unwrap();
+            invalid_role["metadata"]["input_metadata"]["public"] = serde_json::json!({
+                "kind": "context", "body": "public system projection", "presentation": {"kind": "context"}
+            });
+            assert!(decode(invalid_role));
+            let mut oversized = wire.clone();
+            if generic {
+                oversized["item"]["body"] = "x"
+                    .repeat(crate::input_metadata::MAX_SYSTEM_INPUT_BYTES + 1)
+                    .into();
+            } else {
+                oversized["item"]["content"][0]["text"] = "x"
+                    .repeat(crate::input_metadata::MAX_SYSTEM_INPUT_BYTES + 1)
+                    .into();
+            }
+            assert!(decode(oversized));
+        }
+    }
+
     #[test]
     fn annotated_segment_start_is_restore_visible_without_projecting_metadata() {
         let session_id = uuid::Uuid::now_v7();

crates/session-store/src/input_metadata.rs

@@ -0,0 +1,563 @@
+//! Validated, Feature-neutral history-input policy and System extensions.
+//!
+//! The enclosing history annotation owns identity, origin and derivation. None of
+//! those descriptive facts selects a use policy here. Model text, independent use
+//! policies, private Feature data and an explicit public projection travel as one
+//! value. Restoring this value does not load a Feature or invoke domain behavior.
+//!
+//! Payload validation bounds the decoded value; enclosing log readers must also
+//! enforce their record allocation limit before decoding untrusted persisted input.
+
+use agen::Item;
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+use crate::PublicSystemItem;
+
+pub const MAX_FEATURE_PAYLOAD_BYTES: usize = 128 * 1024;
+pub const MAX_SYSTEM_INPUT_BYTES: usize = 4 * 1024 * 1024;
+pub const MAX_SYSTEM_PUBLIC_BYTES: usize = 256 * 1024;
+const MAX_SCHEMA_BYTES: usize = 128;
+const MAX_JSON_DEPTH: usize = 16;
+const MAX_JSON_NODES: usize = 8192;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, thiserror::Error)]
+pub enum InputMetadataError {
+    #[error("history input payload schema is invalid")]
+    InvalidSchema,
+    #[error("history input payload version must be nonzero")]
+    InvalidVersion,
+    #[error("system input resource limit exceeded")]
+    ResourceLimit,
+    #[error("history input payload could not be serialized")]
+    Serialization,
+    #[error("history input payload schema or version is unsupported by this consumer")]
+    UnsupportedPayload,
+    #[error("history input payload does not match the owner's typed contract")]
+    InvalidTypedPayload,
+    #[error("provided input is missing explicit metadata")]
+    MissingMetadata,
+    #[error("input metadata does not match its logical record")]
+    InconsistentRecord,
+}
+
+/// One private payload owned by a Feature's versioned typed decoder.
+/// Unknown valid schemas/versions remain data, never execution instructions.
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(try_from = "PayloadWire")]
+pub struct FeatureInputPayload {
+    schema: String,
+    version: u32,
+    value: Value,
+}
+
+impl std::fmt::Debug for FeatureInputPayload {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("FeatureInputPayload")
+            .field("schema", &self.schema)
+            .field("version", &self.version)
+            .finish_non_exhaustive()
+    }
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct PayloadWire {
+    schema: String,
+    version: u32,
+    value: Value,
+}
+
+impl TryFrom<PayloadWire> for FeatureInputPayload {
+    type Error = InputMetadataError;
+
+    fn try_from(wire: PayloadWire) -> Result<Self, Self::Error> {
+        if wire.schema.is_empty()
+            || wire.schema.len() > MAX_SCHEMA_BYTES
+            || !wire.schema.as_bytes()[0].is_ascii_lowercase()
+            || !wire.schema.bytes().all(|byte| {
+                byte.is_ascii_lowercase() || byte.is_ascii_digit() || b"-_.:/".contains(&byte)
+            })
+        {
+            return Err(InputMetadataError::InvalidSchema);
+        }
+        if wire.version == 0 {
+            return Err(InputMetadataError::InvalidVersion);
+        }
+        validate_json(&wire.value, MAX_FEATURE_PAYLOAD_BYTES)?;
+        Ok(Self {
+            schema: wire.schema,
+            version: wire.version,
+            value: wire.value,
+        })
+    }
+}
+
+impl FeatureInputPayload {
+    pub fn encode<T: Serialize>(
+        schema: impl Into<String>,
+        version: u32,
+        value: &T,
+    ) -> Result<Self, InputMetadataError> {
+        PayloadWire {
+            schema: schema.into(),
+            version,
+            value: serde_json::to_value(value).map_err(|_| InputMetadataError::Serialization)?,
+        }
+        .try_into()
+    }
+
+    pub fn schema(&self) -> &str {
+        &self.schema
+    }
+
+    pub fn version(&self) -> u32 {
+        self.version
+    }
+
+    /// The owner explicitly selects its contract before decoding. A valid unknown
+    /// payload can be retained and round-tripped without calling this operation.
+    pub fn decode<T: DeserializeOwned>(
+        &self,
+        schema: &str,
+        version: u32,
+    ) -> Result<T, InputMetadataError> {
+        if self.schema != schema || self.version != version {
+            return Err(InputMetadataError::UnsupportedPayload);
+        }
+        serde_json::from_value(self.value.clone())
+            .map_err(|_| InputMetadataError::InvalidTypedPayload)
+    }
+}
+
+/// Eligibility is supplied independently for recording and Memory evidence.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum InputEvidenceUse {
+    Include,
+    Exclude,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum InputObservationUse {
+    Readable,
+    Hidden,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum InputCompactionUse {
+    /// Ordinary history eligible for the selected retained tail.
+    Retain,
+    /// A full opening summary consumed separately and superseded by compaction.
+    OpeningSummary,
+    /// Full historical context for the compactor, not an accumulating retained tail.
+    ReferenceInput,
+}
+
+/// No permissive defaults: malformed/unknown policies cannot turn into eligibility.
+/// Public presentation is deliberately not one of these use decisions.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct HistoryInputUsePolicy {
+    pub recording_material: InputEvidenceUse,
+    pub memory_evidence: InputEvidenceUse,
+    pub observation: InputObservationUse,
+    pub compaction: InputCompactionUse,
+}
+
+/// Use policy is independent of logical role. Non-System derived Tool context
+/// carries policy only; private Feature payload and public presentation belong
+/// to the System envelope and are rejected on other roles at the history boundary.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(try_from = "MetadataWire")]
+pub struct HistoryInputMetadata {
+    usage: HistoryInputUsePolicy,
+    feature_payload: Option<FeatureInputPayload>,
+    public: Option<PublicSystemItem>,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct MetadataWire {
+    usage: HistoryInputUsePolicy,
+    feature_payload: Option<FeatureInputPayload>,
+    public: Option<PublicSystemItem>,
+}
+
+impl TryFrom<MetadataWire> for HistoryInputMetadata {
+    type Error = InputMetadataError;
+
+    fn try_from(wire: MetadataWire) -> Result<Self, Self::Error> {
+        if let Some(public) = &wire.public {
+            // Kind is a descriptive label, not a Feature dispatch or authority key.
+            if public.kind.is_empty()
+                || public.kind.len() > MAX_SCHEMA_BYTES
+                || public.kind.chars().any(char::is_control)
+            {
+                return Err(InputMetadataError::InvalidSchema);
+            }
+            let value =
+                serde_json::to_value(public).map_err(|_| InputMetadataError::Serialization)?;
+            validate_json(&value, MAX_SYSTEM_PUBLIC_BYTES)?;
+        }
+        Ok(Self {
+            usage: wire.usage,
+            feature_payload: wire.feature_payload,
+            public: wire.public,
+        })
+    }
+}
+
+impl HistoryInputMetadata {
+    pub fn new(
+        usage: HistoryInputUsePolicy,
+        feature_payload: Option<FeatureInputPayload>,
+        public: Option<PublicSystemItem>,
+    ) -> Result<Self, InputMetadataError> {
+        MetadataWire {
+            usage,
+            feature_payload,
+            public,
+        }
+        .try_into()
+    }
+
+    pub fn usage(&self) -> HistoryInputUsePolicy {
+        self.usage
+    }
+
+    pub fn feature_payload(&self) -> Option<&FeatureInputPayload> {
+        self.feature_payload.as_ref()
+    }
+
+    pub fn public_item(&self) -> Option<&PublicSystemItem> {
+        self.public.as_ref()
+    }
+
+    pub fn public_use_policy(&self) -> protocol::SessionEntryUsePolicy {
+        protocol::SessionEntryUsePolicy {
+            observation_readable: self.usage.observation == InputObservationUse::Readable,
+            memory_evidence: self.usage.memory_evidence == InputEvidenceUse::Include,
+        }
+    }
+
+    pub fn public_system_use_policy(&self) -> protocol::SessionEntryUsePolicy {
+        if self.public.is_some() {
+            self.public_use_policy()
+        } else {
+            protocol::SessionEntryUsePolicy {
+                observation_readable: false,
+                memory_evidence: false,
+            }
+        }
+    }
+
+    pub fn public_projection(&self) -> PublicSystemItem {
+        self.public.clone().unwrap_or_else(|| PublicSystemItem {
+            kind: "input".into(),
+            body: String::new(),
+            presentation: crate::PublicSystemPresentation::Ignored,
+        })
+    }
+}
+
+/// System role is invariant; provenance and use policies are attached data.
+/// An absent public projection never implicitly publishes the model body.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(try_from = "InputWire")]
+pub struct SystemInputEnvelope {
+    body: String,
+    metadata: HistoryInputMetadata,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct InputWire {
+    body: String,
+    metadata: HistoryInputMetadata,
+}
+
+impl TryFrom<InputWire> for SystemInputEnvelope {
+    type Error = InputMetadataError;
+
+    fn try_from(wire: InputWire) -> Result<Self, Self::Error> {
+        if wire.body.len() > MAX_SYSTEM_INPUT_BYTES {
+            return Err(InputMetadataError::ResourceLimit);
+        }
+        Ok(Self {
+            body: wire.body,
+            metadata: wire.metadata,
+        })
+    }
+}
+
+impl SystemInputEnvelope {
+    pub fn new(
+        body: impl Into<String>,
+        metadata: HistoryInputMetadata,
+    ) -> Result<Self, InputMetadataError> {
+        InputWire {
+            body: body.into(),
+            metadata,
+        }
+        .try_into()
+    }
+
+    pub fn body(&self) -> &str {
+        &self.body
+    }
+
+    pub fn metadata(&self) -> &HistoryInputMetadata {
+        &self.metadata
+    }
+
+    pub fn to_history_item(&self) -> Item {
+        Item::system_message(self.body.clone())
+    }
+
+    pub fn into_parts(self) -> (String, HistoryInputMetadata) {
+        (self.body, self.metadata)
+    }
+}
+
+fn validate_json(value: &Value, max_bytes: usize) -> Result<(), InputMetadataError> {
+    fn walk(value: &Value, depth: usize, remaining: &mut usize) -> Result<(), InputMetadataError> {
+        if depth > MAX_JSON_DEPTH || *remaining == 0 {
+            return Err(InputMetadataError::ResourceLimit);
+        }
+        *remaining -= 1;
+        match value {
+            Value::Array(values) => {
+                for value in values {
+                    walk(value, depth + 1, remaining)?;
+                }
+            }
+            Value::Object(values) => {
+                for value in values.values() {
+                    walk(value, depth + 1, remaining)?;
+                }
+            }
+            _ => {}
+        }
+        Ok(())
+    }
+    let mut remaining = MAX_JSON_NODES;
+    walk(value, 0, &mut remaining)?;
+    let bytes = serde_json::to_vec(value).map_err(|_| InputMetadataError::Serialization)?;
+    if bytes.len() > max_bytes {
+        return Err(InputMetadataError::ResourceLimit);
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{LoggedItem, LoggedRole, PublicSystemPresentation};
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    struct OwnerPayload {
+        source_digest: String,
+        omitted: bool,
+    }
+
+    fn reference_policy() -> HistoryInputUsePolicy {
+        HistoryInputUsePolicy {
+            recording_material: InputEvidenceUse::Exclude,
+            memory_evidence: InputEvidenceUse::Exclude,
+            observation: InputObservationUse::Hidden,
+            compaction: InputCompactionUse::ReferenceInput,
+        }
+    }
+
+    #[test]
+    fn unknown_valid_payload_round_trips_without_domain_decode_or_public_exposure() {
+        let payload = FeatureInputPayload::encode(
+            "future-owner:context",
+            99,
+            &OwnerPayload {
+                source_digest: "private-digest".into(),
+                omitted: true,
+            },
+        )
+        .unwrap();
+        let envelope = SystemInputEnvelope::new(
+            "private model context",
+            HistoryInputMetadata::new(reference_policy(), Some(payload), None).unwrap(),
+        )
+        .unwrap();
+        let restored: SystemInputEnvelope =
+            serde_json::from_slice(&serde_json::to_vec(&envelope).unwrap()).unwrap();
+        assert_eq!(restored.body(), "private model context");
+        assert!(restored.metadata().public_item().is_none());
+        let saved_payload = restored.metadata().feature_payload().unwrap();
+        assert_eq!(saved_payload.schema(), "future-owner:context");
+        assert_eq!(saved_payload.version(), 99);
+        assert_eq!(
+            saved_payload.decode::<OwnerPayload>("known-owner:context", 1),
+            Err(InputMetadataError::UnsupportedPayload)
+        );
+        assert_eq!(
+            serde_json::to_value(&restored).unwrap(),
+            serde_json::to_value(&envelope).unwrap()
+        );
+        assert!(!format!("{saved_payload:?}").contains("private-digest"));
+    }
+
+    #[test]
+    fn owner_decodes_typed_payload_only_for_its_explicit_contract() {
+        let input = OwnerPayload {
+            source_digest: "rev".into(),
+            omitted: false,
+        };
+        let payload = FeatureInputPayload::encode("owner:context", 1, &input).unwrap();
+        assert_eq!(
+            payload.decode::<OwnerPayload>("owner:context", 1).unwrap(),
+            input
+        );
+        let invalid = FeatureInputPayload::encode(
+            "owner:context",
+            1,
+            &serde_json::json!({ "omitted": "not a bool" }),
+        )
+        .unwrap();
+        assert_eq!(
+            invalid.decode::<OwnerPayload>("owner:context", 1),
+            Err(InputMetadataError::InvalidTypedPayload)
+        );
+    }
+
+    #[test]
+    fn malformed_or_oversized_payload_is_rejected_at_construction_and_restore() {
+        for (schema, version, value) in [
+            ("", 1, Value::Null),
+            ("invalid schema", 1, Value::Null),
+            ("owner:context", 0, Value::Null),
+            (
+                "owner:context",
+                1,
+                Value::String("x".repeat(MAX_FEATURE_PAYLOAD_BYTES)),
+            ),
+            (
+                "owner:context",
+                1,
+                Value::Array(vec![Value::Null; MAX_JSON_NODES]),
+            ),
+            (
+                "owner:context",
+                1,
+                (0..=MAX_JSON_DEPTH).fold(Value::Null, |inner, _| Value::Array(vec![inner])),
+            ),
+        ] {
+            assert!(FeatureInputPayload::encode(schema, version, &value).is_err());
+            assert!(
+                serde_json::from_value::<FeatureInputPayload>(
+                    serde_json::json!({ "schema": schema, "version": version, "value": value })
+                )
+                .is_err()
+            );
+        }
+    }
+
+    #[test]
+    fn policy_is_required_and_unknown_or_malformed_fields_fail_closed() {
+        let valid = serde_json::to_value(reference_policy()).unwrap();
+        for field in [
+            "recording_material",
+            "memory_evidence",
+            "observation",
+            "compaction",
+        ] {
+            let mut absent = valid.clone();
+            absent.as_object_mut().unwrap().remove(field);
+            assert!(serde_json::from_value::<HistoryInputUsePolicy>(absent).is_err());
+            let mut unknown = valid.clone();
+            unknown[field] = Value::String("future-allow".into());
+            assert!(serde_json::from_value::<HistoryInputUsePolicy>(unknown).is_err());
+        }
+        let mut extra = valid;
+        extra["feature_name"] = Value::String("infer-policy-from-me".into());
+        assert!(serde_json::from_value::<HistoryInputUsePolicy>(extra).is_err());
+    }
+
+    #[test]
+    fn feature_name_and_model_body_do_not_select_policies_or_public_projection() {
+        for (schema, body) in [
+            ("owner:journal", "past context"),
+            ("unrelated:skill", "do not extract this; legitimate wording"),
+        ] {
+            let public = PublicSystemItem {
+                kind: "context-label".into(),
+                body: "explicit public text".into(),
+                presentation: PublicSystemPresentation::Context,
+            };
+            let metadata = HistoryInputMetadata::new(
+                reference_policy(),
+                Some(
+                    FeatureInputPayload::encode(
+                        schema,
+                        1,
+                        &OwnerPayload {
+                            source_digest: "private".into(),
+                            omitted: false,
+                        },
+                    )
+                    .unwrap(),
+                ),
+                Some(public),
+            )
+            .unwrap();
+            let input = SystemInputEnvelope::new(body, metadata).unwrap();
+            assert_eq!(input.metadata().usage(), reference_policy());
+            let history: LoggedItem = input.to_history_item().into();
+            assert!(matches!(
+                history,
+                LoggedItem::Message {
+                    role: LoggedRole::System,
+                    ..
+                }
+            ));
+            assert_eq!(input.to_history_item().as_text(), Some(body));
+            let public = serde_json::to_string(input.metadata().public_item().unwrap()).unwrap();
+            assert!(!public.contains("private"));
+            assert!(!public.contains(schema));
+            assert!(!public.contains(body));
+        }
+    }
+
+    #[test]
+    fn use_policies_remain_independent_of_each_other_and_of_public_display() {
+        let usage = HistoryInputUsePolicy {
+            recording_material: InputEvidenceUse::Include,
+            memory_evidence: InputEvidenceUse::Exclude,
+            observation: InputObservationUse::Readable,
+            compaction: InputCompactionUse::Retain,
+        };
+        let metadata = HistoryInputMetadata::new(usage, None, None).unwrap();
+        let restored: HistoryInputMetadata =
+            serde_json::from_value(serde_json::to_value(&metadata).unwrap()).unwrap();
+        assert_eq!(restored.usage(), usage);
+        assert!(restored.public_item().is_none());
+        assert!(restored.feature_payload().is_none());
+    }
+
+    #[test]
+    fn model_body_and_public_projection_have_independent_resource_limits() {
+        let metadata = HistoryInputMetadata::new(reference_policy(), None, None).unwrap();
+        assert!(
+            SystemInputEnvelope::new("x".repeat(MAX_SYSTEM_INPUT_BYTES + 1), metadata).is_err()
+        );
+        let public = PublicSystemItem {
+            kind: "context".into(),
+            body: "x".repeat(MAX_SYSTEM_PUBLIC_BYTES),
+            presentation: PublicSystemPresentation::Context,
+        };
+        assert!(HistoryInputMetadata::new(reference_policy(), None, Some(public)).is_err());
+        let invalid = serde_json::json!({ "body": "small", "metadata": { "public": null, "feature_payload": null } });
+        assert!(serde_json::from_value::<SystemInputEnvelope>(invalid).is_err());
+    }
+}

crates/session-store/src/legacy_session_log.rs

@@ -1,12 +1,12 @@
-//! Versioned decoder for Session schemas that predate canonical annotated history.
+//! Versioned decoder for Session schemas v1-5, including frozen Feature wire.
 //!
 //! These types are intentionally private to `session-store`. Current writers,
 //! replay, and public projections use [`crate::LogEntry`] exclusively; only the
-//! Worker Session schema migration is allowed to deserialize these shapes.
+//! explicit Session schema migration is allowed to deserialize these shapes.
 
 use agen::llm_client::types::RequestConfig;
 use protocol::Segment;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 
 #[cfg(test)]
 mod tests;
@@ -17,6 +17,212 @@ use crate::{
     SegmentOrigin, SessionExtension, SessionId, SystemItem,
 };
 
+// Frozen v1-4 Feature wire. These types are deliberately not exported and are
+// never used by LogEntry/SystemItem's current deserializers. Payload structs
+// retain the owner's v1 shape rather than erasing typed fields into arbitrary JSON.
+#[derive(Debug, Serialize, Deserialize)]
+struct JournalStartupPayload {
+    snapshot: serde_json::Value,
+    snapshot_sha256: String,
+    prompt_provenance: crate::PromptRenderProvenance,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct ResidentSummaryPayload {
+    #[serde(default)]
+    prompt_provenance: Option<crate::PromptRenderProvenance>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct SubjectBehaviorPayload {
+    #[serde(default)]
+    behavior_md: String,
+    #[serde(default)]
+    prompt_provenance: Option<crate::PromptRenderProvenance>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct SkillActivationPayload {
+    name: String,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct InvocationResultPayload {
+    result: protocol::FeatureInvocationResult,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+enum LegacyFeatureSystemItem {
+    JournalStartup {
+        body: String,
+        #[serde(flatten)]
+        payload: JournalStartupPayload,
+    },
+    ResidentSummaryRefresh {
+        body: String,
+        #[serde(flatten)]
+        payload: ResidentSummaryPayload,
+    },
+    SubjectBehaviorRefresh {
+        body: String,
+        #[serde(flatten)]
+        payload: SubjectBehaviorPayload,
+    },
+    SkillActivation {
+        body: String,
+        #[serde(flatten)]
+        payload: SkillActivationPayload,
+    },
+    FeatureInvocationResult {
+        body: String,
+        #[serde(flatten)]
+        payload: InvocationResultPayload,
+    },
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum LegacySystemItem {
+    Feature(LegacyFeatureSystemItem),
+    // Includes already-migrated Input records for interrupted migration retry.
+    Core(SystemItem),
+}
+
+impl LegacySystemItem {
+    fn into_entry(
+        self,
+        mut metadata: LoggedSessionHistoryMetadata,
+    ) -> Result<LoggedSystemHistoryEntry, crate::InputMetadataError> {
+        use crate::InputCompactionUse::{ReferenceInput, Retain};
+        let item = match self {
+            Self::Core(item) => item,
+            Self::Feature(feature) => {
+                metadata.validate_input_metadata()?;
+                if metadata.input_metadata.is_some() {
+                    return Err(crate::InputMetadataError::InconsistentRecord);
+                }
+                let (body, input_metadata) = match feature {
+                    LegacyFeatureSystemItem::JournalStartup { body, payload } => {
+                        migrated_feature_input(
+                            body,
+                            "journal_startup",
+                            "journal:startup",
+                            payload,
+                            ReferenceInput,
+                        )?
+                    }
+                    LegacyFeatureSystemItem::ResidentSummaryRefresh { body, payload } => {
+                        migrated_feature_input(
+                            body,
+                            "resident_summary_refresh",
+                            "memory:resident-summary",
+                            payload,
+                            Retain,
+                        )?
+                    }
+                    LegacyFeatureSystemItem::SubjectBehaviorRefresh { body, payload } => {
+                        migrated_feature_input(
+                            body,
+                            "subject_behavior_refresh",
+                            "subject:behavior",
+                            payload,
+                            Retain,
+                        )?
+                    }
+                    LegacyFeatureSystemItem::SkillActivation { body, payload } => {
+                        migrated_feature_input(
+                            body,
+                            "skill_activation",
+                            "skill:activation",
+                            payload,
+                            Retain,
+                        )?
+                    }
+                    LegacyFeatureSystemItem::FeatureInvocationResult { body, payload } => {
+                        migrated_feature_input(
+                            body,
+                            "feature_invocation_result",
+                            "feature:invocation-result",
+                            payload,
+                            Retain,
+                        )?
+                    }
+                };
+                // Identity/origin/derivation are retained, never re-inferred.
+                metadata.input_metadata = Some(input_metadata);
+                SystemItem::Input { body }
+            }
+        };
+        let entry = LoggedSystemHistoryEntry { item, metadata };
+        entry.validate_input_metadata()?;
+        Ok(entry)
+    }
+}
+
+fn migrated_feature_input<T: Serialize>(
+    body: String,
+    label: &str,
+    schema: &str,
+    payload: T,
+    compaction: crate::InputCompactionUse,
+) -> Result<(String, crate::HistoryInputMetadata), crate::InputMetadataError> {
+    let metadata = crate::HistoryInputMetadata::new(
+        migration_policy(compaction),
+        Some(crate::FeatureInputPayload::encode(schema, 1, &payload)?),
+        Some(crate::PublicSystemItem {
+            kind: label.into(),
+            body: body.clone(),
+            presentation: crate::PublicSystemPresentation::Context,
+        }),
+    )?;
+    Ok((body, metadata))
+}
+
+/// Annotated old wire used by v3/v4, and by already-converted files when an
+/// older marker survived an interrupted migration. No ordinary decoder uses it.
+#[derive(Debug, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+enum LegacyAnnotatedLogEntry {
+    AnnotatedSystemItem {
+        ts: u64,
+        entry: LegacySystemHistoryEntry,
+        #[serde(default)]
+        extensions: Vec<SessionExtension>,
+    },
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct LegacySystemHistoryEntry {
+    item: LegacySystemItem,
+    metadata: LoggedSessionHistoryMetadata,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum LegacyAnnotatedOrCurrent {
+    Annotated(LegacyAnnotatedLogEntry),
+    Current(LogEntry),
+}
+
+impl LegacyAnnotatedOrCurrent {
+    fn into_current(self) -> Result<LogEntry, crate::InputMetadataError> {
+        match self {
+            Self::Annotated(LegacyAnnotatedLogEntry::AnnotatedSystemItem {
+                ts,
+                entry,
+                extensions,
+            }) => Ok(LogEntry::AnnotatedSystemItem {
+                ts,
+                entry: entry.item.into_entry(entry.metadata)?,
+                extensions,
+            }),
+            Self::Current(entry) => Ok(entry),
+        }
+    }
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(tag = "kind", rename_all = "snake_case")]
 enum LegacyHistoryLogEntry {
@@ -47,7 +253,9 @@ enum LegacyHistoryLogEntry {
     },
     SystemItem {
         ts: u64,
-        item: SystemItem,
+        item: LegacySystemItem,
+        #[serde(default)]
+        extensions: Vec<SessionExtension>,
     },
 }
 
@@ -57,7 +265,7 @@ enum LegacyHistoryLogEntry {
 #[serde(untagged)]
 enum LegacySessionLogEntryV1 {
     History(LegacyHistoryLogEntry),
-    Current(LogEntry),
+    Current(LegacyAnnotatedOrCurrent),
 }
 
 /// Schema v2 retained the v1 history shapes while adding non-history records.
@@ -67,7 +275,7 @@ enum LegacySessionLogEntryV1 {
 #[serde(untagged)]
 enum LegacySessionLogEntryV2 {
     History(LegacyHistoryLogEntry),
-    Current(LogEntry),
+    Current(LegacyAnnotatedOrCurrent),
 }
 
 pub(crate) fn decode_entry(
@@ -77,24 +285,75 @@ pub(crate) fn decode_entry(
     segment_id: SegmentId,
     line_index: usize,
 ) -> Result<LogEntry, serde_json::Error> {
+    let mut wire: serde_json::Value = serde_json::from_str(line)?;
+    migrate_legacy_metadata_field(&mut wire)?;
     let entry = match schema_version {
-        1 => match serde_json::from_str::<LegacySessionLogEntryV1>(line)? {
+        1 => match serde_json::from_value::<LegacySessionLogEntryV1>(wire)? {
             LegacySessionLogEntryV1::History(entry) => Entry::History(entry),
             LegacySessionLogEntryV1::Current(entry) => Entry::Current(entry),
         },
-        2 => match serde_json::from_str::<LegacySessionLogEntryV2>(line)? {
+        2 => match serde_json::from_value::<LegacySessionLogEntryV2>(wire)? {
             LegacySessionLogEntryV2::History(entry) => Entry::History(entry),
             LegacySessionLogEntryV2::Current(entry) => Entry::Current(entry),
         },
-        3 => Entry::Current(serde_json::from_str(line)?),
+        3 | 4 => Entry::Current(serde_json::from_value(wire)?),
+        5 => return serde_json::from_value(wire),
         _ => unreachable!("legacy decoder called for unsupported schema {schema_version}"),
     };
-    Ok(match entry {
+    match entry {
         Entry::History(entry) => {
             canonicalize_history_entry(session_id, segment_id, line_index, entry)
         }
-        Entry::Current(entry) => entry,
-    })
+        Entry::Current(entry) => entry.into_current(),
+    }
+    .map_err(serde::de::Error::custom)
+}
+
+// The v5 System-only metadata field was widened to role-neutral input metadata
+// in v6. Touch only known history slots, never arbitrary Feature payload objects.
+// Both keys are an ambiguous source, not permission to discard either value.
+fn migrate_legacy_metadata_field(record: &mut serde_json::Value) -> Result<(), serde_json::Error> {
+    fn entry(value: &mut serde_json::Value) -> Result<(), serde_json::Error> {
+        if let Some(metadata) = value
+            .get_mut("metadata")
+            .and_then(serde_json::Value::as_object_mut)
+        {
+            if let Some(old) = metadata.remove("system_input") {
+                if metadata.contains_key("input_metadata") {
+                    return Err(serde::de::Error::custom(
+                        "ambiguous legacy input metadata fields",
+                    ));
+                }
+                metadata.insert("input_metadata".into(), old);
+            }
+        }
+        Ok(())
+    }
+    let kind = record
+        .get("kind")
+        .and_then(serde_json::Value::as_str)
+        .unwrap_or_default()
+        .to_owned();
+    if matches!(
+        kind.as_str(),
+        "annotated_system_item"
+            | "annotated_assistant_item"
+            | "annotated_tool_result"
+            | "tool_result_corrected"
+    ) {
+        if let Some(value) = record.get_mut("entry") {
+            entry(value)?;
+        }
+    }
+    if let Some(history) = record
+        .get_mut("history")
+        .and_then(serde_json::Value::as_array_mut)
+    {
+        for value in history {
+            entry(value)?;
+        }
+    }
+    Ok(())
 }
 
 /// Schema 3 used DerivedSummary for Host compaction seeds. Only the trusted
@@ -152,9 +411,81 @@ pub(crate) fn migrate_compaction_origins(
     }
 }
 
+/// Explicit legacy-to-current boundary. No Feature inference belongs in ordinary
+/// readers/restoration. Invalid or oversized payloads fail migration; the generic
+/// payload/body/public limits are deliberately not relaxed for legacy data.
+pub(crate) fn migrate_system_inputs(entry: &mut LogEntry) -> Result<(), crate::InputMetadataError> {
+    entry.validate_input_metadata()?;
+    match entry {
+        // Feature wire has already been converted by the explicit old-schema
+        // decoder. Ordinary LogEntry can contain only generic Input/core events.
+        LogEntry::AnnotatedSystemItem { entry, .. } => entry.validate_input_metadata()?,
+        LogEntry::AnnotatedSegmentStart { history, .. }
+        | LogEntry::AnnotatedUserInput { history, .. } => {
+            for entry in history {
+                migrate_flattened_system_input(entry)?;
+            }
+        }
+        LogEntry::AnnotatedAssistantItem { entry, .. }
+        | LogEntry::AnnotatedToolResult { entry, .. }
+        | LogEntry::ToolResultCorrected { entry, .. } => {
+            migrate_flattened_system_input(entry)?;
+        }
+        _ => {}
+    }
+    entry.validate_input_metadata()
+}
+
+fn migration_policy(compaction: crate::InputCompactionUse) -> crate::HistoryInputUsePolicy {
+    crate::HistoryInputUsePolicy {
+        recording_material: crate::InputEvidenceUse::Exclude,
+        memory_evidence: crate::InputEvidenceUse::Exclude,
+        observation: crate::InputObservationUse::Hidden,
+        compaction,
+    }
+}
+
+fn migrate_flattened_system_input(
+    entry: &mut LoggedHistoryEntry,
+) -> Result<(), crate::InputMetadataError> {
+    // Check before supplying legacy policy: Provided without metadata is a
+    // malformed NEW record, not permission to synthesize a producer policy.
+    entry.validate_input_metadata()?;
+    if entry.metadata.input_metadata.is_none()
+        && (matches!(
+            entry.item,
+            LoggedItem::Message {
+                role: crate::LoggedRole::System,
+                ..
+            }
+        ) || matches!(
+            entry.metadata.origin,
+            LoggedSessionHistoryOrigin::DerivedSummary
+                | LoggedSessionHistoryOrigin::CompactionSummary
+        ))
+    {
+        let compaction = match entry.metadata.origin {
+            LoggedSessionHistoryOrigin::JournalContext => crate::InputCompactionUse::ReferenceInput,
+            LoggedSessionHistoryOrigin::CompactionSummary => {
+                crate::InputCompactionUse::OpeningSummary
+            }
+            _ => crate::InputCompactionUse::Retain,
+        };
+        // Legacy derived context was excluded from independent evidence. Preserve
+        // that established decision explicitly, including synthetic Tool roles;
+        // never guess from Tool names or body text. Payload/public stay absent.
+        entry.metadata.input_metadata = Some(crate::HistoryInputMetadata::new(
+            migration_policy(compaction),
+            None,
+            None,
+        )?);
+    }
+    entry.validate_input_metadata()
+}
+
 enum Entry {
     History(LegacyHistoryLogEntry),
-    Current(LogEntry),
+    Current(LegacyAnnotatedOrCurrent),
 }
 
 fn legacy_metadata(
@@ -167,6 +498,7 @@ fn legacy_metadata(
     identity.extend_from_slice(&(line_index as u64).to_be_bytes());
     identity.extend_from_slice(&(item_index as u64).to_be_bytes());
     LoggedSessionHistoryMetadata {
+        input_metadata: None,
         entry_id: LoggedSessionHistoryEntryId(format!(
             "l-{}",
             base64::Engine::encode(&base64::engine::general_purpose::URL_SAFE_NO_PAD, identity)
@@ -181,8 +513,8 @@ fn canonicalize_history_entry(
     segment_id: SegmentId,
     line_index: usize,
     entry: LegacyHistoryLogEntry,
-) -> LogEntry {
-    match entry {
+) -> Result<LogEntry, crate::InputMetadataError> {
+    Ok(match entry {
         LegacyHistoryLogEntry::SegmentStart {
             ts,
             session_id,
@@ -236,13 +568,14 @@ fn canonicalize_history_entry(
                 metadata: legacy_metadata(segment_id, line_index, 0),
             },
         },
-        LegacyHistoryLogEntry::SystemItem { ts, item } => LogEntry::AnnotatedSystemItem {
+        LegacyHistoryLogEntry::SystemItem {
             ts,
-            entry: LoggedSystemHistoryEntry {
-                item,
-                metadata: legacy_metadata(segment_id, line_index, 0),
-            },
-            extensions: Vec::new(),
+            item,
+            extensions,
+        } => LogEntry::AnnotatedSystemItem {
+            ts,
+            entry: item.into_entry(legacy_metadata(segment_id, line_index, 0))?,
+            extensions,
         },
-    }
+    })
 }

crates/session-store/src/legacy_session_log/tests.rs

@@ -1,5 +1,7 @@
 use super::*;
 
+mod v5;
+
 fn seed(
     origin: LoggedSessionHistoryOrigin,
     compacted: bool,
@@ -22,6 +24,7 @@ fn seed(
                 content: vec![crate::LoggedContentPart::Text { text: text.into() }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId("summary".into()),
                 origin,
                 derivation: Some(crate::LoggedHistoryDerivation {

crates/session-store/src/legacy_session_log/tests/fixtures/v1-system-inputs.jsonl

@@ -0,0 +1,3 @@
+{"kind":"system_item","ts":1,"item":{"kind":"skill_activation","name":"legacy-skill","body":"legacy skill body"}}
+{"kind":"user_input","ts":2,"segments":[{"kind":"text","content":"legacy user body"}],"extensions":[{"domain":"old","payload":{"kept":true}}]}
+{"kind":"assistant_item","ts":3,"item":{"kind":"message","role":"assistant","content":[{"kind":"text","text":"legacy reply"}]}}

crates/session-store/src/legacy_session_log/tests/fixtures/v4-system-inputs.jsonl

@@ -0,0 +1,8 @@
+{"kind":"annotated_system_item","ts":101,"entry":{"item":{"kind":"journal_startup","body":"journal body\nunchanged","snapshot":{"entries":[{"text":"private snapshot"}]},"snapshot_sha256":"snapshot-digest","prompt_provenance":{"workspace_id":"workspace","source_digest":"source","projection_digest":"projection","logical_name":"journal_startup"}},"metadata":{"entry_id":"journal-id","origin":{"kind":"legacy_unknown"},"derivation":{"sources":["source-id"]}}},"extensions":[{"domain":"migration-fixture","payload":{"kept":true}}]}
+{"kind":"annotated_system_item","ts":102,"entry":{"item":{"kind":"resident_summary_refresh","body":"resident body"},"metadata":{"entry_id":"resident-id","origin":{"kind":"derived_summary"}}}}
+{"kind":"annotated_system_item","ts":103,"entry":{"item":{"kind":"subject_behavior_refresh","body":"rendered subject body","behavior_md":"exact behavior","prompt_provenance":{"source_digest":"subject-source","projection_digest":"subject-projection","logical_name":"subject_behavior"}},"metadata":{"entry_id":"subject-id","origin":{"kind":"backend_instruction","operation_id":"op"}}}}
+{"kind":"annotated_system_item","ts":104,"entry":{"item":{"kind":"skill_activation","body":"skill body","name":"example-skill"},"metadata":{"entry_id":"skill-id","origin":{"kind":"legacy_unknown"}}}}
+{"kind":"annotated_system_item","ts":105,"entry":{"item":{"kind":"feature_invocation_result","body":"result body","result":{"invocation_id":"invoke-id","identity":"builtin:test/prepare","status":"outcome_unknown","message":"may have committed","context":null}},"metadata":{"entry_id":"result-id","origin":{"kind":"legacy_unknown"}}}}
+{"kind":"annotated_user_input","ts":106,"segments":[],"history":[{"item":{"kind":"message","role":"system","content":[{"kind":"text","text":"[Journal] prefix is not Feature evidence"}]},"metadata":{"entry_id":"flat-journal","origin":{"kind":"journal_context"},"derivation":{"sources":["journal-id"]}}},{"item":{"kind":"message","role":"system","content":[{"kind":"text","text":"summary body"}]},"metadata":{"entry_id":"flat-summary","origin":{"kind":"compaction_summary"}}},{"item":{"kind":"message","role":"system","content":[{"kind":"text","text":"[Skill: example] never infer Feature"}]},"metadata":{"entry_id":"flat-other","origin":{"kind":"legacy_unknown"}}}]}
+{"kind":"annotated_system_item","ts":107,"entry":{"item":{"kind":"notification","message":"raw message","body":"wrapped message"},"metadata":{"entry_id":"core-id","origin":{"kind":"legacy_unknown"}}}}
+{"kind":"annotated_system_item","ts":108,"entry":{"item":{"kind":"input","body":"already generic body"},"metadata":{"entry_id":"generic-id","origin":{"kind":"provided","producer":"future-owner"},"derivation":{"sources":["source-id"]},"system_input":{"usage":{"recording_material":"include","memory_evidence":"exclude","observation":"readable","compaction":"retain"},"feature_payload":{"schema":"future:unknown","version":99,"value":{"opaque":"retained"}},"public":null}}}}

crates/session-store/src/legacy_session_log/tests/fixtures/v5-role-metadata.jsonl

@@ -0,0 +1,5 @@
+{"kind":"annotated_system_item","ts":201,"entry":{"item":{"kind":"input","body":"frozen v5 reference"},"metadata":{"entry_id":"reference-v5","origin":{"kind":"provided","producer":"owner-v5"},"system_input":{"usage":{"recording_material":"exclude","memory_evidence":"exclude","observation":"hidden","compaction":"reference_input"},"feature_payload":{"schema":"future:owner","version":8,"value":{"system_input":"opaque owner field must not be renamed"}},"public":null}}}}
+{"kind":"annotated_assistant_item","ts":202,"entry":{"item":{"kind":"tool_call","call_id":"original-call","name":"ArbitraryTool","arguments":"{}"},"metadata":{"entry_id":"original-call-entry","origin":{"kind":"model_output","worker":{"worker_id":"body"}}}}}
+{"kind":"annotated_tool_result","ts":203,"entry":{"item":{"kind":"tool_result","call_id":"original-call","summary":"original result"},"metadata":{"entry_id":"original-result-entry","origin":{"kind":"tool_output","worker":{"worker_id":"body"}}}}}
+{"kind":"annotated_assistant_item","ts":204,"entry":{"item":{"kind":"tool_call","call_id":"derived-call","name":"ArbitraryTool","arguments":"{}"},"metadata":{"entry_id":"derived-call-entry","origin":{"kind":"derived_summary"},"derivation":{"sources":["original-call-entry","original-result-entry"]}}}}
+{"kind":"annotated_tool_result","ts":205,"entry":{"item":{"kind":"tool_result","call_id":"derived-call","summary":"derived retrieval result"},"metadata":{"entry_id":"derived-result-entry","origin":{"kind":"derived_summary"},"derivation":{"sources":["original-call-entry","original-result-entry"]}}}}

crates/session-store/src/legacy_session_log/tests/v5.rs

@@ -0,0 +1,709 @@
+//! Fixed old wire bytes, not fixtures generated by the current serializer.
+use super::*;
+use crate::{FsStore, InputCompactionUse, Store, WorkerSessionStore};
+use serde_json::{Value, json};
+use std::{fs, path::Path};
+
+const V4: &str = include_str!("fixtures/v4-system-inputs.jsonl");
+const V1: &str = include_str!("fixtures/v1-system-inputs.jsonl");
+
+fn decode_fixture(version: u32, source: &str, segment: SegmentId) -> Vec<LogEntry> {
+    source
+        .lines()
+        .enumerate()
+        .map(|(index, line)| decode_entry(version, line, SessionId::nil(), segment, index).unwrap())
+        .collect()
+}
+
+fn encode(entries: &[LogEntry]) -> Vec<u8> {
+    let mut bytes = Vec::new();
+    for entry in entries {
+        serde_json::to_writer(&mut bytes, entry).unwrap();
+        bytes.push(b'\n');
+    }
+    bytes
+}
+
+fn migrate(entries: &mut [LogEntry]) {
+    for entry in entries {
+        migrate_system_inputs(entry).unwrap();
+        entry.validate_input_metadata().unwrap();
+    }
+}
+
+fn write_worker(root: &Path, version: u32, source: &[u8]) -> (SessionId, SegmentId) {
+    let session = SessionId::now_v7();
+    let segment = SegmentId::from_u128(1);
+    fs::create_dir_all(root.join("segments")).unwrap();
+    fs::write(
+        root.join("session.json"),
+        serde_json::to_vec(&json!({
+            "schema_version": version, "session_id": session,
+        }))
+        .unwrap(),
+    )
+    .unwrap();
+    fs::write(
+        root.join("segments").join(format!("{segment}.jsonl")),
+        source,
+    )
+    .unwrap();
+    (session, segment)
+}
+
+fn assert_marker(root: &Path, version: u32) {
+    let manifest: Value =
+        serde_json::from_slice(&fs::read(root.join("session.json")).unwrap()).unwrap();
+    assert_eq!(manifest["schema_version"], version);
+}
+
+#[test]
+fn v4_fixed_wire_preserves_identity_body_payload_public_and_independent_policy() {
+    let mut entries = decode_fixture(4, V4, SegmentId::nil());
+    let before = entries.clone();
+    migrate(&mut entries);
+    let schemas = [
+        "journal:startup",
+        "memory:resident-summary",
+        "subject:behavior",
+        "skill:activation",
+        "feature:invocation-result",
+    ];
+    let old_wire: Vec<Value> = V4
+        .lines()
+        .map(|line| serde_json::from_str(line).unwrap())
+        .collect();
+    for index in 0..5 {
+        let LogEntry::AnnotatedSystemItem {
+            ts,
+            entry,
+            extensions,
+        } = &entries[index]
+        else {
+            panic!()
+        };
+        let old = &old_wire[index];
+        let old_item = &old["entry"]["item"];
+        let old_metadata: LoggedSessionHistoryMetadata =
+            serde_json::from_value(old["entry"]["metadata"].clone()).unwrap();
+        let old_ext: Vec<crate::SessionExtension> = old
+            .get("extensions")
+            .map(|value| serde_json::from_value(value.clone()).unwrap())
+            .unwrap_or_default();
+        assert_eq!(*ts, old["ts"].as_u64().unwrap());
+        assert_eq!(extensions, &old_ext);
+        assert!(matches!(entry.item, SystemItem::Input { .. }));
+        assert_eq!(
+            entry.item.history_text(),
+            old_item["body"].as_str().unwrap()
+        );
+        assert_eq!(entry.metadata.entry_id, old_metadata.entry_id);
+        assert_eq!(entry.metadata.origin, old_metadata.origin);
+        assert_eq!(entry.metadata.derivation, old_metadata.derivation);
+        let metadata = entry.metadata.input_metadata.as_ref().unwrap();
+        let public = metadata.public_item().unwrap();
+        assert_eq!(public.kind, old_item["kind"].as_str().unwrap());
+        assert_eq!(public.body, old_item["body"].as_str().unwrap());
+        assert_eq!(
+            public.presentation,
+            crate::PublicSystemPresentation::Context
+        );
+        assert_eq!(
+            metadata.usage(),
+            migration_policy(if index == 0 {
+                InputCompactionUse::ReferenceInput
+            } else {
+                InputCompactionUse::Retain
+            })
+        );
+        let payload = metadata.feature_payload().unwrap();
+        assert_eq!(payload.schema(), schemas[index]);
+        assert_eq!(payload.version(), 1);
+        let value: Value = payload.decode(schemas[index], 1).unwrap();
+        // Independently require each frozen owner's typed v1 payload contract.
+        match index {
+            0 => {
+                let _: JournalStartupPayload = payload.decode(schemas[index], 1).unwrap();
+            }
+            1 => {
+                let _: ResidentSummaryPayload = payload.decode(schemas[index], 1).unwrap();
+            }
+            2 => {
+                let _: SubjectBehaviorPayload = payload.decode(schemas[index], 1).unwrap();
+            }
+            3 => {
+                let _: SkillActivationPayload = payload.decode(schemas[index], 1).unwrap();
+            }
+            4 => {
+                let _: InvocationResultPayload = payload.decode(schemas[index], 1).unwrap();
+            }
+            _ => unreachable!(),
+        }
+        let mut expected = old_item.clone();
+        expected.as_object_mut().unwrap().remove("kind");
+        expected.as_object_mut().unwrap().remove("body");
+        // Optional provenance is an explicit Option in the v1 payload contract.
+        if index == 1 {
+            expected["prompt_provenance"] = Value::Null;
+        }
+        if index == 4 {
+            let result: protocol::FeatureInvocationResult =
+                serde_json::from_value(old_item["result"].clone()).unwrap();
+            let typed: InvocationResultPayload = payload.decode(schemas[index], 1).unwrap();
+            assert_eq!(typed.result, result);
+            // Preserve the protocol's typed serialization contract, including
+            // its canonical representation of optional result context.
+            expected["result"] = serde_json::to_value(result).unwrap();
+        }
+        assert_eq!(value, expected);
+        assert!(value.get("body").is_none());
+    }
+    let LogEntry::AnnotatedUserInput { history, .. } = &entries[5] else {
+        panic!()
+    };
+    let LogEntry::AnnotatedUserInput { history: old, .. } = &before[5] else {
+        panic!()
+    };
+    for (index, compaction) in [
+        InputCompactionUse::ReferenceInput,
+        InputCompactionUse::OpeningSummary,
+        InputCompactionUse::Retain,
+    ]
+    .into_iter()
+    .enumerate()
+    {
+        assert_eq!(history[index].item, old[index].item);
+        assert_eq!(
+            history[index].metadata.entry_id,
+            old[index].metadata.entry_id
+        );
+        assert_eq!(history[index].metadata.origin, old[index].metadata.origin);
+        assert_eq!(
+            history[index].metadata.derivation,
+            old[index].metadata.derivation
+        );
+        let metadata = history[index].metadata.input_metadata.as_ref().unwrap();
+        assert_eq!(metadata.usage(), migration_policy(compaction));
+        assert!(metadata.public_item().is_none());
+        assert!(metadata.feature_payload().is_none());
+    }
+    // Core notification is unchanged; existing generic Input and unknown valid
+    // owner payload are retained without decoding/reclassifying a Feature.
+    assert_eq!(encode(&entries[6..]), encode(&before[6..]));
+    let once = encode(&entries);
+    migrate(&mut entries);
+    assert_eq!(encode(&entries), once);
+}
+
+#[test]
+fn v1_through_v4_worker_migration_reopen_and_mixed_file_retry() {
+    for version in 1..=4 {
+        let source = if version <= 2 { V1 } else { V4 };
+        let root = tempfile::tempdir().unwrap();
+        let (session, segment) = write_worker(root.path(), version, source.as_bytes());
+        let path = root
+            .path()
+            .join("segments")
+            .join(format!("{segment}.jsonl"));
+        // Simulate an interrupted publication: v5 records precede legacy records
+        // in one file, and a fully new file coexists with an untouched old file.
+        let mut converted = decode_fixture(version, source, segment);
+        migrate(&mut converted);
+        let mut mixed = encode(&converted[..1]);
+        mixed.extend_from_slice(source.split_once('\n').unwrap().1.as_bytes());
+        fs::write(&path, &mixed).unwrap();
+        let new_path = root
+            .path()
+            .join("segments")
+            .join(format!("{}.jsonl", SegmentId::from_u128(2)));
+        let new_bytes = encode(&converted);
+        fs::write(&new_path, &new_bytes).unwrap();
+        let old_path = root
+            .path()
+            .join("segments")
+            .join(format!("{}.jsonl", SegmentId::from_u128(3)));
+        fs::write(&old_path, source).unwrap();
+
+        let marker = fs::read(root.path().join("session.json")).unwrap();
+        WorkerSessionStore::validate_migration(root.path()).unwrap();
+        assert_eq!(fs::read(&path).unwrap(), mixed);
+        assert_eq!(fs::read(&old_path).unwrap(), source.as_bytes());
+        assert_eq!(fs::read(root.path().join("session.json")).unwrap(), marker);
+        let store = WorkerSessionStore::new(root.path()).unwrap();
+        assert_marker(root.path(), 6);
+        let restored = store.read_all(session, segment).unwrap();
+        assert_eq!(encode(&restored), new_bytes);
+        assert_eq!(fs::read(&new_path).unwrap(), new_bytes);
+        let once = fs::read(&path).unwrap();
+        let old_once = fs::read(&old_path).unwrap();
+        drop(store);
+        let reopened = WorkerSessionStore::new(root.path()).unwrap();
+        assert_eq!(encode(&reopened.read_all(session, segment).unwrap()), once);
+        assert_eq!(fs::read(&path).unwrap(), once);
+        assert_eq!(fs::read(&old_path).unwrap(), old_once);
+    }
+}
+
+#[test]
+fn all_segments_preflight_keeps_old_bytes_on_decode_or_conversion_failure() {
+    let mut oversized: Value = serde_json::from_str(V4.lines().next().unwrap()).unwrap();
+    oversized["entry"]["item"]["snapshot"] =
+        json!({"large": "x".repeat(crate::input_metadata::MAX_FEATURE_PAYLOAD_BYTES + 1)});
+    let mut unknown: Value = serde_json::from_str(V4.lines().next().unwrap()).unwrap();
+    unknown["entry"]["item"]["kind"] = json!("unsupported_future_feature");
+    let mut malformed = unknown.clone();
+    malformed["entry"]["item"] = json!({"kind":"journal_startup", "body":"missing snapshot"});
+    let mut missing_metadata: Value = serde_json::from_str(V4.lines().last().unwrap()).unwrap();
+    missing_metadata["entry"]["metadata"]
+        .as_object_mut()
+        .unwrap()
+        .remove("system_input");
+    let mut missing_input = missing_metadata.clone();
+    missing_input["entry"]["metadata"]["origin"] = json!({"kind":"legacy_unknown"});
+    let mut invalid_policy: Value = serde_json::from_str(V4.lines().last().unwrap()).unwrap();
+    invalid_policy["entry"]["metadata"]["system_input"]["usage"]["compaction"] = json!("unknown");
+    let mut invalid_payload = invalid_policy.clone();
+    invalid_payload["entry"]["metadata"]["system_input"]["usage"]["compaction"] = json!("retain");
+    invalid_payload["entry"]["metadata"]["system_input"]["feature_payload"]["version"] = json!(0);
+    let mut flat_provided: Value = serde_json::from_str(V4.lines().nth(5).unwrap()).unwrap();
+    flat_provided["history"][0]["metadata"]["origin"] =
+        json!({"kind":"provided", "producer":"owner"});
+    for bad in [
+        "{broken-json}\n".to_owned(),
+        format!("{}\n", oversized),
+        format!("{}\n", unknown),
+        format!("{}\n", malformed),
+        format!("{}\n", missing_metadata),
+        format!("{}\n", invalid_policy),
+        format!("{}\n", invalid_payload),
+        format!("{}\n", flat_provided),
+        format!("{}\n", missing_input),
+    ] {
+        let root = tempfile::tempdir().unwrap();
+        let (_, segment) = write_worker(root.path(), 4, V4.as_bytes());
+        let first = root
+            .path()
+            .join("segments")
+            .join(format!("{segment}.jsonl"));
+        let later = root
+            .path()
+            .join("segments")
+            .join(format!("{}.jsonl", SegmentId::from_u128(2)));
+        fs::write(&later, &bad).unwrap();
+        let marker = fs::read(root.path().join("session.json")).unwrap();
+        assert!(WorkerSessionStore::validate_migration(root.path()).is_err());
+        assert!(WorkerSessionStore::new(root.path()).is_err());
+        assert_eq!(fs::read(&first).unwrap(), V4.as_bytes());
+        assert_eq!(fs::read(&later).unwrap(), bad.as_bytes());
+        assert_eq!(fs::read(root.path().join("session.json")).unwrap(), marker);
+    }
+}
+
+#[test]
+fn unsupported_schema_preserves_all_old_bytes() {
+    for version in [0, 7, 99] {
+        let root = tempfile::tempdir().unwrap();
+        let (_, segment) = write_worker(root.path(), version, V4.as_bytes());
+        let path = root
+            .path()
+            .join("segments")
+            .join(format!("{segment}.jsonl"));
+        let marker = fs::read(root.path().join("session.json")).unwrap();
+        assert!(WorkerSessionStore::new(root.path()).is_err());
+        assert_eq!(fs::read(&path).unwrap(), V4.as_bytes());
+        assert_eq!(fs::read(root.path().join("session.json")).unwrap(), marker);
+    }
+}
+
+#[test]
+fn standalone_store_uses_same_v1_through_v4_migration_and_reopens() {
+    // None represents the existing unmarked annotated standalone layout (v3).
+    for version in [None, Some(1), Some(2), Some(3), Some(4)] {
+        let root = tempfile::tempdir().unwrap();
+        let session = SessionId::now_v7();
+        let segment = SegmentId::from_u128(1);
+        let dir = root.path().join(session.to_string());
+        fs::create_dir_all(&dir).unwrap();
+        let source = if version.is_some_and(|v| v <= 2) {
+            V1
+        } else {
+            V4
+        };
+        let path = dir.join(format!("{segment}.jsonl"));
+        fs::write(&path, source).unwrap();
+        if let Some(version) = version {
+            fs::write(dir.join("session-schema.json"), version.to_string()).unwrap();
+        }
+        let store = FsStore::new(root.path()).unwrap();
+        let entries = store.read_all(session, segment).unwrap();
+        for entry in entries {
+            entry.validate_input_metadata().unwrap();
+        }
+        assert_eq!(
+            fs::read_to_string(dir.join("session-schema.json"))
+                .unwrap()
+                .trim(),
+            "6"
+        );
+        let once = fs::read(&path).unwrap();
+        drop(store);
+        FsStore::new(root.path()).unwrap();
+        assert_eq!(fs::read(&path).unwrap(), once);
+    }
+}
+
+#[test]
+fn compaction_origin_upgrade_is_retained_only_for_pre_v4_sources() {
+    for version in [3, 4] {
+        let root = tempfile::tempdir().unwrap();
+        let creation = seed(
+            LoggedSessionHistoryOrigin::DerivedSummary,
+            true,
+            crate::LoggedRole::System,
+            "[Compacted context summary]\n\nold summary",
+        );
+        let inherited = seed(
+            LoggedSessionHistoryOrigin::DerivedSummary,
+            false,
+            crate::LoggedRole::System,
+            "[Compacted context summary]\n\nold summary",
+        );
+        let (session, segment) =
+            write_worker(root.path(), version, &encode(&[creation, inherited]));
+        let store = WorkerSessionStore::new(root.path()).unwrap();
+        for record in store.read_all(session, segment).unwrap() {
+            let LogEntry::AnnotatedSegmentStart { history, .. } = record else {
+                panic!()
+            };
+            let metadata = &history[0].metadata;
+            assert_eq!(metadata.entry_id.0, "summary");
+            assert_eq!(metadata.derivation.as_ref().unwrap().sources[0].0, "source");
+            assert_eq!(
+                metadata.origin,
+                if version == 3 {
+                    LoggedSessionHistoryOrigin::CompactionSummary
+                } else {
+                    LoggedSessionHistoryOrigin::DerivedSummary
+                }
+            );
+            assert_eq!(
+                metadata.input_metadata.as_ref().unwrap().usage().compaction,
+                if version == 3 {
+                    InputCompactionUse::OpeningSummary
+                } else {
+                    InputCompactionUse::Retain
+                }
+            );
+        }
+    }
+}
+
+#[test]
+fn standalone_preflight_and_unsupported_marker_leave_sources_unchanged() {
+    for version in [4, 99] {
+        let root = tempfile::tempdir().unwrap();
+        let session = SessionId::now_v7();
+        let dir = root.path().join(session.to_string());
+        fs::create_dir_all(&dir).unwrap();
+        let first = dir.join(format!("{}.jsonl", SegmentId::from_u128(1)));
+        let later = dir.join(format!("{}.jsonl", SegmentId::from_u128(2)));
+        fs::write(&first, V4).unwrap();
+        fs::write(&later, "{broken-json}\n").unwrap();
+        let marker = version.to_string();
+        fs::write(dir.join("session-schema.json"), &marker).unwrap();
+        assert!(FsStore::new(root.path()).is_err());
+        assert_eq!(fs::read(&first).unwrap(), V4.as_bytes());
+        assert_eq!(fs::read_to_string(&later).unwrap(), "{broken-json}\n");
+        assert_eq!(
+            fs::read_to_string(dir.join("session-schema.json")).unwrap(),
+            marker
+        );
+    }
+}
+
+#[test]
+fn current_v5_rejects_all_legacy_feature_kinds_without_rewriting_sources() {
+    for line in V4.lines().take(5) {
+        // Current serde, writable open and read-only restore share the same
+        // current wire contract. None may dispatch to the old Feature decoder.
+        assert!(serde_json::from_str::<LogEntry>(line).is_err());
+        let bytes = format!("{line}\n");
+        let root = tempfile::tempdir().unwrap();
+        let (session, segment) = write_worker(root.path(), 6, bytes.as_bytes());
+        let path = root
+            .path()
+            .join("segments")
+            .join(format!("{segment}.jsonl"));
+        let marker = fs::read(root.path().join("session.json")).unwrap();
+        let readonly = WorkerSessionStore::open_read_only(root.path()).unwrap();
+        assert!(readonly.read_all_read_only(session, segment).is_err());
+        assert!(WorkerSessionStore::new(root.path()).is_err());
+        assert_eq!(fs::read(&path).unwrap(), bytes.as_bytes());
+        assert_eq!(fs::read(root.path().join("session.json")).unwrap(), marker);
+
+        let standalone = tempfile::tempdir().unwrap();
+        let dir = standalone.path().join(session.to_string());
+        fs::create_dir_all(&dir).unwrap();
+        let path = dir.join(format!("{segment}.jsonl"));
+        fs::write(&path, &bytes).unwrap();
+        fs::write(dir.join("session-schema.json"), "5").unwrap();
+        assert!(FsStore::new(standalone.path()).is_err());
+        assert_eq!(fs::read(&path).unwrap(), bytes.as_bytes());
+        assert_eq!(
+            fs::read_to_string(dir.join("session-schema.json")).unwrap(),
+            "5"
+        );
+    }
+}
+
+#[test]
+fn v1_v2_feature_wire_uses_the_same_typed_payloads_and_stable_legacy_identity() {
+    let segment = SegmentId::from_u128(42);
+    for version in [1, 2] {
+        for (index, line) in V4.lines().take(5).enumerate() {
+            let annotated: Value = serde_json::from_str(line).unwrap();
+            let wire = json!({
+                "kind": "system_item", "ts": annotated["ts"],
+                "item": annotated["entry"]["item"],
+                "extensions": [{"domain":"old-owner", "payload":{"kept":true}}],
+            })
+            .to_string();
+            let entry = decode_entry(version, &wire, SessionId::nil(), segment, index).unwrap();
+            let retry = decode_entry(version, &wire, SessionId::nil(), segment, index).unwrap();
+            assert_eq!(encode(&[entry.clone()]), encode(&[retry]));
+            let LogEntry::AnnotatedSystemItem {
+                ts,
+                entry,
+                extensions,
+            } = entry
+            else {
+                panic!()
+            };
+            assert_eq!(ts, annotated["ts"].as_u64().unwrap());
+            assert!(matches!(entry.item, SystemItem::Input { .. }));
+            assert_eq!(
+                entry.item.history_text(),
+                annotated["entry"]["item"]["body"].as_str().unwrap()
+            );
+            assert_eq!(
+                entry.metadata.entry_id,
+                legacy_metadata(segment, index, 0).entry_id
+            );
+            assert_eq!(
+                entry.metadata.origin,
+                LoggedSessionHistoryOrigin::LegacyUnknown
+            );
+            assert!(entry.metadata.derivation.is_none());
+            assert_eq!(extensions[0].domain, "old-owner");
+            assert_eq!(extensions[0].payload, json!({"kept":true}));
+            let LogEntry::AnnotatedSystemItem { entry: v4, .. } =
+                decode_entry(4, line, SessionId::nil(), segment, index).unwrap()
+            else {
+                panic!()
+            };
+            assert_eq!(entry.metadata.input_metadata, v4.metadata.input_metadata);
+        }
+    }
+}
+
+#[test]
+fn migration_rejects_malformed_typed_feature_fields_instead_of_retaining_unchecked_json() {
+    let mut items: Vec<Value> = V4
+        .lines()
+        .take(5)
+        .map(|line| serde_json::from_str::<Value>(line).unwrap()["entry"]["item"].clone())
+        .collect();
+    items[0]["snapshot_sha256"] = json!(17);
+    items[1]["prompt_provenance"] = json!({"logical_name":"missing digests"});
+    items[2]["behavior_md"] = json!(["not a string"]);
+    items[3]["name"] = json!({"not":"a name"});
+    items[4]["result"]["status"] = json!("unsupported_status");
+    for version in 1..=4 {
+        for item in &items {
+            let wire = if version <= 2 {
+                json!({"kind":"system_item", "ts":1, "item":item})
+            } else {
+                json!({"kind":"annotated_system_item", "ts":1, "entry":{
+                    "item":item, "metadata":{
+                        "entry_id":"malformed-id", "origin":{"kind":"legacy_unknown"},
+                    },
+                }})
+            }
+            .to_string();
+            assert!(decode_entry(version, &wire, SessionId::nil(), SegmentId::nil(), 0).is_err());
+        }
+    }
+}
+
+#[test]
+fn frozen_behavior_counter_is_accepted_only_at_the_old_schema_boundary() {
+    for version in 1..=4 {
+        let item = json!({
+            "kind":"subject_behavior_refresh", "body":"exact archived body",
+            "behavior_revision":7,
+        });
+        let wire = if version <= 2 {
+            json!({"kind":"system_item", "ts":1, "item":item})
+        } else {
+            json!({"kind":"annotated_system_item", "ts":1, "entry":{
+                "item":item, "metadata":{
+                    "entry_id":"behavior-id", "origin":{"kind":"legacy_unknown"},
+                },
+            }})
+        }
+        .to_string();
+        assert!(serde_json::from_str::<LogEntry>(&wire).is_err());
+        let LogEntry::AnnotatedSystemItem { entry, .. } =
+            decode_entry(version, &wire, SessionId::nil(), SegmentId::nil(), 0).unwrap()
+        else {
+            panic!()
+        };
+        assert_eq!(entry.item.history_text(), "exact archived body");
+        let payload = entry
+            .metadata
+            .input_metadata
+            .as_ref()
+            .unwrap()
+            .feature_payload()
+            .unwrap();
+        let typed: SubjectBehaviorPayload = payload.decode("subject:behavior", 1).unwrap();
+        assert_eq!(typed.behavior_md, "");
+        assert!(typed.prompt_provenance.is_none());
+        assert_eq!(
+            serde_json::to_value(typed).unwrap(),
+            json!({
+                "behavior_md":"", "prompt_provenance":null,
+            })
+        );
+    }
+}
+
+#[test]
+fn current_schema_rejects_generic_input_without_metadata_instead_of_migrating_it() {
+    let mut missing: Value = serde_json::from_str(V4.lines().last().unwrap()).unwrap();
+    missing["entry"]["metadata"]
+        .as_object_mut()
+        .unwrap()
+        .remove("system_input");
+    let bytes = format!("{}\n", missing);
+    let root = tempfile::tempdir().unwrap();
+    let (_, segment) = write_worker(root.path(), 6, bytes.as_bytes());
+    assert!(WorkerSessionStore::new(root.path()).is_err());
+    assert_eq!(
+        fs::read(
+            root.path()
+                .join("segments")
+                .join(format!("{segment}.jsonl"))
+        )
+        .unwrap(),
+        bytes.as_bytes()
+    );
+    assert_marker(root.path(), 6);
+}
+
+const V5: &str = include_str!("fixtures/v5-role-metadata.jsonl");
+
+#[test]
+fn v5_metadata_and_derived_tool_context_upgrade_without_changing_roles_or_original_evidence() {
+    for standalone in [false, true] {
+        let root = tempfile::tempdir().unwrap();
+        let (session, segment) = if standalone {
+            let session = SessionId::now_v7();
+            let segment = SegmentId::now_v7();
+            let dir = root.path().join(session.to_string());
+            fs::create_dir_all(&dir).unwrap();
+            fs::write(dir.join("session-schema.json"), b"5").unwrap();
+            fs::write(dir.join(format!("{segment}.jsonl")), V5).unwrap();
+            (session, segment)
+        } else {
+            write_worker(root.path(), 5, V5.as_bytes())
+        };
+        let entries = if standalone {
+            FsStore::new(root.path())
+                .unwrap()
+                .read_all(session, segment)
+                .unwrap()
+        } else {
+            WorkerSessionStore::new(root.path())
+                .unwrap()
+                .read_all(session, segment)
+                .unwrap()
+        };
+        let originals: Vec<Value> = V5
+            .lines()
+            .map(|line| serde_json::from_str(line).unwrap())
+            .collect();
+        assert_eq!(entries.len(), originals.len());
+        for (index, (entry, old)) in entries.iter().zip(originals).enumerate() {
+            let wire = serde_json::to_value(entry).unwrap();
+            assert_eq!(wire["ts"], old["ts"]);
+            assert_eq!(wire["entry"]["item"], old["entry"]["item"]);
+            for field in ["entry_id", "origin", "derivation"] {
+                assert_eq!(
+                    wire["entry"]["metadata"][field],
+                    old["entry"]["metadata"][field]
+                );
+            }
+            let metadata = &wire["entry"]["metadata"];
+            if index == 0 {
+                assert_eq!(
+                    metadata["input_metadata"],
+                    old["entry"]["metadata"]["system_input"]
+                );
+                assert_eq!(
+                    metadata["input_metadata"]["feature_payload"]["value"]["system_input"],
+                    "opaque owner field must not be renamed"
+                );
+            } else if index < 3 {
+                assert!(
+                    metadata.get("input_metadata").is_none(),
+                    "ordinary model Tool originals must not acquire exclusion policy"
+                );
+            } else {
+                assert_eq!(
+                    metadata["input_metadata"]["usage"],
+                    json!({
+                        "recording_material":"exclude", "memory_evidence":"exclude", "observation":"hidden", "compaction":"retain"
+                    })
+                );
+            }
+        }
+        let before = encode(&entries);
+        let reopened = if standalone {
+            FsStore::new(root.path())
+                .unwrap()
+                .read_all(session, segment)
+                .unwrap()
+        } else {
+            WorkerSessionStore::new(root.path())
+                .unwrap()
+                .read_all(session, segment)
+                .unwrap()
+        };
+        assert_eq!(encode(&reopened), before);
+    }
+}
+
+#[test]
+fn legacy_metadata_alias_conflict_fails_preflight_without_dropping_either_value() {
+    let mut bad: Value = serde_json::from_str(V5.lines().next().unwrap()).unwrap();
+    bad["entry"]["metadata"]["input_metadata"] = bad["entry"]["metadata"]["system_input"].clone();
+    for version in [4, 5] {
+        let root = tempfile::tempdir().unwrap();
+        let (_, segment) = write_worker(root.path(), version, V5.as_bytes());
+        let path = root
+            .path()
+            .join("segments")
+            .join(format!("{segment}.jsonl"));
+        let later = root
+            .path()
+            .join("segments")
+            .join(format!("{}.jsonl", SegmentId::from_u128(2)));
+        let bad_bytes = format!("{bad}\n");
+        fs::write(&later, &bad_bytes).unwrap();
+        assert!(WorkerSessionStore::new(root.path()).is_err());
+        assert_eq!(fs::read(path).unwrap(), V5.as_bytes());
+        assert_eq!(fs::read(later).unwrap(), bad_bytes.as_bytes());
+        assert_marker(root.path(), version);
+    }
+}

crates/session-store/src/lib.rs

@@ -41,6 +41,7 @@ pub(crate) fn read_without_atime_bounded(path: &Path, max_bytes: u64) -> io::Res
 pub mod event_trace;
 pub mod fs_store;
 pub mod history;
+pub mod input_metadata;
 mod legacy_session_log;
 pub mod logged_item;
 mod paste_artifact;
@@ -65,6 +66,10 @@ pub use history::{
     LoggedSessionHistoryMetadata, LoggedSessionHistoryOrigin, LoggedSystemHistoryEntry,
     LoggedWorkerSubject,
 };
+pub use input_metadata::{
+    FeatureInputPayload, HistoryInputMetadata, HistoryInputUsePolicy, InputCompactionUse,
+    InputEvidenceUse, InputMetadataError, InputObservationUse, SystemInputEnvelope,
+};
 pub use logged_item::{LoggedContentPart, LoggedItem, LoggedRole, from_logged, to_logged};
 pub use paste_artifact::PasteArtifactLimits;
 pub use public_index::{
@@ -98,7 +103,8 @@ pub use segment::{
 pub use segment_log::{LogEntry, RestoredState, SegmentOrigin, SessionExtension, collect_state};
 pub use store::{Store, StoreError};
 pub use system_item::{
-    PromptRenderProvenance, SystemItem, SystemReminder, SystemReminderSource, render_worker_event,
+    PromptRenderProvenance, PublicSystemItem, PublicSystemPresentation, SystemItem, SystemReminder,
+    SystemReminderSource, render_worker_event,
 };
 pub use uploaded_file::{
     DEFAULT_MAX_FILES_PER_SUBMISSION, DEFAULT_MAX_SESSION_ARTIFACT_BYTES,

crates/session-store/src/public_index.rs

@@ -1296,6 +1296,7 @@ mod tests {
         LoggedHistoryEntry {
             item,
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId(id.to_owned()),
                 origin,
                 derivation: None,
@@ -1537,6 +1538,7 @@ mod tests {
                         prompt_provenance: None,
                     },
                     metadata: LoggedSessionHistoryMetadata {
+                        input_metadata: None,
                         entry_id: LoggedSessionHistoryEntryId("system-item".into()),
                         origin: LoggedSessionHistoryOrigin::BackendInstruction {
                             operation_id: None,

crates/session-store/src/public_material.rs

@@ -148,15 +148,24 @@ struct SegmentHeader {
     file_len: u64,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PublicMaterialUse {
+    Recording,
+    MemoryEvidence,
+}
+
 /// A fixed material catalog. Opening a new catalog observes newly appended
 /// records; reading a body through this catalog verifies its saved digest and
 /// byte length again. Missing/corrected/deleted sources are explicit failures.
+/// Evidence eligibility never publishes private model text or Feature payload:
+/// System inputs also require an explicit public projection for every public use.
 pub struct SessionPublicMaterialReader {
     session_id: SessionId,
     active_segment_id: SegmentId,
     layout: Layout,
     limits: PublicMaterialLimits,
     materials: Vec<Material>,
+    purpose: PublicMaterialUse,
     retention: Option<crate::retention::SessionRetentionStore>,
 }
 
@@ -180,7 +189,13 @@ impl SessionPublicMaterialReader {
         active_segment_id: SegmentId,
         limits: PublicMaterialLimits,
     ) -> Result<Self, PublicMaterialError> {
-        Self::open_worker_guarded(session_root, active_segment_id, limits, None)
+        Self::open_worker_guarded(
+            session_root,
+            active_segment_id,
+            limits,
+            None,
+            PublicMaterialUse::Recording,
+        )
     }
 
     /// Uses the Host's aggregate-external control root for the whole scan and every body read.
@@ -191,7 +206,30 @@ impl SessionPublicMaterialReader {
         limits: PublicMaterialLimits,
         retention: crate::retention::SessionRetentionStore,
     ) -> Result<Self, PublicMaterialError> {
-        Self::open_worker_guarded(session_root, active_segment_id, limits, Some(retention))
+        Self::open_worker_for_use(
+            session_root,
+            active_segment_id,
+            limits,
+            retention,
+            PublicMaterialUse::Recording,
+        )
+    }
+
+    /// Selects the evidence purpose independently of public display and observation.
+    pub fn open_worker_for_use(
+        session_root: &Path,
+        active_segment_id: SegmentId,
+        limits: PublicMaterialLimits,
+        retention: crate::retention::SessionRetentionStore,
+        purpose: PublicMaterialUse,
+    ) -> Result<Self, PublicMaterialError> {
+        Self::open_worker_guarded(
+            session_root,
+            active_segment_id,
+            limits,
+            Some(retention),
+            purpose,
+        )
     }
 
     fn open_worker_guarded(
@@ -199,6 +237,7 @@ impl SessionPublicMaterialReader {
         active_segment_id: SegmentId,
         limits: PublicMaterialLimits,
         retention: Option<crate::retention::SessionRetentionStore>,
+        purpose: PublicMaterialUse,
     ) -> Result<Self, PublicMaterialError> {
         let store = WorkerSessionStore::open_read_only(session_root)
             .map_err(|_| PublicMaterialError::Unavailable)?;
@@ -212,6 +251,7 @@ impl SessionPublicMaterialReader {
             Layout::Worker(session_root.into()),
             limits,
             retention,
+            purpose,
         )
     }
 
@@ -237,6 +277,25 @@ impl SessionPublicMaterialReader {
         active_segment_id: SegmentId,
         limits: PublicMaterialLimits,
         retention: crate::retention::SessionRetentionStore,
+    ) -> Result<Self, PublicMaterialError> {
+        Self::open_fs_for_use(
+            sessions_root,
+            session_id,
+            active_segment_id,
+            limits,
+            retention,
+            PublicMaterialUse::Recording,
+        )
+    }
+
+    /// Uses retained originals with the independently selected evidence policy.
+    pub fn open_fs_for_use(
+        sessions_root: &Path,
+        session_id: SessionId,
+        active_segment_id: SegmentId,
+        limits: PublicMaterialLimits,
+        retention: crate::retention::SessionRetentionStore,
+        purpose: PublicMaterialUse,
     ) -> Result<Self, PublicMaterialError> {
         Self::open(
             session_id,
@@ -244,6 +303,7 @@ impl SessionPublicMaterialReader {
             Layout::Fs(sessions_root.join(session_id.to_string())),
             limits,
             Some(retention),
+            purpose,
         )
     }
 
@@ -263,6 +323,7 @@ impl SessionPublicMaterialReader {
         layout: Layout,
         limits: PublicMaterialLimits,
         retention: Option<crate::retention::SessionRetentionStore>,
+        purpose: PublicMaterialUse,
     ) -> Result<Self, PublicMaterialError> {
         let _guard = retention
             .as_ref()
@@ -310,11 +371,10 @@ impl SessionPublicMaterialReader {
             let source_ids: Option<Vec<String>> = if compact {
                 let summaries: Vec<_> = history
                     .iter()
-                    .filter(|e| {
-                        matches!(
-                            e.metadata.origin,
-                            LoggedSessionHistoryOrigin::CompactionSummary
-                        )
+                    .filter(|entry| {
+                        entry.metadata.input_metadata.as_ref().is_some_and(|input| {
+                            input.usage().compaction == crate::InputCompactionUse::OpeningSummary
+                        })
                     })
                     .collect();
                 if summaries.len() != 1 {
@@ -435,23 +495,19 @@ impl SessionPublicMaterialReader {
                     } => turn = *total_turn_count,
                     _ => {}
                 }
+                let system_history;
                 let entries: &[LoggedHistoryEntry] = match &record {
                     LogEntry::AnnotatedSegmentStart { history, .. }
                     | LogEntry::AnnotatedUserInput { history, .. } => history,
                     LogEntry::AnnotatedAssistantItem { entry, .. }
                     | LogEntry::AnnotatedToolResult { entry, .. }
                     | LogEntry::ToolResultCorrected { entry, .. } => std::slice::from_ref(entry),
+                    LogEntry::AnnotatedSystemItem { entry, .. } => {
+                        system_history = entry.to_history_entry();
+                        std::slice::from_ref(&system_history)
+                    }
                     _ => &[],
                 };
-                if let LogEntry::AnnotatedSystemItem { entry, .. } = &record {
-                    charge(&mut examined, limits.max_entries)?;
-                    if entry.metadata.entry_id.0.is_empty()
-                        || !history_seen.insert(entry.metadata.entry_id.0.clone())
-                    {
-                        return Err(PublicMaterialError::Inconsistent);
-                    }
-                    history_ids.push(entry.metadata.entry_id.0.clone());
-                }
                 for (history_index, entry) in entries.iter().enumerate() {
                     charge(&mut examined, limits.max_entries)?;
                     let id = &entry.metadata.entry_id.0;
@@ -468,7 +524,7 @@ impl SessionPublicMaterialReader {
                     if in_run && ai_materialized(&entry.item) {
                         safe = true;
                     }
-                    let Some((sha256, total_bytes)) = canonical_metadata(entry)? else {
+                    let Some((sha256, total_bytes)) = canonical_metadata(entry, purpose)? else {
                         continue;
                     };
                     let location = Location {
@@ -621,6 +677,7 @@ impl SessionPublicMaterialReader {
             layout,
             limits,
             materials,
+            purpose,
             retention: retention.clone(),
         })
     }
@@ -660,6 +717,7 @@ impl SessionPublicMaterialReader {
         let Some((_, record)) = reader.next()? else {
             return Err(PublicMaterialError::Missing);
         };
+        let system_history;
         let (body, origin) = if let Some(boundary) = run_boundary(&record) {
             if boundary_reference(
                 &record,
@@ -683,12 +741,16 @@ impl SessionPublicMaterialReader {
                 LogEntry::AnnotatedAssistantItem { entry, .. }
                 | LogEntry::AnnotatedToolResult { entry, .. }
                 | LogEntry::ToolResultCorrected { entry, .. } => Some(entry),
+                LogEntry::AnnotatedSystemItem { entry, .. } => {
+                    system_history = entry.to_history_entry();
+                    Some(&system_history)
+                }
                 _ => None,
             }
             .filter(|e| format!("E{}", e.metadata.entry_id.0) == descriptor.identity.entry_ref)
             .ok_or(PublicMaterialError::Changed)?;
             (
-                canonical_body(entry).ok_or(PublicMaterialError::Changed)?,
+                canonical_body(entry, self.purpose).ok_or(PublicMaterialError::Changed)?,
                 PublicMaterialOrigin::History {
                     origin: entry.metadata.origin.clone(),
                 },
@@ -765,7 +827,7 @@ enum CanonicalBody<'a> {
     Message {
         origin: &'a LoggedSessionHistoryOrigin,
         role: LoggedRole,
-        content: &'a [crate::LoggedContentPart],
+        content: std::borrow::Cow<'a, [crate::LoggedContentPart]>,
     },
     ToolCall {
         origin: &'a LoggedSessionHistoryOrigin,
@@ -828,14 +890,33 @@ fn boundary_reference(
         .unwrap_or_else(|| format!("El-run-{session}-{segment}-{offset}"))
 }
 
-fn canonical_body(entry: &LoggedHistoryEntry) -> Option<CanonicalBody<'_>> {
-    if matches!(
-        entry.metadata.origin,
-        LoggedSessionHistoryOrigin::DerivedSummary
-            | LoggedSessionHistoryOrigin::CompactionSummary
-            | LoggedSessionHistoryOrigin::JournalContext
-    ) {
-        return None;
+fn canonical_body(
+    entry: &LoggedHistoryEntry,
+    purpose: PublicMaterialUse,
+) -> Option<CanonicalBody<'_>> {
+    if let Some(input) = &entry.metadata.input_metadata {
+        let usage = input.usage();
+        let allowed = match purpose {
+            PublicMaterialUse::Recording => usage.recording_material,
+            PublicMaterialUse::MemoryEvidence => usage.memory_evidence,
+        };
+        if allowed == crate::InputEvidenceUse::Exclude {
+            return None;
+        }
+        if let LoggedItem::Message {
+            role: LoggedRole::System,
+            ..
+        } = &entry.item
+        {
+            let public = input.public_item()?;
+            return Some(CanonicalBody::Message {
+                origin: &entry.metadata.origin,
+                role: LoggedRole::System,
+                content: std::borrow::Cow::Owned(vec![crate::LoggedContentPart::Text {
+                    text: public.body.clone(),
+                }]),
+            });
+        }
     }
     match &entry.item {
         LoggedItem::Message {
@@ -847,7 +928,7 @@ fn canonical_body(entry: &LoggedHistoryEntry) -> Option<CanonicalBody<'_>> {
         LoggedItem::Message { role, content } => Some(CanonicalBody::Message {
             origin: &entry.metadata.origin,
             role: *role,
-            content,
+            content: std::borrow::Cow::Borrowed(content),
         }),
         LoggedItem::ToolCall {
             call_id,
@@ -880,8 +961,9 @@ fn canonical_body(entry: &LoggedHistoryEntry) -> Option<CanonicalBody<'_>> {
 
 fn canonical_metadata(
     entry: &LoggedHistoryEntry,
+    purpose: PublicMaterialUse,
 ) -> Result<Option<(String, u64)>, PublicMaterialError> {
-    let Some(body) = canonical_body(entry) else {
+    let Some(body) = canonical_body(entry, purpose) else {
         return Ok(None);
     };
     let mut sink = BodySink::new(0, 0);

crates/session-store/src/public_material/tests.rs

@@ -9,6 +9,7 @@ fn entry(id: &str, item: LoggedItem) -> LoggedHistoryEntry {
     LoggedHistoryEntry {
         item,
         metadata: LoggedSessionHistoryMetadata {
+            input_metadata: None,
             entry_id: LoggedSessionHistoryEntryId(id.into()),
             origin: LoggedSessionHistoryOrigin::LocalHumanInput,
             derivation: None,
@@ -24,6 +25,27 @@ fn message(id: &str, role: LoggedRole, text: &str) -> LoggedHistoryEntry {
         },
     )
 }
+fn system_context(
+    id: &str,
+    text: &str,
+    compaction: crate::InputCompactionUse,
+) -> LoggedHistoryEntry {
+    let mut entry = message(id, LoggedRole::System, text);
+    entry.metadata.input_metadata = Some(
+        crate::HistoryInputMetadata::new(
+            crate::HistoryInputUsePolicy {
+                recording_material: crate::InputEvidenceUse::Exclude,
+                memory_evidence: crate::InputEvidenceUse::Exclude,
+                observation: crate::InputObservationUse::Hidden,
+                compaction,
+            },
+            None,
+            None,
+        )
+        .unwrap(),
+    );
+    entry
+}
 fn seed(session: SessionId, history: Vec<LoggedHistoryEntry>) -> LogEntry {
     LogEntry::AnnotatedSegmentStart {
         ts: 1,
@@ -347,7 +369,11 @@ fn yield_resume_cancel_keep_original_boundary_identity_across_compaction() {
         .descriptors()
         .cloned()
         .collect();
-    let mut summary = message("summary", LoggedRole::User, "must not replace originals");
+    let mut summary = system_context(
+        "summary",
+        "must not replace originals",
+        crate::InputCompactionUse::OpeningSummary,
+    );
     summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
     summary.metadata.derivation = Some(crate::LoggedHistoryDerivation {
         sources: vec![
@@ -543,14 +569,18 @@ fn reasoning_proves_rollback_safety_but_private_and_derived_items_are_not_materi
     let store = FsStore::new(temp.path()).unwrap();
     let session = crate::new_session_id();
     let segment = crate::new_segment_id();
-    let mut derived = message("derived", LoggedRole::User, "summary");
+    let mut derived = system_context("derived", "summary", crate::InputCompactionUse::Retain);
     derived.metadata.origin = LoggedSessionHistoryOrigin::DerivedSummary;
-    let mut journal = message("journal", LoggedRole::User, "frozen Journal reference");
+    let mut journal = system_context(
+        "journal",
+        "frozen Journal reference",
+        crate::InputCompactionUse::ReferenceInput,
+    );
     journal.metadata.origin = LoggedSessionHistoryOrigin::JournalContext;
-    let mut summary = message(
+    let mut summary = system_context(
         "compaction-summary",
-        LoggedRole::User,
         "complementary summary",
+        crate::InputCompactionUse::OpeningSummary,
     );
     summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
     let reasoning = entry(
@@ -579,18 +609,23 @@ fn reasoning_proves_rollback_safety_but_private_and_derived_items_are_not_materi
                 LogEntry::AnnotatedSystemItem {
                     ts: 1,
                     entry: crate::LoggedSystemHistoryEntry {
-                        item: crate::SystemItem::JournalStartup {
+                        item: crate::SystemItem::Input {
                             body: "previous Journal must not become new recording material".into(),
-                            snapshot: serde_json::json!({"journals": []}),
-                            snapshot_sha256: "retained-digest".into(),
-                            prompt_provenance: crate::PromptRenderProvenance {
-                                workspace_id: None,
-                                source_digest: "source".into(),
-                                projection_digest: "projection".into(),
-                                logical_name: "internal.subjektiv_journal_startup".into(),
-                            },
                         },
                         metadata: LoggedSessionHistoryMetadata {
+                            input_metadata: Some(
+                                crate::HistoryInputMetadata::new(
+                                    crate::HistoryInputUsePolicy {
+                                        recording_material: crate::InputEvidenceUse::Exclude,
+                                        memory_evidence: crate::InputEvidenceUse::Exclude,
+                                        observation: crate::InputObservationUse::Hidden,
+                                        compaction: crate::InputCompactionUse::ReferenceInput,
+                                    },
+                                    None,
+                                    None,
+                                )
+                                .unwrap(),
+                            ),
                             entry_id: LoggedSessionHistoryEntryId("startup-journal".into()),
                             origin: LoggedSessionHistoryOrigin::DerivedSummary,
                             derivation: None,
@@ -777,6 +812,19 @@ fn schema_v3_compaction_migrates_persistently_and_strict_reader_keeps_original_i
             panic!()
         };
         summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
+        summary.metadata.input_metadata = Some(
+            crate::HistoryInputMetadata::new(
+                crate::HistoryInputUsePolicy {
+                    recording_material: crate::InputEvidenceUse::Exclude,
+                    memory_evidence: crate::InputEvidenceUse::Exclude,
+                    observation: crate::InputObservationUse::Hidden,
+                    compaction: crate::InputCompactionUse::OpeningSummary,
+                },
+                None,
+                None,
+            )
+            .unwrap(),
+        );
         assert_eq!(history, &[summary]);
         // Run-transition ids synthesized from byte offsets must be frozen before
         // the changed summary record shifts every subsequent record offset.
@@ -825,8 +873,14 @@ fn midturn_compaction_uses_exact_source_ids_and_preserves_discarded_originals()
             ],
         )
         .unwrap();
-    let mut summary = message("summary", LoggedRole::User, "never use as original");
-    summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
+    let mut summary = system_context(
+        "summary",
+        "never use as original",
+        crate::InputCompactionUse::OpeningSummary,
+    );
+    summary.metadata.origin = LoggedSessionHistoryOrigin::Provided {
+        producer: "renamed-summary-owner".into(),
+    };
     summary.metadata.derivation = Some(crate::LoggedHistoryDerivation {
         sources: vec![
             LoggedSessionHistoryEntryId("u".into()),
@@ -1030,7 +1084,11 @@ fn zero_turn_fork_from_seed_and_consecutive_compactions_preserve_original_identi
     for index in 0..3 {
         let compact = crate::new_segment_id();
         let summary_id = format!("summary-{index}");
-        let mut summary = message(&summary_id, LoggedRole::User, "not original");
+        let mut summary = system_context(
+            &summary_id,
+            "not original",
+            crate::InputCompactionUse::OpeningSummary,
+        );
         summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
         summary.metadata.derivation = Some(crate::LoggedHistoryDerivation {
             sources: source_ids
@@ -1178,7 +1236,11 @@ fn correction_preserves_original_identity_across_compaction_without_summary_fall
             ],
         )
         .unwrap();
-    let mut summary = message("summary", LoggedRole::User, "not original");
+    let mut summary = system_context(
+        "summary",
+        "not original",
+        crate::InputCompactionUse::OpeningSummary,
+    );
     summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
     summary.metadata.derivation = Some(crate::LoggedHistoryDerivation {
         sources: vec![LoggedSessionHistoryEntryId("result".into())],
@@ -1226,7 +1288,11 @@ fn compaction_without_exact_derivation_or_with_invalid_turn_is_rejected() {
         ),
     ] {
         let segment = crate::new_segment_id();
-        let mut summary = message("summary", LoggedRole::User, "not original");
+        let mut summary = system_context(
+            "summary",
+            "not original",
+            crate::InputCompactionUse::OpeningSummary,
+        );
         summary.metadata.origin = LoggedSessionHistoryOrigin::CompactionSummary;
         summary.metadata.derivation = derivation;
         let mut start = seed(session, vec![summary]);
@@ -1243,3 +1309,181 @@ fn compaction_without_exact_derivation_or_with_invalid_turn_is_rejected() {
         ));
     }
 }
+
+#[test]
+fn generic_system_material_uses_explicit_evidence_purpose_not_producer_or_body() {
+    use crate::{
+        FeatureInputPayload, HistoryInputMetadata, HistoryInputUsePolicy, InputCompactionUse,
+        InputEvidenceUse, InputObservationUse, LoggedSystemHistoryEntry, SystemInputEnvelope,
+    };
+    for worker_layout in [false, true] {
+        let temp = tempfile::tempdir().unwrap();
+        let session = crate::new_session_id();
+        let segment = crate::new_segment_id();
+        let fork = crate::new_segment_id();
+        let make =
+            |producer: &str, recording_material, memory_evidence, body: &str, public: bool| {
+                LoggedSystemHistoryEntry::from_input(
+                    LoggedSessionHistoryOrigin::Provided {
+                        producer: producer.into(),
+                    },
+                    None,
+                    SystemInputEnvelope::new(
+                        format!("private model text: {body}"),
+                        HistoryInputMetadata::new(
+                            HistoryInputUsePolicy {
+                                recording_material,
+                                memory_evidence,
+                                observation: InputObservationUse::Hidden,
+                                compaction: InputCompactionUse::Retain,
+                            },
+                            Some(
+                                FeatureInputPayload::encode(
+                                    "unknown:future",
+                                    99,
+                                    &serde_json::json!({"private": "not-public"}),
+                                )
+                                .unwrap(),
+                            ),
+                            public.then(|| crate::PublicSystemItem {
+                                kind: "context".into(),
+                                body: body.into(),
+                                presentation: crate::PublicSystemPresentation::Context,
+                            }),
+                        )
+                        .unwrap(),
+                    )
+                    .unwrap(),
+                )
+            };
+        let inputs = [
+            make(
+                "same-owner",
+                InputEvidenceUse::Include,
+                InputEvidenceUse::Exclude,
+                "do not extract this; original material",
+                true,
+            ),
+            make(
+                "same-owner",
+                InputEvidenceUse::Exclude,
+                InputEvidenceUse::Include,
+                "memory-only original",
+                true,
+            ),
+            make(
+                "renamed-owner",
+                InputEvidenceUse::Exclude,
+                InputEvidenceUse::Exclude,
+                "reference without warning text",
+                true,
+            ),
+            make(
+                "private-only",
+                InputEvidenceUse::Include,
+                InputEvidenceUse::Include,
+                "must not publish without projection",
+                false,
+            ),
+        ];
+        let root = if worker_layout {
+            temp.path().join("worker")
+        } else {
+            temp.path().join(session.to_string())
+        };
+        let store: Box<dyn Store> = if worker_layout {
+            Box::new(WorkerSessionStore::new(&root).unwrap())
+        } else {
+            Box::new(FsStore::new(temp.path()).unwrap())
+        };
+        store
+            .create_segment(session, segment, &[seed(session, vec![])])
+            .unwrap();
+        for entry in &inputs {
+            store
+                .append(
+                    session,
+                    segment,
+                    &LogEntry::AnnotatedSystemItem {
+                        ts: 2,
+                        entry: entry.clone(),
+                        extensions: vec![],
+                    },
+                )
+                .unwrap();
+        }
+        store
+            .append(
+                session,
+                segment,
+                &LogEntry::TurnEnd {
+                    ts: 3,
+                    turn_count: 1,
+                },
+            )
+            .unwrap();
+        let mut fork_seed = seed(
+            session,
+            inputs
+                .iter()
+                .map(LoggedSystemHistoryEntry::to_history_entry)
+                .collect(),
+        );
+        if let LogEntry::AnnotatedSegmentStart { forked_from, .. } = &mut fork_seed {
+            *forked_from = Some(crate::SegmentOrigin {
+                segment_id: segment,
+                at_turn_index: 1,
+            });
+        }
+        store.create_segment(session, fork, &[fork_seed]).unwrap();
+        let open = |active, purpose| {
+            if worker_layout {
+                SessionPublicMaterialReader::open_worker_for_use(
+                    &root,
+                    active,
+                    Default::default(),
+                    crate::retention::fs_retention(temp.path()),
+                    purpose,
+                )
+                .unwrap()
+            } else {
+                SessionPublicMaterialReader::open_fs_for_use(
+                    temp.path(),
+                    session,
+                    active,
+                    Default::default(),
+                    crate::retention::fs_retention(temp.path()),
+                    purpose,
+                )
+                .unwrap()
+            }
+        };
+        for (purpose, selected, expected_text) in [
+            (
+                PublicMaterialUse::Recording,
+                0,
+                "do not extract this; original material",
+            ),
+            (PublicMaterialUse::MemoryEvidence, 1, "memory-only original"),
+        ] {
+            let original = open(segment, purpose);
+            let inherited = open(fork, purpose);
+            assert_eq!(
+                ids(&original),
+                vec![format!("E{}", inputs[selected].metadata.entry_id.0)]
+            );
+            assert_eq!(ids(&inherited), ids(&original));
+            let descriptor = inherited.descriptors().next().unwrap();
+            let body = inherited
+                .read_content(descriptor, 0, 16 * 1024)
+                .unwrap()
+                .content;
+            let value: serde_json::Value = serde_json::from_str(&body).unwrap();
+            assert_eq!(value["role"], "system");
+            assert_eq!(value["content"][0]["text"], expected_text);
+            assert!(!body.contains("not-public"));
+            assert!(!body.contains("private model text"));
+            assert!(!body.contains("unknown:future"));
+        }
+    }
+}

crates/session-store/src/public_snapshot.rs

@@ -27,7 +27,7 @@ use thiserror::Error;
 
 use crate::{
     LogEntry, LoggedContentPart, LoggedHistoryEntry, LoggedItem, LoggedRole,
-    LoggedSessionHistoryOrigin, SegmentId, SegmentOrigin, SessionId, StoreError, SystemItem,
+    LoggedSessionHistoryOrigin, SegmentId, SegmentOrigin, SessionId, StoreError,
     WorkerAggregateStore, WorkerSessionStore, WorkerStoreError,
 };
 
@@ -1165,7 +1165,7 @@ fn capture_tool_correction(
     let LogEntry::ToolResultCorrected { entry, .. } = record else {
         return false;
     };
-    if let Some(data) = project_item(&entry.metadata.entry_id.0, &entry.item) {
+    if let Some(data) = project_history_item(entry) {
         // We read backwards: the first correction seen is the latest one.
         corrections
             .entry(entry.metadata.entry_id.0.clone())
@@ -1600,12 +1600,12 @@ pub(crate) fn project_session_snapshot_for_segment(
             } => extend_history(&mut entries, history, Some(segments), *ts),
             LogEntry::AnnotatedAssistantItem { ts, entry }
             | LogEntry::AnnotatedToolResult { ts, entry } => {
-                if let Some(data) = project_item(&entry.metadata.entry_id.0, &entry.item) {
+                if let Some(data) = project_history_item(entry) {
                     entries.push(history_entry(entry, *ts, data));
                 }
             }
             LogEntry::ToolResultCorrected { ts, entry } => {
-                if let Some(data) = project_item(&entry.metadata.entry_id.0, &entry.item) {
+                if let Some(data) = project_history_item(entry) {
                     if let Some(existing) = entries
                         .iter_mut()
                         .find(|existing| existing.entry_id == entry.metadata.entry_id.0)
@@ -1618,11 +1618,16 @@ pub(crate) fn project_session_snapshot_for_segment(
                 }
             }
             LogEntry::AnnotatedSystemItem { ts, entry, .. } => entries.push(system_entry(
-                &entry.item,
+                &entry.public_item(),
                 entry.metadata.entry_id.0.clone(),
                 *ts,
                 provenance(&entry.metadata.origin),
                 derivation_ids(entry),
+                entry
+                    .metadata
+                    .input_metadata
+                    .as_ref()
+                    .map(crate::HistoryInputMetadata::public_system_use_policy),
             )),
             LogEntry::RunYielded {
                 ts,
@@ -1775,7 +1780,7 @@ fn extend_history(
                 segments: input_segments.cloned().unwrap_or_default(),
             }
         } else {
-            let Some(data) = project_item(&entry.metadata.entry_id.0, &entry.item) else {
+            let Some(data) = project_history_item(entry) else {
                 continue;
             };
             data
@@ -1790,6 +1795,19 @@ fn history_entry(
     data: SessionSnapshotEntryData,
 ) -> SessionSnapshotEntry {
     SessionSnapshotEntry {
+        use_policy: entry.metadata.input_metadata.as_ref().map(|input| {
+            if matches!(
+                entry.item,
+                LoggedItem::Message {
+                    role: LoggedRole::System,
+                    ..
+                }
+            ) {
+                input.public_system_use_policy()
+            } else {
+                input.public_use_policy()
+            }
+        }),
         entry_id: entry.metadata.entry_id.0.clone(),
         timestamp,
         provenance: provenance(&entry.metadata.origin),
@@ -1833,6 +1851,7 @@ fn run_transition_entry(
     data: SessionSnapshotEntryData,
 ) -> SessionSnapshotEntry {
     SessionSnapshotEntry {
+        use_policy: None,
         entry_id: persisted_entry_id
             .map(|entry_id| entry_id.0.clone())
             .unwrap_or_else(|| legacy_entry_id(session_key, segment_id, log_index, 0)),
@@ -1852,6 +1871,7 @@ fn legacy_entry(
     data: SessionSnapshotEntryData,
 ) -> SessionSnapshotEntry {
     SessionSnapshotEntry {
+        use_policy: None,
         entry_id: legacy_entry_id(session_key, segment_id, log_index, item_index),
         timestamp,
         provenance: SessionEntryProvenance::LegacyUnknown,
@@ -1884,9 +1904,8 @@ fn provenance(origin: &LoggedSessionHistoryOrigin) -> SessionEntryProvenance {
         LoggedSessionHistoryOrigin::FlowInstruction { .. } => {
             SessionEntryProvenance::FlowInstruction
         }
-        LoggedSessionHistoryOrigin::BackendInstruction { .. } => {
-            SessionEntryProvenance::BackendInstruction
-        }
+        LoggedSessionHistoryOrigin::BackendInstruction { .. }
+        | LoggedSessionHistoryOrigin::Provided { .. } => SessionEntryProvenance::BackendInstruction,
         LoggedSessionHistoryOrigin::ModelOutput { .. } => SessionEntryProvenance::ModelOutput,
         LoggedSessionHistoryOrigin::ToolOutput { .. } => SessionEntryProvenance::ToolOutput,
         LoggedSessionHistoryOrigin::CompactionSummary
@@ -1914,6 +1933,35 @@ pub fn session_tool_attachment_id(
     URL_SAFE_NO_PAD.encode(hash.finalize())
 }
 
+fn project_history_item(entry: &LoggedHistoryEntry) -> Option<SessionSnapshotEntryData> {
+    if let Some(input) = &entry.metadata.input_metadata {
+        if matches!(
+            entry.item,
+            LoggedItem::Message {
+                role: LoggedRole::System,
+                ..
+            }
+        ) {
+            let public = input.public_projection();
+            return Some(SessionSnapshotEntryData::SystemItem {
+                item_kind: public.kind.clone(),
+                content: public.body.clone(),
+                data: Some(
+                    serde_json::to_value(public).expect("public system input is serializable"),
+                ),
+            });
+        }
+        let usage = input.usage();
+        if usage.recording_material == crate::InputEvidenceUse::Exclude
+            && usage.memory_evidence == crate::InputEvidenceUse::Exclude
+            && usage.observation == crate::InputObservationUse::Hidden
+        {
+            return None;
+        }
+    }
+    project_item(&entry.metadata.entry_id.0, &entry.item)
+}
+
 fn project_item(entry_id: &str, item: &LoggedItem) -> Option<SessionSnapshotEntryData> {
     match item {
         LoggedItem::Message { role, content } => {
@@ -1986,30 +2034,26 @@ fn project_item(entry_id: &str, item: &LoggedItem) -> Option<SessionSnapshotEntr
 }
 
 fn system_entry(
-    item: &SystemItem,
+    item: &crate::PublicSystemItem,
     entry_id: String,
     timestamp: u64,
     provenance: SessionEntryProvenance,
     derived_from: Vec<String>,
+    use_policy: Option<protocol::SessionEntryUsePolicy>,
 ) -> SessionSnapshotEntry {
-    let mut data = serde_json::to_value(item).ok();
-    if let Some(serde_json::Value::Object(object)) = data.as_mut() {
-        object.remove("prompt_provenance");
-    }
-    let item_kind = data
-        .as_ref()
-        .and_then(|value| value.get("kind"))
-        .and_then(serde_json::Value::as_str)
-        .unwrap_or("system_item")
-        .to_owned();
+    let public = item.clone();
+    let data = Some(serde_json::to_value(&public).expect("public system input is serializable"));
+    let item_kind = public.kind;
+    let content = public.body;
     SessionSnapshotEntry {
+        use_policy,
         entry_id,
         timestamp,
         provenance,
         derived_from,
         data: SessionSnapshotEntryData::SystemItem {
             item_kind,
-            content: item.history_text(),
+            content,
             data,
         },
     }
@@ -2291,6 +2335,7 @@ mod tests {
                 content: vec![LoggedContentPart::Text { text: text.into() }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId(entry_id.into()),
                 origin,
                 derivation: None,
@@ -3589,6 +3634,7 @@ mod tests {
             .map(|item| LoggedHistoryEntry {
                 item,
                 metadata: LoggedSessionHistoryMetadata {
+                    input_metadata: None,
                     entry_id: LoggedSessionHistoryEntryId::new(),
                     origin: LoggedSessionHistoryOrigin::LegacyUnknown,
                     derivation: None,
@@ -3643,6 +3689,7 @@ mod tests {
                         }],
                     },
                     metadata: LoggedSessionHistoryMetadata {
+                        input_metadata: None,
                         entry_id: user_entry_id,
                         origin: LoggedSessionHistoryOrigin::HumanInput {
                             account_id: "account-1".into(),
@@ -3712,6 +3759,7 @@ mod tests {
                                 }],
                             },
                             metadata: LoggedSessionHistoryMetadata {
+                                input_metadata: None,
                                 entry_id: LoggedSessionHistoryEntryId::new(),
                                 origin: LoggedSessionHistoryOrigin::FlowInstruction {
                                     selector: "builtin:coder-review".into(),
@@ -3731,6 +3779,7 @@ mod tests {
                                 }],
                             },
                             metadata: LoggedSessionHistoryMetadata {
+                                input_metadata: None,
                                 entry_id: user_entry_id.clone(),
                                 origin: origin.clone(),
                                 derivation: Some(LoggedHistoryDerivation {
@@ -3761,6 +3810,7 @@ mod tests {
     fn annotated_projection_preserves_identity_and_provenance() {
         let session_id = crate::new_session_id();
         let metadata = LoggedSessionHistoryMetadata {
+            input_metadata: None,
             entry_id: LoggedSessionHistoryEntryId::new(),
             origin: LoggedSessionHistoryOrigin::ModelOutput {
                 worker: LoggedWorkerSubject {
@@ -4323,6 +4373,7 @@ mod tests {
                 is_error: false,
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId("ancestor-image".into()),
                 origin: LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,
@@ -4417,6 +4468,7 @@ mod tests {
                 is_error: false,
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId("tool-images".into()),
                 origin: LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,

crates/session-store/src/public_snapshot/run_stats.rs

@@ -103,6 +103,7 @@ fn finish(
     stats.insert(
         anchor.clone(),
         SessionSnapshotEntry {
+            use_policy: None,
             entry_id: format!("run-stats:{anchor}"),
             timestamp: ended_at,
             provenance: SessionEntryProvenance::LegacyUnknown,

crates/session-store/src/segment_log.rs

@@ -254,6 +254,23 @@ pub struct SegmentOrigin {
 }
 
 impl LogEntry {
+    /// Validate generic System records before a Store publishes any bytes.
+    pub fn validate_input_metadata(&self) -> Result<(), crate::InputMetadataError> {
+        match self {
+            Self::AnnotatedSegmentStart { history, .. }
+            | Self::AnnotatedUserInput { history, .. } => {
+                for entry in history {
+                    entry.validate_input_metadata()?;
+                }
+            }
+            Self::AnnotatedAssistantItem { entry, .. }
+            | Self::AnnotatedToolResult { entry, .. }
+            | Self::ToolResultCorrected { entry, .. } => entry.validate_input_metadata()?,
+            Self::AnnotatedSystemItem { entry, .. } => entry.validate_input_metadata()?,
+            _ => {}
+        }
+        Ok(())
+    }
     /// Allocate the durable public identity for a newly committed Run
     /// transition. Calling this repeatedly is idempotent so the exact value
     /// written to storage is also the value published to live subscribers.
@@ -537,6 +554,7 @@ mod tests {
         LoggedHistoryEntry {
             item: LoggedItem::from(item),
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId::new(),
                 origin: LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,

crates/session-store/src/store.rs

@@ -27,6 +27,9 @@ pub enum StoreError {
     #[error("serialization error: {0}")]
     Serde(#[from] serde_json::Error),
 
+    #[error("invalid history input metadata: {0}")]
+    InvalidInputMetadata(#[from] crate::InputMetadataError),
+
     #[error("segment not found: {0}")]
     NotFound(SegmentId),
 

crates/session-store/src/system_item.rs

@@ -86,20 +86,16 @@ pub struct PromptRenderProvenance {
 /// `notify_wrapper` template) re-shape the live rendering on a later
 /// resume.
 ///
-/// New variants get added here as fresh injection kinds come online
-/// (e.g. `TaskReminder`). The `kind` JSON tag is the snake_case form of
-/// the variant name.
+/// Feature-owned inputs use `Input` plus explicit annotated metadata; adding a
+/// Feature must not extend this enum or ordinary replay. Only core events have
+/// dedicated variants. Pre-v5 Feature kinds exist exclusively in the migration
+/// decoder, not in this current wire contract.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "kind", rename_all = "snake_case")]
 pub enum SystemItem {
-    /// One-time derived Journal reference context. The bounded Host snapshot is
-    /// retained as JSON independently of its rendered body and prompt projection.
-    JournalStartup {
-        body: String,
-        snapshot: serde_json::Value,
-        snapshot_sha256: String,
-        prompt_provenance: PromptRenderProvenance,
-    },
+    /// Generic System body; private metadata and public presentation are supplied
+    /// independently by the producer in the same annotated history record.
+    Input { body: String },
     /// Free-form notification sent in by an external caller via
     /// `Method::Notify`. `message` is the raw caller-supplied text;
     /// `body` is the wrapped LLM-context form (Worker renders it via
@@ -122,14 +118,6 @@ pub enum SystemItem {
         prompt_provenance: Option<PromptRenderProvenance>,
     },
 
-    /// Result of an explicitly selected chat Feature invocation. The typed
-    /// result is retained for clients; `body` is the exact bounded context made
-    /// visible to the Worker model.
-    FeatureInvocationResult {
-        result: protocol::FeatureInvocationResult,
-        body: String,
-    },
-
     /// `@<path>` file reference resolution. `body` is the rendered
     /// LLM-context text (`[File: <path>]\n…` for regular files,
     /// `[Dir: <path>]\n…` for directory listings, possibly with a
@@ -137,10 +125,6 @@ pub enum SystemItem {
     /// byte-identical to what was sent.
     FileAttachment { path: String, body: String },
 
-    /// Explicit Agent Skill activation. `body` is the exact LLM-facing
-    /// Skill text committed before any subsequent LLM request can use it.
-    SkillActivation { name: String, body: String },
-
     /// Historical persisted Knowledge reference resolution. Knowledge is no
     /// longer active, so restored sessions ignore this item instead of replaying
     /// archived record text into model context.
@@ -164,29 +148,6 @@ pub enum SystemItem {
         prompt_provenance: Option<PromptRenderProvenance>,
     },
 
-    /// Restore-boundary refresh of the current resident Memory projection.
-    /// The exact rendered body is retained so replay is byte-identical; a
-    /// refresh with no ready summary explicitly supersedes older resident
-    /// context without deleting or rewriting history.
-    ResidentSummaryRefresh {
-        body: String,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        prompt_provenance: Option<PromptRenderProvenance>,
-    },
-
-    /// A Host-fetched change to user-managed Subject behavior. Each changed
-    /// body is appended rather than rewriting prior prompt/session content.
-    SubjectBehaviorRefresh {
-        body: String,
-        /// Exact user-managed behavior acknowledged after durable commit. Old
-        /// logs omit this value; an empty value is not an acknowledgement of a
-        /// nonempty behavior and does not replace their stored rendered body.
-        #[serde(default)]
-        behavior_md: String,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        prompt_provenance: Option<PromptRenderProvenance>,
-    },
-
     /// Synthetic note inserted after an interrupted turn before the next
     /// user input. `body` is the exact LLM-context text explaining that the
     /// previous turn was cut short.
@@ -197,24 +158,67 @@ pub enum SystemItem {
     },
 }
 
+/// Allowlisted presentation data shared by live events and retained snapshots.
+/// Private Feature payloads and render provenance never cross this boundary.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
+pub struct PublicSystemItem {
+    pub kind: String,
+    pub body: String,
+    pub presentation: PublicSystemPresentation,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]
+pub enum PublicSystemPresentation {
+    Notification { message: String },
+    WorkerEvent { event: WorkerEvent },
+    Context,
+    TaskReminder,
+    Ignored,
+}
+
 impl SystemItem {
+    pub fn public_item(&self) -> PublicSystemItem {
+        let presentation = match self {
+            Self::Notification { message, .. } => PublicSystemPresentation::Notification {
+                message: message.clone(),
+            },
+            Self::WorkerEvent { event, .. } => PublicSystemPresentation::WorkerEvent {
+                event: event.clone(),
+            },
+            Self::TaskReminder { .. } => PublicSystemPresentation::TaskReminder,
+            Self::Input { .. }
+            | Self::LegacyKnowledgeIgnored { .. }
+            | Self::LegacyIgnored { .. } => PublicSystemPresentation::Ignored,
+            Self::FileAttachment { .. } | Self::Interrupt { .. } => {
+                PublicSystemPresentation::Context
+            }
+        };
+        PublicSystemItem {
+            kind: self.kind_label().to_owned(),
+            body: if matches!(presentation, PublicSystemPresentation::Ignored) {
+                String::new()
+            } else {
+                self.history_text()
+            },
+            presentation,
+        }
+    }
+
     /// Free-text body the LLM sees inside its `role:system` message
     /// for this item. Returns the variant's stored `body` verbatim.
     pub fn history_text(&self) -> String {
         match self {
-            SystemItem::JournalStartup { body, .. } => body.clone(),
+            SystemItem::Input { body } => body.clone(),
             SystemItem::Notification { body, .. } => body.clone(),
             SystemItem::WorkerEvent { body, .. } => body.clone(),
-            SystemItem::FeatureInvocationResult { body, .. } => body.clone(),
             SystemItem::FileAttachment { body, .. } => body.clone(),
-            SystemItem::SkillActivation { body, .. } => body.clone(),
             SystemItem::LegacyKnowledgeIgnored { .. } => String::new(),
             SystemItem::LegacyIgnored { slug } => {
                 format!("Ignored legacy procedure item: /{slug}")
             }
             SystemItem::TaskReminder { body, .. } => body.clone(),
-            SystemItem::ResidentSummaryRefresh { body, .. } => body.clone(),
-            SystemItem::SubjectBehaviorRefresh { body, .. } => body.clone(),
             SystemItem::Interrupt { body, .. } => body.clone(),
         }
     }
@@ -229,17 +233,13 @@ impl SystemItem {
     /// wire — keep flexible.
     pub fn kind_label(&self) -> &'static str {
         match self {
-            SystemItem::JournalStartup { .. } => "journal_startup",
+            SystemItem::Input { .. } => "input",
             SystemItem::Notification { .. } => "notification",
             SystemItem::WorkerEvent { .. } => "worker_event",
-            SystemItem::FeatureInvocationResult { .. } => "feature_invocation_result",
             SystemItem::FileAttachment { .. } => "file_attachment",
-            SystemItem::SkillActivation { .. } => "skill_activation",
             SystemItem::LegacyKnowledgeIgnored { .. } => "legacy_knowledge_ignored",
             SystemItem::LegacyIgnored { .. } => "legacy_ignored",
             SystemItem::TaskReminder { .. } => "task_reminder",
-            SystemItem::ResidentSummaryRefresh { .. } => "resident_summary_refresh",
-            SystemItem::SubjectBehaviorRefresh { .. } => "subject_behavior_refresh",
             SystemItem::Interrupt { .. } => "interrupt",
         }
     }
@@ -297,33 +297,45 @@ mod tests {
     }
 
     #[test]
-    fn subject_behavior_refresh_round_trips_with_exact_body() {
-        let item = SystemItem::SubjectBehaviorRefresh {
-            body: "current Subject context".to_string(),
-            behavior_md: "exact behavior".to_string(),
-            prompt_provenance: None,
-        };
-        let raw = serde_json::to_string(&item).unwrap();
-        let parsed: SystemItem = serde_json::from_str(&raw).unwrap();
-        assert_eq!(parsed.history_text(), "current Subject context");
-        assert!(
-            matches!(parsed, SystemItem::SubjectBehaviorRefresh { behavior_md, .. } if behavior_md == "exact behavior")
-        );
+    fn current_system_item_rejects_frozen_feature_kinds() {
+        // Even well-formed old payloads cannot enter normal v5 decode/replay.
+        for line in include_str!("legacy_session_log/tests/fixtures/v4-system-inputs.jsonl")
+            .lines()
+            .take(5)
+        {
+            let record: serde_json::Value = serde_json::from_str(line).unwrap();
+            assert!(serde_json::from_value::<SystemItem>(record["entry"]["item"].clone()).is_err());
+            assert!(
+                serde_json::from_value::<crate::LoggedSystemHistoryEntry>(record["entry"].clone())
+                    .is_err()
+            );
+            assert!(serde_json::from_str::<crate::LogEntry>(line).is_err());
+        }
     }
 
     #[test]
-    fn frozen_subject_behavior_log_reads_old_counter_without_republishing_it() {
-        let old = r#"{"kind":"subject_behavior_refresh","body":"exact archived body","behavior_revision":7}"#;
-        let item: SystemItem = serde_json::from_str(old).unwrap();
-        assert_eq!(item.history_text(), "exact archived body");
-        assert_eq!(
-            serde_json::to_value(item).unwrap(),
-            serde_json::json!({
-                "kind": "subject_behavior_refresh",
-                "body": "exact archived body",
-                "behavior_md": ""
-            })
-        );
+    fn public_system_input_decoder_rejects_private_fields_and_unknown_presentations() {
+        let valid = serde_json::json!({
+            "kind": "new-feature-label",
+            "body": "explicit public content",
+            "presentation": { "kind": "context" },
+        });
+        let public: PublicSystemItem = serde_json::from_value(valid.clone()).unwrap();
+        assert_eq!(public.body, "explicit public content");
+        for private_field in [
+            "payload",
+            "prompt_provenance",
+            "policy",
+            "snapshot",
+            "behavior_md",
+        ] {
+            let mut malformed = valid.clone();
+            malformed[private_field] = serde_json::json!({ "private": true });
+            assert!(serde_json::from_value::<PublicSystemItem>(malformed).is_err());
+        }
+        let mut unknown = valid;
+        unknown["presentation"] = serde_json::json!({ "kind": "execute_feature_payload" });
+        assert!(serde_json::from_value::<PublicSystemItem>(unknown).is_err());
     }
 
     #[test]
@@ -419,29 +431,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn invocation_result_retains_typed_outcome_and_exact_context() {
-        let result = protocol::FeatureInvocationResult {
-            invocation_id: "stable-invoke".into(),
-            identity: protocol::FeatureInvocationIdentity("builtin:test/prepare".into()),
-            status: protocol::FeatureInvocationStatus::OutcomeUnknown,
-            message: "operation may have committed".into(),
-            context: None,
-        };
-        let body = "Outcome unknown; do not retry automatically";
-        let item = SystemItem::FeatureInvocationResult {
-            result: result.clone(),
-            body: body.into(),
-        };
-        let restored: SystemItem =
-            serde_json::from_str(&serde_json::to_string(&item).unwrap()).unwrap();
-        assert_eq!(restored.history_text(), body);
-        assert_eq!(restored.kind_label(), "feature_invocation_result");
-        assert!(
-            matches!(restored, SystemItem::FeatureInvocationResult { result: saved, .. } if saved == result)
-        );
-    }
-
     #[test]
     fn round_trip_worker_event() {
         let item = SystemItem::WorkerEvent {

crates/session-store/src/worker_metadata.rs

@@ -210,18 +210,6 @@ impl WorkerMetadata {
     }
 }
 
-fn replace_active_session(metadata: &mut WorkerMetadata, active: Option<WorkerActiveSegmentRef>) {
-    if let Some(session_id) = active.as_ref().map(|active| active.session_id)
-        && metadata
-            .subjektiv_session_attribution
-            .as_ref()
-            .is_some_and(|state| state.session_id() != session_id)
-    {
-        metadata.subjektiv_session_attribution = None;
-    }
-    metadata.active = active;
-}
-
 /// Sync persistence backend for Worker metadata.
 pub trait WorkerMetadataStore: Send + Sync {
     /// Create or replace metadata for its `worker_name` key.
@@ -297,7 +285,7 @@ pub trait WorkerMetadataStore: Send + Sync {
         workspace_root: Option<PathBuf>,
     ) -> Result<WorkerMetadata, WorkerStoreError> {
         self.update_by_name(worker_name, |metadata| {
-            replace_active_session(metadata, active);
+            metadata.active = active;
             metadata.resolved_manifest_snapshot = resolved_manifest_snapshot;
             if let Some(workspace_id) = workspace_id {
                 metadata.workspace_id = Some(workspace_id);
@@ -317,7 +305,7 @@ pub trait WorkerMetadataStore: Send + Sync {
         workspace_id: Option<String>,
     ) -> Result<WorkerMetadata, WorkerStoreError> {
         self.update_by_name(worker_name, |metadata| {
-            replace_active_session(metadata, active);
+            metadata.active = active;
             metadata.resolved_manifest_snapshot = resolved_manifest_snapshot;
             if let Some(workspace_id) = workspace_id {
                 metadata.workspace_id = Some(workspace_id);
@@ -334,7 +322,7 @@ pub trait WorkerMetadataStore: Send + Sync {
         workspace_root: Option<PathBuf>,
     ) -> Result<WorkerMetadata, WorkerStoreError> {
         self.update_by_name(worker_name, |metadata| {
-            replace_active_session(metadata, active);
+            metadata.active = active;
             metadata.resolved_manifest_snapshot = resolved_manifest_snapshot;
             if let Some(workspace_root) = workspace_root {
                 metadata.workspace_root = Some(workspace_root);
@@ -342,18 +330,6 @@ pub trait WorkerMetadataStore: Send + Sync {
         })
     }
 
-    /// Set the Host-owned Subjektiv Session attribution lifecycle state while
-    /// preserving the active Session pointer and every unrelated field.
-    fn set_subjektiv_session_attribution(
-        &self,
-        worker_name: &str,
-        state: SubjektivSessionAttributionState,
-    ) -> Result<WorkerMetadata, WorkerStoreError> {
-        self.update_by_name(worker_name, |metadata| {
-            metadata.subjektiv_session_attribution = Some(state);
-        })
-    }
-
     /// Set spawned-child registry state while preserving active pointer and manifest snapshot.
     fn set_spawned_children(
         &self,
@@ -1087,13 +1063,13 @@ mod tests {
             ))
             .unwrap();
         store
-            .set_subjektiv_session_attribution(
-                "subject-worker",
-                SubjektivSessionAttributionState::OutcomeUnknown {
-                    session_id,
-                    diagnostic: "request interrupted".to_string(),
-                },
-            )
+            .update_by_name("subject-worker", |metadata| {
+                metadata.subjektiv_session_attribution =
+                    Some(SubjektivSessionAttributionState::OutcomeUnknown {
+                        session_id,
+                        diagnostic: "request interrupted".to_string(),
+                    });
+            })
             .unwrap();
         store
             .set_active(
@@ -1117,7 +1093,7 @@ mod tests {
     }
 
     #[test]
-    fn new_active_session_clears_prior_session_attribution_state() {
+    fn generic_active_update_does_not_interpret_host_attribution() {
         let tmp = tempfile::TempDir::new().unwrap();
         let store = FsWorkerStore::new(tmp.path()).unwrap();
         let old_session_id = crate::new_session_id();
@@ -1129,13 +1105,13 @@ mod tests {
             ))
             .unwrap();
         store
-            .set_subjektiv_session_attribution(
-                "subject-worker",
-                SubjektivSessionAttributionState::Confirmed {
-                    session_id: old_session_id,
-                    subject_id: "subject-1".to_string(),
-                },
-            )
+            .update_by_name("subject-worker", |metadata| {
+                metadata.subjektiv_session_attribution =
+                    Some(SubjektivSessionAttributionState::Confirmed {
+                        session_id: old_session_id,
+                        subject_id: "subject-1".to_string(),
+                    });
+            })
             .unwrap();
 
         store
@@ -1151,7 +1127,9 @@ mod tests {
             restored.active,
             Some(WorkerActiveSegmentRef::pending_segment(new_session_id))
         );
-        assert!(restored.subjektiv_session_attribution.is_none());
+        assert!(
+            matches!(restored.subjektiv_session_attribution, Some(SubjektivSessionAttributionState::Confirmed { session_id, .. }) if session_id == old_session_id)
+        );
     }
 
     #[test]

crates/session-store/src/worker_session_store.rs

@@ -36,7 +36,9 @@ use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 use std::time::SystemTime;
 
-const SESSION_SCHEMA_VERSION: u32 = 4;
+const SESSION_SCHEMA_VERSION: u32 = 6;
+const SYSTEM_INPUT_SESSION_SCHEMA_VERSION: u32 = 5;
+const COMPACTION_SESSION_SCHEMA_VERSION: u32 = 4;
 const ANNOTATED_SESSION_SCHEMA_VERSION: u32 = 3;
 const PREVIOUS_SESSION_SCHEMA_VERSION: u32 = 2;
 const LEGACY_SESSION_SCHEMA_VERSION: u32 = 1;
@@ -204,7 +206,15 @@ impl WorkerSessionStore {
 
     /// Open the Session store rooted at `<worker-aggregate>/session`.
     pub fn new(root: impl Into<PathBuf>) -> Result<Self, StoreError> {
-        let root = root.into();
+        Self::new_with_migration_writer(root.into(), atomic_write_bytes)
+    }
+
+    // Keep fault injection at the storage publication boundary, without global
+    // flags or a public alternate restore API. Production always uses atomic writes.
+    fn new_with_migration_writer(
+        root: PathBuf,
+        write_segment: impl FnMut(&Path, &[u8]) -> Result<(), StoreError>,
+    ) -> Result<Self, StoreError> {
         fs::create_dir_all(root.join(SEGMENTS_DIR))?;
         let session_id = match fs::read(root.join(SESSION_FILE)) {
             Ok(bytes) => {
@@ -215,11 +225,14 @@ impl WorkerSessionStore {
                     }
                     LEGACY_SESSION_SCHEMA_VERSION
                     | PREVIOUS_SESSION_SCHEMA_VERSION
-                    | ANNOTATED_SESSION_SCHEMA_VERSION => {
-                        migrate_segment_logs_to_v4(
+                    | ANNOTATED_SESSION_SCHEMA_VERSION
+                    | COMPACTION_SESSION_SCHEMA_VERSION
+                    | SYSTEM_INPUT_SESSION_SCHEMA_VERSION => {
+                        migrate_segment_logs_to_current(
                             segment_log_paths(&root)?,
                             manifest.session_id,
                             manifest.schema_version,
+                            write_segment,
                         )?;
                         manifest.schema_version = SESSION_SCHEMA_VERSION;
                         atomic_write_json(&root.join(SESSION_FILE), &manifest)?;
@@ -246,6 +259,33 @@ impl WorkerSessionStore {
         })
     }
 
+    /// Validate an existing Session's conversion without publishing any bytes.
+    /// Hosts can isolate unreadable archives before admitting a staged migration;
+    /// the versioned decoder and conversion checks remain owned by this store.
+    pub fn validate_migration(root: &Path) -> Result<(), StoreError> {
+        let manifest: SessionManifest =
+            serde_json::from_slice(&fs::read(root.join(SESSION_FILE))?)?;
+        match manifest.schema_version {
+            SESSION_SCHEMA_VERSION => validate_canonical_segment_logs(root),
+            LEGACY_SESSION_SCHEMA_VERSION
+            | PREVIOUS_SESSION_SCHEMA_VERSION
+            | ANNOTATED_SESSION_SCHEMA_VERSION
+            | COMPACTION_SESSION_SCHEMA_VERSION
+            | SYSTEM_INPUT_SESSION_SCHEMA_VERSION => migrate_segment_logs_to_current(
+                segment_log_paths(root)?,
+                manifest.session_id,
+                manifest.schema_version,
+                |_, _| Ok(()),
+            ),
+            version => Err(StoreError::Corrupt {
+                line: 0,
+                message: format!(
+                    "unsupported Worker Session schema version {version}, expected {SESSION_SCHEMA_VERSION}"
+                ),
+            }),
+        }
+    }
+
     /// Open an already-retained Session without creating directories or migrating
     /// persisted data. Observation paths must never mutate retained state.
     pub fn open_read_only(root: impl Into<PathBuf>) -> Result<Self, StoreError> {
@@ -742,6 +782,7 @@ impl Store for WorkerSessionStore {
         segment_id: SegmentId,
         entry: &LogEntry,
     ) -> Result<(), StoreError> {
+        entry.validate_input_metadata()?;
         let _retention = self.lock_publication(session_id)?;
         self.ensure_session(session_id, true)?;
         self.append_log_entry(&self.log_path(segment_id), entry)
@@ -800,6 +841,9 @@ impl Store for WorkerSessionStore {
         segment_id: SegmentId,
         entries: &[LogEntry],
     ) -> Result<(), StoreError> {
+        for entry in entries {
+            entry.validate_input_metadata()?;
+        }
         let _retention = self.lock_publication(session_id)?;
         self.ensure_session(session_id, true)?;
         let mut content = Vec::new();
@@ -1158,10 +1202,11 @@ fn segment_log_paths_in_directory(
     Ok(paths)
 }
 
-fn migrate_segment_logs_to_v4(
+fn migrate_segment_logs_to_current(
     paths: Vec<(SegmentId, PathBuf)>,
     session_id: SessionId,
     source_schema_version: u32,
+    mut write_segment: impl FnMut(&Path, &[u8]) -> Result<(), StoreError>,
 ) -> Result<(), StoreError> {
     struct MigrationPlan {
         path: PathBuf,
@@ -1192,12 +1237,19 @@ fn migrate_segment_logs_to_v4(
     }
     // Resolve trusted creation boundaries first, then update inherited copies by
     // logical identity too (fork/rewind seeds retain the same entry id).
-    let summaries = crate::legacy_session_log::compaction_summary_ids(
-        plans.iter().flat_map(|plan| plan.entries.iter()),
-    );
+    let summaries = if source_schema_version < COMPACTION_SESSION_SCHEMA_VERSION {
+        crate::legacy_session_log::compaction_summary_ids(
+            plans.iter().flat_map(|plan| plan.entries.iter()),
+        )
+    } else {
+        // v4 already made the explicit origin migration. Preserve its origins.
+        Default::default()
+    };
     for plan in &mut plans {
         crate::legacy_session_log::migrate_compaction_origins(&mut plan.entries, &summaries);
-        for entry in std::mem::take(&mut plan.entries) {
+        for mut entry in std::mem::take(&mut plan.entries) {
+            crate::legacy_session_log::migrate_system_inputs(&mut entry)?;
+            entry.validate_input_metadata()?;
             serde_json::to_writer(&mut plan.output, &entry)?;
             plan.output.push(b'\n');
         }
@@ -1219,7 +1271,7 @@ fn migrate_segment_logs_to_v4(
     }
 
     for plan in plans {
-        atomic_write_bytes(&plan.path, &plan.output)?;
+        write_segment(&plan.path, &plan.output)?;
     }
     Ok(())
 }
@@ -1236,9 +1288,20 @@ pub(crate) fn migrate_fs_session(root: &Path, session_id: SessionId) -> Result<(
         Err(error) => return Err(error.into()),
     };
     match version {
-        SESSION_SCHEMA_VERSION => Ok(()),
-        ANNOTATED_SESSION_SCHEMA_VERSION => {
-            migrate_segment_logs_to_v4(segment_log_paths_in_directory(root)?, session_id, version)?;
+        SESSION_SCHEMA_VERSION => {
+            validate_canonical_segment_paths(segment_log_paths_in_directory(root)?)
+        }
+        LEGACY_SESSION_SCHEMA_VERSION
+        | PREVIOUS_SESSION_SCHEMA_VERSION
+        | ANNOTATED_SESSION_SCHEMA_VERSION
+        | COMPACTION_SESSION_SCHEMA_VERSION
+        | SYSTEM_INPUT_SESSION_SCHEMA_VERSION => {
+            migrate_segment_logs_to_current(
+                segment_log_paths_in_directory(root)?,
+                session_id,
+                version,
+                atomic_write_bytes,
+            )?;
             atomic_write_json(&marker, &SESSION_SCHEMA_VERSION)
         }
         _ => Err(StoreError::Corrupt {
@@ -1249,8 +1312,15 @@ pub(crate) fn migrate_fs_session(root: &Path, session_id: SessionId) -> Result<(
 }
 
 fn validate_canonical_segment_logs(root: &Path) -> Result<(), StoreError> {
-    for (_, path) in segment_log_paths(root)? {
-        let _: Vec<LogEntry> = parse_jsonl(&fs::read(&path)?)?;
+    validate_canonical_segment_paths(segment_log_paths(root)?)
+}
+
+fn validate_canonical_segment_paths(paths: Vec<(SegmentId, PathBuf)>) -> Result<(), StoreError> {
+    for (_, path) in paths {
+        let entries: Vec<LogEntry> = parse_jsonl(&fs::read(&path)?)?;
+        for entry in entries {
+            entry.validate_input_metadata()?;
+        }
     }
     Ok(())
 }
@@ -1430,6 +1500,7 @@ mod tests {
         LoggedHistoryEntry {
             item: LoggedItem::from(item),
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId::new(),
                 origin: LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,
@@ -2017,6 +2088,146 @@ mod tests {
         );
     }
 
+    #[test]
+    fn v5_migration_retries_after_second_file_publication_fails() {
+        fn identity_and_body(entries: &[LogEntry]) -> Vec<serde_json::Value> {
+            entries
+                .iter()
+                .flat_map(|record| match record {
+                    LogEntry::AnnotatedSystemItem { entry, .. } => vec![entry.to_history_entry()],
+                    LogEntry::AnnotatedUserInput { history, .. } => history.clone(),
+                    _ => panic!("unexpected record in fixed migration fixture"),
+                })
+                .map(|entry| {
+                    serde_json::json!({
+                        "entry_id": entry.metadata.entry_id,
+                        "origin": entry.metadata.origin,
+                        "derivation": entry.metadata.derivation,
+                        "item": entry.item,
+                    })
+                })
+                .collect()
+        }
+
+        const SOURCE: &str =
+            include_str!("legacy_session_log/tests/fixtures/v4-system-inputs.jsonl");
+        let root = tempfile::tempdir().unwrap();
+        let session_id = new_session_id();
+        let first_id = SegmentId::from_u128(1);
+        let second_id = SegmentId::from_u128(2);
+        fs::create_dir_all(root.path().join(SEGMENTS_DIR)).unwrap();
+        let marker_path = root.path().join(SESSION_FILE);
+        atomic_write_json(
+            &marker_path,
+            &SessionManifest {
+                schema_version: COMPACTION_SESSION_SCHEMA_VERSION,
+                session_id,
+            },
+        )
+        .unwrap();
+        let old_marker = fs::read(&marker_path).unwrap();
+        let first_path = root
+            .path()
+            .join(SEGMENTS_DIR)
+            .join(format!("{first_id}.jsonl"));
+        let second_path = root
+            .path()
+            .join(SEGMENTS_DIR)
+            .join(format!("{second_id}.jsonl"));
+        let second_source = SOURCE.replace("-id", "-second-id");
+        fs::write(&first_path, SOURCE).unwrap();
+        fs::write(&second_path, &second_source).unwrap();
+        let old_first = fs::read(&first_path).unwrap();
+        let old_second = fs::read(&second_path).unwrap();
+        let first_identity =
+            identity_and_body(&parse_legacy_jsonl(4, session_id, first_id, &old_first).unwrap());
+        let second_identity =
+            identity_and_body(&parse_legacy_jsonl(4, session_id, second_id, &old_second).unwrap());
+
+        let mut writes = 0;
+        let mut first_published = None;
+        let failure = WorkerSessionStore::new_with_migration_writer(
+            root.path().to_path_buf(),
+            |path, bytes| {
+                writes += 1;
+                match writes {
+                    1 => {
+                        assert_eq!(path, first_path.as_path());
+                        // Both files are still old when the first publication starts.
+                        assert_eq!(fs::read(&first_path).unwrap(), old_first);
+                        assert_eq!(fs::read(&second_path).unwrap(), old_second);
+                        atomic_write_bytes(path, bytes)?;
+                        first_published = Some(bytes.to_vec());
+                        Ok(())
+                    }
+                    2 => {
+                        assert_eq!(path, second_path.as_path());
+                        assert_eq!(
+                            fs::read(&first_path).unwrap(),
+                            *first_published.as_ref().unwrap()
+                        );
+                        assert_eq!(fs::read(&second_path).unwrap(), old_second);
+                        // Fail only this atomic-write boundary, after complete
+                        // preflight and a real successful first-file publication.
+                        Err(std::io::Error::other("injected second migration write failure").into())
+                    }
+                    _ => panic!("publication continued after its write failure"),
+                }
+            },
+        );
+        let error = match failure {
+            Ok(_) => panic!("the injected publication failure must reject store open"),
+            Err(error) => error,
+        };
+        assert!(
+            error
+                .to_string()
+                .contains("injected second migration write failure")
+        );
+        assert_eq!(writes, 2);
+        let first_published = first_published.unwrap();
+        assert_ne!(first_published, old_first);
+        assert_eq!(fs::read(&first_path).unwrap(), first_published);
+        assert_eq!(fs::read(&second_path).unwrap(), old_second);
+        assert_eq!(fs::read(&marker_path).unwrap(), old_marker);
+        let updated_first: Vec<LogEntry> = parse_jsonl(&first_published).unwrap();
+        for entry in &updated_first {
+            entry.validate_input_metadata().unwrap();
+        }
+        assert!(matches!(
+            &updated_first[0],
+            LogEntry::AnnotatedSystemItem {
+                entry: crate::LoggedSystemHistoryEntry {
+                    item: crate::SystemItem::Input { .. },
+                    ..
+                },
+                ..
+            }
+        ));
+        assert_eq!(identity_and_body(&updated_first), first_identity);
+
+        // Retry via the public production constructor, without any injection or
+        // hand-built mixed fixture. The old marker drives the same migration.
+        let store = WorkerSessionStore::new(root.path()).unwrap();
+        let first = store.read_all(session_id, first_id).unwrap();
+        let second = store.read_all(session_id, second_id).unwrap();
+        assert_eq!(identity_and_body(&first), first_identity);
+        assert_eq!(identity_and_body(&second), second_identity);
+        for entry in first.iter().chain(second.iter()) {
+            entry.validate_input_metadata().unwrap();
+        }
+        assert_eq!(fs::read(&first_path).unwrap(), first_published);
+        let second_published = fs::read(&second_path).unwrap();
+        assert_ne!(second_published, old_second);
+        let manifest: SessionManifest =
+            serde_json::from_slice(&fs::read(&marker_path).unwrap()).unwrap();
+        assert_eq!(manifest.schema_version, SESSION_SCHEMA_VERSION);
+        drop(store);
+        WorkerSessionStore::new(root.path()).unwrap();
+        assert_eq!(fs::read(&first_path).unwrap(), first_published);
+        assert_eq!(fs::read(&second_path).unwrap(), second_published);
+    }
+
     #[test]
     fn current_jsonl_requires_annotations_across_append_rewrite_and_reopen() {
         let root = tempfile::tempdir().unwrap();

crates/session-store/tests/fs_store_test.rs

@@ -11,6 +11,7 @@ fn annotated(item: Item) -> LoggedHistoryEntry {
     LoggedHistoryEntry {
         item: LoggedItem::from(item),
         metadata: LoggedSessionHistoryMetadata {
+            input_metadata: None,
             entry_id: LoggedSessionHistoryEntryId::new(),
             origin: LoggedSessionHistoryOrigin::LegacyUnknown,
             derivation: None,
@@ -421,3 +422,177 @@ fn lookup_session_of_finds_owning_session() {
 
     assert_eq!(store.lookup_session_of(segid).unwrap(), Some(sid));
 }
+
+// Storage/projection component test: both production layouts, temporary originals,
+// no Feature, model, runtime or Host authority is substituted into this boundary.
+#[test]
+fn generic_system_append_and_fork_preserve_metadata_without_public_payload_leak() {
+    use session_store::{
+        FeatureInputPayload, HistoryInputMetadata, HistoryInputUsePolicy, InputCompactionUse,
+        InputEvidenceUse, InputObservationUse, LoggedHistoryDerivation, LoggedSystemHistoryEntry,
+        PublicSystemItem, PublicSystemPresentation, SystemInputEnvelope, WorkerSessionStore,
+    };
+    for worker_layout in [false, true] {
+        let dir = tempfile::tempdir().unwrap();
+        let sid = new_session_id();
+        let segment = new_segment_id();
+        let fork = new_segment_id();
+        let store: Box<dyn Store> = if worker_layout {
+            Box::new(WorkerSessionStore::new(dir.path()).unwrap())
+        } else {
+            Box::new(FsStore::new(dir.path()).unwrap())
+        };
+        store
+            .create_segment(sid, segment, &[nil_session_start(1, sid)])
+            .unwrap();
+        let entry = LoggedSystemHistoryEntry::from_input(
+            LoggedSessionHistoryOrigin::Provided {
+                producer: "new-feature".into(),
+            },
+            Some(LoggedHistoryDerivation {
+                sources: vec![LoggedSessionHistoryEntryId("source-entry".into())],
+            }),
+            SystemInputEnvelope::new(
+                "private model body",
+                HistoryInputMetadata::new(
+                    HistoryInputUsePolicy {
+                        recording_material: InputEvidenceUse::Exclude,
+                        memory_evidence: InputEvidenceUse::Exclude,
+                        observation: InputObservationUse::Hidden,
+                        compaction: InputCompactionUse::ReferenceInput,
+                    },
+                    Some(
+                        FeatureInputPayload::encode(
+                            "new-feature:context",
+                            101,
+                            &serde_json::json!({"private": "secret-detail"}),
+                        )
+                        .unwrap(),
+                    ),
+                    Some(PublicSystemItem {
+                        kind: "context".into(),
+                        body: "explicit public body".into(),
+                        presentation: PublicSystemPresentation::Context,
+                    }),
+                )
+                .unwrap(),
+            )
+            .unwrap(),
+        );
+        store
+            .append(
+                sid,
+                segment,
+                &LogEntry::AnnotatedSystemItem {
+                    ts: 2,
+                    entry: entry.clone(),
+                    extensions: vec![],
+                },
+            )
+            .unwrap();
+        let saved = store.read_all(sid, segment).unwrap();
+        let LogEntry::AnnotatedSystemItem {
+            entry: restored, ..
+        } = &saved[1]
+        else {
+            panic!("missing system input")
+        };
+        assert_eq!(restored.to_history_entry(), entry.to_history_entry());
+        assert_eq!(
+            collect_state(&saved).history[0].as_text(),
+            Some("private model body")
+        );
+        let mut fork_seed = nil_session_start(3, sid);
+        if let LogEntry::AnnotatedSegmentStart {
+            history,
+            forked_from,
+            ..
+        } = &mut fork_seed
+        {
+            history.push(restored.to_history_entry());
+            *forked_from = Some(session_store::SegmentOrigin {
+                segment_id: segment,
+                at_turn_index: 0,
+            });
+        }
+        store.create_segment(sid, fork, &[fork_seed]).unwrap();
+        let fork_saved = store.read_all(sid, fork).unwrap();
+        let LogEntry::AnnotatedSegmentStart { history, .. } = &fork_saved[0] else {
+            unreachable!()
+        };
+        assert_eq!(history, &[entry.to_history_entry()]);
+        let original = session_store::public_snapshot::project_session_snapshot(sid, &saved);
+        let inherited = session_store::public_snapshot::project_session_snapshot(sid, &fork_saved);
+        let public = serde_json::to_string(&original.entries).unwrap();
+        assert!(public.contains("explicit public body"));
+        for private in ["private model body", "secret-detail", "new-feature:context"] {
+            assert!(!public.contains(private), "private field leaked: {private}");
+        }
+        assert_eq!(original.entries.len(), 1);
+        assert_eq!(inherited.entries.len(), 1);
+        assert_eq!(original.entries[0].entry_id, inherited.entries[0].entry_id);
+        assert_eq!(
+            original.entries[0].derived_from,
+            inherited.entries[0].derived_from
+        );
+        assert_eq!(
+            original.entries[0].provenance,
+            inherited.entries[0].provenance
+        );
+        assert_eq!(
+            serde_json::to_value(&original.entries[0].data).unwrap(),
+            serde_json::to_value(&inherited.entries[0].data).unwrap()
+        );
+    }
+}
+
+#[test]
+fn invalid_generic_system_input_rejects_append_create_and_external_json_without_changing_originals()
+{
+    use session_store::{StoreError, SystemItem, WorkerSessionStore};
+    for worker_layout in [false, true] {
+        let dir = tempfile::tempdir().unwrap();
+        let sid = new_session_id();
+        let segment = new_segment_id();
+        let store: Box<dyn Store> = if worker_layout {
+            Box::new(WorkerSessionStore::new(dir.path()).unwrap())
+        } else {
+            Box::new(FsStore::new(dir.path()).unwrap())
+        };
+        let seed = nil_session_start(1, sid);
+        store
+            .create_segment(sid, segment, std::slice::from_ref(&seed))
+            .unwrap();
+        let path = if worker_layout {
+            dir.path().join("segments").join(format!("{segment}.jsonl"))
+        } else {
+            dir.path()
+                .join(sid.to_string())
+                .join(format!("{segment}.jsonl"))
+        };
+        let before = std::fs::read(&path).unwrap();
+        let invalid = LogEntry::AnnotatedSystemItem {
+            ts: 2,
+            extensions: vec![],
+            entry: session_store::LoggedSystemHistoryEntry {
+                item: SystemItem::Input {
+                    body: "no policy".into(),
+                },
+                metadata: LoggedSessionHistoryMetadata::legacy_unknown(),
+            },
+        };
+        assert!(matches!(
+            store.append(sid, segment, &invalid),
+            Err(StoreError::InvalidInputMetadata(_))
+        ));
+        assert!(matches!(
+            store.create_segment(sid, segment, &[seed, invalid.clone()]),
+            Err(StoreError::InvalidInputMetadata(_))
+        ));
+        assert!(
+            serde_json::from_value::<LogEntry>(serde_json::to_value(invalid).unwrap()).is_err()
+        );
+        assert_eq!(std::fs::read(path).unwrap(), before);
+        assert_eq!(store.read_all(sid, segment).unwrap().len(), 1);
+    }
+}

crates/session-store/tests/session_test.rs

@@ -24,6 +24,7 @@ fn annotated(items: &[Item]) -> Vec<session_store::LoggedHistoryEntry> {
         .map(|item| session_store::LoggedHistoryEntry {
             item: session_store::LoggedItem::from(item),
             metadata: session_store::LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: session_store::LoggedSessionHistoryEntryId::new(),
                 origin: session_store::LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,

crates/standalone/src/host.rs

@@ -23,9 +23,7 @@ use session_store::{
     CombinedStore, FsStore, FsWorkerStore, WorkerActiveSegmentRef, WorkerMetadataStore,
 };
 use thiserror::Error;
-use worker::bootstrap::{
-    WorkerBootstrap, WorkerBootstrapError, WorkerBootstrapLayout, bash_output_dir_for_worker_id,
-};
+use worker::bootstrap::{WorkerBootstrap, WorkerBootstrapError, WorkerBootstrapLayout};
 use worker::controller::WorkerControllerTransport;
 use worker::ipc::protocol_session::{
     WorkerProtocolSessionStreams, dispatch_worker_protocol_method, live_log_entry_event,
@@ -216,7 +214,6 @@ impl StandaloneHost {
             WorkerFilesystemAuthority::local(launch.cwd.clone(), launch.cwd.clone());
         let workspace_context = WorkerWorkspaceContext::local_filesystem(None);
         let runtime_base = store.runtime_dir(worker_id);
-        let bash_output_dir = bash_output_dir_for_worker_id(worker_id);
 
         let mut bootstrap = WorkerBootstrap::new(
             bootstrap_manifest,
@@ -224,10 +221,7 @@ impl StandaloneHost {
             launch.prompt_catalog,
             workspace_context,
             filesystem_authority,
-            WorkerBootstrapLayout::Direct {
-                runtime_base,
-                bash_output_dir,
-            },
+            WorkerBootstrapLayout::Direct { runtime_base },
             WorkerControllerTransport::InProcess,
         );
         if let Some(subject) = &subject {
@@ -428,7 +422,6 @@ impl StandaloneHost {
         );
         let workspace_context = WorkerWorkspaceContext::local_filesystem(None);
         let runtime_base = store.runtime_dir(worker_id);
-        let bash_output_dir = bash_output_dir_for_worker_id(worker_id);
 
         let mut bootstrap = WorkerBootstrap::new(
             manifest,
@@ -436,10 +429,7 @@ impl StandaloneHost {
             worker::PromptCatalogSource::builtins_only(),
             workspace_context,
             filesystem_authority,
-            WorkerBootstrapLayout::Direct {
-                runtime_base,
-                bash_output_dir,
-            },
+            WorkerBootstrapLayout::Direct { runtime_base },
             WorkerControllerTransport::InProcess,
         );
         if let Some(subject) = &subject {

crates/standalone/src/subjektiv/journal/tests.rs

@@ -212,6 +212,7 @@ fn message(id: &str, text: &str) -> session_store::LoggedHistoryEntry {
             content: vec![session_store::LoggedContentPart::Text { text: text.into() }],
         },
         metadata: session_store::LoggedSessionHistoryMetadata {
+            input_metadata: None,
             entry_id: session_store::LoggedSessionHistoryEntryId(id.into()),
             origin: session_store::LoggedSessionHistoryOrigin::LocalHumanInput,
             derivation: None,

crates/standalone/src/subjektiv/journal/tests/compaction.rs

@@ -215,6 +215,7 @@ async fn public_mid_turn_compactions_preserve_originals_and_drain_after_cancel_a
                 }
                 protocol::Event::TextDelta { text } if text.contains(PARTIAL) => break,
                 protocol::Event::RunEnd { .. } => panic!("dialog ended before cancellation"),
+                protocol::Event::SessionEntryCommitted { entry } if matches!(entry.data, protocol::SessionSnapshotEntryData::RunError { .. }) => panic!("dialog failed before cancellation: {entry:?}"),
                 protocol::Event::Error { code, message } => panic!("{code:?}: {message}"),
                 _ => {}
             }
@@ -294,6 +295,32 @@ async fn public_mid_turn_compactions_preserve_originals_and_drain_after_cancel_a
             .iter()
             .flat_map(|segment| source_store.read_all(session, *segment).unwrap())
             .collect();
+        for history in raw.iter().filter_map(|record| match record {
+            session_store::LogEntry::AnnotatedSegmentStart { history, compacted_from: Some(_), .. } => Some(history),
+            _ => None,
+        }) {
+            let mut calls = std::collections::HashSet::new();
+            let mut results = 0;
+            for entry in history {
+                let is_tool = matches!(entry.item, session_store::LoggedItem::ToolCall { .. } | session_store::LoggedItem::ToolResult { .. });
+                let Some(metadata) = entry.metadata.input_metadata.as_ref().filter(|_| is_tool) else { continue; };
+                assert_eq!(metadata.usage().recording_material, session_store::InputEvidenceUse::Exclude);
+                assert_eq!(metadata.usage().memory_evidence, session_store::InputEvidenceUse::Exclude);
+                assert_eq!(metadata.usage().observation, session_store::InputObservationUse::Hidden);
+                assert!(metadata.public_item().is_none());
+                assert!(entry.metadata.derivation.is_some());
+                match &entry.item {
+                    session_store::LoggedItem::ToolCall { call_id, .. } => { calls.insert(call_id.clone()); }
+                    session_store::LoggedItem::ToolResult { call_id, .. } => {
+                        assert!(calls.contains(call_id), "derived Tool result must follow its real logical call");
+                        results += 1;
+                    }
+                    _ => unreachable!(),
+                }
+            }
+            assert!(!calls.is_empty());
+            assert!(results >= calls.len());
+        }
         assert_eq!(
             raw.iter()
                 .filter(|entry| matches!(

crates/standalone/src/subjektiv/journal/tests/connected_compaction.rs

@@ -11,7 +11,7 @@ use agen::llm_client::{
     types::Item,
 };
 use futures::Stream;
-use session_store::{CombinedStore, FsWorkerStore, LogEntry, LoggedSessionHistoryOrigin};
+use session_store::{CombinedStore, FsWorkerStore, LogEntry};
 use std::pin::Pin;
 
 const BEFORE: &str = "FROZEN_POSITION: B partially implemented; tests not run; result unconfirmed";
@@ -126,7 +126,7 @@ async fn local_host_compaction_freezes_pending_journal_through_request_and_durab
             worker::PromptCatalogSource::builtins_only(),
             worker::WorkerWorkspaceContext::no_workspace(),
             worker::WorkerFilesystemAuthority::None,
-            worker::WorkerBootstrapLayout::Direct { runtime_base: fixture._temp.path().join("runtime"), bash_output_dir: fixture._temp.path().join("bash") },
+            worker::WorkerBootstrapLayout::Direct { runtime_base: fixture._temp.path().join("runtime") },
             worker::WorkerControllerTransport::InProcess,
         ).with_model_client(model.clone()).with_subjektiv_host(fixture.host().clone()).prepare_restored("journal-test").await.unwrap();
         assert_eq!(prepared.worker().session_id().to_string(), fixture.context.session_id);
@@ -139,14 +139,14 @@ async fn local_host_compaction_freezes_pending_journal_through_request_and_durab
         let worker = prepared.worker();
         assert_ne!(worker.segment_id(), source_segment);
         let seed = worker.store().read_all(worker.session_id(), worker.segment_id()).unwrap().into_iter().find_map(|entry| match entry { LogEntry::AnnotatedSegmentStart { history, .. } => Some(history), _ => None }).expect("durable compacted seed");
-        let journal_items: Vec<_> = seed.iter().filter(|entry| entry.metadata.origin == LoggedSessionHistoryOrigin::JournalContext).collect();
+        let journal_items: Vec<_> = seed.iter().filter(|entry| entry.metadata.input_metadata.as_ref().is_some_and(|input| input.usage().compaction == session_store::InputCompactionUse::ReferenceInput)).collect();
         assert_eq!(journal_items.len(), 1);
         let journal_item = Item::from(journal_items[0].item.clone());
         let body = journal_item.as_text().unwrap();
         assert!(body.contains(&expected_json), "durable seed contains the full selected JSON and processing checkpoint");
         assert!(body.contains(BEFORE));
         assert!(!body.contains(AFTER));
-        assert!(seed.iter().any(|entry| entry.metadata.origin == LoggedSessionHistoryOrigin::CompactionSummary && Item::from(entry.item.clone()).as_text().is_some_and(|text| text.contains(COMPLEMENT))));
+        assert!(seed.iter().any(|entry| entry.metadata.input_metadata.as_ref().is_some_and(|input| input.usage().compaction == session_store::InputCompactionUse::OpeningSummary) && Item::from(entry.item.clone()).as_text().is_some_and(|text| text.contains(COMPLEMENT))));
         let requests = model.requests.lock().unwrap();
         let input = requests[0].items.iter().find_map(|item| match item {
             Item::Message { role: agen::llm_client::types::Role::User, .. } => item.as_text().filter(|text| text.contains("## Conversation overview/index")),

crates/standalone/src/subjektiv/journal/tests/handoff.rs

@@ -79,7 +79,7 @@ async fn recorded_idle_body_handoff_preserves_open_after_source_deletion_and_see
         let sessions = session_store::FsStore::new_with_retention(workers.sessions_dir(second.worker_id()), crate::store::session_retention(&state)).unwrap();
         let pointer = session_store::FsWorkerStore::new(workers.worker_metadata_dir(second.worker_id())).unwrap().read_by_name(&second.record().storage_key).unwrap().unwrap().active.unwrap();
         let entries = sessions.read_all(session, pointer.segment_id.unwrap()).unwrap();
-        let journal_items = entries.iter().filter(|entry| matches!(entry, session_store::LogEntry::AnnotatedSystemItem { entry, .. } if matches!(entry.item, session_store::SystemItem::JournalStartup { .. }))).count();
+        let journal_items = entries.iter().filter(|entry| matches!(entry, session_store::LogEntry::AnnotatedSystemItem { entry, .. } if entry.metadata.input_metadata.as_ref().and_then(|input| input.feature_payload()).is_some_and(|payload| payload.schema() == "journal:startup"))).count();
         assert_eq!(journal_items, 1);
         assert_eq!(catalog.store.subject(&subject.id).unwrap().unwrap().behavior_md, "BEHAVIOR_ORIGINAL_UNCHANGED");
         second.shutdown().await.unwrap();

crates/standalone/src/subjektiv_sessions.rs

@@ -1621,6 +1621,7 @@ allow = []
         let history = |id: &str, item: LoggedItem| LoggedHistoryEntry {
             item,
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId(id.into()),
                 origin: LoggedSessionHistoryOrigin::BackendInstruction { operation_id: None },
                 derivation: None,

crates/subjektiv/src/api.rs

@@ -1299,6 +1299,14 @@ pub type OperationResult<T> = std::result::Result<T, OperationError>;
 
 pub fn subjektiv_store_error(error: crate::SubjektivError) -> OperationError {
     match error {
+        crate::SubjektivError::AuthorizationDenied(reason) => {
+            OperationError::PermissionDenied(reason)
+        }
+        crate::SubjektivError::SubjectPermissionsConflict(_)
+        | crate::SubjektivError::PermissionOperationConflict(_)
+        | crate::SubjektivError::WorkerExecutionGrantConflict(_) => {
+            OperationError::Conflict(error.to_string())
+        }
         crate::SubjektivError::SubjectScopeMismatch { .. } => {
             OperationError::PermissionDenied(format!("subject_scope_mismatch: {error}"))
         }

crates/subjektiv/src/journal/binding.rs

@@ -67,6 +67,27 @@ impl SubjektivStore {
         })
     }
 
+    /// Absence proof for failed body creation, including bindings never attached to a Session
+    /// and released lifetimes. The Host must hold its lifecycle fence across this observation
+    /// and recovery; absence alone does not fence a delayed Runtime create.
+    pub fn journal_body_is_unpublished(
+        &self,
+        subject: &str,
+        runtime: &str,
+        worker: &str,
+    ) -> JournalResult<bool> {
+        self.database.try_with_connection(|tx| {
+            Ok(tx.query_row(
+                "SELECT NOT EXISTS(SELECT 1 FROM journal_writer_bindings
+                   WHERE subject_id=?1 AND runtime_id=?2 AND worker_id=?3)
+                 AND NOT EXISTS(SELECT 1 FROM subject_session_attributions
+                   WHERE subject_id=?1 AND runtime_id=?2 AND worker_id=?3)",
+                params![subject, runtime, worker],
+                |row| row.get(0),
+            )?)
+        })
+    }
+
     pub fn journal_worker_was_released(
         &self,
         subject: &str,
@@ -203,3 +224,82 @@ impl SubjektivStore {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn unpublished_body_rejects_orphan_and_released_bindings_and_attribution_only() {
+        let temp = tempfile::tempdir().unwrap();
+        let (_manager, _workspace, store) = crate::tests::open_store(temp.path(), "absence-tests");
+        let subject = store
+            .create_subject(crate::SubjectRole::new("companion").unwrap())
+            .unwrap();
+        let other_subject = store
+            .create_subject(crate::SubjectRole::new("companion").unwrap())
+            .unwrap();
+        assert!(
+            store
+                .journal_body_is_unpublished(&subject.id, "runtime", "worker")
+                .unwrap()
+        );
+        // No Session was attached: an orphan binding is still published body evidence.
+        let binding = store
+            .claim_journal_writer(&subject.id, "runtime", "worker")
+            .unwrap();
+        assert!(
+            !store
+                .journal_body_is_unpublished(&subject.id, "runtime", "worker")
+                .unwrap()
+        );
+        for (subject_id, runtime, worker) in [
+            (other_subject.id.as_str(), "runtime", "worker"),
+            (subject.id.as_str(), "other-runtime", "worker"),
+            (subject.id.as_str(), "runtime", "other-worker"),
+        ] {
+            assert!(
+                store
+                    .journal_body_is_unpublished(subject_id, runtime, worker)
+                    .unwrap()
+            );
+        }
+        store.release_journal_writer(&binding).unwrap();
+        assert!(
+            !store
+                .journal_body_is_unpublished(&subject.id, "runtime", "worker")
+                .unwrap()
+        );
+        store
+            .record_session_attribution(
+                SubjectSessionAttribution::new(
+                    &subject.id,
+                    "runtime",
+                    "attribution-only",
+                    "session",
+                )
+                .unwrap(),
+            )
+            .unwrap();
+        assert!(
+            !store
+                .journal_body_is_unpublished(&subject.id, "runtime", "attribution-only")
+                .unwrap()
+        );
+        assert!(
+            store
+                .journal_body_is_unpublished(&subject.id, "other-runtime", "attribution-only")
+                .unwrap()
+        );
+        assert!(
+            store
+                .journal_body_is_unpublished(&other_subject.id, "runtime", "attribution-only")
+                .unwrap()
+        );
+        assert!(
+            store
+                .journal_body_is_unpublished(&subject.id, "runtime", "never-published")
+                .unwrap()
+        );
+    }
+}

crates/subjektiv/src/legacy_migrations.rs

@@ -929,7 +929,7 @@ mod tests {
         let (_manager, _workspace, store) = open_store(&root, "workspace-a");
         let migrated_subject = store.subject(&subject_id).unwrap().unwrap();
         assert!(migrated_subject.behavior_md.is_empty());
-        assert!(migrated_subject.behavior_md.is_empty());
+        assert!(store.subject_permissions(&subject_id).unwrap().is_none());
         let lifecycle_attribution = attribution(
             &subject_id,
             "runtime-1",

crates/subjektiv/src/lib.rs

@@ -4,6 +4,7 @@ pub mod api;
 pub mod job;
 pub mod journal;
 mod legacy_migrations;
+pub mod permissions;
 mod schema;
 use legacy_migrations::{
     add_candidate_decision_receipts, add_subject_behavior, add_subject_session_attribution,
@@ -82,6 +83,16 @@ pub enum SubjektivError {
     },
     #[error("subject `{subject_id}` behavior content changed")]
     SubjectBehaviorConflict { subject_id: String },
+    #[error("subject `{0}` permission source changed")]
+    SubjectPermissionsConflict(String),
+    #[error("permission operation `{0}` was reused with different input")]
+    PermissionOperationConflict(String),
+    #[error("authorization denied: {0}")]
+    AuthorizationDenied(String),
+    #[error("Worker execution grant binding conflicts for `{0}`")]
+    WorkerExecutionGrantConflict(String),
+    #[error("Subject `{subject_id}` has more than {limit} retained Worker execution grants")]
+    WorkerExecutionGrantListOverflow { subject_id: String, limit: usize },
     #[error("surface generation conflict: {0}")]
     SurfaceGenerationConflict(String),
     #[error("memory `{memory_id}` cannot transition from {from:?} to {to:?}")]
@@ -623,6 +634,11 @@ static MIGRATIONS: &[FeatureMigration] = &[
         "add immutable candidate Journal context links",
         journal::memory_links::migrate,
     ),
+    FeatureMigration::new(
+        12,
+        "add explicit Subject permission sources and immutable child execution grants",
+        permissions::migrate,
+    ),
 ];
 
 pub const REGISTRATION: FeatureRegistration =

crates/subjektiv/src/permissions.rs

@@ -0,0 +1,288 @@
+//! Host-administered permission sources and immutable child grants, separate from behavior.
+//!
+//! The Host authenticates administrators before source writes and binds verified Worker/Profile
+//! identities before grant writes. These records are not a Worker registry. The Host alone
+//! authenticates root execution ownership against its canonical Backend singleton and checks
+//! every live lineage edge; Journal bindings and retained grants cannot establish ownership.
+//! Replays return historical evidence without restoring a source or granting current authority.
+use super::*;
+use server_api::authorization::{
+    PermissionResource, ScopedPermission, SubjectPermissions, SubjectPermissionsUpdate,
+    WorkerExecutionGrant, validate_authorization_identifier, validate_scoped_permissions,
+};
+use sha2::{Digest, Sha256};
+
+pub const MAX_SUBJECT_WORKER_EXECUTION_GRANTS: usize = 1_000;
+
+pub(super) fn migrate(tx: &Transaction<'_>) -> feature_storage::Result<()> {
+    tx.execute_batch(include_str!("permissions.sql"))?;
+    Ok(())
+}
+
+impl SubjektivStore {
+    /// Unset sources are `None` (deny), including migrated Subjects. This is an admin read,
+    /// not an effective-authorization decision; retired Subjects retain their source evidence.
+    pub fn subject_permissions(&self, subject_id: &str) -> Result<Option<SubjectPermissions>> {
+        self.database.try_with_connection(|connection| {
+            require_subject_in_connection(connection, subject_id)?;
+            source_in_connection(connection, subject_id)
+        })
+    }
+
+    /// Host-admin-only replacement. Every replacement issues a fresh change ID, including
+    /// identical contents. Revocation is an explicit empty replacement. A scope-wide operation
+    /// ID binds Subject, CAS input, and both permission vectors; result and receipt commit together.
+    pub fn set_subject_permissions(
+        &self,
+        subject_id: &str,
+        update: &SubjectPermissionsUpdate,
+    ) -> Result<SubjectPermissions> {
+        validate_authorization_identifier(subject_id).map_err(SubjektivError::InvalidRecord)?;
+        validate_authorization_identifier(&update.operation_id)
+            .map_err(SubjektivError::InvalidRecord)?;
+        if let Some(change) = &update.expected_change_id {
+            validate_authorization_identifier(change).map_err(SubjektivError::InvalidRecord)?;
+        }
+        validate_scope(self.scope_id(), &update.execution)?;
+        validate_scope(self.scope_id(), &update.delegation)?;
+        let fingerprint: String = Sha256::digest(serde_json::to_vec(&(subject_id, update))?)
+            .iter()
+            .map(|byte| format!("{byte:02x}"))
+            .collect();
+        self.database.try_transaction(|tx| {
+            require_subject(tx, subject_id)?;
+            let receipt: Option<(String, String)> = tx.query_row(
+                "SELECT request_fingerprint, change_id FROM subject_permission_receipts WHERE operation_id=?1",
+                [&update.operation_id], |row| Ok((row.get(0)?, row.get(1)?)),
+            ).optional()?;
+            if let Some((saved, change_id)) = receipt {
+                if saved != fingerprint {
+                    return Err(SubjektivError::PermissionOperationConflict(update.operation_id.clone()));
+                }
+                let raw: String = tx.query_row(
+                    "SELECT record_json FROM subject_permission_changes WHERE subject_id=?1 AND change_id=?2",
+                    params![subject_id, change_id], |row| row.get(0),
+                )?;
+                return Ok(serde_json::from_str(&raw)?);
+            }
+            require_active_subject(tx, subject_id)?;
+            let current = source_in_connection(tx, subject_id)?;
+            if current.as_ref().map(|source| &source.change_id) != update.expected_change_id.as_ref() {
+                return Err(SubjektivError::SubjectPermissionsConflict(subject_id.into()));
+            }
+            let source = SubjectPermissions {
+                change_id: issued_id("permissions"),
+                execution: update.execution.clone(),
+                delegation: update.delegation.clone(),
+            };
+            tx.execute("INSERT INTO subject_permission_changes(subject_id,change_id,record_json) VALUES(?1,?2,?3)",
+                params![subject_id, source.change_id, serde_json::to_string(&source)?])?;
+            tx.execute("INSERT INTO subject_permissions(subject_id,change_id) VALUES(?1,?2) ON CONFLICT(subject_id) DO UPDATE SET change_id=excluded.change_id",
+                params![subject_id, source.change_id])?;
+            tx.execute("INSERT INTO subject_permission_receipts(operation_id,subject_id,request_fingerprint,change_id) VALUES(?1,?2,?3,?4)",
+                params![update.operation_id, subject_id, fingerprint, source.change_id])?;
+            Ok(source)
+        })
+    }
+
+    /// Binds child grants only. Exact retries recover an immutable binding even after revocation;
+    /// that success is not authorization to execute or redelegate. New bindings require the
+    /// current source, an active Subject and explicit delegation containment. The Host must
+    /// authenticate root singleton ownership and every live lineage edge before calling;
+    /// a missing retained parent is not ownership evidence. Profile resolution, provider scope,
+    /// Worker creation and caller authentication also remain Host duties.
+    pub fn bind_worker_execution_grant(&self, grant: &WorkerExecutionGrant) -> Result<()> {
+        validate_grant(self.scope_id(), grant)?;
+        self.database.try_transaction(|tx| {
+            if let Some(existing) = grant_in_connection(tx, &grant.runtime_id, &grant.worker_id)? {
+                return if existing == *grant { Ok(()) } else {
+                    Err(SubjektivError::WorkerExecutionGrantConflict(format!("{}/{}", grant.runtime_id, grant.worker_id)))
+                };
+            }
+            require_active_subject(tx, &grant.subject_id)?;
+            let source = source_in_connection(tx, &grant.subject_id)?
+                .ok_or_else(|| denied("Subject permissions are unset"))?;
+            if source.change_id != grant.source_change_id {
+                return Err(denied("Subject permission source is no longer current"));
+            }
+            require_covered(&source.delegation, &grant.permissions)?;
+            require_covered(&source.delegation, &grant.redelegation)?;
+            // A child grant cannot turn a body (including a released historical body) into a
+            // delegated child or attach a Worker historically attributed to a different Subject.
+            let invalid_target: bool = tx.query_row(
+                "SELECT EXISTS(SELECT 1 FROM journal_writer_bindings WHERE runtime_id=?1 AND worker_id=?2) OR EXISTS(SELECT 1 FROM subject_session_attributions WHERE runtime_id=?1 AND worker_id=?2 AND subject_id<>?3)",
+                params![grant.runtime_id, grant.worker_id, grant.subject_id], |row| row.get(0),
+            )?;
+            if invalid_target { return Err(denied("target is a body or belongs to another Subject")); }
+            let origin = require_retained_origin(tx, grant)?;
+            if let Some(origin) = origin {
+                require_covered(&origin.redelegation, &grant.permissions)?;
+                require_covered(&origin.redelegation, &grant.redelegation)?;
+            }
+            tx.execute("INSERT INTO worker_execution_grants(runtime_id,worker_id,subject_id,source_change_id,record_json) VALUES(?1,?2,?3,?4,?5)",
+                params![grant.runtime_id, grant.worker_id, grant.subject_id, grant.source_change_id, serde_json::to_string(grant)?])?;
+            Ok(())
+        })
+    }
+
+    /// Returns this Subject's retained grants, including stale grants needed for cancellation
+    /// and reporting. Never an ownership list or effective-authorization decision. Overflow is
+    /// explicit rather than silently omitting Workers from a cancellation/reporting pass.
+    pub fn list_subject_worker_execution_grants(
+        &self,
+        subject_id: &str,
+    ) -> Result<Vec<WorkerExecutionGrant>> {
+        validate_authorization_identifier(subject_id).map_err(SubjektivError::InvalidRecord)?;
+        self.database.try_with_connection(|connection| {
+            require_subject_in_connection(connection, subject_id)?;
+            let mut statement = connection.prepare(
+                "SELECT record_json FROM worker_execution_grants WHERE subject_id=?1 ORDER BY runtime_id,worker_id LIMIT ?2",
+            )?;
+            let mut rows = statement.query(params![subject_id, MAX_SUBJECT_WORKER_EXECUTION_GRANTS + 1])?;
+            let mut grants = Vec::new();
+            while let Some(row) = rows.next()? {
+                if grants.len() == MAX_SUBJECT_WORKER_EXECUTION_GRANTS {
+                    return Err(SubjektivError::WorkerExecutionGrantListOverflow {
+                        subject_id: subject_id.into(),
+                        limit: MAX_SUBJECT_WORKER_EXECUTION_GRANTS,
+                    });
+                }
+                grants.push(serde_json::from_str(&row.get::<_, String>(0)?)?);
+            }
+            Ok(grants)
+        })
+    }
+
+    /// Returns retained binding evidence, not current authorization. The Host must compare the
+    /// active Subject, source change, current origin ownership, Profile and provider constraints.
+    pub fn worker_execution_grant(
+        &self,
+        runtime: &str,
+        worker: &str,
+    ) -> Result<Option<WorkerExecutionGrant>> {
+        validate_authorization_identifier(runtime).map_err(SubjektivError::InvalidRecord)?;
+        validate_authorization_identifier(worker).map_err(SubjektivError::InvalidRecord)?;
+        self.database
+            .try_with_connection(|connection| grant_in_connection(connection, runtime, worker))
+    }
+}
+
+fn source_in_connection(
+    connection: &Connection,
+    subject: &str,
+) -> Result<Option<SubjectPermissions>> {
+    let raw: Option<String> = connection.query_row(
+        "SELECT c.record_json FROM subject_permissions p JOIN subject_permission_changes c ON c.subject_id=p.subject_id AND c.change_id=p.change_id WHERE p.subject_id=?1",
+        [subject], |row| row.get(0),
+    ).optional()?;
+    raw.map(|raw| serde_json::from_str(&raw).map_err(Into::into))
+        .transpose()
+}
+
+fn grant_in_connection(
+    connection: &Connection,
+    runtime: &str,
+    worker: &str,
+) -> Result<Option<WorkerExecutionGrant>> {
+    let raw: Option<String> = connection
+        .query_row(
+            "SELECT record_json FROM worker_execution_grants WHERE runtime_id=?1 AND worker_id=?2",
+            params![runtime, worker],
+            |row| row.get(0),
+        )
+        .optional()?;
+    raw.map(|raw| serde_json::from_str(&raw).map_err(Into::into))
+        .transpose()
+}
+
+fn validate_scope(scope: &str, permissions: &[ScopedPermission]) -> Result<()> {
+    validate_scoped_permissions(permissions).map_err(SubjektivError::InvalidRecord)?;
+    for permission in permissions {
+        if let PermissionResource::Workspace { workspace_id } = &permission.resource
+            && workspace_id != scope
+        {
+            return Err(denied("Workspace permission is outside this store scope"));
+        }
+    }
+    Ok(())
+}
+
+fn validate_grant(scope: &str, grant: &WorkerExecutionGrant) -> Result<()> {
+    for value in [
+        &grant.subject_id,
+        &grant.origin_runtime_id,
+        &grant.origin_worker_id,
+        &grant.source_change_id,
+        &grant.runtime_id,
+        &grant.worker_id,
+        &grant.profile,
+        &grant.profile_digest,
+    ] {
+        validate_authorization_identifier(value).map_err(SubjektivError::InvalidRecord)?;
+    }
+    if grant.origin_runtime_id == grant.runtime_id && grant.origin_worker_id == grant.worker_id {
+        return Err(denied("a child grant cannot originate from itself"));
+    }
+    validate_scope(scope, &grant.permissions)?;
+    validate_scope(scope, &grant.redelegation)
+}
+
+fn require_covered(ceiling: &[ScopedPermission], requested: &[ScopedPermission]) -> Result<()> {
+    if requested
+        .iter()
+        .all(|permission| ceiling.iter().any(|allowed| allowed.covers(permission)))
+    {
+        Ok(())
+    } else {
+        Err(denied(
+            "requested permission or redelegation exceeds its explicit ceiling",
+        ))
+    }
+}
+
+fn require_retained_origin(
+    tx: &Transaction<'_>,
+    grant: &WorkerExecutionGrant,
+) -> Result<Option<WorkerExecutionGrant>> {
+    let mut runtime = grant.origin_runtime_id.clone();
+    let mut worker = grant.origin_worker_id.clone();
+    let mut direct_origin = None;
+    let mut visited = HashSet::from([(grant.runtime_id.clone(), grant.worker_id.clone())]);
+    // Validate retained lineage only. Absence terminates at a Host-authenticated root;
+    // neither Journal active state nor absence of a grant proves current singleton ownership.
+    for _ in 0..64 {
+        if !visited.insert((runtime.clone(), worker.clone())) {
+            return Err(denied("cyclic grant origin"));
+        }
+        let foreign_attribution: bool = tx.query_row(
+            "SELECT EXISTS(SELECT 1 FROM journal_writer_bindings WHERE runtime_id=?1 AND worker_id=?2 AND subject_id<>?3) OR EXISTS(SELECT 1 FROM subject_session_attributions WHERE runtime_id=?1 AND worker_id=?2 AND subject_id<>?3)",
+            params![runtime, worker, grant.subject_id], |row| row.get(0),
+        )?;
+        if foreign_attribution {
+            return Err(denied("grant origin is attributed to another Subject"));
+        }
+        let Some(origin) = grant_in_connection(tx, &runtime, &worker)? else {
+            return Ok(direct_origin);
+        };
+        if origin.subject_id != grant.subject_id
+            || origin.source_change_id != grant.source_change_id
+        {
+            return Err(denied(
+                "grant origin belongs to another Subject or permission source",
+            ));
+        }
+        if direct_origin.is_none() {
+            direct_origin = Some(origin.clone());
+        }
+        runtime = origin.origin_runtime_id;
+        worker = origin.origin_worker_id;
+    }
+    Err(denied("grant origin exceeds maximum delegation depth"))
+}
+
+fn denied(reason: &str) -> SubjektivError {
+    SubjektivError::AuthorizationDenied(reason.into())
+}
+
+#[cfg(test)]
+mod tests;

crates/subjektiv/src/permissions.sql

@@ -0,0 +1,45 @@
+CREATE TABLE subject_permission_changes (
+    subject_id TEXT NOT NULL REFERENCES subjects(subject_id) ON DELETE RESTRICT,
+    change_id TEXT NOT NULL CHECK (length(change_id) > 0),
+    record_json TEXT NOT NULL,
+    PRIMARY KEY (subject_id, change_id)
+);
+CREATE TABLE subject_permissions (
+    subject_id TEXT PRIMARY KEY REFERENCES subjects(subject_id) ON DELETE RESTRICT,
+    change_id TEXT NOT NULL,
+    FOREIGN KEY (subject_id, change_id) REFERENCES subject_permission_changes(subject_id, change_id) ON DELETE RESTRICT
+);
+CREATE TABLE subject_permission_receipts (
+    operation_id TEXT PRIMARY KEY CHECK (length(operation_id) > 0),
+    subject_id TEXT NOT NULL,
+    request_fingerprint TEXT NOT NULL,
+    change_id TEXT NOT NULL,
+    FOREIGN KEY (subject_id, change_id) REFERENCES subject_permission_changes(subject_id, change_id) ON DELETE RESTRICT
+);
+CREATE TABLE worker_execution_grants (
+    runtime_id TEXT NOT NULL,
+    worker_id TEXT NOT NULL,
+    subject_id TEXT NOT NULL,
+    source_change_id TEXT NOT NULL,
+    record_json TEXT NOT NULL,
+    PRIMARY KEY (runtime_id, worker_id),
+    FOREIGN KEY (subject_id, source_change_id) REFERENCES subject_permission_changes(subject_id, change_id) ON DELETE RESTRICT
+);
+CREATE TRIGGER subject_permission_changes_no_update BEFORE UPDATE ON subject_permission_changes BEGIN
+    SELECT RAISE(ABORT, 'Subject permission changes are immutable');
+END;
+CREATE TRIGGER subject_permission_changes_no_delete BEFORE DELETE ON subject_permission_changes BEGIN
+    SELECT RAISE(ABORT, 'Subject permission changes are retained');
+END;
+CREATE TRIGGER subject_permission_receipts_no_update BEFORE UPDATE ON subject_permission_receipts BEGIN
+    SELECT RAISE(ABORT, 'Subject permission receipts are immutable');
+END;
+CREATE TRIGGER subject_permission_receipts_no_delete BEFORE DELETE ON subject_permission_receipts BEGIN
+    SELECT RAISE(ABORT, 'Subject permission receipts are retained');
+END;
+CREATE TRIGGER worker_execution_grants_no_update BEFORE UPDATE ON worker_execution_grants BEGIN
+    SELECT RAISE(ABORT, 'Worker execution grants are immutable');
+END;
+CREATE TRIGGER worker_execution_grants_no_delete BEFORE DELETE ON worker_execution_grants BEGIN
+    SELECT RAISE(ABORT, 'Worker execution grants are retained');
+END;

crates/subjektiv/src/permissions/tests.rs

@@ -0,0 +1,656 @@
+//! Real SQLite component tests through store APIs; Host authentication, canonical singleton
+//! ownership and live lineage checks are outside this suite. Root origins are Host-attested inputs;
+//! Journal fixtures exercise defensive attribution only, never execution authority.
+use super::*;
+use crate::tests::{open_store, role};
+use feature_storage::FeatureStorage;
+use std::path::Path;
+
+fn permission(operation: &str, path: &str, recursive: bool) -> ScopedPermission {
+    ScopedPermission {
+        operation: operation.into(),
+        resource: PermissionResource::Workdir {
+            working_directory_id: "wd".into(),
+            path: path.into(),
+            recursive,
+        },
+    }
+}
+
+fn update(
+    operation: &str,
+    expected: Option<&str>,
+    delegation: Vec<ScopedPermission>,
+) -> SubjectPermissionsUpdate {
+    SubjectPermissionsUpdate {
+        operation_id: operation.into(),
+        expected_change_id: expected.map(Into::into),
+        execution: Vec::new(),
+        delegation,
+    }
+}
+
+fn grant(subject: &str, source: &str, worker: &str) -> WorkerExecutionGrant {
+    WorkerExecutionGrant {
+        subject_id: subject.into(),
+        origin_runtime_id: "runtime".into(),
+        origin_worker_id: "body".into(),
+        source_change_id: source.into(),
+        runtime_id: "runtime".into(),
+        worker_id: worker.into(),
+        profile: "builtin:coder".into(),
+        profile_digest: "resolved-profile-sha256".into(),
+        permissions: vec![permission("file.read", "src", false)],
+        redelegation: Vec::new(),
+    }
+}
+
+fn schema(store: &SubjektivStore) -> Vec<(String, String)> {
+    store.database.try_with_connection::<_, SubjektivError>(|connection| {
+        let mut statement = connection.prepare("SELECT name,sql FROM sqlite_master WHERE name NOT LIKE 'sqlite_%' AND sql IS NOT NULL ORDER BY name")?;
+        Ok(statement.query_map([], |row| Ok((row.get(0)?, row.get(1)?)))?.collect::<std::result::Result<_, _>>()?)
+    }).unwrap()
+}
+
+fn open_version(
+    root: &Path,
+    version: usize,
+) -> (FeatureStorage, ScopedFeatureStorage, SubjektivStore) {
+    let manager = FeatureStorage::new(root);
+    let scope = manager.scope("workspace-a").unwrap();
+    let registration = scope
+        .register(FeatureRegistration::new(
+            SUBJEKTIV_FEATURE_ID,
+            &MIGRATIONS[..version],
+        ))
+        .unwrap();
+    let store = SubjektivStore::open(&scope, &registration).unwrap();
+    (manager, scope, store)
+}
+
+#[test]
+fn replacements_are_cas_fenced_replayable_and_never_restore_old_permissions() {
+    let temp = tempfile::tempdir().unwrap();
+    let subject;
+    let first;
+    let first_update = update("allow", None, vec![permission("file.read", ".", true)]);
+    {
+        let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+        subject = store.create_subject(role()).unwrap().id;
+        assert!(store.subject_permissions(&subject).unwrap().is_none());
+        first = store
+            .set_subject_permissions(&subject, &first_update)
+            .unwrap();
+        assert_eq!(
+            store
+                .set_subject_permissions(&subject, &first_update)
+                .unwrap(),
+            first
+        );
+        assert!(matches!(
+            store.set_subject_permissions(&subject, &update("stale", None, Vec::new())),
+            Err(SubjektivError::SubjectPermissionsConflict(_))
+        ));
+        assert!(matches!(
+            store.set_subject_permissions(&subject, &update("allow", None, Vec::new())),
+            Err(SubjektivError::PermissionOperationConflict(_))
+        ));
+        let other = store.create_subject(role()).unwrap();
+        assert!(matches!(
+            store.set_subject_permissions(&other.id, &first_update),
+            Err(SubjektivError::PermissionOperationConflict(_))
+        ));
+        let same = store
+            .set_subject_permissions(
+                &subject,
+                &update("same", Some(&first.change_id), first.delegation.clone()),
+            )
+            .unwrap();
+        assert_ne!(same.change_id, first.change_id);
+        let revoked = store
+            .set_subject_permissions(
+                &subject,
+                &update("revoke", Some(&same.change_id), Vec::new()),
+            )
+            .unwrap();
+        assert!(revoked.delegation.is_empty());
+        assert_eq!(
+            store
+                .set_subject_permissions(&subject, &first_update)
+                .unwrap(),
+            first
+        );
+        assert_eq!(store.subject_permissions(&subject).unwrap(), Some(revoked));
+    }
+    let (_reopened_manager, _reopened_scope, reopened) = open_store(temp.path(), "workspace-a");
+    assert!(
+        reopened
+            .subject_permissions(&subject)
+            .unwrap()
+            .unwrap()
+            .delegation
+            .is_empty()
+    );
+    assert_eq!(
+        reopened
+            .set_subject_permissions(&subject, &first_update)
+            .unwrap(),
+        first
+    );
+}
+
+#[test]
+fn failed_receipt_insert_rolls_back_source_history_and_projection() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let first = store
+        .set_subject_permissions(&subject, &update("first", None, Vec::new()))
+        .unwrap();
+    store.database.try_transaction::<_, SubjektivError>(|tx| {
+        tx.execute_batch("CREATE TRIGGER fail_permission_receipt BEFORE INSERT ON subject_permission_receipts BEGIN SELECT RAISE(ABORT,'injected receipt failure'); END;")?;
+        Ok(())
+    }).unwrap();
+    let replacement = update(
+        "second",
+        Some(&first.change_id),
+        vec![permission("file.read", ".", true)],
+    );
+    assert!(
+        store
+            .set_subject_permissions(&subject, &replacement)
+            .is_err()
+    );
+    assert_eq!(store.subject_permissions(&subject).unwrap(), Some(first));
+    store.database.try_transaction::<_, SubjektivError>(|tx| {
+        let counts: (u32, u32) = tx.query_row("SELECT (SELECT count(*) FROM subject_permission_changes),(SELECT count(*) FROM subject_permission_receipts)", [], |r| Ok((r.get(0)?, r.get(1)?)))?;
+        assert_eq!(counts, (1, 1));
+        tx.execute_batch("DROP TRIGGER fail_permission_receipt")?;
+        Ok(())
+    }).unwrap();
+    assert!(
+        store
+            .set_subject_permissions(&subject, &replacement)
+            .is_ok()
+    );
+}
+
+#[test]
+fn scope_and_validation_rejections_do_not_issue_permission_sources() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_a_manager, _a_scope, a) = open_store(&temp.path().join("a"), "workspace-a");
+    let (_b_manager, _b_scope, b) = open_store(&temp.path().join("b"), "workspace-b");
+    let subject = a.create_subject(role()).unwrap().id;
+    assert!(
+        b.set_subject_permissions(&subject, &update("cross-subject", None, Vec::new()))
+            .is_err()
+    );
+    let cross_workspace = ScopedPermission {
+        operation: "ticket.create".into(),
+        resource: PermissionResource::Workspace {
+            workspace_id: "workspace-b".into(),
+        },
+    };
+    assert!(
+        a.set_subject_permissions(
+            &subject,
+            &update("cross-workspace", None, vec![cross_workspace])
+        )
+        .is_err()
+    );
+    for (operation, path) in [
+        ("file.*", "src"),
+        ("file..read", "src"),
+        ("file.read", "../src"),
+        ("file.read", "src/../escape"),
+    ] {
+        assert!(
+            a.set_subject_permissions(
+                &subject,
+                &update("invalid", None, vec![permission(operation, path, true)])
+            )
+            .is_err()
+        );
+    }
+    assert!(a.subject_permissions(&subject).unwrap().is_none());
+}
+
+#[test]
+fn child_grants_are_immutable_bounded_and_do_not_create_subject_ownership() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", "src", true)]),
+        )
+        .unwrap();
+    let child = grant(&subject, &source.change_id, "child");
+    store.bind_worker_execution_grant(&child).unwrap();
+    store.bind_worker_execution_grant(&child).unwrap();
+    assert_eq!(
+        store.worker_execution_grant("runtime", "child").unwrap(),
+        Some(child.clone())
+    );
+    assert!(
+        store
+            .journal_body_is_unpublished(&subject, "runtime", "child")
+            .unwrap()
+    );
+    let mut changed = child.clone();
+    changed.profile_digest = "changed-profile".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&changed),
+        Err(SubjektivError::WorkerExecutionGrantConflict(_))
+    ));
+    for (worker, requested) in [
+        ("write", permission("file.write", "src", false)),
+        ("escape", permission("file.read", ".", true)),
+        ("prefix", permission("file.read", "src-other", false)),
+    ] {
+        let mut candidate = grant(&subject, &source.change_id, worker);
+        candidate.permissions = vec![requested];
+        assert!(store.bind_worker_execution_grant(&candidate).is_err());
+        assert!(
+            store
+                .worker_execution_grant("runtime", worker)
+                .unwrap()
+                .is_none()
+        );
+    }
+    let mut self_origin = child.clone();
+    self_origin.worker_id = "body".into();
+    assert!(store.bind_worker_execution_grant(&self_origin).is_err());
+    let other = store.create_subject(role()).unwrap();
+    store
+        .claim_journal_writer(&other.id, "runtime", "other-body")
+        .unwrap();
+    let mut invalid = grant(&subject, &source.change_id, "other-body");
+    assert!(store.bind_worker_execution_grant(&invalid).is_err());
+    invalid.worker_id = "forged-child".into();
+    invalid.origin_worker_id = "other-body".into();
+    assert!(store.bind_worker_execution_grant(&invalid).is_err());
+}
+
+#[test]
+fn redelegation_requires_current_source_and_explicit_retained_parent_ceiling() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", ".", true)]),
+        )
+        .unwrap();
+    let mut child = grant(&subject, &source.change_id, "child");
+    child.redelegation = vec![permission("file.read", "src", true)];
+    store.bind_worker_execution_grant(&child).unwrap();
+    let mut descendant = grant(&subject, &source.change_id, "grandchild");
+    descendant.origin_worker_id = "child".into();
+    store.bind_worker_execution_grant(&descendant).unwrap();
+    let mut excessive = descendant.clone();
+    excessive.worker_id = "excessive".into();
+    excessive.redelegation = vec![permission("file.read", ".", true)];
+    assert!(store.bind_worker_execution_grant(&excessive).is_err());
+    let mut nondelegator = descendant.clone();
+    nondelegator.origin_worker_id = "grandchild".into();
+    nondelegator.worker_id = "great-grandchild".into();
+    assert!(store.bind_worker_execution_grant(&nondelegator).is_err());
+    let mut stale = descendant.clone();
+    stale.worker_id = "after-source-replacement".into();
+    let revoked = store
+        .set_subject_permissions(
+            &subject,
+            &update("revoke", Some(&source.change_id), Vec::new()),
+        )
+        .unwrap();
+    assert_ne!(revoked.change_id, source.change_id);
+    stale.origin_worker_id = "new-body".into();
+    assert!(store.bind_worker_execution_grant(&stale).is_err());
+    // Exact retries/readback recover evidence but cannot revive the source or origin.
+    store.bind_worker_execution_grant(&child).unwrap();
+    assert_eq!(
+        store.worker_execution_grant("runtime", "child").unwrap(),
+        Some(child)
+    );
+    store.retire_subject(&subject).unwrap();
+    stale.source_change_id = revoked.change_id;
+    assert!(store.bind_worker_execution_grant(&stale).is_err());
+}
+
+#[test]
+fn journal_state_neither_authenticates_roots_nor_bypasses_retained_child_ceilings() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", ".", true)]),
+        )
+        .unwrap();
+    // The Host has authenticated root ownership outside this store. No Journal record is
+    // required; changing Journal writer state cannot supply or invalidate that authentication.
+    store
+        .bind_worker_execution_grant(&grant(&subject, &source.change_id, "without-journal"))
+        .unwrap();
+    let journal = store
+        .claim_journal_writer(&subject, "runtime", "body")
+        .unwrap();
+    store
+        .bind_worker_execution_grant(&grant(&subject, &source.change_id, "with-active-journal"))
+        .unwrap();
+    store.release_journal_writer(&journal).unwrap();
+    store
+        .bind_worker_execution_grant(&grant(&subject, &source.change_id, "with-released-journal"))
+        .unwrap();
+    // An active Journal binding must never upgrade a child's empty redelegation ceiling.
+    store
+        .claim_journal_writer(&subject, "runtime", "without-journal")
+        .unwrap();
+    let mut descendant = grant(&subject, &source.change_id, "descendant");
+    descendant.origin_worker_id = "without-journal".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&descendant),
+        Err(SubjektivError::AuthorizationDenied(_))
+    ));
+    assert!(
+        store
+            .worker_execution_grant("runtime", "descendant")
+            .unwrap()
+            .is_none()
+    );
+}
+
+#[test]
+fn retained_origins_reject_cycles_foreign_subjects_and_stale_parent_sources() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", ".", true)]),
+        )
+        .unwrap();
+    let mut child = grant(&subject, &source.change_id, "child");
+    child.redelegation = source.delegation.clone();
+    store.bind_worker_execution_grant(&child).unwrap();
+    // Closing a retained chain back through its previously unbound root must not create a cycle.
+    let mut cycle = grant(&subject, &source.change_id, "body");
+    cycle.origin_worker_id = "child".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&cycle),
+        Err(SubjektivError::AuthorizationDenied(_))
+    ));
+    let other = store.create_subject(role()).unwrap().id;
+    let other_source = store
+        .set_subject_permissions(&other, &update("other", None, source.delegation.clone()))
+        .unwrap();
+    let mut foreign = grant(&other, &other_source.change_id, "foreign-child");
+    foreign.origin_worker_id = "child".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&foreign),
+        Err(SubjektivError::AuthorizationDenied(_))
+    ));
+    let current = store
+        .set_subject_permissions(
+            &subject,
+            &update("replace", Some(&source.change_id), source.delegation),
+        )
+        .unwrap();
+    let mut stale_parent = grant(&subject, &current.change_id, "stale-parent-child");
+    stale_parent.origin_worker_id = "child".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&stale_parent),
+        Err(SubjektivError::AuthorizationDenied(_))
+    ));
+}
+
+#[test]
+fn failed_grant_insert_leaves_no_binding_and_can_retry_same_grant() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", ".", true)]),
+        )
+        .unwrap();
+    let child = grant(&subject, &source.change_id, "child");
+    store.database.try_transaction::<_, SubjektivError>(|tx| {
+        tx.execute_batch("CREATE TRIGGER fail_grant BEFORE INSERT ON worker_execution_grants BEGIN SELECT RAISE(ABORT,'injected grant failure'); END;")?;
+        Ok(())
+    }).unwrap();
+    assert!(store.bind_worker_execution_grant(&child).is_err());
+    assert!(
+        store
+            .worker_execution_grant("runtime", "child")
+            .unwrap()
+            .is_none()
+    );
+    store
+        .database
+        .try_transaction::<_, SubjektivError>(|tx| {
+            tx.execute_batch("DROP TRIGGER fail_grant")?;
+            Ok(())
+        })
+        .unwrap();
+    store.bind_worker_execution_grant(&child).unwrap();
+    for sql in [
+        "UPDATE worker_execution_grants SET source_change_id='forged'",
+        "DELETE FROM worker_execution_grants",
+        "UPDATE subject_permission_changes SET record_json='{}'",
+        "DELETE FROM subject_permission_receipts",
+    ] {
+        assert!(
+            store
+                .database
+                .try_transaction::<_, SubjektivError>(|tx| {
+                    tx.execute_batch(sql)?;
+                    Ok(())
+                })
+                .is_err(),
+            "{sql}"
+        );
+    }
+    assert_eq!(
+        store.worker_execution_grant("runtime", "child").unwrap(),
+        Some(child)
+    );
+}
+
+#[test]
+fn current_schema_migration_preserves_subject_and_matches_new_database() {
+    let temp = tempfile::tempdir().unwrap();
+    let root = temp.path().join("migrated");
+    let original;
+    {
+        let (_old_manager, _old_scope, old) = open_version(&root, 11);
+        original = old
+            .create_subject_with_behavior(role(), "Keep behavior separate".into())
+            .unwrap();
+    }
+    let (_migrated_manager, _migrated_scope, migrated) = open_store(&root, "workspace-a");
+    assert_eq!(
+        migrated.subject(&original.id).unwrap(),
+        Some(original.clone())
+    );
+    assert!(
+        migrated
+            .subject_permissions(&original.id)
+            .unwrap()
+            .is_none()
+    );
+    let (_fresh_manager, _fresh_scope, fresh) =
+        open_store(&temp.path().join("fresh"), "workspace-a");
+    assert_eq!(schema(&migrated), schema(&fresh));
+    let source = migrated
+        .set_subject_permissions(&original.id, &update("new-source", None, Vec::new()))
+        .unwrap();
+    assert!(!source.change_id.is_empty());
+    assert_eq!(migrated.subject(&original.id).unwrap(), Some(original));
+}
+
+#[test]
+fn unset_or_execution_only_source_cannot_issue_child_grants_and_saved_grants_survive_reopen() {
+    let temp = tempfile::tempdir().unwrap();
+    let saved;
+    {
+        let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+        let subject = store.create_subject(role()).unwrap().id;
+        assert!(
+            store
+                .bind_worker_execution_grant(&grant(&subject, "unset", "child"))
+                .is_err()
+        );
+        let mut execution_only = update("execution", None, Vec::new());
+        execution_only.execution = vec![permission("file.read", ".", true)];
+        let source = store
+            .set_subject_permissions(&subject, &execution_only)
+            .unwrap();
+        assert!(
+            store
+                .bind_worker_execution_grant(&grant(&subject, &source.change_id, "child"))
+                .is_err()
+        );
+        let source = store
+            .set_subject_permissions(
+                &subject,
+                &update(
+                    "delegation",
+                    Some(&source.change_id),
+                    execution_only.execution,
+                ),
+            )
+            .unwrap();
+        saved = grant(&subject, &source.change_id, "child");
+        store.bind_worker_execution_grant(&saved).unwrap();
+    }
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    assert_eq!(
+        store.worker_execution_grant("runtime", "child").unwrap(),
+        Some(saved.clone())
+    );
+    store.bind_worker_execution_grant(&saved).unwrap();
+    let mut conflicting = saved;
+    conflicting.profile = "builtin:default".into();
+    assert!(matches!(
+        store.bind_worker_execution_grant(&conflicting),
+        Err(SubjektivError::WorkerExecutionGrantConflict(_))
+    ));
+}
+
+#[test]
+fn subject_grant_listing_is_scoped_retained_ordered_and_fails_on_overflow() {
+    let temp = tempfile::tempdir().unwrap();
+    let (_manager, _scope, store) = open_store(temp.path(), "workspace-a");
+    let subject = store.create_subject(role()).unwrap().id;
+    let other = store.create_subject(role()).unwrap().id;
+    assert!(
+        store
+            .list_subject_worker_execution_grants(&subject)
+            .unwrap()
+            .is_empty()
+    );
+    let source = store
+        .set_subject_permissions(
+            &subject,
+            &update("allow", None, vec![permission("file.read", ".", true)]),
+        )
+        .unwrap();
+    let other_source = store
+        .set_subject_permissions(&other, &update("other", None, source.delegation.clone()))
+        .unwrap();
+    let other_grant = grant(&other, &other_source.change_id, "other-child");
+    store.bind_worker_execution_grant(&other_grant).unwrap();
+    for index in (0..MAX_SUBJECT_WORKER_EXECUTION_GRANTS).rev() {
+        store
+            .bind_worker_execution_grant(&grant(
+                &subject,
+                &source.change_id,
+                &format!("child-{index:04}"),
+            ))
+            .unwrap();
+    }
+    store
+        .set_subject_permissions(
+            &subject,
+            &update("revoke", Some(&source.change_id), Vec::new()),
+        )
+        .unwrap();
+    store.retire_subject(&subject).unwrap();
+    let listed = store
+        .list_subject_worker_execution_grants(&subject)
+        .unwrap();
+    assert_eq!(listed.len(), MAX_SUBJECT_WORKER_EXECUTION_GRANTS);
+    assert!(
+        listed
+            .iter()
+            .all(|grant| grant.subject_id == subject && grant.source_change_id == source.change_id)
+    );
+    assert!(
+        listed
+            .windows(2)
+            .all(|pair| (&pair[0].runtime_id, &pair[0].worker_id)
+                < (&pair[1].runtime_id, &pair[1].worker_id))
+    );
+    assert_eq!(
+        store.list_subject_worker_execution_grants(&other).unwrap(),
+        vec![other_grant.clone()]
+    );
+    // Seed one more retained row directly: the retired Subject cannot issue new grants.
+    // Listing must report overflow rather than returning a seemingly complete cancellation set.
+    let overflow = grant(&subject, &source.change_id, "overflow");
+    store.database.try_transaction::<_, SubjektivError>(|tx| {
+        tx.execute("INSERT INTO worker_execution_grants(runtime_id,worker_id,subject_id,source_change_id,record_json) VALUES(?1,?2,?3,?4,?5)",
+            params![overflow.runtime_id, overflow.worker_id, overflow.subject_id, overflow.source_change_id, serde_json::to_string(&overflow)?])?;
+        Ok(())
+    }).unwrap();
+    assert!(
+        matches!(store.list_subject_worker_execution_grants(&subject), Err(SubjektivError::WorkerExecutionGrantListOverflow { subject_id, limit: MAX_SUBJECT_WORKER_EXECUTION_GRANTS }) if subject_id == subject)
+    );
+    assert_eq!(
+        store.list_subject_worker_execution_grants(&other).unwrap(),
+        vec![other_grant]
+    );
+    let (_foreign_manager, _foreign_scope, foreign) =
+        open_store(&temp.path().join("foreign"), "workspace-b");
+    assert!(matches!(
+        foreign.list_subject_worker_execution_grants(&subject),
+        Err(SubjektivError::SubjectNotFound(_))
+    ));
+}
+
+#[test]
+fn failed_schema_migration_rolls_back_new_tables_and_preserves_old_data() {
+    let temp = tempfile::tempdir().unwrap();
+    let original;
+    {
+        let (_old_manager, _old_scope, old) = open_version(temp.path(), 11);
+        original = old.create_subject(role()).unwrap();
+        old.database
+            .try_transaction::<_, SubjektivError>(|tx| {
+                tx.execute_batch("CREATE TABLE subject_permissions (collision TEXT)")?;
+                Ok(())
+            })
+            .unwrap();
+    }
+    {
+        let manager = FeatureStorage::new(temp.path());
+        let scope = manager.scope("workspace-a").unwrap();
+        let registration = SubjektivStore::register(&scope).unwrap();
+        assert!(SubjektivStore::open(&scope, &registration).is_err());
+    }
+    let (_old_manager, _old_scope, old) = open_version(temp.path(), 11);
+    assert_eq!(old.database.schema_version().unwrap(), 11);
+    assert_eq!(old.subject(&original.id).unwrap(), Some(original));
+    old.database.try_with_connection::<_, SubjektivError>(|connection| {
+        let created: bool = connection.query_row("SELECT EXISTS(SELECT 1 FROM sqlite_master WHERE name='subject_permission_changes')", [], |row| row.get(0))?;
+        assert!(!created);
+        Ok(())
+    }).unwrap();
+}

crates/tools/Cargo.toml

@@ -23,7 +23,8 @@ thiserror = { workspace = true }
 tokio = { workspace = true, features = ["process", "rt", "sync", "time"] }
 tracing = { workspace = true }
 workdir = { workspace = true }
+uuid = { workspace = true, features = ["v7"] }
 
 [dev-dependencies]
 filetime = "0.2.27"
-tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
+tokio = { workspace = true, features = ["macros", "rt-multi-thread", "test-util"] }

crates/tools/src/bash.rs

@@ -1,19 +1,19 @@
 //! Bash Tool using WorkdirSession command capability.
 //!
-//! The selected session owns cwd, process launch, bounded output, timeout, and cancellation.
+//! Workdir owns launch and byte transport; Bash owns bounded preview and retained evidence.
 //! Bash is not a sandbox; the Runtime process and OS user define the execution boundary.
 //! Per-execution handles and nonces prevent cancellation of another command. Dropping a future
-//! does not confirm termination; active registrations remain until cleanup requests cancellation
-//! and observes terminal output.
+//! does not confirm termination. Registrations remain during bounded cancellation/drain cleanup;
+//! an unconfirmed provider outcome leaves partial evidence, never a fabricated terminal fence.
 
 use std::collections::{HashMap, HashSet};
-use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 
+use crate::bash_output::{BashOutputMetadata, BashOutputView, BashOutputWriter};
 use agen::tool::{Tool, ToolDefinition, ToolError, ToolMeta, ToolOutput};
 use async_trait::async_trait;
 use schemars::JsonSchema;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 use workdir::{
     CommandHandle, CommandOutputRequest, CommandRequest, WorkdirPath, WorkdirSessionHandle,
     WorkdirSessionRouter,
@@ -35,9 +35,9 @@ struct BashParams {
     timeout: Option<u64>,
 }
 
-pub(crate) struct BashTool {
+pub struct BashTool {
     router: Arc<WorkdirSessionRouter>,
-    output_dir: PathBuf,
+    output: BashOutputView,
     state: Arc<Mutex<BashExecutionState>>,
 }
 
@@ -63,6 +63,8 @@ struct CommandGuard {
     execution_id: String,
     execution_nonce: u64,
     handle: Option<CommandHandle>,
+    cursor: u64,
+    retained: Option<BashOutputWriter>,
 }
 
 impl Drop for CommandGuard {
@@ -74,20 +76,66 @@ impl Drop for CommandGuard {
         let state = Arc::clone(&self.state);
         let execution_id = self.execution_id.clone();
         let execution_nonce = self.execution_nonce;
+        let mut retained = self.retained.take();
+        let cursor = self.cursor;
         // A dropped provider future is not terminal confirmation. Keep the live
         // execution registered until cleanup has both requested cancellation and
         // observed terminal command output, so cancellation/session teardown
         // cannot race with an apparently empty registry.
         tokio::spawn(async move {
-            let _ = workdir.cancel_command(handle.clone()).await;
-            let _ = workdir
-                .command_output(CommandOutputRequest {
-                    handle,
-                    cursor: 0,
-                    limit: INLINE_BYTE_BUDGET,
-                    wait: true,
-                })
-                .await;
+            let result = tokio::time::timeout(std::time::Duration::from_secs(10), async {
+                let _ = workdir.cancel_command(handle.clone()).await;
+                let mut cursor = cursor;
+                loop {
+                    let page = command_page(
+                        &workdir,
+                        CommandOutputRequest {
+                            handle: handle.clone(),
+                            cursor,
+                            limit: workdir::MAX_COMMAND_READ_BYTES,
+                            wait: true,
+                        },
+                    )
+                    .await?;
+                    if let Some(writer) = &mut retained {
+                        let mut next = cursor;
+                        for chunk in &page.chunks {
+                            if chunk.sequence != next {
+                                return Err(workdir::WorkdirError::Unavailable(
+                                    "command cleanup sequence gap".into(),
+                                ));
+                            }
+                            writer
+                                .append_chunk(chunk)
+                                .map_err(workdir::WorkdirError::Unavailable)?;
+                            next = next.checked_add(chunk.bytes.len() as u64).ok_or_else(|| {
+                                workdir::WorkdirError::Unavailable(
+                                    "command cleanup cursor overflow".into(),
+                                )
+                            })?;
+                        }
+                        if page.next_cursor != next {
+                            return Err(workdir::WorkdirError::Unavailable(
+                                "command cleanup cursor gap".into(),
+                            ));
+                        }
+                    }
+                    cursor = page.next_cursor;
+                    if let Some(terminal) = page.terminal {
+                        if let Some(writer) = &mut retained {
+                            writer
+                                .finish_transport(&terminal)
+                                .map_err(workdir::WorkdirError::Unavailable)?;
+                        }
+                        return Ok::<(), workdir::WorkdirError>(());
+                    }
+                }
+            })
+            .await;
+            // Bounded cleanup can end with an unknown provider outcome. The writer then
+            // terminalizes partial evidence on drop; retaining a dead collector in `active`
+            // would leak registrations and falsely suggest it could still collect output.
+            let _ = result;
             let mut state = state.lock().unwrap();
             if state
                 .active
@@ -101,15 +149,49 @@ impl Drop for CommandGuard {
     }
 }
 
-#[async_trait]
-impl Tool for BashTool {
-    async fn execute(
+// Output pages are replayable only with the exact same command/cursor/limit.
+// Retry read transport failures, never command start, and cap both attempts and
+// backoff. The caller's deadline bounds a disconnected or unresponsive provider.
+async fn command_page(
+    session: &workdir::WorkdirSessionHandle,
+    request: CommandOutputRequest,
+) -> Result<workdir::CommandOutput, workdir::WorkdirError> {
+    for attempt in 0..3 {
+        match session.command_output(request.clone()).await {
+            Err(
+                workdir::WorkdirError::Transport(_)
+                | workdir::WorkdirError::Unavailable(_)
+                | workdir::WorkdirError::OutcomeUnknown(_),
+            ) if attempt < 2 => {
+                tokio::time::sleep(std::time::Duration::from_millis(100 << attempt)).await;
+            }
+            result => return result,
+        }
+    }
+    unreachable!("bounded retry loop returns its last result")
+}
+
+impl BashTool {
+    pub fn input_schema() -> serde_json::Value {
+        serde_json::to_value(schemars::schema_for!(BashParams)).expect("Bash schema serialization")
+    }
+
+    pub fn new(router: Arc<WorkdirSessionRouter>, output: BashOutputView) -> Self {
+        Self {
+            router,
+            output,
+            state: Arc::new(Mutex::new(BashExecutionState::default())),
+        }
+    }
+
+    pub async fn execute_result(
         &self,
         input_json: &str,
         ctx: agen::tool::ToolExecutionContext,
-    ) -> Result<ToolOutput, ToolError> {
+    ) -> Result<BashResult, ToolError> {
         let params: BashParams = serde_json::from_str(input_json)
             .map_err(|error| ToolError::InvalidArgument(format!("invalid Bash input: {error}")))?;
+        let retained = self.output.begin().map_err(ToolError::ExecutionFailed)?;
         let selected = crate::routing::resolve_session(
             &self.router,
             params.target_workdir.as_deref(),
@@ -134,14 +216,15 @@ impl Tool for BashTool {
             execution_id: execution_id.clone(),
             execution_nonce,
             handle: None,
+            cursor: 0,
+            retained: Some(retained),
         };
         let handle = session
             .start_command(CommandRequest {
                 command: params.command,
                 timeout_secs,
-                output_limit: INLINE_BYTE_BUDGET,
+                transport_byte_budget: self.output.byte_budget(),
                 cwd: params.cwd,
-                spill_dir: Some(self.output_dir.clone()),
                 tool_call_id: Some(call_id.clone()),
             })
             .await
@@ -167,15 +250,101 @@ impl Tool for BashTool {
                 .await
                 .map_err(crate::ToolsError::from)?;
         }
-        let output = session
-            .command_output(CommandOutputRequest {
-                handle,
-                cursor: 0,
-                limit: INLINE_BYTE_BUDGET,
-                wait: true,
-            })
+        let mut cursor = 0;
+        let mut stdout_preview = Vec::new();
+        let mut stderr_preview = Vec::new();
+        let mut seen = [0_u64; 2];
+        let mut empty_polls = 0;
+        let deadline =
+            tokio::time::Instant::now() + std::time::Duration::from_secs(timeout_secs + 30);
+        let terminal = loop {
+            let page = tokio::time::timeout_at(
+                deadline,
+                command_page(
+                    &session,
+                    CommandOutputRequest {
+                        handle: handle.clone(),
+                        cursor,
+                        limit: workdir::MAX_COMMAND_READ_BYTES,
+                        wait: true,
+                    },
+                ),
+            )
             .await
+            .map_err(|_| {
+                ToolError::ExecutionFailed(
+                    "command byte transport deadline exceeded; terminal outcome unknown".into(),
+                )
+            })?
             .map_err(crate::ToolsError::from)?;
+            let mut next = cursor;
+            for chunk in &page.chunks {
+                if chunk.sequence != next || chunk.bytes.is_empty() {
+                    return Err(ToolError::ExecutionFailed(
+                        "command byte transport sequence gap".into(),
+                    ));
+                }
+                next = next
+                    .checked_add(chunk.bytes.len() as u64)
+                    .filter(|n| *n <= self.output.byte_budget())
+                    .ok_or_else(|| {
+                        ToolError::ExecutionFailed(
+                            "command byte transport exceeds delivery budget".into(),
+                        )
+                    })?;
+                let index = if chunk.stream == workdir::CommandStream::Stdout {
+                    0
+                } else {
+                    1
+                };
+                if chunk.offset != seen[index] {
+                    return Err(ToolError::ExecutionFailed(
+                        "command byte transport offset gap".into(),
+                    ));
+                }
+                seen[index] += chunk.bytes.len() as u64;
+                guard
+                    .retained
+                    .as_mut()
+                    .unwrap()
+                    .append_chunk(chunk)
+                    .map_err(ToolError::ExecutionFailed)?;
+                let available =
+                    INLINE_BYTE_BUDGET.saturating_sub(stdout_preview.len() + stderr_preview.len());
+                let preview = if index == 0 {
+                    &mut stdout_preview
+                } else {
+                    &mut stderr_preview
+                };
+                preview.extend_from_slice(&chunk.bytes[..available.min(chunk.bytes.len())]);
+            }
+            if page.next_cursor != next {
+                return Err(ToolError::ExecutionFailed(
+                    "command byte transport cursor does not fence the page".into(),
+                ));
+            }
+            if page.chunks.is_empty() && page.terminal.is_none() {
+                empty_polls += 1;
+                if empty_polls > 32 {
+                    return Err(ToolError::ExecutionFailed(
+                        "command byte transport made no progress after bounded polls".into(),
+                    ));
+                }
+            } else {
+                empty_polls = 0;
+            }
+            cursor = page.next_cursor;
+            guard.cursor = cursor;
+            if let Some(terminal) = page.terminal {
+                break terminal;
+            }
+        };
+        let metadata = guard
+            .retained
+            .as_mut()
+            .unwrap()
+            .finish_transport(&terminal)
+            .map_err(ToolError::ExecutionFailed)?;
         let cancellation_requested = {
             let mut state = self.state.lock().unwrap();
             let owns_registration = state
@@ -193,41 +362,78 @@ impl Tool for BashTool {
         };
         guard.handle = None;
 
-        let timed_out = output.timed_out;
-        let summary = if cancellation_requested {
-            format!("$ {cmd_summary} (cancelled)")
-        } else if output.timed_out {
-            format!("$ {cmd_summary} (timed out after {timeout_secs}s)")
-        } else {
-            match output.exit_code {
-                Some(0) => format!("$ {cmd_summary}"),
-                Some(code) => format!("$ {cmd_summary} (exit {code})"),
-                None => format!("$ {cmd_summary} (terminated)"),
-            }
-        };
-        let content = if output.content.is_empty() {
-            None
-        } else if output.truncated {
-            let notice = match output.output_path {
-                Some(path) => format!(
-                    "[showing bounded WorkdirSession command output; full output saved to {}]",
-                    path.display()
-                ),
-                None => "[showing bounded WorkdirSession command output; additional output was truncated]"
-                    .to_owned(),
+        let timed_out = terminal.status == workdir::CommandStatus::TimedOut;
+        let summary =
+            if cancellation_requested || terminal.status == workdir::CommandStatus::Cancelled {
+                format!("$ {cmd_summary} (cancelled)")
+            } else if timed_out {
+                format!("$ {cmd_summary} (timed out after {timeout_secs}s)")
+            } else {
+                match terminal.exit_code {
+                    Some(0) => format!("$ {cmd_summary}"),
+                    Some(code) => format!("$ {cmd_summary} (exit {code})"),
+                    None => format!("$ {cmd_summary} (terminated)"),
+                }
             };
-            Some(format!("{notice}\n{}", output.content))
-        } else {
-            Some(output.content)
-        };
-        let output = ToolOutput {
+        Ok(BashResult {
             summary,
-            content,
-            attachments: Vec::new(),
-        };
-        if cancellation_requested {
+            stdout_preview: String::from_utf8_lossy(&stdout_preview).into_owned(),
+            stderr_preview: String::from_utf8_lossy(&stderr_preview).into_owned(),
+            preview_omitted: terminal.stdout_bytes.saturating_add(terminal.stderr_bytes)
+                > (stdout_preview.len() + stderr_preview.len()) as u64,
+            metadata,
+            cancelled: cancellation_requested
+                || terminal.status == workdir::CommandStatus::Cancelled,
+        })
+    }
+}
+
+#[derive(Debug, Serialize)]
+pub struct BashResult {
+    pub summary: String,
+    pub stdout_preview: String,
+    pub stderr_preview: String,
+    pub preview_omitted: bool,
+    pub metadata: BashOutputMetadata,
+    pub cancelled: bool,
+}
+
+impl BashResult {
+    pub fn stdout_entry(&self) -> String {
+        format!("/bash-output/{}/stdout", self.metadata.id)
+    }
+    pub fn stderr_entry(&self) -> String {
+        format!("/bash-output/{}/stderr", self.metadata.id)
+    }
+    pub fn order_entry(&self) -> String {
+        format!("/bash-output/{}/order", self.metadata.id)
+    }
+    pub fn tool_output(&self) -> ToolOutput {
+        let content = serde_json::json!({
+            "stdout_preview": self.stdout_preview, "stderr_preview": self.stderr_preview,
+            "preview_omitted": self.preview_omitted, "output": self.metadata,
+            "stdout_entry": self.stdout_entry(), "stderr_entry": self.stderr_entry(), "order_entry": self.order_entry(),
+        });
+        ToolOutput {
+            summary: self.summary.clone(),
+            content: Some(content.to_string()),
+            attachments: vec![],
+        }
+    }
+}
+
+#[async_trait]
+impl Tool for BashTool {
+    async fn execute(
+        &self,
+        input: &str,
+        ctx: agen::tool::ToolExecutionContext,
+    ) -> Result<ToolOutput, ToolError> {
+        let result = self.execute_result(input, ctx).await?;
+        let output = result.tool_output();
+        if result.cancelled {
             Err(ToolError::Cancelled(output))
-        } else if timed_out {
+        } else if result.metadata.terminal.status == Some(workdir::CommandStatus::TimedOut) {
             Err(ToolError::Interrupted(output))
         } else {
             Ok(output)
@@ -288,164 +494,19 @@ fn truncate_for_summary(command: &str) -> String {
     summary
 }
 
-pub fn bash_tool(session: WorkdirSessionHandle, output_dir: PathBuf) -> ToolDefinition {
-    routed_bash_tool(crate::routing::singleton_router(session), output_dir)
+pub fn bash_tool(session: WorkdirSessionHandle, output: BashOutputView) -> ToolDefinition {
+    routed_bash_tool(crate::routing::singleton_router(session), output)
 }
 
 pub(crate) fn routed_bash_tool(
     router: Arc<WorkdirSessionRouter>,
-    output_dir: PathBuf,
+    output: BashOutputView,
 ) -> ToolDefinition {
     Arc::new(move || {
-        let schema = schemars::schema_for!(BashParams);
         let meta = ToolMeta::new("Bash")
-            .description("Execute a shell command in one selected Workdir. Process start, bounded inline output, full-output spill, timeout and cancellation are owned by that WorkdirSession provider. This is not a sandbox.")
-            .input_schema(serde_json::to_value(schema).expect("Bash schema serialization"));
-        let tool: Arc<dyn Tool> = Arc::new(BashTool {
-            router: router.clone(),
-            output_dir: output_dir.clone(),
-            state: Arc::new(Mutex::new(BashExecutionState::default())),
-        });
+            .description("Execute a shell command in one selected Workdir. Workdir owns launch, lossless bounded byte transport, timeout and cancel; Bash owns preview, quota-limited ephemeral output and read-only virtual references. This is not a sandbox.")
+            .input_schema(BashTool::input_schema());
+        let tool: Arc<dyn Tool> = Arc::new(BashTool::new(router.clone(), output.clone()));
         (meta, tool)
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use std::sync::Arc;
-
-    use manifest::{Permission, Scope, ScopeConfig, ScopeRule};
-    use tempfile::TempDir;
-    use workdir::{LocalWorkdirSession, WorkdirSessionHandle};
-
-    use super::bash_tool;
-    use crate::{grep::grep_tool, read::read_tool, tracker::Tracker};
-
-    fn session_with_output_scope(root: &TempDir, output: &TempDir) -> WorkdirSessionHandle {
-        let scope = Scope::from_config(&ScopeConfig {
-            allow: vec![
-                ScopeRule {
-                    target: root.path().to_path_buf(),
-                    permission: Permission::Write,
-                    recursive: true,
-                    symlink_policy: Default::default(),
-                },
-                ScopeRule {
-                    target: output.path().to_path_buf(),
-                    permission: Permission::Read,
-                    recursive: true,
-                    symlink_policy: Default::default(),
-                },
-            ],
-            deny: Vec::new(),
-        })
-        .unwrap();
-        Arc::new(LocalWorkdirSession::new(scope, root.path().to_path_buf()))
-    }
-
-    #[tokio::test]
-    async fn long_output_is_spilled_and_available_to_read_and_grep() {
-        let root = TempDir::new().unwrap();
-        let output = TempDir::new().unwrap();
-        let session = session_with_output_scope(&root, &output);
-        let (_, bash) = bash_tool(session.clone(), output.path().to_path_buf())();
-        let command = "i=0; while [ $i -lt 2000 ]; do printf 'line-%04d\\n' \"$i\"; i=$((i+1)); done; printf 'FINAL-NEEDLE\\n'";
-        let result = bash
-            .execute(
-                &serde_json::json!({ "command": command, "cwd": "." }).to_string(),
-                Default::default(),
-            )
-            .await
-            .unwrap();
-        let rendered = result.content.expect("bounded Bash output");
-        let artifact = std::fs::read_dir(output.path())
-            .unwrap()
-            .next()
-            .expect("artifact entry")
-            .unwrap()
-            .path();
-
-        assert!(rendered.contains("full output saved to"));
-        assert!(rendered.contains(&artifact.display().to_string()));
-        let retained = std::fs::read_to_string(&artifact).unwrap();
-        assert!(retained.starts_with("line-0000\n"));
-        assert!(retained.ends_with("FINAL-NEEDLE\n"));
-        assert_eq!(retained.lines().count(), 2001);
-
-        let (_, read) = read_tool(session.clone(), Tracker::new())();
-        let read_result = read
-            .execute(
-                &serde_json::json!({
-                    "file_path": artifact,
-                    "offset": 2000,
-                    "limit": 1,
-                })
-                .to_string(),
-                Default::default(),
-            )
-            .await
-            .unwrap();
-        assert!(
-            read_result
-                .content
-                .expect("Read content")
-                .contains("FINAL-NEEDLE")
-        );
-
-        let (_, grep) = grep_tool(session)();
-        let grep_result = grep
-            .execute(
-                &serde_json::json!({
-                    "pattern": "FINAL-NEEDLE",
-                    "path": artifact,
-                    "output_mode": "content",
-                })
-                .to_string(),
-                Default::default(),
-            )
-            .await
-            .unwrap();
-        let grep_content = grep_result.content.expect("Grep content");
-        assert!(
-            grep_content.contains("FINAL-NEEDLE"),
-            "unexpected Grep content: {grep_content:?}"
-        );
-    }
-
-    #[tokio::test]
-    async fn missing_cwd_is_rejected_before_command_start() {
-        let root = TempDir::new().unwrap();
-        let output = TempDir::new().unwrap();
-        let session = session_with_output_scope(&root, &output);
-        let (_, bash) = bash_tool(session, output.path().to_path_buf())();
-
-        let error = bash
-            .execute(
-                &serde_json::json!({ "command": "printf hidden" }).to_string(),
-                Default::default(),
-            )
-            .await
-            .unwrap_err();
-
-        assert!(error.to_string().contains("missing field `cwd`"));
-    }
-
-    #[tokio::test]
-    async fn short_output_does_not_leave_a_spill_artifact() {
-        let root = TempDir::new().unwrap();
-        let output = TempDir::new().unwrap();
-        let session = session_with_output_scope(&root, &output);
-        let (_, bash) = bash_tool(session, output.path().to_path_buf())();
-
-        let result = bash
-            .execute(
-                &serde_json::json!({ "command": "printf short", "cwd": "." }).to_string(),
-                Default::default(),
-            )
-            .await
-            .unwrap();
-
-        assert_eq!(result.content.as_deref(), Some("short"));
-        assert_eq!(std::fs::read_dir(output.path()).unwrap().count(), 0);
-    }
-}

crates/tools/src/bash_output.rs

@@ -0,0 +1,605 @@
+//! Bash-owned bounded output, independent of Workdir transport and Console subscribers.
+//!
+//! Output is ephemeral evidence, not a filesystem grant. Every lookup checks the live view;
+//! children can see their own subtree and ancestors can retain evidence after child revocation.
+//! Root teardown clears all bytes. A new root (including restore) has a new incarnation and
+//! never reconstructs grants from history. Expiry is measured from admission, enforced on
+//! lookup and by a weak reaper once commands run in Tokio. Parent and all descendants share
+//! one pool: admission reserves a whole command budget, evicts the oldest terminal evidence
+//! first, and refuses rather than evicting a live collector. Revoking a child denies access
+//! but leaves ancestor evidence until pool eviction/expiry; root teardown clears the pool.
+
+use std::collections::VecDeque;
+use std::sync::{
+    Arc, Mutex, Weak,
+    atomic::{AtomicBool, Ordering},
+};
+use std::time::{Duration, Instant};
+
+use serde::Serialize;
+use workdir::{CommandStatus, CommandStream};
+
+const COMMAND_BYTES: usize = 4 * 1024 * 1024;
+const STORE_BYTES: usize = 32 * 1024 * 1024;
+const STORE_COUNT: usize = 64;
+const ORDER_COUNT: usize = 4096;
+const RETENTION: Duration = Duration::from_secs(3600);
+
+#[derive(Clone)]
+pub struct BashOutputView {
+    store: Arc<Mutex<Store>>,
+    lineage: Vec<String>,
+    active: Arc<AtomicBool>,
+    authority: Arc<dyn Fn() -> bool + Send + Sync>,
+}
+
+struct Store {
+    records: VecDeque<Arc<Mutex<Record>>>,
+    reserved: usize,
+    retention: Duration,
+    reaper_started: bool,
+    _shutdown: tokio::sync::watch::Sender<()>,
+}
+
+struct Record {
+    id: String,
+    owner: Vec<String>,
+    created: Instant,
+    stdout: Vec<u8>,
+    stderr: Vec<u8>,
+    order: Vec<OutputRange>,
+    stdout_seen: u64,
+    stderr_seen: u64,
+    truncated: bool,
+    limit: Option<RetentionLimit>,
+    transport_counts: Option<(u64, u64)>,
+    transport_truncation: Option<workdir::CommandOutputTruncation>,
+    terminal: Option<OutputTerminal>,
+}
+
+#[derive(Clone, Debug, Serialize)]
+pub struct OutputRange {
+    pub stream: CommandStream,
+    pub start: u64,
+    pub end: u64,
+}
+
+#[derive(Clone, Debug, Serialize)]
+pub struct OutputTerminal {
+    pub status: Option<CommandStatus>,
+    pub exit_code: Option<i32>,
+    /// False on a forcibly dropped collector or failed transport: received bytes are retained,
+    /// but they are not a claim about the unobserved process tail.
+    pub transport_complete: bool,
+}
+
+#[derive(Clone, Copy, Debug, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum RetentionLimit {
+    ByteQuota,
+    OrderQuota,
+}
+
+#[derive(Clone, Debug, Serialize)]
+pub struct BashOutputMetadata {
+    pub id: String,
+    pub stdout_saved: usize,
+    pub stderr_saved: usize,
+    pub stdout_seen: u64,
+    pub stderr_seen: u64,
+    pub stdout_delivered: u64,
+    pub stderr_delivered: u64,
+    pub retention_limit: Option<RetentionLimit>,
+    pub transport_truncation: Option<workdir::CommandOutputTruncation>,
+    pub storage_truncated: bool,
+    pub terminal: OutputTerminal,
+    pub text_encoding: &'static str,
+    pub ordering: &'static str,
+}
+
+/// A bounded reservation acquired before command start. Drop terminalizes partial evidence.
+pub struct BashOutputWriter {
+    record: Arc<Mutex<Record>>,
+}
+
+impl Default for BashOutputView {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl BashOutputView {
+    pub fn new() -> Self {
+        let (shutdown, _) = tokio::sync::watch::channel(());
+        let store = Arc::new(Mutex::new(Store {
+            records: VecDeque::new(),
+            reserved: 0,
+            retention: RETENTION,
+            reaper_started: false,
+            _shutdown: shutdown,
+        }));
+        let view = Self {
+            store,
+            lineage: vec![uuid::Uuid::now_v7().to_string()],
+            active: Arc::new(AtomicBool::new(true)),
+            authority: Arc::new(|| true),
+        };
+        view.start_reaper();
+        view
+    }
+
+    fn start_reaper(&self) {
+        let Ok(runtime) = tokio::runtime::Handle::try_current() else {
+            return;
+        };
+        let mut store = self.store.lock().unwrap();
+        if store.reaper_started {
+            return;
+        }
+        let receiver = store._shutdown.subscribe();
+        store.reaper_started = true;
+        let weak = Arc::downgrade(&self.store);
+        runtime.spawn(reap(weak, receiver));
+    }
+
+    pub fn byte_budget(&self) -> u64 {
+        COMMAND_BYTES as u64
+    }
+
+    pub fn child(&self, authority: Arc<dyn Fn() -> bool + Send + Sync>) -> Self {
+        let parent = self.clone();
+        let mut lineage = self.lineage.clone();
+        lineage.push(uuid::Uuid::now_v7().to_string());
+        Self {
+            store: self.store.clone(),
+            lineage,
+            active: Arc::new(AtomicBool::new(true)),
+            authority: Arc::new(move || parent.is_active() && authority()),
+        }
+    }
+
+    pub fn is_active(&self) -> bool {
+        self.active.load(Ordering::Acquire) && (self.authority)()
+    }
+
+    pub fn is_root(&self) -> bool {
+        self.lineage.len() == 1
+    }
+
+    pub fn revoke(&self) {
+        self.active.store(false, Ordering::Release);
+        if self.lineage.len() == 1 {
+            let mut store = self.store.lock().unwrap();
+            store.records.clear();
+            store.reserved = 0;
+        }
+    }
+
+    pub fn begin(&self) -> Result<BashOutputWriter, String> {
+        if !self.is_active() {
+            return Err("Bash output authority revoked".into());
+        }
+        // A host may construct the Feature before entering Tokio. Command admission
+        // happens inside the runtime, so idle expiry must start here as well.
+        self.start_reaper();
+        let mut store = self.store.lock().unwrap();
+        if !self.is_active() {
+            return Err("Bash output authority revoked".into());
+        }
+        store.expire(Instant::now());
+        while store.records.len() >= STORE_COUNT || store.reserved + COMMAND_BYTES > STORE_BYTES {
+            let Some(index) = store
+                .records
+                .iter()
+                .position(|r| r.lock().unwrap().terminal.is_some())
+            else {
+                return Err("Bash output capacity is occupied by live commands".into());
+            };
+            store.records.remove(index);
+            store.reserved -= COMMAND_BYTES;
+        }
+        let record = Arc::new(Mutex::new(Record {
+            id: uuid::Uuid::now_v7().to_string(),
+            owner: self.lineage.clone(),
+            created: Instant::now(),
+            stdout: Vec::new(),
+            stderr: Vec::new(),
+            order: Vec::new(),
+            stdout_seen: 0,
+            stderr_seen: 0,
+            truncated: false,
+            limit: None,
+            transport_counts: None,
+            transport_truncation: None,
+            terminal: None,
+        }));
+        store.records.push_back(record.clone());
+        store.reserved += COMMAND_BYTES;
+        Ok(BashOutputWriter { record })
+    }
+
+    fn record(&self, id: &str) -> Option<Arc<Mutex<Record>>> {
+        if !self.is_active() {
+            return None;
+        }
+        let mut store = self.store.lock().unwrap();
+        if !self.is_active() {
+            return None;
+        }
+        store.expire(Instant::now());
+        store
+            .records
+            .iter()
+            .find(|r| {
+                let r = r.lock().unwrap();
+                r.id == id && r.owner.starts_with(&self.lineage) && r.terminal.is_some()
+            })
+            .cloned()
+    }
+
+    pub fn metadata(&self, id: &str) -> Option<BashOutputMetadata> {
+        let record = self.record(id)?;
+        let r = record.lock().unwrap();
+        Some(r.metadata())
+    }
+
+    /// Copies at most the caller's bounded range; never publishes output bodies in descriptors.
+    pub fn read(
+        &self,
+        id: &str,
+        stream: CommandStream,
+        offset: usize,
+        limit: usize,
+    ) -> Option<Vec<u8>> {
+        let record = self.record(id)?;
+        let r = record.lock().unwrap();
+        let bytes = match stream {
+            CommandStream::Stdout => &r.stdout,
+            CommandStream::Stderr => &r.stderr,
+        };
+        let start = offset.min(bytes.len());
+        Some(bytes[start..start.saturating_add(limit.min(64 * 1024)).min(bytes.len())].to_vec())
+    }
+
+    /// Scan the bounded raw source without cloning it, decoding only the requested line window.
+    /// A long single line uses the common byte reader instead of allocating an oversized text page.
+    pub fn line_window(
+        &self,
+        id: &str,
+        stream: CommandStream,
+        offset: usize,
+        limit: usize,
+    ) -> Option<Result<(String, bool), String>> {
+        let record = self.record(id)?;
+        let r = record.lock().unwrap();
+        let bytes = match stream {
+            CommandStream::Stdout => &r.stdout,
+            CommandStream::Stderr => &r.stderr,
+        };
+        let mut lines = bytes.split_inclusive(|b| *b == b'\n').skip(offset);
+        let mut window = Vec::new();
+        for line in lines.by_ref().take(limit.min(2000)) {
+            if window.len() + line.len() > 64 * 1024 {
+                return Some(Err(
+                    "text source window exceeds 64 KiB; use the common byte reader".into(),
+                ));
+            }
+            window.extend_from_slice(line);
+        }
+        let more = lines.next().is_some();
+        Some(Ok((String::from_utf8_lossy(&window).into_owned(), more)))
+    }
+
+    pub fn order(&self, id: &str) -> Option<Vec<OutputRange>> {
+        let record = self.record(id)?;
+        let r = record.lock().unwrap();
+        Some(r.order.clone())
+    }
+}
+
+impl Record {
+    fn metadata(&self) -> BashOutputMetadata {
+        BashOutputMetadata {
+            id: self.id.clone(),
+            stdout_saved: self.stdout.len(),
+            stderr_saved: self.stderr.len(),
+            stdout_seen: self.transport_counts.map_or(self.stdout_seen, |c| c.0),
+            stderr_seen: self.transport_counts.map_or(self.stderr_seen, |c| c.1),
+            stdout_delivered: self.stdout_seen,
+            stderr_delivered: self.stderr_seen,
+            retention_limit: self.limit,
+            transport_truncation: self.transport_truncation.clone(),
+            storage_truncated: self.truncated || self.transport_truncation.is_some(),
+            terminal: self.terminal.clone().expect("finalized record"),
+            text_encoding: "utf8_lossy",
+            ordering: "provider_read_observation",
+        }
+    }
+}
+
+impl Store {
+    fn expire(&mut self, now: Instant) {
+        let before = self.records.len();
+        self.records
+            .retain(|r| now.duration_since(r.lock().unwrap().created) < self.retention);
+        self.reserved -= (before - self.records.len()) * COMMAND_BYTES;
+    }
+}
+
+async fn reap(weak: Weak<Mutex<Store>>, mut shutdown: tokio::sync::watch::Receiver<()>) {
+    loop {
+        tokio::select! {
+            _ = tokio::time::sleep(Duration::from_secs(30)) => {},
+            _ = shutdown.changed() => return,
+        }
+        let Some(store) = weak.upgrade() else {
+            return;
+        };
+        store.lock().unwrap().expire(Instant::now());
+    }
+}
+
+impl BashOutputWriter {
+    pub fn append_chunk(&mut self, chunk: &workdir::CommandByteChunk) -> Result<(), String> {
+        let expected = {
+            let r = self.record.lock().unwrap();
+            match chunk.stream {
+                CommandStream::Stdout => r.stdout_seen,
+                CommandStream::Stderr => r.stderr_seen,
+            }
+        };
+        if chunk.offset != expected || chunk.bytes.is_empty() {
+            return Err("command byte transport stream gap or empty chunk".into());
+        }
+        self.append(chunk.stream, &chunk.bytes);
+        Ok(())
+    }
+
+    pub fn append(&mut self, stream: CommandStream, bytes: &[u8]) {
+        let mut r = self.record.lock().unwrap();
+        let seen = match stream {
+            CommandStream::Stdout => &mut r.stdout_seen,
+            CommandStream::Stderr => &mut r.stderr_seen,
+        };
+        let start = *seen;
+        *seen = seen.saturating_add(bytes.len() as u64);
+        let available = COMMAND_BYTES.saturating_sub(r.stdout.len() + r.stderr.len());
+        let n = if r.truncated || r.order.len() >= ORDER_COUNT {
+            0
+        } else {
+            available.min(bytes.len())
+        };
+        if n < bytes.len() {
+            r.truncated = true;
+            if r.limit.is_none() {
+                r.limit = Some(if r.order.len() >= ORDER_COUNT {
+                    RetentionLimit::OrderQuota
+                } else {
+                    RetentionLimit::ByteQuota
+                });
+            }
+        }
+        if n > 0 {
+            match stream {
+                CommandStream::Stdout => r.stdout.extend_from_slice(&bytes[..n]),
+                CommandStream::Stderr => r.stderr.extend_from_slice(&bytes[..n]),
+            }
+            if let Some(last) = r
+                .order
+                .last_mut()
+                .filter(|last| last.stream == stream && last.end == start)
+            {
+                last.end += n as u64;
+            } else {
+                r.order.push(OutputRange {
+                    stream,
+                    start,
+                    end: start + n as u64,
+                });
+            }
+        }
+    }
+
+    pub fn finish_transport(
+        &mut self,
+        terminal: &workdir::CommandTerminal,
+    ) -> Result<BashOutputMetadata, String> {
+        let mut r = self.record.lock().unwrap();
+        if terminal.stdout_delivered_bytes != r.stdout_seen
+            || terminal.stderr_delivered_bytes != r.stderr_seen
+            || terminal.stdout_bytes < r.stdout_seen
+            || terminal.stderr_bytes < r.stderr_seen
+            || ((terminal.stdout_bytes != r.stdout_seen || terminal.stderr_bytes != r.stderr_seen)
+                != terminal.truncation_reason.is_some())
+        {
+            return Err("command terminal counts do not fence delivered bytes".into());
+        }
+        r.transport_counts = Some((terminal.stdout_bytes, terminal.stderr_bytes));
+        r.transport_truncation = terminal.truncation_reason.clone();
+        r.terminal = Some(OutputTerminal {
+            status: Some(terminal.status),
+            exit_code: terminal.exit_code,
+            transport_complete: true,
+        });
+        Ok(r.metadata())
+    }
+
+    pub fn finish(&mut self, terminal: OutputTerminal) -> BashOutputMetadata {
+        let mut r = self.record.lock().unwrap();
+        r.terminal = Some(terminal);
+        r.metadata()
+    }
+}
+
+impl Drop for BashOutputWriter {
+    fn drop(&mut self) {
+        let mut r = self.record.lock().unwrap();
+        if r.terminal.is_none() {
+            r.terminal = Some(OutputTerminal {
+                status: None,
+                exit_code: None,
+                transport_complete: false,
+            });
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn finish(view: &BashOutputView, text: &[u8]) -> String {
+        let mut writer = view.begin().unwrap();
+        writer.append(CommandStream::Stdout, text);
+        writer
+            .finish(OutputTerminal {
+                status: Some(CommandStatus::Completed),
+                exit_code: Some(0),
+                transport_complete: true,
+            })
+            .id
+    }
+
+    #[test]
+    fn revoked_child_is_denied_while_parent_keeps_evidence_and_sibling_is_denied() {
+        let root = BashOutputView::new();
+        let lease = Arc::new(AtomicBool::new(true));
+        let child = root.child({
+            let lease = lease.clone();
+            Arc::new(move || lease.load(Ordering::Acquire))
+        });
+        let sibling = root.child(Arc::new(|| true));
+        let id = finish(&child, b"child");
+        assert_eq!(
+            child.read(&id, CommandStream::Stdout, 0, 20).unwrap(),
+            b"child"
+        );
+        assert!(sibling.metadata(&id).is_none());
+        assert!(BashOutputView::new().metadata(&id).is_none());
+        lease.store(false, Ordering::Release);
+        assert!(child.metadata(&id).is_none());
+        assert_eq!(
+            root.read(&id, CommandStream::Stdout, 0, 20).unwrap(),
+            b"child"
+        );
+        root.revoke();
+        let restored = BashOutputView::new();
+        assert!(root.metadata(&id).is_none());
+        assert!(restored.metadata(&id).is_none());
+        let new_id = finish(&restored, b"new incarnation");
+        assert_ne!(new_id, id);
+        assert!(child.metadata(&new_id).is_none());
+        assert!(root.begin().is_err());
+    }
+
+    #[test]
+    fn parent_and_descendants_share_admission_without_evicting_live_evidence() {
+        let root = BashOutputView::new();
+        let child = root.child(Arc::new(|| true));
+        let sibling = root.child(Arc::new(|| true));
+        let mut writers = (0..STORE_BYTES / COMMAND_BYTES)
+            .map(|index| {
+                if index % 2 == 0 {
+                    root.begin()
+                } else {
+                    child.begin()
+                }
+                .unwrap()
+            })
+            .collect::<Vec<_>>();
+        assert!(sibling.begin().is_err());
+        let mut first = writers.remove(0);
+        first.append(CommandStream::Stdout, b"finished");
+        let metadata = first.finish(OutputTerminal {
+            status: Some(CommandStatus::Completed),
+            exit_code: Some(0),
+            transport_complete: true,
+        });
+        assert!(root.metadata(&metadata.id).is_some());
+        let _replacement = sibling.begin().unwrap();
+        assert!(root.metadata(&metadata.id).is_none());
+        assert!(root.begin().is_err());
+        assert_eq!(writers.len(), STORE_BYTES / COMMAND_BYTES - 1);
+    }
+
+    #[test]
+    fn quota_and_forced_drop_are_distinct_from_preview_omission() {
+        let root = BashOutputView::new();
+        let mut writer = root.begin().unwrap();
+        writer.append(CommandStream::Stdout, &vec![b'x'; COMMAND_BYTES + 1]);
+        writer.append(CommandStream::Stderr, b"tail");
+        let id = writer.record.lock().unwrap().id.clone();
+        drop(writer);
+        let m = root.metadata(&id).unwrap();
+        assert_eq!(m.stdout_saved, COMMAND_BYTES);
+        assert_eq!(m.stdout_seen, COMMAND_BYTES as u64 + 1);
+        assert_eq!(m.stderr_seen, 4);
+        assert!(m.storage_truncated);
+        assert!(!m.terminal.transport_complete);
+        assert_eq!(
+            root.read(&id, CommandStream::Stdout, 0, usize::MAX)
+                .unwrap()
+                .len(),
+            64 * 1024
+        );
+    }
+
+    #[test]
+    fn expiry_and_count_eviction_never_reuse_old_references() {
+        let root = BashOutputView::new();
+        let id = finish(&root, b"old");
+        root.store.lock().unwrap().retention = Duration::ZERO;
+        assert!(root.metadata(&id).is_none());
+        root.store.lock().unwrap().retention = RETENTION;
+        let first = finish(&root, b"first");
+        for _ in 0..STORE_COUNT {
+            finish(&root, b"later");
+        }
+        assert!(root.metadata(&first).is_none());
+        assert!(root.store.lock().unwrap().reserved <= STORE_BYTES);
+    }
+    #[tokio::test(start_paused = true)]
+    async fn expiry_reclaims_bytes_without_another_read_and_reaper_ends_with_owner() {
+        // Exercise host construction outside a runtime, followed by real async admission.
+        let root = std::thread::spawn(BashOutputView::new).join().unwrap();
+        finish(&root, b"expires without lookup");
+        let mut closed = root.store.lock().unwrap()._shutdown.subscribe();
+        tokio::task::yield_now().await;
+        // The store uses monotonic wall time for publication and Tokio time only for scheduling.
+        // Age the record deterministically rather than delaying this test in real time.
+        root.store.lock().unwrap().records[0]
+            .lock()
+            .unwrap()
+            .created = Instant::now() - RETENTION;
+        tokio::time::advance(Duration::from_secs(31)).await;
+        tokio::task::yield_now().await;
+        assert_eq!(root.store.lock().unwrap().reserved, 0);
+        drop(root);
+        assert!(closed.changed().await.is_err());
+    }
+    #[test]
+    fn terminal_counts_must_fence_the_received_prefix_before_marking_evidence_complete() {
+        let root = BashOutputView::new();
+        let mut writer = root.begin().unwrap();
+        writer.append(CommandStream::Stdout, b"abc");
+        let mut terminal = serde_json::json!({"status":"completed","exit_code":0,"stdout_bytes":9,"stderr_bytes":0,"stdout_delivered_bytes":4,"stderr_delivered_bytes":0,"truncation_reason":"byte_budget"});
+        assert!(
+            writer
+                .finish_transport(&serde_json::from_value(terminal.clone()).unwrap())
+                .is_err()
+        );
+        terminal["stdout_delivered_bytes"] = serde_json::json!(3);
+        let metadata = writer
+            .finish_transport(&serde_json::from_value(terminal).unwrap())
+            .unwrap();
+        assert_eq!(metadata.stdout_saved, 3);
+        assert_eq!(metadata.stdout_delivered, 3);
+        assert_eq!(metadata.stdout_seen, 9);
+        assert!(metadata.storage_truncated);
+        assert!(metadata.retention_limit.is_none());
+        assert_eq!(
+            metadata.transport_truncation,
+            Some(workdir::CommandOutputTruncation::ByteBudget)
+        );
+    }
+}

crates/tools/src/checkout.rs

@@ -403,3 +403,71 @@ fn check_pattern(pattern: &str) -> Result<(), ToolError> {
 #[cfg(test)]
 #[path = "checkout_tests.rs"]
 mod tests;
+
+/// Read a bounded native text window through the same checked target.
+/// The returned one-shot action records prior-Read only after the caller's presentation succeeds.
+#[allow(clippy::too_many_arguments)]
+pub async fn read_checkout_text(
+    router: Arc<WorkdirSessionRouter>,
+    tracker: Tracker,
+    alias: &str,
+    generation: u64,
+    path: WorkdirPath,
+    validator: Vec<u8>,
+    offset: usize,
+    limit: usize,
+    max_bytes: usize,
+) -> Result<(workdir::ReadResult, Option<Vec<u8>>, impl FnOnce()), ToolError> {
+    let selected =
+        crate::routing::resolve_session(&router, Some(alias), WorkdirSessionCapability::Read)?;
+    if selected.generation != generation {
+        return Err(stale_checkout("checkout connection changed"));
+    }
+    let tracker = tracker.scoped_attachment(&selected.alias, selected.generation);
+    let target = FileTarget {
+        session: selected.session.clone(),
+        path: path.clone(),
+        validator: Some(validator),
+    };
+    let (result, validator) = target.read(offset, limit, max_bytes).await?;
+    let hash = result.content_hash.clone();
+    let total_lines = result.total_lines;
+    Ok((result, validator, move || {
+        tracker.record_workdir_observation(&path, hash, total_lines);
+    }))
+}
+
+/// Binary-safe checked byte window. This does not establish a text prior-Read observation.
+#[allow(clippy::too_many_arguments)]
+pub async fn read_checkout_bytes(
+    router: Arc<WorkdirSessionRouter>,
+    alias: &str,
+    generation: u64,
+    path: WorkdirPath,
+    validator: Vec<u8>,
+    offset: u64,
+    max_bytes: usize,
+) -> Result<(workdir::ReadBytesResult, Vec<u8>), ToolError> {
+    let selected =
+        crate::routing::resolve_session(&router, Some(alias), WorkdirSessionCapability::Read)?;
+    if selected.generation != generation {
+        return Err(stale_checkout("checkout connection changed"));
+    }
+    let result = selected
+        .session
+        .checkout_execute(workdir::CheckoutRequest {
+            target: path.clone(),
+            validator,
+            operation: workdir::CheckoutOperation::ReadBytes { offset, max_bytes },
+        })
+        .await
+        .map_err(crate::file_target::checked_error)?;
+    match result.output {
+        workdir::CheckoutOutput::ReadBytes(read)
+            if read.path == path && read.offset == offset && read.bytes.len() <= max_bytes =>
+        {
+            Ok((read, result.observation.validator))
+        }
+        _ => Err(crate::file_target::readonly_result_error("ReadBytes")),
+    }
+}

crates/tools/src/lib.rs

@@ -5,6 +5,7 @@ pub mod error;
 pub mod tracker;
 
 mod bash;
+pub mod bash_output;
 mod edit;
 mod file_target;
 mod glob;
@@ -16,7 +17,7 @@ pub mod view_image;
 mod web;
 mod write;
 
-pub use bash::bash_tool;
+pub use bash::{BashResult, BashTool, bash_tool};
 pub use checkout::{CheckoutToolOutput, execute_checkout_tool};
 pub use edit::edit_tool;
 pub use error::ToolsError;
@@ -35,7 +36,7 @@ pub use write::write_tool;
 pub fn core_builtin_tools(
     session: workdir::WorkdirSessionHandle,
     tracker: Tracker,
-    bash_output_dir: std::path::PathBuf,
+    bash_output: bash_output::BashOutputView,
 ) -> Vec<agen::tool::ToolDefinition> {
     use workdir::WorkdirSessionCapability;
 
@@ -58,7 +59,7 @@ pub fn core_builtin_tools(
         tools.push(grep::routed_grep_tool(router.clone()));
     }
     if capabilities.supports(WorkdirSessionCapability::Command) {
-        tools.push(bash::routed_bash_tool(router, bash_output_dir));
+        tools.push(bash::routed_bash_tool(router, bash_output));
     }
     tools
 }
@@ -71,7 +72,7 @@ pub fn core_builtin_tools(
 pub fn routed_builtin_tools(
     router: std::sync::Arc<workdir::WorkdirSessionRouter>,
     tracker: Tracker,
-    bash_output_dir: std::path::PathBuf,
+    bash_output: bash_output::BashOutputView,
 ) -> Vec<agen::tool::ToolDefinition> {
     vec![
         read::routed_read_tool(router.clone(), tracker.clone()),
@@ -79,14 +80,14 @@ pub fn routed_builtin_tools(
         edit::routed_edit_tool(router.clone(), tracker),
         glob::routed_glob_tool(router.clone()),
         grep::routed_grep_tool(router.clone()),
-        bash::routed_bash_tool(router, bash_output_dir),
+        bash::routed_bash_tool(router, bash_output),
     ]
 }
 
 pub fn routed_builtin_tools_for_current_capabilities(
     router: std::sync::Arc<workdir::WorkdirSessionRouter>,
     tracker: Tracker,
-    bash_output_dir: std::path::PathBuf,
+    bash_output: bash_output::BashOutputView,
 ) -> Vec<agen::tool::ToolDefinition> {
     use workdir::WorkdirSessionCapability;
 
@@ -108,7 +109,7 @@ pub fn routed_builtin_tools_for_current_capabilities(
         tools.push(grep::routed_grep_tool(router.clone()));
     }
     if capabilities.supports(WorkdirSessionCapability::Command) {
-        tools.push(bash::routed_bash_tool(router, bash_output_dir));
+        tools.push(bash::routed_bash_tool(router, bash_output));
     }
     tools
 }
@@ -121,7 +122,7 @@ pub fn read_only_builtin_tools(
         workdir::WorkdirSessionCapabilities::READ_ONLY,
         "read-only tool projection requires a read-only Workdir session"
     );
-    core_builtin_tools(session, Tracker::new(), std::path::PathBuf::new())
+    core_builtin_tools(session, Tracker::new(), bash_output::BashOutputView::new())
 }
 
 pub fn read_only_routed_builtin_tools(
@@ -173,7 +174,7 @@ mod workdir_tool_tests {
             SharedScope::new(Scope::writable(dir.path()).unwrap()),
             WorkdirSessionCapabilities::READ_ONLY,
         ));
-        let names = core_builtin_tools(session, Tracker::new(), dir.path().join("output"))
+        let names = core_builtin_tools(session, Tracker::new(), bash_output::BashOutputView::new())
             .into_iter()
             .map(|definition| definition().0.name)
             .collect::<Vec<_>>();

crates/tools/tests/edge_cases.rs

@@ -3,7 +3,7 @@
 use std::sync::Arc;
 
 use agen::tool::{Tool, ToolDefinition};
-use manifest::{Permission, Scope, ScopeConfig, ScopeRule};
+use manifest::Scope;
 use serde_json::json;
 use tempfile::TempDir;
 use tools::{Tracker, core_builtin_tools};
@@ -28,31 +28,23 @@ impl Registry {
     }
 }
 
-fn setup() -> (TempDir, TempDir, Registry) {
+fn setup() -> (TempDir, Registry) {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let base = Scope::writable(dir.path()).unwrap();
-    let mut config = ScopeConfig {
-        allow: base.allow_rules(),
-        deny: base.deny_rules(),
-    };
-    config.allow.push(ScopeRule {
-        target: spill.path().to_path_buf(),
-        permission: Permission::Read,
-        recursive: true,
-        symlink_policy: Default::default(),
-    });
-    let scope = Scope::from_config(&config).unwrap();
+    let scope = Scope::writable(dir.path()).unwrap();
     let fs: WorkdirSessionHandle =
         std::sync::Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let tracker = Tracker::new();
-    let reg = Registry::new(core_builtin_tools(fs, tracker, spill.path().to_path_buf()));
-    (dir, spill, reg)
+    let reg = Registry::new(core_builtin_tools(
+        fs,
+        tracker,
+        tools::bash_output::BashOutputView::new(),
+    ));
+    (dir, reg)
 }
 
 #[tokio::test]
 async fn unicode_path_and_content() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("日本語ファイル.txt");
     let content = "こんにちは 🦀 世界\nabc\n";
 
@@ -87,7 +79,7 @@ async fn unicode_path_and_content() {
 async fn symlink_to_outside_scope_is_rejected_for_write() {
     use std::os::unix::fs::symlink;
 
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let outside = TempDir::new().unwrap();
     let outside_target = outside.path().join("secret.txt");
     std::fs::write(&outside_target, "secret").unwrap();
@@ -151,7 +143,7 @@ async fn symlink_to_outside_scope_is_rejected_for_write() {
 async fn broken_symlink_reports_target_and_repair_hint() {
     use std::os::unix::fs::symlink;
 
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let link = dir.path().join("external-project");
     let target = dir.path().join("missing-target");
     symlink(&target, &link).unwrap();
@@ -173,7 +165,7 @@ async fn broken_symlink_reports_target_and_repair_hint() {
 
 #[tokio::test]
 async fn empty_file_read_and_edit() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("empty.txt");
     std::fs::write(&file, "").unwrap();
 
@@ -207,7 +199,7 @@ async fn empty_file_read_and_edit() {
 
 #[tokio::test]
 async fn very_long_single_line() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("long.txt");
     let big: String = "x".repeat(1024 * 1024); // 1 MiB, no newlines
     std::fs::write(&file, &big).unwrap();
@@ -226,7 +218,7 @@ async fn very_long_single_line() {
 
 #[tokio::test]
 async fn absolute_path_requires_matching_read_scope() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     let outside = tempfile::tempdir().unwrap();
     let outside_file = outside.path().join("outside.txt");
     std::fs::write(&outside_file, "secret").unwrap();
@@ -247,7 +239,7 @@ async fn absolute_path_requires_matching_read_scope() {
 
 #[tokio::test]
 async fn directory_target_is_rejected_for_read() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     let read = reg.get("Read");
     let err = read
         .execute(&json!({ "file_path": "." }).to_string(), Default::default())
@@ -258,7 +250,7 @@ async fn directory_target_is_rejected_for_read() {
 
 #[tokio::test]
 async fn deeply_nested_new_file_is_created() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let deep = dir.path().join("a/b/c/d/e/deep.txt");
     let write = reg.get("Write");
     write
@@ -277,7 +269,7 @@ async fn deeply_nested_new_file_is_created() {
 
 #[tokio::test]
 async fn replace_preserves_unicode() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("u.txt");
     std::fs::write(&file, "🦀 rust 🦀\n").unwrap();
 
@@ -306,7 +298,7 @@ async fn replace_preserves_unicode() {
 
 #[tokio::test]
 async fn grep_handles_unicode_pattern() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("u.txt");
     std::fs::write(&file, "English\n日本語\nрусский\n").unwrap();
 

crates/tools/tests/integration.rs

@@ -11,7 +11,7 @@ use agen::tool::{
     Tool, ToolDefinition, ToolError, ToolExecutionContext, ToolExecutionHandle,
     ToolExecutionTerminal, ToolMeta,
 };
-use manifest::{Permission, Scope, ScopeConfig, ScopeRule};
+use manifest::Scope;
 use serde_json::json;
 use tempfile::TempDir;
 use tools::{
@@ -23,21 +23,6 @@ use workdir::{
     WorkdirToolScopeRule,
 };
 
-fn scope_with_spill(workspace: &Path, spill: &Path) -> Scope {
-    let base = Scope::writable(workspace).unwrap();
-    let mut config = ScopeConfig {
-        allow: base.allow_rules(),
-        deny: base.deny_rules(),
-    };
-    config.allow.push(ScopeRule {
-        target: spill.to_path_buf(),
-        permission: Permission::Read,
-        recursive: true,
-        symlink_policy: Default::default(),
-    });
-    Scope::from_config(&config).unwrap()
-}
-
 struct Registry {
     entries: Vec<(ToolMeta, Arc<dyn Tool>)>,
 }
@@ -61,39 +46,38 @@ impl Registry {
     }
 }
 
-fn setup() -> (TempDir, TempDir, Registry) {
+fn setup() -> (TempDir, Registry) {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let fs: WorkdirSessionHandle =
         Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let tracker = Tracker::new();
-    let reg = Registry::new(core_builtin_tools(fs, tracker, spill.path().to_path_buf()));
-    (dir, spill, reg)
+    let reg = Registry::new(core_builtin_tools(
+        fs,
+        tracker,
+        tools::bash_output::BashOutputView::new(),
+    ));
+    (dir, reg)
 }
 
-fn setup_routed() -> (
-    TempDir,
-    TempDir,
-    TempDir,
-    Arc<WorkdirSessionRouter>,
-    Registry,
-) {
+fn setup_routed() -> (TempDir, TempDir, Arc<WorkdirSessionRouter>, Registry) {
     let left = TempDir::new().unwrap();
     let right = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
     let router = Arc::new(WorkdirSessionRouter::new());
     for (alias, dir) in [("left", &left), ("right", &right)] {
-        let scope = scope_with_spill(dir.path(), spill.path());
+        let scope = Scope::writable(dir.path()).unwrap();
         let session: WorkdirSessionHandle =
             Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
         router
             .attach(WorkdirAttachmentAlias::new(alias).unwrap(), session)
             .unwrap();
     }
-    let definitions =
-        routed_builtin_tools(router.clone(), Tracker::new(), spill.path().to_path_buf());
-    (left, right, spill, router, Registry::new(definitions))
+    let definitions = routed_builtin_tools(
+        router.clone(),
+        Tracker::new(),
+        tools::bash_output::BashOutputView::new(),
+    );
+    (left, right, router, Registry::new(definitions))
 }
 
 fn valid_gif_with_len(target_len: usize) -> Vec<u8> {
@@ -137,7 +121,7 @@ async fn call_err(tool: &Arc<dyn Tool>, input: serde_json::Value) -> agen::tool:
 
 #[test]
 fn core_builtin_tools_registers_full_set() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     let mut names = reg.names();
     names.sort();
     assert_eq!(names, vec!["Bash", "Edit", "Glob", "Grep", "Read", "Write"]);
@@ -145,7 +129,7 @@ fn core_builtin_tools_registers_full_set() {
 
 #[test]
 fn meta_has_description_and_schema() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     for (meta, _) in &reg.entries {
         assert!(
             !meta.description.is_empty(),
@@ -163,7 +147,7 @@ fn meta_has_description_and_schema() {
 
 #[test]
 fn routed_tool_schemas_share_optional_target_workdir() {
-    let (_left, _right, _spill, router, mut reg) = setup_routed();
+    let (_left, _right, router, mut reg) = setup_routed();
     reg.entries.push(routed_view_image_tool(router)());
     for (meta, _) in &reg.entries {
         let target = &meta.input_schema["properties"]["target_workdir"];
@@ -174,7 +158,7 @@ fn routed_tool_schemas_share_optional_target_workdir() {
 
 #[tokio::test]
 async fn routed_tools_require_alias_only_when_attachment_set_is_ambiguous() {
-    let (_left, _right, _spill, router, reg) = setup_routed();
+    let (_left, _right, router, reg) = setup_routed();
     let error = call_err(&reg.get("Read"), json!({ "file_path": "same.txt" })).await;
     let message = error.to_string();
     assert!(message.contains("target_workdir_required"), "{message}");
@@ -199,7 +183,7 @@ async fn empty_routed_surface_returns_no_attachment_error() {
     let reg = Registry::new(routed_builtin_tools(
         router,
         Tracker::new(),
-        Path::new("unused").to_path_buf(),
+        tools::bash_output::BashOutputView::new(),
     ));
     let message = call_err(&reg.get("Read"), json!({ "file_path": "file.txt" }))
         .await
@@ -209,7 +193,7 @@ async fn empty_routed_surface_returns_no_attachment_error() {
 
 #[tokio::test]
 async fn target_alias_routes_each_tool_and_isolates_read_before_edit() {
-    let (left, right, _spill, router, mut reg) = setup_routed();
+    let (left, right, router, mut reg) = setup_routed();
     std::fs::write(left.path().join("same.txt"), "left value\n").unwrap();
     std::fs::write(right.path().join("same.txt"), "right value\n").unwrap();
     std::fs::write(left.path().join("only-left.log"), "LEFT-NEEDLE\n").unwrap();
@@ -282,7 +266,7 @@ async fn target_alias_routes_each_tool_and_isolates_read_before_edit() {
     )
     .await;
     assert_eq!(
-        std::fs::canonicalize(bash.content.unwrap().trim()).unwrap(),
+        std::fs::canonicalize(serde_json::from_str::<serde_json::Value>(&bash.content.unwrap()).unwrap()["stdout_preview"].as_str().unwrap().trim()).unwrap(),
         std::fs::canonicalize(right.path()).unwrap()
     );
 
@@ -304,13 +288,12 @@ async fn target_alias_routes_each_tool_and_isolates_read_before_edit() {
 async fn selected_attachment_capability_is_checked_without_fallback() {
     let left = TempDir::new().unwrap();
     let right = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
     let router = Arc::new(WorkdirSessionRouter::new());
     router
         .attach(
             WorkdirAttachmentAlias::new("writable").unwrap(),
             Arc::new(LocalWorkdirSession::new(
-                scope_with_spill(left.path(), spill.path()),
+                Scope::writable(left.path()).unwrap(),
                 left.path().to_path_buf(),
             )),
         )
@@ -322,7 +305,7 @@ async fn selected_attachment_capability_is_checked_without_fallback() {
                 workdir::Workdir::new("readonly"),
                 right.path().to_path_buf(),
                 right.path().to_path_buf(),
-                manifest::SharedScope::new(scope_with_spill(right.path(), spill.path())),
+                manifest::SharedScope::new(Scope::writable(right.path()).unwrap()),
                 workdir::WorkdirSessionCapabilities::READ_ONLY,
             )),
         )
@@ -330,7 +313,7 @@ async fn selected_attachment_capability_is_checked_without_fallback() {
     let reg = Registry::new(routed_builtin_tools(
         router.clone(),
         Tracker::new(),
-        spill.path().to_path_buf(),
+        tools::bash_output::BashOutputView::new(),
     ));
 
     let message = call_err(
@@ -352,7 +335,7 @@ async fn selected_attachment_capability_is_checked_without_fallback() {
 
 #[tokio::test]
 async fn routed_tools_observe_detach_after_registration() {
-    let (_left, _right, _spill, router, reg) = setup_routed();
+    let (_left, _right, router, reg) = setup_routed();
     let alias = WorkdirAttachmentAlias::new("left").unwrap();
     router.detach(&alias).await.unwrap();
 
@@ -372,7 +355,6 @@ async fn routed_tools_observe_detach_after_registration() {
 async fn detach_and_reattach_same_alias_requires_a_fresh_read() {
     let first = TempDir::new().unwrap();
     let second = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
     std::fs::write(first.path().join("same.txt"), "same bytes\n").unwrap();
     std::fs::write(second.path().join("same.txt"), "same bytes\n").unwrap();
 
@@ -382,7 +364,7 @@ async fn detach_and_reattach_same_alias_requires_a_fresh_read() {
         .attach(
             alias.clone(),
             Arc::new(LocalWorkdirSession::new(
-                scope_with_spill(first.path(), spill.path()),
+                Scope::writable(first.path()).unwrap(),
                 first.path().to_path_buf(),
             )),
         )
@@ -390,7 +372,7 @@ async fn detach_and_reattach_same_alias_requires_a_fresh_read() {
     let reg = Registry::new(routed_builtin_tools(
         router.clone(),
         Tracker::new(),
-        spill.path().to_path_buf(),
+        tools::bash_output::BashOutputView::new(),
     ));
     call(
         &reg.get("Read"),
@@ -403,7 +385,7 @@ async fn detach_and_reattach_same_alias_requires_a_fresh_read() {
         .attach(
             alias.clone(),
             Arc::new(LocalWorkdirSession::new(
-                scope_with_spill(second.path(), spill.path()),
+                Scope::writable(second.path()).unwrap(),
                 second.path().to_path_buf(),
             )),
         )
@@ -432,6 +414,8 @@ async fn detach_and_reattach_same_alias_requires_a_fresh_read() {
 struct ExternalValidatingSession {
     inner: LocalWorkdirSession,
     truncate_first_binary_response: bool,
+    command_response_losses: std::sync::atomic::AtomicUsize,
+    lose_terminal_only: bool,
     mutate_after_first_binary_response: Option<std::path::PathBuf>,
 }
 
@@ -550,7 +534,23 @@ impl workdir::WorkdirSession for ExternalValidatingSession {
         &self,
         request: workdir::CommandOutputRequest,
     ) -> Result<workdir::CommandOutput, workdir::WorkdirError> {
-        self.inner.command_output(request).await
+        let output = self.inner.command_output(request).await?;
+        if (!self.lose_terminal_only || output.terminal.is_some())
+            && self
+                .command_response_losses
+                .fetch_update(
+                    std::sync::atomic::Ordering::AcqRel,
+                    std::sync::atomic::Ordering::Acquire,
+                    |remaining| remaining.checked_sub(1),
+                )
+                .is_ok()
+        {
+            // The production provider has committed a page, but its response is lost.
+            return Err(workdir::WorkdirError::Transport(
+                "injected lost response".into(),
+            ));
+        }
+        Ok(output)
     }
 
     async fn cancel_command(
@@ -568,11 +568,12 @@ impl workdir::WorkdirSession for ExternalValidatingSession {
 #[tokio::test]
 async fn external_view_image_uses_a_protocol_bounded_request() {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let session: WorkdirSessionHandle = Arc::new(ExternalValidatingSession {
         inner: LocalWorkdirSession::new(scope, dir.path().to_path_buf()),
         truncate_first_binary_response: false,
+        command_response_losses: std::sync::atomic::AtomicUsize::new(0),
+        lose_terminal_only: false,
         mutate_after_first_binary_response: None,
     });
     let png = include_bytes!("fixtures/view-image/valid.png");
@@ -590,13 +591,14 @@ async fn external_view_image_uses_a_protocol_bounded_request() {
 #[tokio::test]
 async fn external_view_image_rejects_truncated_and_cross_version_chunks() {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
     let image_path = dir.path().join("image.png");
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     std::fs::write(&image_path, include_bytes!("fixtures/view-image/valid.png")).unwrap();
     let truncated: WorkdirSessionHandle = Arc::new(ExternalValidatingSession {
         inner: LocalWorkdirSession::new(scope.clone(), dir.path().to_path_buf()),
         truncate_first_binary_response: true,
+        command_response_losses: std::sync::atomic::AtomicUsize::new(0),
+        lose_terminal_only: false,
         mutate_after_first_binary_response: None,
     });
     let (_meta, tool) = view_image_tool(truncated)();
@@ -613,6 +615,8 @@ async fn external_view_image_rejects_truncated_and_cross_version_chunks() {
     let changing: WorkdirSessionHandle = Arc::new(ExternalValidatingSession {
         inner: LocalWorkdirSession::new(scope, dir.path().to_path_buf()),
         truncate_first_binary_response: false,
+        command_response_losses: std::sync::atomic::AtomicUsize::new(0),
+        lose_terminal_only: false,
         mutate_after_first_binary_response: Some(image_path),
     });
     let (_meta, tool) = view_image_tool(changing)();
@@ -626,8 +630,7 @@ async fn external_view_image_rejects_truncated_and_cross_version_chunks() {
 async fn view_image_enforces_the_ten_mib_boundary_without_partial_attachments() {
     const LIMIT: usize = 10 * 1024 * 1024;
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let session: WorkdirSessionHandle =
         Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let (_meta, tool) = view_image_tool(session)();
@@ -650,8 +653,7 @@ async fn view_image_enforces_the_ten_mib_boundary_without_partial_attachments()
 #[tokio::test]
 async fn view_image_attaches_valid_supported_image_fixtures() {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let session: WorkdirSessionHandle =
         Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let (_meta, tool) = view_image_tool(session)();
@@ -726,8 +728,7 @@ async fn delegated_view_image_preserves_caller_relative_path_identity() {
 #[tokio::test]
 async fn view_image_reads_scoped_bytes_into_durable_tool_detail() {
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let session: WorkdirSessionHandle =
         Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let png = include_bytes!("fixtures/view-image/valid.png");
@@ -752,7 +753,7 @@ async fn view_image_reads_scoped_bytes_into_durable_tool_detail() {
 
 #[tokio::test]
 async fn read_then_edit_then_read_roundtrip() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("a.txt");
     std::fs::write(&file, "hello world\n").unwrap();
     let p = "a.txt";
@@ -784,7 +785,7 @@ async fn read_then_edit_then_read_roundtrip() {
 
 #[tokio::test]
 async fn write_then_grep_finds_content() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let write = reg.get("Write");
     let grep = reg.get("Grep");
 
@@ -813,7 +814,7 @@ async fn write_then_grep_finds_content() {
 
 #[tokio::test]
 async fn glob_finds_written_files() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     let write = reg.get("Write");
     let glob = reg.get("Glob");
 
@@ -837,7 +838,7 @@ async fn glob_finds_written_files() {
 
 #[tokio::test]
 async fn absolute_path_is_rejected() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     let outside = TempDir::new().unwrap();
     let write = reg.get("Write");
 
@@ -859,7 +860,7 @@ async fn absolute_path_is_rejected() {
 
 #[tokio::test]
 async fn write_to_existing_without_read_fails() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("exists.txt");
     std::fs::write(&file, "preexisting").unwrap();
 
@@ -880,7 +881,7 @@ async fn write_to_existing_without_read_fails() {
 async fn shared_workdir_across_tools() {
     // The key invariant: all builtin tools share the same WorkdirSession instance,
     // so read-history set by Read is visible to Edit and Write.
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("shared.txt");
     std::fs::write(&file, "one\n").unwrap();
 
@@ -907,7 +908,7 @@ async fn shared_workdir_across_tools() {
 
 #[tokio::test]
 async fn edit_requires_read_across_tools() {
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let file = dir.path().join("a.txt");
     std::fs::write(&file, "foo\n").unwrap();
 
@@ -928,7 +929,7 @@ async fn edit_requires_read_across_tools() {
 
 #[tokio::test]
 async fn deterministic_tool_order_is_registration_order() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     // Registration order from core_builtin_tools(): Read, Write, Edit, Glob, Grep, Bash
     let names: Vec<&str> = reg.entries.iter().map(|(m, _)| m.name.as_str()).collect();
     assert_eq!(
@@ -940,7 +941,7 @@ async fn deterministic_tool_order_is_registration_order() {
 // Regression: tool name capitalization matches Claude Code reference
 #[test]
 fn tool_names_match_reference_spec() {
-    let (_dir, _spill, reg) = setup();
+    let (_dir, reg) = setup();
     for expected in ["Read", "Write", "Edit", "Glob", "Grep", "Bash"] {
         assert!(
             reg.entries.iter().any(|(m, _)| m.name == expected),
@@ -953,15 +954,14 @@ fn tool_names_match_reference_spec() {
 async fn tracker_recent_files_tracks_read_write_edit() {
     // Build a fresh registry that shares a tracker we can query afterwards.
     let dir = TempDir::new().unwrap();
-    let spill = TempDir::new().unwrap();
-    let scope = scope_with_spill(dir.path(), spill.path());
+    let scope = Scope::writable(dir.path()).unwrap();
     let fs: WorkdirSessionHandle =
         Arc::new(LocalWorkdirSession::new(scope, dir.path().to_path_buf()));
     let tracker = Tracker::new();
     let reg = Registry::new(core_builtin_tools(
         fs,
         tracker.clone(),
-        spill.path().to_path_buf(),
+        tools::bash_output::BashOutputView::new(),
     ));
 
     let a = dir.path().join("a.txt");
@@ -1003,118 +1003,314 @@ async fn tracker_recent_files_tracks_read_write_edit() {
 async fn bash_inherits_workdir_cwd() {
     // The Bash tool starts at the WorkdirSession's pwd. Without any `cd`, its
     // `pwd` should canonicalize to the workspace root we set up.
-    let (dir, _spill, reg) = setup();
+    let (dir, reg) = setup();
     let bash = reg.get("Bash");
     let out = call(&bash, json!({ "command": "pwd", "cwd": "." })).await;
     let body = out.content.unwrap();
-    let actual = std::fs::canonicalize(body.trim()).unwrap();
+    let parsed: serde_json::Value = serde_json::from_str(&body).unwrap();
+    let actual = std::fs::canonicalize(parsed["stdout_preview"].as_str().unwrap().trim()).unwrap();
     let expected = std::fs::canonicalize(dir.path()).unwrap();
     assert_eq!(actual, expected);
 }
 
+fn output_fixture() -> (
+    TempDir,
+    WorkdirSessionHandle,
+    tools::bash_output::BashOutputView,
+    Arc<dyn Tool>,
+) {
+    let root = TempDir::new().unwrap();
+    let session: WorkdirSessionHandle = Arc::new(LocalWorkdirSession::new(
+        Scope::writable(root.path()).unwrap(),
+        root.path().into(),
+    ));
+    let view = tools::bash_output::BashOutputView::new();
+    let (_, bash) = tools::bash_tool(session.clone(), view.clone())();
+    (root, session, view, bash)
+}
+
 #[tokio::test]
-async fn bash_provider_output_exposes_readable_retained_path() {
-    let (_dir, spill, reg) = setup();
-    let bash = reg.get("Bash");
+async fn bash_output_is_retained_without_a_filesystem_grant_or_telemetry_subscriber() {
+    let (root, _session, view, bash) = output_fixture();
     let out = call(
         &bash,
-        json!({ "command": "printf 'x%.0s' {1..20480}", "cwd": "." }),
+        json!({ "command": "printf 'x%.0s' {1..20480}; printf '\\377€' >&2; exit 7", "cwd": "." }),
     )
     .await;
-    let body = out.content.unwrap();
-    assert!(body.contains("bounded WorkdirSession command output"));
-    assert!(body.contains("full output saved to"));
-    assert!(body.contains(spill.path().to_str().unwrap()));
-    let artifact = std::fs::read_dir(spill.path())
-        .unwrap()
-        .next()
-        .expect("retained output")
-        .unwrap()
-        .path();
-    assert_eq!(std::fs::metadata(artifact).unwrap().len(), 20_480);
+    let body: serde_json::Value = serde_json::from_str(&out.content.unwrap()).unwrap();
+    assert_eq!(body["output"]["terminal"]["exit_code"], 7);
+    assert_eq!(body["preview_omitted"], true);
+    assert_eq!(body["output"]["storage_truncated"], false);
+    let id = body["output"]["id"].as_str().unwrap();
+    assert_eq!(
+        view.read(id, workdir::CommandStream::Stdout, 0, 65536)
+            .unwrap(),
+        vec![b'x'; 20480]
+    );
+    assert_eq!(
+        view.read(id, workdir::CommandStream::Stderr, 0, 65536)
+            .unwrap(),
+        [vec![255], "€".as_bytes().to_vec()].concat()
+    );
+    assert!(
+        body["stdout_entry"]
+            .as_str()
+            .unwrap()
+            .starts_with("/bash-output/")
+    );
+    assert!(!body.to_string().contains(root.path().to_str().unwrap()));
+    assert_eq!(std::fs::read_dir(root.path()).unwrap().count(), 0);
+}
+
+async fn await_command_output(
+    events: &mut tokio::sync::broadcast::Receiver<workdir::CommandEvent>,
+) {
+    tokio::time::timeout(std::time::Duration::from_secs(5), async {
+        loop {
+            if matches!(
+                events.recv().await.unwrap(),
+                workdir::CommandEvent::Output { .. }
+            ) {
+                break;
+            }
+        }
+    })
+    .await
+    .expect("command output readiness");
+}
+async fn await_command_terminal(
+    events: &mut tokio::sync::broadcast::Receiver<workdir::CommandEvent>,
+) {
+    tokio::time::timeout(std::time::Duration::from_secs(5), async {
+        loop {
+            if let workdir::CommandEvent::Terminal { status, .. } = events.recv().await.unwrap() {
+                assert_eq!(status, workdir::CommandStatus::Cancelled);
+                break;
+            }
+        }
+    })
+    .await
+    .expect("command terminal fence");
 }
 
 #[tokio::test]
 async fn bash_cancellation_returns_bounded_progress_as_terminal_output() {
-    let (dir, _spill, reg) = setup();
-    let marker = dir.path().join("must-not-run-after-cancel");
-    let command = format!(
-        "printf 'before\\n'; printf 'err-before\\n' >&2; sleep 1; touch {}; printf 'after\\n'",
-        marker.display()
-    );
-    let input = serde_json::to_string(&json!({ "command": command, "cwd": "." })).unwrap();
+    let (_root, session, _view, bash) = output_fixture();
+    let mut events = session.subscribe_command_events().unwrap();
     let context = ToolExecutionContext::new("call-heavy", "attempt-heavy", 0);
-    let bash = reg.get("Bash");
     let executing = bash.clone();
     let execution_context = context.clone();
-    let execution = tokio::spawn(async move { executing.execute(&input, execution_context).await });
-
-    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
-    bash.cancel_execution(&context)
-        .await
-        .expect("signal exact execution cancellation");
-    let error = tokio::time::timeout(std::time::Duration::from_secs(2), execution)
-        .await
-        .expect("cancelled Bash should terminate inside the Engine grace budget")
-        .expect("Bash task join");
-
-    let ToolError::Cancelled(output) = error.expect_err("cancelled command is non-success") else {
-        panic!("expected typed cancellation result");
+    let execution = tokio::spawn(async move {
+        executing.execute(r#"{"command":"printf 'before'; printf 'err-before' >&2; while :; do :; done","cwd":"."}"#, execution_context).await
+    });
+    await_command_output(&mut events).await;
+    bash.cancel_execution(&context).await.unwrap();
+    let ToolError::Cancelled(output) =
+        tokio::time::timeout(std::time::Duration::from_secs(5), execution)
+            .await
+            .unwrap()
+            .unwrap()
+            .unwrap_err()
+    else {
+        panic!("expected cancellation");
     };
-    let content = output.content.expect("bounded progress output");
-    assert!(
-        content.contains("before"),
-        "missing pre-cancel stdout: {content}"
-    );
-    assert!(
-        content.contains("err-before"),
-        "missing pre-cancel stderr: {content}"
-    );
-    assert!(
-        !content.contains("after"),
-        "post-cancel output leaked: {content}"
-    );
-    assert!(content.len() <= 16 * 1024, "output must remain bounded");
-
-    tokio::time::sleep(std::time::Duration::from_millis(1_100)).await;
-    assert!(
-        !marker.exists(),
-        "the cancelled command continued executing after terminal confirmation"
-    );
+    let body: serde_json::Value = serde_json::from_str(&output.content.unwrap()).unwrap();
+    assert_eq!(body["stdout_preview"], "before");
+    assert_eq!(body["stderr_preview"], "err-before");
+    assert_eq!(body["output"]["terminal"]["status"], "cancelled");
+    assert_eq!(body["output"]["terminal"]["transport_complete"], true);
 }
 
 #[tokio::test]
 async fn bash_force_close_cleanup_stops_command_and_keeps_session_reusable() {
-    let (dir, _spill, reg) = setup();
-    let marker = dir.path().join("must-not-survive-force-close");
-    let command = format!("sleep 1; touch {}", marker.display());
-    let input = serde_json::to_string(&json!({ "command": command, "cwd": "." })).unwrap();
-    let bash = reg.get("Bash");
+    let (_root, session, _view, bash) = output_fixture();
+    let mut events = session.subscribe_command_events().unwrap();
     let context = ToolExecutionContext::new("call-force", "attempt-force", 0);
-    let (handle, terminal) = ToolExecutionHandle::start(bash.clone(), input, context);
-
-    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+    let (handle, terminal) = ToolExecutionHandle::start(
+        bash.clone(),
+        r#"{"command":"printf ready; while :; do :; done","cwd":"."}"#.into(),
+        context,
+    );
+    await_command_output(&mut events).await;
     handle.force_close();
     assert!(matches!(
         terminal.await,
         ToolExecutionTerminal::OutcomeUnknown
     ));
-
-    tokio::time::sleep(std::time::Duration::from_millis(1_100)).await;
-    assert!(
-        !marker.exists(),
-        "CommandGuard cleanup allowed a force-closed command to continue"
-    );
-
-    let output = bash
-        .execute(
-            r#"{"command":"printf 'reused'","cwd":"."}"#,
-            Default::default(),
-        )
-        .await
-        .expect("workdir session remains reusable after cleanup");
-    assert_eq!(output.content.as_deref(), Some("reused"));
+    await_command_terminal(&mut events).await;
+    let output = call(&bash, json!({"command":"printf reused", "cwd":"."})).await;
+    let body: serde_json::Value = serde_json::from_str(&output.content.unwrap()).unwrap();
+    assert_eq!(body["stdout_preview"], "reused");
 }
 
 // Sanity: unused Path import guard
 const _: fn() -> &'static Path = || Path::new("/");
+
+#[tokio::test]
+async fn parent_and_sibling_broker_commands_keep_output_ownership_after_revoke() {
+    let (root, source, parent_view, parent_bash) = output_fixture();
+    let broker = WorkdirToolBroker::new(source);
+    let mut leases = Vec::new();
+    let mut views = Vec::new();
+    let mut commands = Vec::new();
+    for name in ["left", "right"] {
+        std::fs::create_dir(root.path().join(name)).unwrap();
+        let lease = Arc::new(
+            broker
+                .scope(WorkdirToolScope {
+                    rules: vec![WorkdirToolScopeRule {
+                        target: WorkdirPath::new(name).unwrap(),
+                        permission: WorkdirToolScopePermission::Write,
+                        recursive: true,
+                        symlink_policy: Default::default(),
+                    }],
+                    cwd: WorkdirPath::new(name).unwrap(),
+                    command: true,
+                })
+                .await
+                .unwrap(),
+        );
+        let authority = lease.clone();
+        let view = parent_view.child(Arc::new(move || authority.is_active()));
+        let (_, bash) = tools::bash_tool(lease.tool_session(), view.clone())();
+        leases.push(lease);
+        views.push(view);
+        commands.push(bash);
+    }
+    let left_input =
+        json!({"command":"printf 'left-%.0s' {1..10000}; printf left-err >&2", "cwd":"."});
+    let right_input =
+        json!({"command":"printf 'right-%.0s' {1..10000}; printf right-err >&2", "cwd":"."});
+    let parent_input = json!({"command":"printf parent; printf parent-err >&2", "cwd":"."});
+    let (left, right, parent) = tokio::join!(
+        call(&commands[0], left_input),
+        call(&commands[1], right_input),
+        call(&parent_bash, parent_input)
+    );
+    let outputs = [left, right, parent]
+        .map(|out| serde_json::from_str::<serde_json::Value>(&out.content.unwrap()).unwrap());
+    for (index, label) in ["left", "right", "parent"].iter().enumerate() {
+        let id = outputs[index]["output"]["id"].as_str().unwrap();
+        let bytes = parent_view
+            .read(id, workdir::CommandStream::Stderr, 0, 65536)
+            .unwrap();
+        assert_eq!(bytes, format!("{label}-err").as_bytes());
+        for (child_index, view) in views.iter().enumerate() {
+            assert_eq!(view.metadata(id).is_some(), child_index == index);
+        }
+    }
+    let left_id = outputs[0]["output"]["id"].as_str().unwrap();
+    leases[0].close().await.unwrap();
+    assert!(views[0].metadata(left_id).is_none());
+    assert!(parent_view.metadata(left_id).is_some());
+    assert!(
+        views[1]
+            .metadata(outputs[1]["output"]["id"].as_str().unwrap())
+            .is_some()
+    );
+    leases[1].close().await.unwrap();
+    broker.close().await.unwrap();
+    parent_view.revoke();
+    assert!(parent_view.metadata(left_id).is_none());
+}
+
+#[tokio::test]
+async fn utf8_quota_boundary_preserves_raw_prefix_and_reports_saved_vs_seen() {
+    let (_root, _session, view, bash) = output_fixture();
+    let out = call(
+        &bash,
+        json!({"command":"printf '%4194303s' ''; printf '€'", "cwd":"."}),
+    )
+    .await;
+    let body: serde_json::Value = serde_json::from_str(&out.content.unwrap()).unwrap();
+    let id = body["output"]["id"].as_str().unwrap();
+    let saved = body["output"]["stdout_saved"].as_u64().unwrap() as usize;
+    assert_eq!(saved, 4 * 1024 * 1024);
+    assert_eq!(body["output"]["stdout_seen"], 4 * 1024 * 1024 + 2);
+    assert_eq!(body["output"]["stderr_seen"], 0);
+    assert_eq!(body["output"]["storage_truncated"], true);
+    assert_eq!(
+        view.read(id, workdir::CommandStream::Stdout, saved - 1, 10)
+            .unwrap(),
+        vec![0xe2]
+    );
+    assert!(
+        view.line_window(id, workdir::CommandStream::Stdout, 0, 1)
+            .unwrap()
+            .is_err()
+    );
+    assert!(out.summary.starts_with("$ "));
+}
+
+#[tokio::test]
+async fn timeout_terminal_fences_retained_stdout_and_stderr() {
+    let (_root, _session, view, bash) = output_fixture();
+    let error = tokio::time::timeout(std::time::Duration::from_secs(5), bash.execute(r#"{"command":"printf before; printf err-before >&2; while :; do :; done","cwd":".","timeout":1}"#, Default::default())).await.unwrap().unwrap_err();
+    let ToolError::Interrupted(out) = error else {
+        panic!("expected timeout output");
+    };
+    let body: serde_json::Value = serde_json::from_str(&out.content.unwrap()).unwrap();
+    let id = body["output"]["id"].as_str().unwrap();
+    assert_eq!(body["output"]["terminal"]["status"], "timed_out");
+    assert_eq!(body["output"]["terminal"]["transport_complete"], true);
+    assert_eq!(
+        view.read(id, workdir::CommandStream::Stdout, 0, 65536)
+            .unwrap(),
+        b"before"
+    );
+    assert_eq!(
+        view.read(id, workdir::CommandStream::Stderr, 0, 65536)
+            .unwrap(),
+        b"err-before"
+    );
+}
+
+// Integration: real process pipes and provider replay into the production Bash collector.
+// Only response delivery is fault-injected; Runtime's HTTP suite covers actual wire routing.
+#[tokio::test]
+async fn lost_page_and_terminal_responses_replay_without_restarting_or_double_appending() {
+    for lose_terminal_only in [false, true] {
+        let dir = TempDir::new().unwrap();
+        let session = Arc::new(ExternalValidatingSession {
+            inner: LocalWorkdirSession::new(
+                Scope::writable(dir.path()).unwrap(),
+                dir.path().into(),
+            ),
+            truncate_first_binary_response: false,
+            mutate_after_first_binary_response: None,
+            command_response_losses: std::sync::atomic::AtomicUsize::new(1),
+            lose_terminal_only,
+        });
+        let view = tools::bash_output::BashOutputView::new();
+        let definitions = core_builtin_tools(session.clone(), Tracker::new(), view.clone());
+        let bash = Registry::new(definitions).get("Bash");
+        let out = call(&bash, json!({"cwd":".","command":"printf once >> effect.txt; printf 'x%.0s' {1..200000}; printf err >&2; exit 3"})).await;
+        let body: serde_json::Value = serde_json::from_str(&out.content.unwrap()).unwrap();
+        assert_eq!(
+            std::fs::read(dir.path().join("effect.txt")).unwrap(),
+            b"once"
+        );
+        assert_eq!(
+            session
+                .command_response_losses
+                .load(std::sync::atomic::Ordering::Acquire),
+            0
+        );
+        assert_eq!(body["output"]["stdout_saved"], 200000);
+        assert_eq!(body["output"]["stdout_delivered"], 200000);
+        assert_eq!(body["output"]["stderr_saved"], 3);
+        assert_eq!(body["output"]["terminal"]["exit_code"], 3);
+        assert_eq!(body["output"]["terminal"]["transport_complete"], true);
+        assert_eq!(body["output"]["storage_truncated"], false);
+        let id = body["output"]["id"].as_str().unwrap();
+        for offset in (0..200000).step_by(65536) {
+            assert_eq!(
+                view.read(id, workdir::CommandStream::Stdout, offset, 65536)
+                    .unwrap(),
+                vec![b'x'; (200000 - offset).min(65536)]
+            );
+        }
+        use workdir::WorkdirSession as _;
+        session.close().await.unwrap();
+    }
+}

crates/tui/src/app.rs

@@ -3013,7 +3013,8 @@ impl App {
     /// `[File: …]` parsing path: each kind maps directly to a typed
     /// block (`Block::Notify`, `Block::WorkerEvent`, …).
     fn apply_system_item(&mut self, value: &serde_json::Value) {
-        let Ok(item) = serde_json::from_value::<session_store::SystemItem>(value.clone()) else {
+        let Ok(item) = serde_json::from_value::<session_store::PublicSystemItem>(value.clone())
+        else {
             // Unknown / forward-compat shape: fall back to rendering the
             // raw text payload (if any) as a generic system message.
             if let Some(text) = value.get("body").and_then(|b| b.as_str()) {
@@ -3024,29 +3025,23 @@ impl App {
             }
             return;
         };
-        match item {
-            session_store::SystemItem::Notification { message, .. } => {
+        let body = item.body;
+        match item.presentation {
+            session_store::PublicSystemPresentation::Notification { message } => {
                 self.blocks.push(Block::Notify { message });
             }
-            session_store::SystemItem::WorkerEvent { event, .. } => {
+            session_store::PublicSystemPresentation::WorkerEvent { event } => {
                 self.blocks.push(Block::WorkerEvent { event });
             }
-            session_store::SystemItem::FeatureInvocationResult { body, .. }
-            | session_store::SystemItem::FileAttachment { body, .. }
-            | session_store::SystemItem::SkillActivation { body, .. }
-            | session_store::SystemItem::JournalStartup { body, .. }
-            | session_store::SystemItem::ResidentSummaryRefresh { body, .. }
-            | session_store::SystemItem::SubjectBehaviorRefresh { body, .. }
-            | session_store::SystemItem::Interrupt { body, .. } => {
+            session_store::PublicSystemPresentation::Context => {
                 self.task_store.apply_system_message_text(&body);
                 self.blocks.push(Block::SystemMessage { text: body });
             }
-            session_store::SystemItem::TaskReminder { body, .. } => {
+            session_store::PublicSystemPresentation::TaskReminder => {
                 self.task_store.apply_system_message_text(&body);
                 self.blocks.push(Block::TaskReminder { text: body });
             }
-            session_store::SystemItem::LegacyIgnored { .. } => {}
-            session_store::SystemItem::LegacyKnowledgeIgnored { .. } => {}
+            session_store::PublicSystemPresentation::Ignored => {}
         }
     }
 
@@ -3572,6 +3567,7 @@ mod completion_flow_tests {
         session_store::LoggedHistoryEntry {
             item: session_store::LoggedItem::from(item),
             metadata: session_store::LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: session_store::LoggedSessionHistoryEntryId::new(),
                 origin: session_store::LoggedSessionHistoryOrigin::LegacyUnknown,
                 derivation: None,
@@ -4329,6 +4325,7 @@ mod completion_flow_tests {
         }));
         app.handle_worker_event(Event::SessionEntryCommitted {
             entry: protocol::SessionSnapshotEntry {
+                use_policy: None,
                 entry_id: "run-failure".into(),
                 timestamp: 2,
                 provenance: protocol::SessionEntryProvenance::LegacyUnknown,
@@ -4450,12 +4447,12 @@ mod completion_flow_tests {
     }
 
     #[test]
-    fn live_legacy_workflow_system_item_is_ignored() {
+    fn retired_system_input_is_ignored() {
         let mut app = App::new("test".into());
         let item = serde_json::json!({
-            "kind": "workflow",
-            "slug": "build",
-            "body": "[Workflow /build]\nRun the build",
+            "kind": "retired_input",
+            "body": "",
+            "presentation": { "kind": "ignored" },
         });
         app.handle_worker_event(Event::SystemItem {
             entry_id: None,
@@ -4861,12 +4858,30 @@ mod completion_flow_tests {
         );
     }
 
+    #[test]
+    fn feature_label_does_not_select_system_input_presentation() {
+        for label in ["journal_startup", "new-unregistered-feature"] {
+            let mut app = App::new("test".into());
+            app.handle_worker_event(Event::SystemItem {
+                entry_id: None,
+                item: serde_json::json!({
+                    "kind": label,
+                    "body": "explicit public content",
+                    "presentation": { "kind": "context" },
+                }),
+            });
+            assert!(
+                matches!(app.blocks.as_slice(), [Block::SystemMessage { text }] if text == "explicit public content")
+            );
+        }
+    }
+
     #[test]
     fn live_system_item_notification_appends_notify_block() {
         let mut app = App::new("test".into());
         let item = serde_json::json!({
             "kind": "notification",
-            "message": "hi",
+            "presentation": { "kind": "notification", "message": "hi" },
             "body": "[Notification] hi",
         });
         app.handle_worker_event(Event::SystemItem {
@@ -4884,7 +4899,7 @@ mod completion_flow_tests {
         let mut app = App::new("test".into());
         let item = serde_json::json!({
             "kind": "worker_event",
-            "event": { "kind": "turn_ended", "worker_name": "child" },
+            "presentation": { "kind": "worker_event", "event": { "kind": "turn_ended", "worker_name": "child" } },
             "body": "[Notification] worker `child` finished a turn",
         });
         app.handle_worker_event(Event::SystemItem {
@@ -5285,6 +5300,7 @@ mod completion_flow_tests {
             item: serde_json::json!({
                 "kind": "task_reminder",
                 "body": snapshot,
+                "presentation": { "kind": "task_reminder" },
             }),
         });
 

crates/tui/src/backend_spawn.rs

@@ -162,6 +162,7 @@ fn request_from_selection(selection: Selection) -> BackendCreateWorkerRequest {
         ticket_assignment: None,
         feature_connections: Default::default(),
         control_operation_id: None,
+        execution_grant: None,
     }
 }
 

crates/workdir/Cargo.toml

@@ -20,7 +20,7 @@ serde_json.workspace = true
 sha2.workspace = true
 tempfile.workspace = true
 thiserror.workspace = true
-tokio = { workspace = true, features = ["process", "rt", "sync", "time"] }
+tokio = { workspace = true, features = ["io-util", "process", "rt", "sync", "time"] }
 
 [dev-dependencies]
 serde_json.workspace = true

crates/workdir/src/checkout.rs

@@ -48,6 +48,10 @@ pub struct CheckoutRequest {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "operation", rename_all = "snake_case", deny_unknown_fields)]
 pub enum CheckoutOperation {
+    ReadBytes {
+        offset: u64,
+        max_bytes: usize,
+    },
     Read {
         offset: usize,
         limit: usize,
@@ -71,7 +75,7 @@ pub enum CheckoutOperation {
 impl CheckoutOperation {
     pub fn capability(&self) -> WorkdirSessionCapability {
         match self {
-            Self::Read { .. } => WorkdirSessionCapability::Read,
+            Self::Read { .. } | Self::ReadBytes { .. } => WorkdirSessionCapability::Read,
             Self::Edit { .. } => WorkdirSessionCapability::Edit,
             Self::Write { .. } | Self::Create { .. } => WorkdirSessionCapability::Write,
         }
@@ -86,6 +90,7 @@ impl CheckoutOperation {
 )]
 pub enum CheckoutOutput {
     Read(ReadResult),
+    ReadBytes(crate::ReadBytesResult),
     Write(WriteResult),
     Edit(EditResult),
 }

crates/workdir/src/command_test_support.rs

@@ -0,0 +1,43 @@
+//! Bounded collection for tests whose subject is command routing/lifecycle,
+//! rather than the byte-page protocol itself.
+
+use crate::*;
+
+#[derive(Debug)]
+pub(crate) struct CollectedCommand {
+    pub content: String,
+    pub status: CommandStatus,
+    pub exit_code: Option<i32>,
+    pub timed_out: bool,
+}
+
+#[async_trait::async_trait]
+pub(crate) trait CollectCommand: WorkdirSession {
+    async fn collect_command_output(
+        &self,
+        mut request: CommandOutputRequest,
+    ) -> Result<CollectedCommand, WorkdirError> {
+        let mut bytes = Vec::new();
+        request.wait = true;
+        loop {
+            let page = self.command_output(request.clone()).await?;
+            for chunk in page.chunks {
+                bytes.extend(chunk.bytes);
+                assert!(
+                    bytes.len() <= 16 * 1024 * 1024,
+                    "fixture output exceeded bounded test collection"
+                );
+            }
+            request.cursor = page.next_cursor;
+            if let Some(terminal) = page.terminal {
+                return Ok(CollectedCommand {
+                    content: String::from_utf8_lossy(&bytes).into_owned(),
+                    status: terminal.status,
+                    exit_code: terminal.exit_code,
+                    timed_out: terminal.status == CommandStatus::TimedOut,
+                });
+            }
+        }
+    }
+}
+impl<T: WorkdirSession + ?Sized> CollectCommand for T {}

crates/workdir/src/external.rs

@@ -9,7 +9,8 @@
 //! COMMAND remains separate explicit authority. General session capability intersections may form
 //! subsets independently of this grant hierarchy; the codec never implicitly expands nonhierarchical
 //! grants. Commands run with the shared host's OS permissions, not a sandbox confining processes
-//! to a directory. Output is bounded and inline; provider-local spill paths are not exposed.
+//! to a directory. Output uses bounded byte pages with cursor acknowledgements;
+//! providers never receive caller-selected output paths.
 
 use std::path::{Component, Path};
 
@@ -18,7 +19,7 @@ use serde::{Deserialize, Serialize};
 use crate::http::{WorkdirSessionOperation, WorkdirSessionOperationResult, WorkdirTransportError};
 use crate::{BoundedReadLimits, WorkdirId, WorkdirPath, WorkdirSessionCapabilities};
 
-pub const EXTERNAL_WORKDIR_PROVIDER_PROTOCOL_VERSION: u16 = 2;
+pub const EXTERNAL_WORKDIR_PROVIDER_PROTOCOL_VERSION: u16 = 3;
 /// Maximum serialized Backend-to-provider command frame size.
 pub const MAX_EXTERNAL_SERVER_FRAME_BYTES: usize = 1024 * 1024;
 /// Maximum serialized provider-to-Backend result frame size. Read bytes are
@@ -33,9 +34,9 @@ const MAX_EXTERNAL_GREP_CONTEXT: usize = 100;
 const MAX_EXTERNAL_SCOPE_RULES: usize = 64;
 pub const MAX_EXTERNAL_WRITE_BYTES: usize = 512 * 1024;
 pub const MAX_EXTERNAL_COMMAND_BYTES: usize = 64 * 1024;
-pub const MAX_EXTERNAL_COMMAND_OUTPUT_BYTES: usize = 512 * 1024;
+pub const MAX_EXTERNAL_COMMAND_OUTPUT_BYTES: usize = crate::MAX_COMMAND_READ_BYTES;
 pub const MAX_EXTERNAL_COMMAND_TIMEOUT_SECS: u64 = 600;
-const MAX_EXTERNAL_COMMAND_CURSOR: usize = 1_000_000;
+const MAX_EXTERNAL_COMMAND_CURSOR: u64 = crate::MAX_COMMAND_TRANSPORT_BYTES;
 
 fn valid_command_handle(handle: &crate::CommandHandle) -> bool {
     !handle.0.is_empty()
@@ -185,6 +186,11 @@ fn validate_external_operation(operation: &WorkdirSessionOperation) -> Result<()
                 && !request.validator.is_empty()
                 && request.validator.len() <= 256
                 && match &request.operation {
+                    crate::CheckoutOperation::ReadBytes { offset, max_bytes } => {
+                        *offset <= 9_007_199_254_740_991
+                            && *max_bytes > 0
+                            && *max_bytes <= BoundedReadLimits::EXTERNAL_DEFAULT.max_response_bytes
+                    }
                     crate::CheckoutOperation::Read {
                         limit, max_bytes, ..
                     } => {
@@ -267,11 +273,10 @@ fn validate_external_operation(operation: &WorkdirSessionOperation) -> Result<()
         }
         WorkdirSessionOperation::CommandStart(request) => {
             !request.command.is_empty()
+                && request.validate().is_ok()
                 && request.command.len() <= MAX_EXTERNAL_COMMAND_BYTES
                 && (1..=MAX_EXTERNAL_COMMAND_TIMEOUT_SECS).contains(&request.timeout_secs)
-                && (1..=MAX_EXTERNAL_COMMAND_OUTPUT_BYTES).contains(&request.output_limit)
                 && is_root_relative(&request.cwd)
-                && request.spill_dir.is_none()
                 && request.tool_call_id.as_ref().is_none_or(|tool_call_id| {
                     !tool_call_id.is_empty()
                         && tool_call_id.len() <= MAX_PROTOCOL_ID_BYTES
@@ -375,6 +380,13 @@ fn validate_external_result(result: &WorkdirSessionOperationResult) -> Result<()
         WorkdirSessionOperationResult::CheckoutExecute(result) => {
             valid_checkout_observation(&result.observation)
                 && match &result.output {
+                    crate::CheckoutOutput::ReadBytes(read) => {
+                        read.path == result.observation.path
+                            && validate_external_result(&WorkdirSessionOperationResult::ReadBytes(
+                                read.clone(),
+                            ))
+                            .is_ok()
+                    }
                     crate::CheckoutOutput::Read(read) => {
                         read.path == result.observation.path
                             && validate_external_result(&WorkdirSessionOperationResult::Read(
@@ -450,11 +462,19 @@ fn validate_external_result(result: &WorkdirSessionOperationResult) -> Result<()
         WorkdirSessionOperationResult::CommandStart(handle) => valid_command_handle(handle),
         WorkdirSessionOperationResult::CommandStatus(_) => true,
         WorkdirSessionOperationResult::CommandOutput(output) => {
-            output.content.len() <= MAX_EXTERNAL_COMMAND_OUTPUT_BYTES
+            output.transport_bounds_valid()
+                && output.chunks.len() <= MAX_EXTERNAL_COMMAND_OUTPUT_BYTES
                 && output
-                    .next_cursor
-                    .is_none_or(|cursor| cursor <= MAX_EXTERNAL_COMMAND_CURSOR)
-                && output.output_path.is_none()
+                    .chunks
+                    .iter()
+                    .map(|chunk| chunk.bytes.len())
+                    .sum::<usize>()
+                    <= MAX_EXTERNAL_COMMAND_OUTPUT_BYTES
+                && output.next_cursor <= MAX_EXTERNAL_COMMAND_CURSOR
+                && output
+                    .terminal
+                    .as_ref()
+                    .is_none_or(|terminal| terminal.status != crate::CommandStatus::Running)
         }
         WorkdirSessionOperationResult::CommandCancel => true,
     };
@@ -801,11 +821,16 @@ mod tests {
 
     #[test]
     fn unsupported_protocol_versions_and_invalid_read_limits_fail_closed() {
-        let future = r#"{
-            "version": 3,
-            "message": {"kind": "heartbeat", "generation": 1, "sequence": 1}
-        }"#;
-        assert!(serde_json::from_str::<ExternalWorkdirServerFrame>(future).is_err());
+        for version in [
+            EXTERNAL_WORKDIR_PROVIDER_PROTOCOL_VERSION - 1,
+            EXTERNAL_WORKDIR_PROVIDER_PROTOCOL_VERSION + 1,
+        ] {
+            let unsupported = serde_json::json!({
+                "version": version,
+                "message": {"kind": "heartbeat", "generation": 1, "sequence": 1}
+            });
+            assert!(serde_json::from_value::<ExternalWorkdirServerFrame>(unsupported).is_err());
+        }
 
         let invalid_limits = r#"{
             "max_source_bytes": 1024,
@@ -825,32 +850,35 @@ mod tests {
         assert!(ExternalWorkdirOperation::try_from(absolute).is_err());
 
         let command = WorkdirSessionOperation::CommandStart(CommandRequest {
-            command: "cat /home/operator/private/session.log".to_string(),
+            transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
+            command: "printf unsafe".to_string(),
             timeout_secs: 1,
-            output_limit: 1024,
-            cwd: WorkdirPath::root(),
-            spill_dir: Some("/home/operator/private/output".into()),
+
+            cwd: serde_json::from_value(serde_json::json!("/absolute")).unwrap(),
+
             tool_call_id: None,
         });
         assert!(ExternalWorkdirOperation::try_from(command).is_err());
 
         let command = WorkdirSessionOperation::CommandStart(CommandRequest {
+            transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
             command: "printf bounded".to_string(),
             timeout_secs: 30,
-            output_limit: 12 * 1024,
+
             cwd: WorkdirPath::root(),
-            spill_dir: None,
+
             tool_call_id: Some("tool-call-1".to_string()),
         });
         assert!(ExternalWorkdirOperation::try_from(command).is_ok());
         assert!(
             ExternalWorkdirOperation::try_from(WorkdirSessionOperation::CommandStart(
                 CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "x".repeat(MAX_EXTERNAL_COMMAND_BYTES + 1),
                     timeout_secs: 30,
-                    output_limit: 12 * 1024,
+
                     cwd: WorkdirPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: None,
                 }
             ))
@@ -887,13 +915,17 @@ mod tests {
         assert!(
             ExternalWorkdirOperationResult::try_from(WorkdirSessionOperationResult::CommandOutput(
                 crate::CommandOutput {
-                    status: crate::CommandStatus::Completed,
-                    exit_code: Some(0),
-                    timed_out: false,
-                    content: "bounded".to_string(),
-                    next_cursor: None,
-                    truncated: false,
-                    output_path: None,
+                    chunks: vec![],
+                    next_cursor: 0,
+                    terminal: Some(crate::CommandTerminal {
+                        status: crate::CommandStatus::Completed,
+                        exit_code: Some(0),
+                        stdout_bytes: 0,
+                        stderr_bytes: 0,
+                        stdout_delivered_bytes: 0,
+                        stderr_delivered_bytes: 0,
+                        truncation_reason: None,
+                    })
                 }
             ))
             .is_ok()
@@ -901,13 +933,14 @@ mod tests {
         assert!(
             ExternalWorkdirOperationResult::try_from(WorkdirSessionOperationResult::CommandOutput(
                 crate::CommandOutput {
-                    status: crate::CommandStatus::Completed,
-                    exit_code: Some(0),
-                    timed_out: false,
-                    content: "bounded".to_string(),
-                    next_cursor: None,
-                    truncated: true,
-                    output_path: Some("/provider/private/output".into()),
+                    chunks: vec![crate::CommandByteChunk {
+                        sequence: 0,
+                        stream: crate::CommandStream::Stdout,
+                        offset: 0,
+                        bytes: vec![0; MAX_EXTERNAL_COMMAND_OUTPUT_BYTES + 1]
+                    }],
+                    next_cursor: 0,
+                    terminal: None
                 }
             ))
             .is_err()
@@ -958,7 +991,7 @@ mod tests {
     #[test]
     fn protocol_rejects_unknown_nested_fields_and_unbounded_requests() {
         let unknown = r#"{
-            "version": 2,
+            "version": 3,
             "message": {
                 "kind": "heartbeat",
                 "generation": 1,
@@ -1012,4 +1045,81 @@ mod tests {
         assert!(ExternalWorkdirOperationId::new("x".repeat(129)).is_err());
         assert!(ExternalWorkdirOperationId::new("operation-1").is_ok());
     }
+
+    #[test]
+    fn command_budget_and_page_metadata_obey_external_hard_bounds() {
+        fn request(budget: u64) -> WorkdirSessionOperation {
+            WorkdirSessionOperation::CommandStart(CommandRequest {
+                command: "true".into(),
+                timeout_secs: 1,
+                cwd: WorkdirPath::root(),
+                transport_byte_budget: budget,
+                tool_call_id: None,
+            })
+        }
+        for budget in [0, crate::MAX_COMMAND_TRANSPORT_BYTES] {
+            let operation = ExternalWorkdirOperation::try_from(request(budget)).unwrap();
+            let wire = serde_json::to_value(operation).unwrap();
+            assert!(serde_json::from_value::<ExternalWorkdirOperation>(wire).is_ok());
+        }
+        assert!(
+            ExternalWorkdirOperation::try_from(request(crate::MAX_COMMAND_TRANSPORT_BYTES + 1))
+                .is_err()
+        );
+        fn page() -> crate::CommandOutput {
+            crate::CommandOutput {
+                chunks: vec![crate::CommandByteChunk {
+                    sequence: 0,
+                    stream: crate::CommandStream::Stdout,
+                    offset: 0,
+                    bytes: b"abc".to_vec(),
+                }],
+                next_cursor: 3,
+                terminal: Some(crate::CommandTerminal {
+                    status: crate::CommandStatus::Completed,
+                    exit_code: Some(0),
+                    stdout_bytes: 100 * 1024 * 1024,
+                    stderr_bytes: 7,
+                    stdout_delivered_bytes: 3,
+                    stderr_delivered_bytes: 0,
+                    truncation_reason: Some(crate::CommandOutputTruncation::ByteBudget),
+                }),
+            }
+        }
+        let accepted = ExternalWorkdirOperationResult::try_from(
+            WorkdirSessionOperationResult::CommandOutput(page()),
+        )
+        .unwrap();
+        assert!(
+            serde_json::from_value::<ExternalWorkdirOperationResult>(
+                serde_json::to_value(accepted).unwrap()
+            )
+            .is_ok()
+        );
+        for mutate in [
+            |p: &mut crate::CommandOutput| p.next_cursor = crate::MAX_COMMAND_TRANSPORT_BYTES + 1,
+            |p: &mut crate::CommandOutput| p.chunks[0].offset = crate::MAX_COMMAND_TRANSPORT_BYTES,
+            |p: &mut crate::CommandOutput| p.chunks[0].sequence = u64::MAX,
+            |p: &mut crate::CommandOutput| p.terminal.as_mut().unwrap().stdout_delivered_bytes = 4,
+            |p: &mut crate::CommandOutput| p.terminal.as_mut().unwrap().stdout_bytes = 2,
+            |p: &mut crate::CommandOutput| p.terminal.as_mut().unwrap().truncation_reason = None,
+        ] {
+            let mut invalid = page();
+            mutate(&mut invalid);
+            let wire = serde_json::to_value(WorkdirSessionOperationResult::CommandOutput(invalid))
+                .unwrap();
+            assert!(serde_json::from_value::<ExternalWorkdirOperationResult>(wire).is_err());
+        }
+        assert!(
+            ExternalWorkdirOperation::try_from(WorkdirSessionOperation::CommandOutput(
+                crate::CommandOutputRequest {
+                    handle: crate::CommandHandle("command-1".into()),
+                    cursor: crate::MAX_COMMAND_TRANSPORT_BYTES + 1,
+                    limit: 1,
+                    wait: false,
+                }
+            ))
+            .is_err()
+        );
+    }
 }

crates/workdir/src/external_local_tests.rs

@@ -1,6 +1,9 @@
+#[cfg(test)]
+use crate::command_test_support::CollectCommand as _;
 use crate::http::{
     WorkdirSessionOperation, WorkdirSessionOperationResult, dispatch_workdir_session_operation,
 };
+
 use crate::{
     BoundedReadLimits, CommandOutputRequest, CommandRequest, EditRequest, ExternalWorkdirRoot,
     GlobRequest, GrepOutputMode, GrepRequest, LocalWorkdirSession, ReadRequest, Workdir,
@@ -59,11 +62,12 @@ async fn external_local_provider_is_strictly_read_only() {
     let command = WorkdirSession::start_command(
         &session,
         CommandRequest {
+            transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
             command: "echo changed > item.txt".to_string(),
             timeout_secs: 1,
-            output_limit: 1024,
+
             cwd: WorkdirPath::root(),
-            spill_dir: None,
+
             tool_call_id: None,
         },
     )
@@ -145,11 +149,12 @@ async fn external_local_provider_read_write_is_filesystem_only() {
     let command = WorkdirSession::start_command(
         &session,
         CommandRequest {
+            transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
             command: "touch command-ran".to_string(),
             timeout_secs: 1,
-            output_limit: 1024,
+
             cwd: WorkdirPath::root(),
-            spill_dir: None,
+
             tool_call_id: None,
         },
     )
@@ -193,17 +198,18 @@ async fn external_command_permission_is_explicit_and_independent_from_file_acces
 
     let handle = session
         .start_command(CommandRequest {
+            transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
             command: "printf command-ok".to_string(),
             timeout_secs: 5,
-            output_limit: 1024,
+
             cwd: WorkdirPath::root(),
-            spill_dir: None,
+
             tool_call_id: None,
         })
         .await
         .unwrap();
     let output = session
-        .command_output(CommandOutputRequest {
+        .collect_command_output(CommandOutputRequest {
             handle,
             cursor: 0,
             limit: 1024,

crates/workdir/src/http.rs

@@ -693,6 +693,12 @@ mod client {
             let mutation = request.operation.capability() != crate::WorkdirSessionCapability::Read;
             let expected_path = request.target.clone();
             let expected_output = request.operation.capability();
+            let byte_range = match &request.operation {
+                crate::CheckoutOperation::ReadBytes { offset, max_bytes } => {
+                    Some((*offset, *max_bytes))
+                }
+                _ => None,
+            };
             match self
                 .operate(WorkdirSessionOperation::CheckoutExecute(request))
                 .await
@@ -702,11 +708,30 @@ mod client {
                         && !result.observation.validator.is_empty()
                         && result.observation.validator.len() <= 256
                         && match (&result.output, expected_output) {
+                            (
+                                crate::CheckoutOutput::ReadBytes(read),
+                                crate::WorkdirSessionCapability::Read,
+                            ) => byte_range.is_some_and(|(offset, max)| {
+                                read.path == expected_path
+                                    && read.offset == offset
+                                    && read.bytes.len() <= max
+                                    && read
+                                        .offset
+                                        .checked_add(read.bytes.len() as u64)
+                                        .is_some_and(|end| {
+                                            end <= read.total_bytes
+                                                || (read.bytes.is_empty() && read.eof)
+                                        })
+                                    && read.eof
+                                        == (read.offset.saturating_add(read.bytes.len() as u64)
+                                            >= read.total_bytes)
+                            }),
                             (
                                 crate::CheckoutOutput::Read(read),
                                 crate::WorkdirSessionCapability::Read,
                             ) => {
-                                read.path == expected_path
+                                byte_range.is_none()
+                                    && read.path == expected_path
                                     && read.bytes.len()
                                         <= crate::BoundedReadLimits::EXTERNAL_DEFAULT
                                             .max_response_bytes
@@ -822,6 +847,7 @@ mod client {
             &self,
             request: CommandRequest,
         ) -> Result<CommandHandle, WorkdirError> {
+            request.validate()?;
             match self
                 .operate(WorkdirSessionOperation::CommandStart(request))
                 .await?
@@ -848,17 +874,39 @@ mod client {
             &self,
             request: CommandOutputRequest,
         ) -> Result<CommandOutput, WorkdirError> {
+            if !(1..=crate::MAX_COMMAND_READ_BYTES).contains(&request.limit) {
+                return Err(WorkdirError::InvalidArgument(
+                    "command byte limit is outside transport bounds".into(),
+                ));
+            }
             let wait = request.wait;
-            loop {
-                match self
-                    .operate(WorkdirSessionOperation::CommandOutput(request.clone()))
-                    .await?
-                {
-                    WorkdirSessionOperationResult::CommandOutput(result)
-                        if wait && result.status == CommandStatus::Running => {}
-                    WorkdirSessionOperationResult::CommandOutput(result) => return Ok(result),
-                    _ => return Err(Self::mismatch("command_output")),
+            match self
+                .operate(WorkdirSessionOperation::CommandOutput(request.clone()))
+                .await?
+            {
+                WorkdirSessionOperationResult::CommandOutput(result) => {
+                    let size = result
+                        .chunks
+                        .iter()
+                        .try_fold(0usize, |size, chunk| size.checked_add(chunk.bytes.len()));
+                    if !result.transport_bounds_valid()
+                        || size.is_none_or(|size| {
+                            size > request.limit
+                                || request.cursor.checked_add(size as u64)
+                                    != Some(result.next_cursor)
+                        })
+                    {
+                        return Err(Self::mismatch("bounded command byte page"));
+                    }
+                    if wait && result.chunks.is_empty() && result.terminal.is_none() {
+                        // A waiting request must block at the provider. Never spin HTTP
+                        // requests against an immediate empty response. A caller may retry
+                        // this exact cursor with its own bounded transport retry policy.
+                        return Err(Self::mismatch("waiting command byte page"));
+                    }
+                    return Ok(result);
                 }
+                _ => return Err(Self::mismatch("command_output")),
             }
         }
 
@@ -917,20 +965,47 @@ mod client {
         response: reqwest::Response,
     ) -> Result<T, WorkdirError> {
         if response.status().is_success() {
-            response.json().await.map_err(http_unavailable)
+            let bytes = bounded_response_bytes(response).await?;
+            serde_json::from_slice(&bytes)
+                .map_err(|_| WorkdirError::Transport("Runtime Workdir response was invalid".into()))
         } else {
             Err(decode_error(response).await)
         }
     }
 
+    async fn bounded_response_bytes(
+        mut response: reqwest::Response,
+    ) -> Result<Vec<u8>, WorkdirError> {
+        const MAX_RESPONSE_BYTES: usize = crate::external::MAX_EXTERNAL_PROVIDER_FRAME_BYTES;
+        if response
+            .content_length()
+            .is_some_and(|size| size > MAX_RESPONSE_BYTES as u64)
+        {
+            return Err(WorkdirError::Transport(
+                "Runtime Workdir response exceeded transport bound".into(),
+            ));
+        }
+        let mut bytes = Vec::new();
+        while let Some(chunk) = response.chunk().await.map_err(http_unavailable)? {
+            if chunk.len() > MAX_RESPONSE_BYTES.saturating_sub(bytes.len()) {
+                return Err(WorkdirError::Transport(
+                    "Runtime Workdir response exceeded transport bound".into(),
+                ));
+            }
+            bytes.extend_from_slice(&chunk);
+        }
+        Ok(bytes)
+    }
+
     async fn decode_error(response: reqwest::Response) -> WorkdirError {
-        response
-            .json::<WorkdirTransportError>()
-            .await
-            .map(WorkdirTransportError::into_workdir_error)
-            .unwrap_or_else(|_| {
-                WorkdirError::Transport("Runtime Workdir error response was invalid".to_string())
-            })
+        match bounded_response_bytes(response).await {
+            Ok(bytes) => serde_json::from_slice::<WorkdirTransportError>(&bytes)
+                .map(WorkdirTransportError::into_workdir_error)
+                .unwrap_or_else(|_| {
+                    WorkdirError::Transport("Runtime Workdir error response was invalid".into())
+                }),
+            Err(error) => error,
+        }
     }
 
     fn http_unavailable(_error: reqwest::Error) -> WorkdirError {

crates/workdir/src/lib.rs

@@ -618,3 +618,6 @@ mod capability_tests {
         assert_eq!(bits(WorkdirSessionCapabilities::ALL), 63);
     }
 }
+
+#[cfg(test)]
+mod command_test_support;

crates/workdir/src/local/command_transport.rs

@@ -0,0 +1,377 @@
+//! Captured process bytes use a bounded queue, never the lossy Console channel.
+//! Pipe backpressure bounds unread process output without temporary-file growth.
+//! A replay page survives a lost HTTP response until its next cursor is sent.
+
+use super::*;
+use tokio::io::{AsyncRead, AsyncReadExt};
+use tokio::sync::mpsc;
+
+const QUEUE_CHUNKS: usize = 8;
+pub(super) const MAX_COMMANDS: usize = 64;
+
+#[derive(Debug)]
+enum Message {
+    Bytes(crate::CommandByteChunk),
+}
+
+#[derive(Debug)]
+pub(super) struct LocalCommand {
+    pub task: JoinHandle<()>,
+    pub cancel: watch::Sender<bool>,
+    pub status: watch::Receiver<Option<crate::CommandTerminal>>,
+    pub transport: Arc<Mutex<Transport>>,
+}
+
+#[derive(Debug)]
+pub(super) struct Transport {
+    receiver: mpsc::Receiver<Message>,
+    pending: Option<crate::CommandByteChunk>,
+    cursor: u64,
+    replay: Option<(u64, CommandOutput)>,
+    terminal: Option<crate::CommandTerminal>,
+    terminal_status: watch::Receiver<Option<crate::CommandTerminal>>,
+}
+
+impl Transport {
+    pub async fn read(
+        &mut self,
+        request: &CommandOutputRequest,
+    ) -> Result<CommandOutput, WorkdirError> {
+        if !(1..=crate::MAX_COMMAND_READ_BYTES).contains(&request.limit) {
+            return Err(WorkdirError::Conflict(
+                "command byte limit is outside transport bounds".into(),
+            ));
+        }
+        if let Some((cursor, page)) = &self.replay {
+            if request.cursor == *cursor {
+                if page
+                    .chunks
+                    .iter()
+                    .map(|chunk| chunk.bytes.len())
+                    .sum::<usize>()
+                    > request.limit
+                {
+                    return Err(WorkdirError::Conflict(
+                        "retry byte limit is smaller than retained page".into(),
+                    ));
+                }
+                return Ok(page.clone());
+            }
+            if request.cursor != page.next_cursor {
+                return Err(WorkdirError::Conflict(
+                    "command cursor is not the current page acknowledgement".into(),
+                ));
+            }
+            self.cursor = page.next_cursor;
+            self.replay = None;
+        }
+        if request.cursor != self.cursor {
+            return Err(WorkdirError::Conflict(
+                "command cursor was acknowledged or is ahead of output".into(),
+            ));
+        }
+        let mut page = CommandOutput {
+            chunks: Vec::new(),
+            next_cursor: self.cursor,
+            terminal: self.terminal.clone(),
+        };
+        let mut remaining = request.limit;
+        loop {
+            let message = if let Some(chunk) = self.pending.take() {
+                Some(Message::Bytes(chunk))
+            } else if page.chunks.is_empty() && page.terminal.is_none() && request.wait {
+                self.receiver.recv().await
+            } else {
+                match self.receiver.try_recv() {
+                    Ok(message) => Some(message),
+                    Err(mpsc::error::TryRecvError::Empty) => break,
+                    Err(mpsc::error::TryRecvError::Disconnected) => None,
+                }
+            };
+            match message {
+                Some(Message::Bytes(mut chunk)) => {
+                    let count = remaining.min(chunk.bytes.len());
+                    if count < chunk.bytes.len() {
+                        let tail = chunk.bytes.split_off(count);
+                        self.pending = Some(crate::CommandByteChunk {
+                            sequence: chunk.sequence + count as u64,
+                            stream: chunk.stream,
+                            offset: chunk.offset + count as u64,
+                            bytes: tail,
+                        });
+                    }
+                    page.next_cursor += count as u64;
+                    remaining -= count;
+                    page.chunks.push(chunk);
+                    if remaining == 0 {
+                        break;
+                    }
+                }
+                None if page.terminal.is_some() => break,
+                None => {
+                    let terminal = self.terminal_status.borrow().clone().ok_or_else(|| {
+                        WorkdirError::Unavailable(
+                            "command transport ended before terminal fence".into(),
+                        )
+                    })?;
+                    self.terminal = Some(terminal.clone());
+                    page.terminal = Some(terminal);
+                    break;
+                }
+            }
+        }
+        // An empty poll must not become a permanently replayed empty page.
+        if !page.chunks.is_empty() || page.terminal.is_some() {
+            self.replay = Some((self.cursor, page.clone()));
+        }
+        Ok(page)
+    }
+
+    pub fn terminal_delivered(&self) -> bool {
+        self.replay
+            .as_ref()
+            .is_some_and(|(_, page)| page.terminal.is_some())
+    }
+
+    pub fn close(&mut self) {
+        self.receiver.close();
+    }
+}
+
+pub(super) fn start(
+    cwd: PathBuf,
+    request: CommandRequest,
+    command_id: String,
+    telemetry: CommandTelemetry,
+    environment: BTreeMap<String, String>,
+    resources: Vec<Arc<dyn WorkdirSessionResource>>,
+) -> LocalCommand {
+    let (sender, receiver) = mpsc::channel(QUEUE_CHUNKS);
+    let (cancel, cancel_rx) = watch::channel(false);
+    let (status_tx, status) = watch::channel(None);
+    let transport = Arc::new(Mutex::new(Transport {
+        receiver,
+        pending: None,
+        cursor: 0,
+        replay: None,
+        terminal: None,
+        terminal_status: status.clone(),
+    }));
+    let task = tokio::spawn(async move {
+        let _resources = resources;
+        let terminal = execute(
+            cwd,
+            request,
+            &command_id,
+            &telemetry,
+            environment,
+            cancel_rx,
+            &sender,
+        )
+        .await;
+        telemetry.terminal(&command_id, terminal.status, terminal.exit_code);
+        // Closing the byte queue fences this already-published terminal, without
+        // requiring spare queue capacity or a receiver to release task resources.
+        let _ = status_tx.send(Some(terminal));
+    });
+    LocalCommand {
+        task,
+        cancel,
+        status,
+        transport,
+    }
+}
+
+#[derive(Default)]
+struct ByteAccounting {
+    stdout: u64,
+    stderr: u64,
+    stdout_delivered: u64,
+    stderr_delivered: u64,
+}
+
+impl ByteAccounting {
+    fn terminal(&self, status: CommandStatus, exit_code: Option<i32>) -> crate::CommandTerminal {
+        crate::CommandTerminal {
+            status,
+            exit_code,
+            stdout_bytes: self.stdout,
+            stderr_bytes: self.stderr,
+            stdout_delivered_bytes: self.stdout_delivered,
+            stderr_delivered_bytes: self.stderr_delivered,
+            truncation_reason: (self.stdout > self.stdout_delivered
+                || self.stderr > self.stderr_delivered)
+                .then_some(crate::CommandOutputTruncation::ByteBudget),
+        }
+    }
+}
+
+async fn pump<R: AsyncRead + Unpin>(
+    mut stdout: R,
+    mut stderr: impl AsyncRead + Unpin,
+    sender: &mpsc::Sender<Message>,
+    telemetry: &CommandTelemetry,
+    command_id: &str,
+    mut remaining: u64,
+    accounting: &mut ByteAccounting,
+) -> std::io::Result<()> {
+    let mut stdout_done = false;
+    let mut stderr_done = false;
+    let mut stdout_decoder = CommandOutputDecoder::default();
+    let mut stderr_decoder = CommandOutputDecoder::default();
+    let mut sequence = 0;
+    let mut stdout_buffer = [0; COMMAND_EVENT_CHUNK_BYTES];
+    let mut stderr_buffer = [0; COMMAND_EVENT_CHUNK_BYTES];
+    while !stdout_done || !stderr_done {
+        // After quota, drain locally even if nobody acknowledges the queue.
+        // Before quota, reserve first to retain bounded pipe backpressure.
+        let permit = if remaining > 0 {
+            let Ok(permit) = sender.reserve().await else {
+                return Ok(());
+            };
+            Some(permit)
+        } else {
+            None
+        };
+        let (stream, result) = tokio::select! {
+            result = stdout.read(&mut stdout_buffer), if !stdout_done => (CommandStream::Stdout, result),
+            result = stderr.read(&mut stderr_buffer), if !stderr_done => (CommandStream::Stderr, result),
+        };
+        let buffer = match stream {
+            CommandStream::Stdout => &stdout_buffer,
+            CommandStream::Stderr => &stderr_buffer,
+        };
+        let count = result?;
+        let decoder = match stream {
+            CommandStream::Stdout => &mut stdout_decoder,
+            CommandStream::Stderr => &mut stderr_decoder,
+        };
+        if count == 0 {
+            match stream {
+                CommandStream::Stdout => stdout_done = true,
+                CommandStream::Stderr => stderr_done = true,
+            }
+            publish_decoded_output(decoder, telemetry, command_id, stream, true);
+            continue;
+        }
+        let (seen, delivered) = match stream {
+            CommandStream::Stdout => (&mut accounting.stdout, &mut accounting.stdout_delivered),
+            CommandStream::Stderr => (&mut accounting.stderr, &mut accounting.stderr_delivered),
+        };
+        *seen = seen.saturating_add(count as u64);
+        let captured = remaining.min(count as u64) as usize;
+        if captured > 0 {
+            let offset = *delivered;
+            decoder.read_offset += captured as u64;
+            decoder.pending.extend_from_slice(&buffer[..captured]);
+            publish_decoded_output(decoder, telemetry, command_id, stream, false);
+            permit
+                .expect("reserved while budget remains")
+                .send(Message::Bytes(crate::CommandByteChunk {
+                    sequence,
+                    stream,
+                    offset,
+                    bytes: buffer[..captured].to_vec(),
+                }));
+            *delivered += captured as u64;
+            sequence += captured as u64;
+            remaining -= captured as u64;
+        }
+    }
+    Ok(())
+}
+
+async fn execute(
+    cwd: PathBuf,
+    request: CommandRequest,
+    command_id: &str,
+    telemetry: &CommandTelemetry,
+    environment: BTreeMap<String, String>,
+    mut cancel: watch::Receiver<bool>,
+    sender: &mpsc::Sender<Message>,
+) -> crate::CommandTerminal {
+    telemetry.started(command_id, request.tool_call_id);
+    let mut command = Command::new("bash");
+    command
+        .arg("-c")
+        .arg(request.command)
+        .current_dir(cwd)
+        .envs(environment)
+        .stdin(Stdio::null())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .kill_on_drop(true);
+    #[cfg(unix)]
+    command.as_std_mut().process_group(0);
+    let mut accounting = ByteAccounting::default();
+    let Ok(mut child) = command.spawn() else {
+        return accounting.terminal(CommandStatus::Failed, None);
+    };
+    let mut process_group = CommandProcessGroupGuard::new(child.id());
+    let stdout = child.stdout.take().expect("piped stdout");
+    let stderr = child.stderr.take().expect("piped stderr");
+    let (status, exit_code) = {
+        let output = pump(
+            stdout,
+            stderr,
+            sender,
+            telemetry,
+            command_id,
+            request.transport_byte_budget,
+            &mut accounting,
+        );
+        tokio::pin!(output);
+        let mut drained = false;
+        let timeout = tokio::time::sleep(Duration::from_secs(request.timeout_secs.max(1)));
+        tokio::pin!(timeout);
+        let terminal = loop {
+            tokio::select! {
+                result = &mut output, if !drained => {
+                    drained = true;
+                    if result.is_err() || sender.is_closed() {
+                        process_group.terminate();
+                        let _ = child.start_kill();
+                        let _ = child.wait().await;
+                        break (CommandStatus::Failed, None);
+                    }
+                }
+                exit = child.wait() => {
+                    process_group.terminate();
+                    break match exit {
+                        Ok(exit) => (if exit.success() { CommandStatus::Completed } else { CommandStatus::Failed }, exit.code()),
+                        Err(_) => (CommandStatus::Failed, None),
+                    };
+                }
+                _ = &mut timeout => {
+                    process_group.terminate();
+                    let _ = child.start_kill();
+                    let code = child.wait().await.ok().and_then(|exit| exit.code());
+                    break (CommandStatus::TimedOut, code);
+                }
+                _ = sender.closed() => {
+                    process_group.terminate();
+                    let _ = child.start_kill();
+                    let _ = child.wait().await;
+                    break (CommandStatus::Cancelled, None);
+                }
+                changed = cancel.changed() => {
+                    if changed.is_err() || *cancel.borrow() {
+                        process_group.terminate();
+                        let _ = child.start_kill();
+                        let code = child.wait().await.ok().and_then(|exit| exit.code());
+                        break (CommandStatus::Cancelled, code);
+                    }
+                }
+            }
+        };
+        // Even after kill, preserve the bounded pipe tail before publishing terminal.
+        if !drained {
+            let _ = output.await;
+        }
+        terminal
+    };
+    accounting.terminal(status, exit_code)
+}
+
+#[cfg(test)]
+mod tests;

crates/workdir/src/local/command_transport/tests.rs

@@ -0,0 +1,490 @@
+//! Process/pipe integration through the production local provider. Temporary roots
+//! and provider tasks are RAII-owned; byte pulls and bounded timeouts synchronize tests.
+
+use super::*;
+use tempfile::TempDir;
+
+struct Harness {
+    session: LocalWorkdirSession,
+    _root: TempDir,
+}
+
+impl Harness {
+    fn new() -> Self {
+        let root = TempDir::new().unwrap();
+        let session = LocalWorkdirSession::new(
+            Scope::writable(root.path()).unwrap(),
+            root.path().to_path_buf(),
+        );
+        Self {
+            session,
+            _root: root,
+        }
+    }
+
+    async fn start(&self, command: &str, timeout_secs: u64) -> CommandHandle {
+        self.start_budget(command, timeout_secs, crate::MAX_COMMAND_TRANSPORT_BYTES)
+            .await
+    }
+
+    fn request(command: &str, timeout_secs: u64, budget: u64) -> CommandRequest {
+        CommandRequest {
+            transport_byte_budget: budget,
+            command: command.into(),
+            timeout_secs,
+            cwd: WorkdirPath::root(),
+            tool_call_id: None,
+        }
+    }
+
+    async fn start_budget(&self, command: &str, timeout_secs: u64, budget: u64) -> CommandHandle {
+        self.session
+            .start_command(Self::request(command, timeout_secs, budget))
+            .await
+            .unwrap()
+    }
+
+    async fn page(&self, handle: &CommandHandle, cursor: u64, limit: usize) -> CommandOutput {
+        tokio::time::timeout(
+            Duration::from_secs(10),
+            self.session.command_output(CommandOutputRequest {
+                handle: handle.clone(),
+                cursor,
+                limit,
+                wait: true,
+            }),
+        )
+        .await
+        .expect("bounded command pull")
+        .unwrap()
+    }
+
+    async fn collect(
+        &self,
+        handle: &CommandHandle,
+        mut cursor: u64,
+    ) -> (Vec<crate::CommandByteChunk>, crate::CommandTerminal) {
+        let mut chunks = Vec::new();
+        loop {
+            let page = self
+                .page(handle, cursor, crate::MAX_COMMAND_READ_BYTES)
+                .await;
+            assert!(
+                page.chunks
+                    .iter()
+                    .map(|chunk| chunk.bytes.len())
+                    .sum::<usize>()
+                    <= crate::MAX_COMMAND_READ_BYTES
+            );
+            cursor = page.next_cursor;
+            chunks.extend(page.chunks);
+            assert!(chunks.iter().map(|chunk| chunk.bytes.len()).sum::<usize>() <= 8 * 1024 * 1024);
+            if let Some(terminal) = page.terminal {
+                return (chunks, terminal);
+            }
+        }
+    }
+}
+
+fn stream_bytes(chunks: &[crate::CommandByteChunk], stream: CommandStream) -> Vec<u8> {
+    let mut bytes = Vec::new();
+    for chunk in chunks.iter().filter(|chunk| chunk.stream == stream) {
+        assert_eq!(chunk.offset, bytes.len() as u64);
+        bytes.extend_from_slice(&chunk.bytes);
+    }
+    bytes
+}
+
+#[tokio::test]
+async fn high_single_line_output_survives_absent_and_lagged_console_subscribers() {
+    for lagged in [false, true] {
+        let harness = Harness::new();
+        let _lagged_receiver = lagged.then(|| harness.session.subscribe_command_events().unwrap());
+        let handle = harness.start("head -c 3145728 /dev/zero | tr '\\0' x; head -c 65536 /dev/zero | tr '\\0' e >&2; exit 7", 20).await;
+        let (chunks, terminal) = harness.collect(&handle, 0).await;
+        assert_eq!(terminal.status, CommandStatus::Failed);
+        assert_eq!(terminal.exit_code, Some(7));
+        assert_eq!(
+            stream_bytes(&chunks, CommandStream::Stdout),
+            vec![b'x'; 3145728]
+        );
+        assert_eq!(
+            stream_bytes(&chunks, CommandStream::Stderr),
+            vec![b'e'; 65536]
+        );
+        let mut cursor = 0;
+        for chunk in chunks {
+            assert_eq!(chunk.sequence, cursor);
+            cursor += chunk.bytes.len() as u64;
+        }
+        harness.session.close().await.unwrap();
+    }
+}
+
+#[tokio::test]
+async fn one_byte_pages_preserve_raw_utf8_invalid_bytes_and_replay_until_acknowledged() {
+    let harness = Harness::new();
+    let handle = harness
+        .start(
+            "printf '\\342\\202\\254\\377\\000'; printf '\\346\\227\\245' >&2",
+            5,
+        )
+        .await;
+    let mut chunks = Vec::new();
+    let mut cursor = 0;
+    loop {
+        let page = harness.page(&handle, cursor, 1).await;
+        assert_eq!(harness.page(&handle, cursor, 1).await, page);
+        cursor = page.next_cursor;
+        chunks.extend(page.chunks);
+        if let Some(terminal) = page.terminal {
+            assert_eq!(terminal.status, CommandStatus::Completed);
+            break;
+        }
+    }
+    assert_eq!(
+        stream_bytes(&chunks, CommandStream::Stdout),
+        b"\xe2\x82\xac\xff\0"
+    );
+    assert_eq!(
+        stream_bytes(&chunks, CommandStream::Stderr),
+        b"\xe6\x97\xa5"
+    );
+    assert!(
+        harness
+            .session
+            .command_output(CommandOutputRequest {
+                handle,
+                cursor: 0,
+                limit: 1,
+                wait: false
+            })
+            .await
+            .is_err()
+    );
+}
+
+#[tokio::test]
+async fn cancellation_while_backpressured_drains_bytes_before_terminal_fence() {
+    let harness = Harness::new();
+    let handle = harness.start("printf ready; exec yes x", 30).await;
+    let first = harness.page(&handle, 0, 1).await;
+    harness
+        .session
+        .cancel_command(handle.clone())
+        .await
+        .unwrap();
+    let (mut chunks, terminal) = harness.collect(&handle, first.next_cursor).await;
+    let mut all = first.chunks;
+    all.append(&mut chunks);
+    assert!(stream_bytes(&all, CommandStream::Stdout).starts_with(b"ready"));
+    assert_eq!(terminal.status, CommandStatus::Cancelled);
+    let final_page = harness
+        .page(
+            &handle,
+            all.iter().map(|chunk| chunk.bytes.len() as u64).sum(),
+            1,
+        )
+        .await;
+    assert!(final_page.chunks.is_empty());
+    assert_eq!(final_page.terminal, Some(terminal));
+}
+
+#[tokio::test]
+async fn timeout_and_session_close_finalize_without_an_output_subscriber() {
+    let harness = Harness::new();
+    let handle = harness
+        .start("printf ready; exec tail -f /dev/null", 1)
+        .await;
+    let (chunks, terminal) = harness.collect(&handle, 0).await;
+    assert_eq!(stream_bytes(&chunks, CommandStream::Stdout), b"ready");
+    assert_eq!(terminal.status, CommandStatus::TimedOut);
+    let handle = harness.start("exec yes x", 30).await;
+    // Receiving one byte establishes actual process output, without a timing sleep.
+    harness.page(&handle, 0, 1).await;
+    tokio::time::timeout(Duration::from_secs(5), harness.session.close())
+        .await
+        .unwrap()
+        .unwrap();
+    assert!(harness.session.command_status(handle).await.is_err());
+}
+
+#[tokio::test]
+async fn interleaved_streams_keep_independent_offsets_and_bounded_read_validation() {
+    let harness = Harness::new();
+    let handle = harness
+        .start(
+            "for ((i=0;i<100;i++)); do printf 'out%s;' \"$i\"; printf 'err%s;' \"$i\" >&2; done",
+            5,
+        )
+        .await;
+    for limit in [0, crate::MAX_COMMAND_READ_BYTES + 1] {
+        assert!(
+            harness
+                .session
+                .command_output(CommandOutputRequest {
+                    handle: handle.clone(),
+                    cursor: 0,
+                    limit,
+                    wait: false
+                })
+                .await
+                .is_err()
+        );
+    }
+    let (chunks, terminal) = harness.collect(&handle, 0).await;
+    let expected = |prefix| {
+        (0..100)
+            .map(|i| format!("{prefix}{i};"))
+            .collect::<String>()
+            .into_bytes()
+    };
+    assert_eq!(
+        stream_bytes(&chunks, CommandStream::Stdout),
+        expected("out")
+    );
+    assert_eq!(
+        stream_bytes(&chunks, CommandStream::Stderr),
+        expected("err")
+    );
+    assert_eq!(terminal.status, CommandStatus::Completed);
+}
+
+#[tokio::test]
+async fn byte_budget_zero_exact_partial_and_shared_keep_seen_and_delivered_distinct() {
+    let harness = Harness::new();
+    for (command, budget, stdout_seen, stderr_seen, exit_code) in [
+        ("printf abc; printf defg >&2", 0, 3, 4, 0),
+        ("printf abc", 3, 3, 0, 0),
+        ("printf abcdefg", 3, 7, 0, 0),
+        ("printf abcdefg; exit 7", 3, 7, 0, 7),
+        (
+            "head -c 32768 /dev/zero; head -c 32768 /dev/zero >&2",
+            12345,
+            32768,
+            32768,
+            0,
+        ),
+    ] {
+        let handle = harness.start_budget(command, 5, budget).await;
+        let (chunks, terminal) = harness.collect(&handle, 0).await;
+        let stdout = stream_bytes(&chunks, CommandStream::Stdout);
+        let stderr = stream_bytes(&chunks, CommandStream::Stderr);
+        let mut cursor = 0;
+        for chunk in &chunks {
+            assert_eq!(chunk.sequence, cursor);
+            cursor += chunk.bytes.len() as u64;
+        }
+        assert_eq!(cursor, budget.min(stdout_seen + stderr_seen));
+        assert_eq!(terminal.stdout_bytes, stdout_seen);
+        assert_eq!(terminal.stderr_bytes, stderr_seen);
+        assert_eq!(terminal.stdout_delivered_bytes, stdout.len() as u64);
+        assert_eq!(terminal.stderr_delivered_bytes, stderr.len() as u64);
+        assert_eq!(terminal.exit_code, Some(exit_code));
+        assert_eq!(
+            terminal.status,
+            if exit_code == 0 {
+                CommandStatus::Completed
+            } else {
+                CommandStatus::Failed
+            }
+        );
+        assert_eq!(
+            terminal.truncation_reason,
+            (cursor < stdout_seen + stderr_seen)
+                .then_some(crate::CommandOutputTruncation::ByteBudget)
+        );
+    }
+}
+
+#[tokio::test]
+async fn exhausted_budget_finishes_without_receiver_and_keeps_timeout_cancel_distinct() {
+    let harness = Harness::new();
+    for budget in [0, 1, (QUEUE_CHUNKS * COMMAND_EVENT_CHUNK_BYTES) as u64] {
+        let handle = harness
+            .start_budget("head -c 1048576 /dev/zero; printf error >&2", 5, budget)
+            .await;
+        let mut status = harness.session.inner.commands.lock().await[&handle.0]
+            .status
+            .clone();
+        let terminal = tokio::time::timeout(
+            Duration::from_secs(5),
+            status.wait_for(|value| value.is_some()),
+        )
+        .await
+        .unwrap()
+        .unwrap()
+        .clone()
+        .unwrap();
+        assert_eq!(terminal.status, CommandStatus::Completed);
+        assert_eq!(terminal.stdout_bytes, 1048576);
+        assert_eq!(terminal.stderr_bytes, 5);
+        assert_eq!(
+            terminal.stdout_delivered_bytes + terminal.stderr_delivered_bytes,
+            budget
+        );
+        // Full capture queue cannot retain the process task or its resources.
+        {
+            let mut commands = harness.session.inner.commands.lock().await;
+            tokio::time::timeout(
+                Duration::from_secs(5),
+                &mut commands.get_mut(&handle.0).unwrap().task,
+            )
+            .await
+            .unwrap()
+            .unwrap();
+        }
+        // Only now acknowledge the captured queue and terminal fence.
+        let (_, delivered_terminal) = harness.collect(&handle, 0).await;
+        assert_eq!(delivered_terminal, terminal);
+    }
+    for (cancel, expected) in [
+        (false, CommandStatus::TimedOut),
+        (true, CommandStatus::Cancelled),
+    ] {
+        let handle = harness
+            .start_budget(
+                "printf ready-extra; head -c 32768 /dev/zero; exec tail -f /dev/null",
+                1,
+                5,
+            )
+            .await;
+        let first = harness.page(&handle, 0, 5).await;
+        assert_eq!(first.next_cursor, 5);
+        if cancel {
+            harness
+                .session
+                .cancel_command(handle.clone())
+                .await
+                .unwrap();
+        }
+        let (rest, terminal) = harness.collect(&handle, first.next_cursor).await;
+        assert!(rest.is_empty());
+        assert_eq!(terminal.status, expected);
+        assert_eq!(terminal.stdout_delivered_bytes, 5);
+        assert!(terminal.stdout_bytes >= 11);
+        assert_eq!(
+            terminal.truncation_reason,
+            Some(crate::CommandOutputTruncation::ByteBudget)
+        );
+        if !cancel {
+            assert_eq!(terminal.stdout_bytes, 32779);
+            assert_eq!(
+                terminal.truncation_reason,
+                Some(crate::CommandOutputTruncation::ByteBudget)
+            );
+        }
+    }
+}
+
+#[tokio::test]
+async fn budget_replay_preserves_unique_bytes_and_rejects_future_and_old_cursors() {
+    let harness = Harness::new();
+    let handle = harness.start_budget("printf abcdefghij", 5, 7).await;
+    let first = harness.page(&handle, 0, 2).await;
+    for _ in 0..3 {
+        assert_eq!(harness.page(&handle, 0, 2).await, first);
+    }
+    assert!(
+        harness
+            .session
+            .command_output(CommandOutputRequest {
+                handle: handle.clone(),
+                cursor: 8,
+                limit: 2,
+                wait: false,
+            })
+            .await
+            .is_err()
+    );
+    let (rest, terminal) = harness.collect(&handle, first.next_cursor).await;
+    let mut all = first.chunks;
+    all.extend(rest);
+    assert_eq!(stream_bytes(&all, CommandStream::Stdout), b"abcdefg");
+    assert_eq!(terminal.stdout_bytes, 10);
+    assert_eq!(terminal.stdout_delivered_bytes, 7);
+    assert!(
+        harness
+            .session
+            .command_output(CommandOutputRequest {
+                handle,
+                cursor: 0,
+                limit: 2,
+                wait: false,
+            })
+            .await
+            .is_err()
+    );
+}
+
+#[tokio::test]
+async fn invalid_budget_is_rejected_before_process_start() {
+    let harness = Harness::new();
+    assert!(matches!(
+        harness
+            .session
+            .start_command(Harness::request(
+                "touch must-not-exist",
+                5,
+                crate::MAX_COMMAND_TRANSPORT_BYTES + 1,
+            ))
+            .await,
+        Err(WorkdirError::InvalidArgument(_))
+    ));
+    assert!(!harness._root.path().join("must-not-exist").exists());
+    assert!(harness.session.inner.commands.lock().await.is_empty());
+}
+
+#[tokio::test]
+async fn slow_receiver_backpressures_before_quota_but_full_queue_does_not_block_discard() {
+    use std::future::Future;
+    use std::task::Poll;
+    let telemetry = CommandTelemetry::new();
+    let input = vec![b'x'; 1024 * 1024];
+    for budget in [
+        crate::MAX_COMMAND_TRANSPORT_BYTES,
+        (QUEUE_CHUNKS * COMMAND_EVENT_CHUNK_BYTES) as u64,
+    ] {
+        let (sender, mut receiver) = mpsc::channel(QUEUE_CHUNKS);
+        let mut accounting = ByteAccounting::default();
+        {
+            let output = pump(
+                input.as_slice(),
+                &b""[..],
+                &sender,
+                &telemetry,
+                "test",
+                budget,
+                &mut accounting,
+            );
+            tokio::pin!(output);
+            let polled = std::future::poll_fn(|cx| Poll::Ready(output.as_mut().poll(cx))).await;
+            if budget == crate::MAX_COMMAND_TRANSPORT_BYTES {
+                assert!(polled.is_pending(), "a slow receiver must stop pipe reads");
+            } else {
+                assert!(
+                    matches!(polled, Poll::Ready(Ok(()))),
+                    "discard must not reserve queue capacity"
+                );
+            }
+        }
+        assert_eq!(receiver.len(), QUEUE_CHUNKS);
+        assert_eq!(
+            accounting.stdout_delivered,
+            (QUEUE_CHUNKS * COMMAND_EVENT_CHUNK_BYTES) as u64
+        );
+        assert_eq!(
+            accounting.stdout,
+            if budget == crate::MAX_COMMAND_TRANSPORT_BYTES {
+                accounting.stdout_delivered
+            } else {
+                input.len() as u64
+            }
+        );
+        let mut queued_bytes = 0;
+        while let Ok(Message::Bytes(chunk)) = receiver.try_recv() {
+            queued_bytes += chunk.bytes.len();
+        }
+        assert_eq!(queued_bytes, QUEUE_CHUNKS * COMMAND_EVENT_CHUNK_BYTES);
+    }
+}

crates/workdir/src/operation.rs

@@ -1,5 +1,3 @@
-use std::path::PathBuf;
-
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
@@ -8,18 +6,18 @@ use serde::{Deserialize, Serialize};
 pub struct CommandHandle(pub String);
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[serde(deny_unknown_fields)]
 pub struct CommandRequest {
     pub command: String,
     #[schemars(range(min = 0, max = 9_007_199_254_740_991_u64))]
     pub timeout_secs: u64,
-    #[schemars(range(min = 0, max = 9_007_199_254_740_991_usize))]
-    pub output_limit: usize,
+    /// Aggregate unique-byte capture allowance, independent of consumer storage.
+    /// Providers drain and count excess bytes without delivering their payload.
+    #[schemars(range(min = 0, max = 67_108_864_u64))]
+    pub transport_byte_budget: u64,
     /// Workdir-relative command directory. Providers validate it against the
     /// active session before process start.
     pub cwd: fs_operation::FsPath,
-    /// Provider-local directory where complete output is retained when the
-    /// inline result exceeds `output_limit`.
-    pub spill_dir: Option<PathBuf>,
     /// Optional caller-owned correlation id. Bash supplies its tool-call id so
     /// user-facing command telemetry can update the corresponding Console row
     /// without exposing provider/session handles.
@@ -27,12 +25,23 @@ pub struct CommandRequest {
     pub tool_call_id: Option<String>,
 }
 
+impl CommandRequest {
+    pub fn validate(&self) -> Result<(), crate::WorkdirError> {
+        if self.transport_byte_budget > MAX_COMMAND_TRANSPORT_BYTES {
+            return Err(crate::WorkdirError::InvalidArgument(
+                "command transport byte budget exceeds provider maximum".into(),
+            ));
+        }
+        Ok(())
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 pub struct CommandOutputRequest {
     pub handle: CommandHandle,
-    #[schemars(range(min = 0, max = 9_007_199_254_740_991_usize))]
-    pub cursor: usize,
-    #[schemars(range(min = 0, max = 9_007_199_254_740_991_usize))]
+    #[schemars(range(min = 0, max = 67_108_864_u64))]
+    pub cursor: u64,
+    #[schemars(range(min = 1, max = 65_536_usize))]
     pub limit: usize,
     pub wait: bool,
 }
@@ -107,16 +116,150 @@ pub enum CommandEvent {
     },
 }
 
+/// Sequence is the merged transport byte position. Offset addresses raw bytes
+/// within the named stream; neither ordering nor offsets depend on UTF-8 decoding.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
-pub struct CommandOutput {
+pub struct CommandByteChunk {
+    pub sequence: u64,
+    pub stream: CommandStream,
+    pub offset: u64,
+    pub bytes: Vec<u8>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum CommandOutputTruncation {
+    ByteBudget,
+}
+
+/// Raw totals include discarded pipe bytes. Delivered totals count only prefixes
+/// admitted to the transport queue, not page reads or retries by a consumer.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+pub struct CommandTerminal {
     pub status: CommandStatus,
-    #[schemars(range(min = -2147483648_i32, max = 2147483647_i32))]
     pub exit_code: Option<i32>,
-    pub timed_out: bool,
-    pub content: String,
-    #[schemars(range(min = 0, max = 9_007_199_254_740_991_usize))]
-    pub next_cursor: Option<usize>,
-    pub truncated: bool,
-    /// Complete output retained by the provider when `truncated` is true.
-    pub output_path: Option<PathBuf>,
+    pub stdout_bytes: u64,
+    pub stderr_bytes: u64,
+    pub stdout_delivered_bytes: u64,
+    pub stderr_delivered_bytes: u64,
+    pub truncation_reason: Option<CommandOutputTruncation>,
+}
+
+/// Sending next_cursor acknowledges this page. Only the current page may be
+/// retried; acknowledged bytes expire. Terminal fences all captured bytes,
+/// including on timeout/cancel. Consumers must pull while the process runs.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[serde(deny_unknown_fields)]
+pub struct CommandOutput {
+    pub chunks: Vec<CommandByteChunk>,
+    pub next_cursor: u64,
+    pub terminal: Option<CommandTerminal>,
+}
+
+impl CommandOutput {
+    pub(crate) fn transport_bounds_valid(&self) -> bool {
+        let mut end = None;
+        let mut stream_ends = [None, None];
+        for chunk in &self.chunks {
+            let stream_index = match chunk.stream {
+                CommandStream::Stdout => 0,
+                CommandStream::Stderr => 1,
+            };
+            if chunk.bytes.is_empty()
+                || chunk.offset > chunk.sequence
+                || stream_ends[stream_index].is_some_and(|end| chunk.offset != end)
+                || end.is_some_and(|end| chunk.sequence != end)
+                || chunk
+                    .sequence
+                    .checked_add(chunk.bytes.len() as u64)
+                    .is_none_or(|end| end > MAX_COMMAND_TRANSPORT_BYTES)
+                || chunk
+                    .offset
+                    .checked_add(chunk.bytes.len() as u64)
+                    .is_none_or(|end| end > MAX_COMMAND_TRANSPORT_BYTES)
+            {
+                return false;
+            }
+            end = chunk.sequence.checked_add(chunk.bytes.len() as u64);
+            stream_ends[stream_index] = chunk.offset.checked_add(chunk.bytes.len() as u64);
+        }
+        self.next_cursor <= MAX_COMMAND_TRANSPORT_BYTES
+            && end.is_none_or(|end| end == self.next_cursor)
+            && self.terminal.as_ref().is_none_or(|terminal| {
+                let truncated = terminal.stdout_bytes > terminal.stdout_delivered_bytes
+                    || terminal.stderr_bytes > terminal.stderr_delivered_bytes;
+                stream_ends[0].is_none_or(|end| end == terminal.stdout_delivered_bytes)
+                    && stream_ends[1].is_none_or(|end| end == terminal.stderr_delivered_bytes)
+                    && terminal.status != CommandStatus::Running
+                    && terminal.stdout_delivered_bytes <= terminal.stdout_bytes
+                    && terminal.stderr_delivered_bytes <= terminal.stderr_bytes
+                    && terminal
+                        .stdout_delivered_bytes
+                        .checked_add(terminal.stderr_delivered_bytes)
+                        == Some(self.next_cursor)
+                    && terminal.truncation_reason
+                        == truncated.then_some(CommandOutputTruncation::ByteBudget)
+            })
+    }
+}
+
+pub const MAX_COMMAND_TRANSPORT_BYTES: u64 = 64 * 1024 * 1024;
+
+pub const MAX_COMMAND_READ_BYTES: usize = 64 * 1024;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn command_wire_rejects_legacy_output_host_paths() {
+        let command = serde_json::json!({
+            "command": "printf bytes", "timeout_secs": 1, "cwd": "", "transport_byte_budget": 0
+        });
+        assert!(serde_json::from_value::<CommandRequest>(command.clone()).is_ok());
+        for field in ["spill_dir", "output_limit"] {
+            let mut legacy = command.clone();
+            legacy[field] = serde_json::json!("/host/private");
+            assert!(serde_json::from_value::<CommandRequest>(legacy).is_err());
+        }
+        let output = serde_json::json!({"chunks": [], "next_cursor": 0, "terminal": null, "output_path": "/host/private"});
+        assert!(serde_json::from_value::<CommandOutput>(output).is_err());
+    }
+
+    #[test]
+    fn command_budget_wire_requires_field_and_checks_provider_hard_bound() {
+        let wire = serde_json::json!({"command": "true", "timeout_secs": 1, "cwd": ""});
+        assert!(serde_json::from_value::<CommandRequest>(wire.clone()).is_err());
+        for budget in [
+            0,
+            MAX_COMMAND_TRANSPORT_BYTES,
+            MAX_COMMAND_TRANSPORT_BYTES + 1,
+        ] {
+            let mut value = wire.clone();
+            value["transport_byte_budget"] = serde_json::json!(budget);
+            let request: CommandRequest = serde_json::from_value(value).unwrap();
+            assert_eq!(
+                request.validate().is_ok(),
+                budget <= MAX_COMMAND_TRANSPORT_BYTES
+            );
+        }
+        let mut negative = wire;
+        negative["transport_byte_budget"] = serde_json::json!(-1);
+        assert!(serde_json::from_value::<CommandRequest>(negative).is_err());
+        assert_eq!(
+            serde_json::to_value(CommandOutputTruncation::ByteBudget).unwrap(),
+            "byte_budget"
+        );
+        let schema = serde_json::to_value(schemars::schema_for!(CommandRequest)).unwrap();
+        assert_eq!(
+            schema["properties"]["transport_byte_budget"]["maximum"],
+            MAX_COMMAND_TRANSPORT_BYTES
+        );
+        assert!(
+            schema["required"]
+                .as_array()
+                .unwrap()
+                .contains(&serde_json::json!("transport_byte_budget"))
+        );
+    }
 }

crates/workdir/src/router.rs

@@ -341,7 +341,9 @@ impl WorkdirSession for RoutedWorkdirSession {
         let _active = self.state.enter()?;
         let handle = request.handle.clone();
         let output = self.state.session.command_output(request).await?;
-        self.state.mark_terminal(&handle, output.status);
+        if let Some(terminal) = &output.terminal {
+            self.state.mark_terminal(&handle, terminal.status);
+        }
         Ok(output)
     }
 
@@ -789,11 +791,12 @@ mod tests {
             .unwrap();
         let handle = routed
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "printf done".to_string(),
                 timeout_secs: 5,
-                output_limit: 1024,
+
                 cwd: crate::WorkdirPath::root(),
-                spill_dir: None,
+
                 tool_call_id: None,
             })
             .await
@@ -823,11 +826,12 @@ mod tests {
         let routed = router.attach(alias, Arc::clone(&underlying)).unwrap();
         let handle = routed
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "sleep 30".to_string(),
                 timeout_secs: 60,
-                output_limit: 1024,
+
                 cwd: crate::WorkdirPath::root(),
-                spill_dir: None,
+
                 tool_call_id: None,
             })
             .await
@@ -850,11 +854,12 @@ mod tests {
         let routed = router.attach(alias.clone(), session("wd", &dir)).unwrap();
         let handle = routed
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "sleep 30".to_string(),
                 timeout_secs: 60,
-                output_limit: 1024,
+
                 cwd: crate::WorkdirPath::root(),
-                spill_dir: None,
+
                 tool_call_id: None,
             })
             .await

crates/workdir/src/scope.rs

@@ -10,6 +10,9 @@
 //! provider-side before name enumeration, descent, or content reads. Returned coordinates are not
 //! prefixed with cwd again.
 
+#[cfg(test)]
+use crate::command_test_support::CollectCommand as _;
+
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::path::Path;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
@@ -124,6 +127,7 @@ impl WorkdirToolBroker {
             next_lease_id: AtomicU64::new(1),
             close_lock: Arc::new(tokio::sync::Mutex::new(())),
             owned_commands: Arc::new(Mutex::new(HashSet::new())),
+            command_reads: Mutex::new(HashMap::new()),
             pending_command_events: Arc::new(Mutex::new(HashMap::new())),
             starting_tool_calls: Arc::new(Mutex::new(HashSet::new())),
             forwarded_starts: Arc::new(Mutex::new(HashSet::new())),
@@ -230,25 +234,48 @@ impl WorkdirScopeLease {
                 .source
                 .cancel_command(handle.clone())
                 .await;
-            let terminal = self
+            let read_cursor = self
                 .broker
                 .authority
-                .source
-                .command_output(CommandOutputRequest {
-                    handle,
-                    cursor: 0,
-                    limit: 1,
-                    wait: true,
-                })
-                .await;
+                .command_reads
+                .lock()
+                .expect("command cursor mutex poisoned")
+                .get(&command_id)
+                .cloned()
+                .expect("owned command cursor");
+            let mut read_cursor = read_cursor.lock().await;
+            let mut cursor = *read_cursor;
+            let terminal = loop {
+                let output = self
+                    .broker
+                    .authority
+                    .source
+                    .command_output(CommandOutputRequest {
+                        handle: handle.clone(),
+                        cursor,
+                        limit: crate::MAX_COMMAND_READ_BYTES,
+                        wait: true,
+                    })
+                    .await;
+                match output {
+                    Ok(output) => {
+                        cursor = output.next_cursor;
+                        *read_cursor = cursor;
+                        if let Some(terminal) = output.terminal {
+                            break Ok(terminal);
+                        }
+                    }
+                    Err(error) => break Err(error),
+                }
+            };
             match (cancel, terminal) {
                 (_, Ok(output)) => {
                     self.broker.authority.publish_terminal_if_missing(
                         &command_id,
                         output.status,
                         output.exit_code,
-                        output.next_cursor.unwrap_or(output.content.len()) as u64,
-                        &output.content,
+                        cursor,
+                        "",
                     );
                     self.broker
                         .authority
@@ -582,7 +609,12 @@ struct ScopedWorkdirSession {
     scope_lock: tokio::sync::Mutex<()>,
     next_lease_id: AtomicU64,
     close_lock: Arc<tokio::sync::Mutex<()>>,
+    // Live cleanup responsibility ends at terminal delivery. Read ownership is
+    // retained separately so a lost terminal response can still be replayed.
     owned_commands: Arc<Mutex<HashSet<String>>>,
+    // Starting commands prunes completed entries at the bounded replay ceiling;
+    // current scope validity is still checked before every read or retry.
+    command_reads: Mutex<HashMap<String, Arc<tokio::sync::Mutex<u64>>>>,
     pending_command_events: Arc<Mutex<HashMap<String, Vec<CommandEvent>>>>,
     starting_tool_calls: Arc<Mutex<HashSet<String>>>,
     forwarded_starts: Arc<Mutex<HashSet<String>>>,
@@ -700,6 +732,11 @@ impl ScopedWorkdirSession {
                 .lock()
                 .expect("scoped command set mutex poisoned")
                 .contains(&handle.0)
+            || self
+                .command_reads
+                .lock()
+                .expect("command cursor mutex poisoned")
+                .contains_key(&handle.0)
         {
             Ok(())
         } else {
@@ -1013,6 +1050,7 @@ impl ScopedWorkdirSession {
             next_lease_id: AtomicU64::new(1),
             close_lock: close_lock.clone(),
             owned_commands,
+            command_reads: Mutex::new(HashMap::new()),
             pending_command_events,
             starting_tool_calls,
             forwarded_starts,
@@ -1222,6 +1260,9 @@ impl WorkdirSession for ScopedWorkdirSession {
                 .intersection(WorkdirSessionCapabilities::READ_ONLY);
         }
         if let crate::CheckoutOutput::Read(read) = &mut result.output {
+            read.path = result_path.clone();
+        }
+        if let crate::CheckoutOutput::ReadBytes(read) = &mut result.output {
             read.path = result_path;
         }
         Ok(result)
@@ -1407,6 +1448,16 @@ impl WorkdirSession for ScopedWorkdirSession {
             .lock()
             .expect("scoped command set mutex poisoned");
         owned.insert(handle.0.clone());
+        {
+            let mut reads = self
+                .command_reads
+                .lock()
+                .expect("command cursor mutex poisoned");
+            if reads.len() >= 64 {
+                reads.retain(|id, _| owned.contains(id));
+            }
+            reads.insert(handle.0.clone(), Arc::new(tokio::sync::Mutex::new(0)));
+        }
         if let Some(tool_call_id) = &tool_call_id {
             self.starting_tool_calls
                 .lock()
@@ -1457,14 +1508,28 @@ impl WorkdirSession for ScopedWorkdirSession {
     ) -> Result<CommandOutput, WorkdirError> {
         self.ensure_owned_command(&request.handle)?;
         let command_id = request.handle.0.clone();
+        let read_cursor = self
+            .command_reads
+            .lock()
+            .expect("command cursor mutex poisoned")
+            .get(&command_id)
+            .cloned();
+        let mut read_cursor = match &read_cursor {
+            Some(cursor) => Some(cursor.lock().await),
+            None => None,
+        };
+        self.ensure_owned_command(&request.handle)?;
         let output = self.source.command_output(request).await?;
-        if !matches!(output.status, CommandStatus::Running) {
+        if let Some(cursor) = &mut read_cursor {
+            **cursor = output.next_cursor;
+        }
+        if let Some(terminal) = &output.terminal {
             self.publish_terminal_if_missing(
                 &command_id,
-                output.status,
-                output.exit_code,
-                output.next_cursor.unwrap_or(output.content.len()) as u64,
-                &output.content,
+                terminal.status,
+                terminal.exit_code,
+                output.next_cursor,
+                "",
             );
             self.owned_commands
                 .lock()
@@ -2080,20 +2145,21 @@ mod tests {
         session: &WorkdirSessionHandle,
         command: impl Into<String>,
         tool_call_id: impl Into<String>,
-    ) -> CommandOutput {
+    ) -> crate::command_test_support::CollectedCommand {
         let handle = session
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: command.into(),
                 timeout_secs: 5,
-                output_limit: 1024,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: Some(tool_call_id.into()),
             })
             .await
             .unwrap();
         session
-            .command_output(CommandOutputRequest {
+            .collect_command_output(CommandOutputRequest {
                 handle,
                 cursor: 0,
                 limit: 1024,
@@ -2112,11 +2178,12 @@ mod tests {
             .expect("delegation wrapper must preserve command observation");
         let handle = parent
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "printf ready; sleep 0.2; printf done".into(),
                 timeout_secs: 5,
-                output_limit: 1024,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: Some("tool-delegated".into()),
             })
             .await
@@ -2139,7 +2206,7 @@ mod tests {
         assert_eq!(snapshots[0].stdout.content, "ready");
 
         let output = parent
-            .command_output(CommandOutputRequest {
+            .collect_command_output(CommandOutputRequest {
                 handle,
                 cursor: 0,
                 limit: 1024,
@@ -2179,11 +2246,12 @@ mod tests {
         );
         let error = child
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "pwd".into(),
                 timeout_secs: 5,
-                output_limit: 1024,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: None,
             })
             .await
@@ -2211,11 +2279,12 @@ mod tests {
 
         let handle = first
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "pwd; sleep 0.2".into(),
                 timeout_secs: 5,
-                output_limit: 4096,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: Some("first-command".into()),
             })
             .await
@@ -2239,7 +2308,7 @@ mod tests {
         ));
 
         let output = first
-            .command_output(CommandOutputRequest {
+            .collect_command_output(CommandOutputRequest {
                 handle,
                 cursor: 0,
                 limit: 4096,
@@ -2316,11 +2385,12 @@ mod tests {
         assert!(matches!(
             child
                 .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "printf denied".into(),
                     timeout_secs: 5,
-                    output_limit: 1024,
+
                     cwd: FsPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: Some("read-only-command".into()),
                 })
                 .await,
@@ -2622,11 +2692,12 @@ mod tests {
         assert!(matches!(
             child
                 .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "printf revoked".into(),
                     timeout_secs: 5,
-                    output_limit: 1024,
+
                     cwd: FsPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: Some("revoked-child-command".into()),
                 })
                 .await,
@@ -2724,11 +2795,12 @@ mod tests {
         for index in 0..MAX_SCOPED_COMMANDS {
             child
                 .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "sleep 30".into(),
                     timeout_secs: 60,
-                    output_limit: 1024,
+
                     cwd: FsPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: Some(format!("command-{index}")),
                 })
                 .await
@@ -2737,11 +2809,12 @@ mod tests {
 
         let error = child
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "sleep 30".into(),
                 timeout_secs: 60,
-                output_limit: 1024,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: Some("command-over-limit".into()),
             })
             .await
@@ -2771,11 +2844,12 @@ mod tests {
         let command = tokio::spawn(async move {
             command_child
                 .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "sleep 30".into(),
                     timeout_secs: 60,
-                    output_limit: 1024,
+
                     cwd: FsPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: Some("racing-command".into()),
                 })
                 .await
@@ -2817,11 +2891,12 @@ mod tests {
         let mut events = child.subscribe_command_events().unwrap();
         let handle = child
             .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "sleep 30; printf leaked > marker".into(),
                 timeout_secs: 60,
-                output_limit: 1024,
+
                 cwd: FsPath::root(),
-                spill_dir: None,
+
                 tool_call_id: Some("owned-command".into()),
             })
             .await
@@ -3012,11 +3087,12 @@ mod tests {
         assert!(matches!(
             parent
                 .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
                     command: "printf closed".into(),
                     timeout_secs: 5,
-                    output_limit: 1024,
+
                     cwd: FsPath::root(),
-                    spill_dir: None,
+
                     tool_call_id: Some("closed-parent-command".into()),
                 })
                 .await,
@@ -3028,4 +3104,180 @@ mod tests {
             "child result after parent close: {child_result:?}"
         );
     }
+    #[tokio::test]
+    async fn scoped_byte_cursor_survives_partial_ack_then_revocation_and_terminal_retry() {
+        let root = TempDir::new().unwrap();
+        fs::create_dir(root.path().join("child")).unwrap();
+        let parent = session(root.path());
+        let child = parent
+            .scope(request("child", WorkdirToolScopePermission::Write))
+            .await
+            .unwrap();
+        let tool = child.tool_session();
+        let handle = tool
+            .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
+                command: "printf ready; exec yes x".into(),
+                timeout_secs: 10,
+                cwd: FsPath::root(),
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+        let mut cursor = 0;
+        for _ in 0..2 {
+            let page = tool
+                .command_output(CommandOutputRequest {
+                    handle: handle.clone(),
+                    cursor,
+                    limit: 1,
+                    wait: true,
+                })
+                .await
+                .unwrap();
+            cursor = page.next_cursor;
+        }
+        tokio::time::timeout(std::time::Duration::from_secs(5), child.close())
+            .await
+            .unwrap()
+            .unwrap();
+        assert!(
+            tool.command_output(CommandOutputRequest {
+                handle,
+                cursor,
+                limit: 1,
+                wait: false
+            })
+            .await
+            .is_err()
+        );
+        let handle = parent
+            .start_command(CommandRequest {
+                transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
+                command: "printf parent".into(),
+                timeout_secs: 5,
+                cwd: FsPath::root(),
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+        let mut cursor = 0;
+        loop {
+            let request = CommandOutputRequest {
+                handle: handle.clone(),
+                cursor,
+                limit: 1024,
+                wait: true,
+            };
+            let page = parent.command_output(request.clone()).await.unwrap();
+            assert_eq!(parent.command_output(request).await.unwrap(), page);
+            cursor = page.next_cursor;
+            if page.terminal.is_some() {
+                break;
+            }
+        }
+    }
+    #[tokio::test]
+    async fn scoped_terminal_response_loss_replays_without_duplicate_capture_and_rejects_invalid_cursors()
+     {
+        tokio::time::timeout(std::time::Duration::from_secs(5), async {
+            let root = TempDir::new().unwrap();
+            fs::create_dir(root.path().join("child")).unwrap();
+            let parent = session(root.path());
+            let child = parent
+                .scope(request("child", WorkdirToolScopePermission::Write))
+                .await
+                .unwrap();
+            let tool = child.tool_session();
+            let handle = tool
+                .start_command(CommandRequest {
+                    transport_byte_budget: crate::MAX_COMMAND_TRANSPORT_BYTES,
+                    command: "printf abcdef".into(),
+                    timeout_secs: 5,
+                    cwd: FsPath::root(),
+                    tool_call_id: None,
+                })
+                .await
+                .unwrap();
+            let mut cursor = 0;
+            let mut captured = Vec::new();
+            let terminal_request = loop {
+                let request = CommandOutputRequest {
+                    handle: handle.clone(),
+                    cursor,
+                    limit: 2,
+                    wait: true,
+                };
+                // Simulate losing each produced HTTP response, including terminal:
+                // append only the retried page, never both copies.
+                let lost = tool.command_output(request.clone()).await.unwrap();
+                let replay = tool.command_output(request.clone()).await.unwrap();
+                assert_eq!(replay, lost);
+                for chunk in &replay.chunks {
+                    captured.extend_from_slice(&chunk.bytes);
+                }
+                cursor = replay.next_cursor;
+                if let Some(terminal) = replay.terminal {
+                    assert_eq!(terminal.status, CommandStatus::Completed);
+                    break request;
+                }
+            };
+            assert_eq!(captured, b"abcdef");
+            assert!(
+                !child
+                    .broker
+                    .authority
+                    .owned_commands
+                    .lock()
+                    .unwrap()
+                    .contains(&handle.0)
+            );
+            assert!(
+                child
+                    .broker
+                    .authority
+                    .command_reads
+                    .lock()
+                    .unwrap()
+                    .contains_key(&handle.0)
+            );
+            assert_eq!(
+                tool.command_status(handle.clone()).await.unwrap(),
+                CommandStatus::Completed
+            );
+            for invalid in [0, cursor + 1] {
+                assert!(
+                    tool.command_output(CommandOutputRequest {
+                        handle: handle.clone(),
+                        cursor: invalid,
+                        limit: 2,
+                        wait: false
+                    })
+                    .await
+                    .is_err()
+                );
+            }
+            // Invalid cursor requests do not destroy the retained terminal page.
+            assert!(
+                tool.command_output(terminal_request)
+                    .await
+                    .unwrap()
+                    .terminal
+                    .is_some()
+            );
+            child.close().await.unwrap();
+            assert!(
+                tool.command_output(CommandOutputRequest {
+                    handle,
+                    cursor,
+                    limit: 2,
+                    wait: false
+                })
+                .await
+                .is_err()
+            );
+        })
+        .await
+        .expect("bounded scoped terminal replay");
+    }
 }

crates/workdir/tests/command_denial_diagnostics.rs

@@ -103,11 +103,12 @@ impl WorkdirSession for CommandFailureSession {
 }
 fn command() -> CommandRequest {
     CommandRequest {
+        transport_byte_budget: workdir::MAX_COMMAND_TRANSPORT_BYTES,
         command: "fake command, never executed".into(),
         timeout_secs: 1,
-        output_limit: 100,
+
         cwd: WorkdirPath::root(),
-        spill_dir: None,
+
         tool_call_id: None,
     }
 }

crates/workdir/tests/denial_reasons.rs

@@ -167,11 +167,12 @@ async fn read_only_and_scoped_capability_refusals_do_not_collapse() {
     assert_reason(
         child
             .start_command(workdir::CommandRequest {
+                transport_byte_budget: workdir::MAX_COMMAND_TRANSPORT_BYTES,
                 command: "must-not-run".into(),
                 timeout_secs: 1,
-                output_limit: 1,
+
                 cwd: WorkdirPath::root(),
-                spill_dir: None,
+
                 tool_call_id: None,
             })
             .await

crates/worker-runtime/Cargo.toml

@@ -56,6 +56,7 @@ server-api = { path = "../server-api" }
 workdir.workspace = true
 
 [dev-dependencies]
+workdir = { workspace = true, features = ["http-client"] }
 futures.workspace = true
 agen.workspace = true
 serial_test = "3.4.0"

crates/worker-runtime/src/execution.rs

@@ -432,6 +432,9 @@ pub struct WorkerExecutionRestoreRequest {
     pub previous_workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     pub logical_workdir_attachments: Vec<crate::catalog::LogicalWorkdirAttachment>,
     pub workdir_attachments: BTreeMap<workdir::WorkdirAttachmentAlias, WorkingDirectoryBinding>,
+    /// Process-owned sessions that open providers only on a Workdir operation.
+    pub deferred_workdir_sessions:
+        BTreeMap<workdir::WorkdirAttachmentAlias, workdir::WorkdirSessionHandle>,
     pub config_bundle: Option<ConfigBundle>,
 }
 
@@ -567,6 +570,15 @@ impl fmt::Debug for WorkerProtocolTransport {
 pub trait WorkerExecutionBackend: Send + Sync + 'static {
     fn backend_id(&self) -> &str;
 
+    /// Confirm actual absence under the backend Worker operation lock. Runtime has
+    /// already durably fenced admission; unsupported or uncertain backends must fail.
+    fn recover_subject_create(
+        &self,
+        _request: &runtime_api::SubjectCreateRecoveryRequest,
+    ) -> Result<(), String> {
+        Err("execution backend cannot confirm Subject create execution absence".into())
+    }
+
     /// Must reserve the actual Controller, not infer Idle from a catalog snapshot.
     fn subject_release(
         &self,
@@ -839,6 +851,13 @@ impl WorkerExecutionBackendRef {
         self.backend.fetch_workspace_config(request)
     }
 
+    pub(crate) fn recover_subject_create(
+        &self,
+        request: &runtime_api::SubjectCreateRecoveryRequest,
+    ) -> Result<(), String> {
+        self.backend.recover_subject_create(request)
+    }
+
     pub(crate) fn subject_release(
         &self,
         request: &runtime_api::SubjectReleaseRequest,

crates/worker-runtime/src/fs_store.rs

@@ -39,9 +39,10 @@ use std::path::{Path, PathBuf};
 use std::sync::Arc;
 use std::sync::atomic::{AtomicU8, AtomicU64, Ordering};
 
-const SCHEMA_VERSION: u32 = 11;
-const EXECUTION_SCHEMA_VERSION: u32 = 10;
+const SCHEMA_VERSION: u32 = 12;
 // Frozen source schemas: do not move their meaning when adding a migration.
+const SOURCE_SCHEMA_VERSION: u32 = 11;
+const EXECUTION_SCHEMA_VERSION: u32 = 10;
 const AGGREGATE_SCHEMA_VERSION: u32 = 9;
 const PREVIOUS_SCHEMA_VERSION: u32 = 8;
 const LEGACY_SCHEMA_VERSION: u32 = 7;
@@ -480,6 +481,8 @@ pub(crate) struct OpenedFsRuntimeStore {
 
 #[derive(Clone, Debug)]
 pub(crate) struct PersistedRuntimeState {
+    pub(crate) subject_create_recovery_fences:
+        BTreeMap<WorkerId, crate::runtime::SubjectCreateRecoveryFence>,
     pub(crate) subject_releases: Vec<(
         runtime_api::SubjectReleaseRequest,
         runtime_api::SubjectReleaseState,
@@ -641,8 +644,8 @@ fn plan_runtime_store_migration(
             format!("Runtime store schema version {schema_version} is out of range"),
         )
     })?;
-    let staging = migration_sibling(root, "schema-v11-staging")?;
-    let backup = migration_sibling(root, "pre-schema-v11-backup")?;
+    let staging = migration_sibling(root, "schema-v12-staging")?;
+    let backup = migration_sibling(root, "pre-schema-v12-backup")?;
     if staging.exists() || backup.exists() {
         return Err(runtime_store_corrupt(
             root,
@@ -654,18 +657,32 @@ fn plan_runtime_store_migration(
         ));
     }
     if current_schema_version == SCHEMA_VERSION {
+        // Runtime and Session schemas evolve independently. Probe only through
+        // Session Store's non-mutating current-schema admission boundary; any
+        // conversion still runs on the existing owner-locked staging tree.
+        let migration_required = crate::retention::sessions_require_migration(root)?;
+        let excluded_ephemeral_paths = if migration_required {
+            runtime_tree_exclusions(root)?
+        } else {
+            Vec::new()
+        };
+        let archived_orphan_worker_count = if migration_required {
+            orphaned_worker_directories(root)?.len()
+        } else {
+            0
+        };
         let plan = FsRuntimeStoreMigrationPlan {
             current_schema_version,
             target_schema_version: SCHEMA_VERSION,
-            migration_required: false,
+            migration_required,
             worker_count: 0,
-            archived_orphan_worker_count: 0,
+            archived_orphan_worker_count,
             migrated_worker_aggregate_count: 0,
             migrated_diagnostic_worker_ref_count: 0,
             cleared_diagnostic_worker_ref_count: 0,
             mapping_digest: legacy_worker_identity_mapping_digest(&[]),
             mappings: Vec::new(),
-            excluded_ephemeral_paths: Vec::new(),
+            excluded_ephemeral_paths,
         };
         return Ok((plan, Vec::new()));
     }
@@ -676,11 +693,12 @@ fn plan_runtime_store_migration(
             | PREVIOUS_SCHEMA_VERSION
             | AGGREGATE_SCHEMA_VERSION
             | EXECUTION_SCHEMA_VERSION
+            | SOURCE_SCHEMA_VERSION
     ) {
         return Err(runtime_store_corrupt(
             &runtime_path,
             format!(
-                "unsupported Runtime store schema version {schema_version}; expected {OLDEST_SCHEMA_VERSION}, {LEGACY_SCHEMA_VERSION}, {PREVIOUS_SCHEMA_VERSION}, {AGGREGATE_SCHEMA_VERSION}, {EXECUTION_SCHEMA_VERSION}, or {SCHEMA_VERSION}"
+                "unsupported Runtime store schema version {schema_version}; expected {OLDEST_SCHEMA_VERSION}, {LEGACY_SCHEMA_VERSION}, {PREVIOUS_SCHEMA_VERSION}, {AGGREGATE_SCHEMA_VERSION}, {EXECUTION_SCHEMA_VERSION}, {SOURCE_SCHEMA_VERSION}, or {SCHEMA_VERSION}"
             ),
         ));
     }
@@ -1010,11 +1028,16 @@ fn migrate_worker_record(
     mapping: Option<&LegacyWorkerIdentityMapping>,
     identity_path: &Path,
 ) -> Result<WorkerAggregateRecord, RuntimeError> {
-    if source_schema_version == EXECUTION_SCHEMA_VERSION {
+    if matches!(
+        source_schema_version,
+        EXECUTION_SCHEMA_VERSION | SOURCE_SCHEMA_VERSION
+    ) {
+        // Schemas 10 and 11 already use the current Worker aggregate layout.
+        // Only advance its version; never regenerate Restore admission identity.
         if identity_document
             .get("schema_version")
             .and_then(serde_json::Value::as_u64)
-            != Some(u64::from(EXECUTION_SCHEMA_VERSION))
+            != Some(u64::from(source_schema_version))
         {
             return Err(runtime_store_corrupt(
                 identity_path,
@@ -1405,11 +1428,18 @@ fn migrate_runtime_document(
         "schema_version".to_string(),
         serde_json::Value::from(SCHEMA_VERSION),
     );
-    object.remove("workers");
-    // This legacy cache is not Runtime lifecycle or restore authority. Bundles
-    // are reacquired from Workspace content authority, never renumbered/rehash-pinned here.
-    object.remove("config_bundles");
-    object.remove("next_worker_sequence");
+    // Intermediate schema-11 writers may already have saved irreversible fences.
+    // Default only a missing field; malformed or existing fences must not be erased.
+    object
+        .entry("subject_create_recovery_fences")
+        .or_insert_with(|| serde_json::json!({}));
+    if source_schema_version != SOURCE_SCHEMA_VERSION {
+        object.remove("workers");
+        // This legacy cache is not Runtime lifecycle or restore authority. Bundles
+        // are reacquired from Workspace content authority, never renumbered/rehash-pinned here.
+        object.remove("config_bundles");
+        object.remove("next_worker_sequence");
+    }
     let snapshot: RuntimeSnapshot = serde_json::from_value(document.clone()).map_err(|error| {
         runtime_store_corrupt(
             runtime_path,
@@ -1523,14 +1553,16 @@ fn recover_runtime_store_migration(root: &Path) -> Result<(), RuntimeError> {
         "pre-schema-v9-backup",
         "schema-v10-staging",
         "pre-schema-v10-backup",
+        "schema-v11-staging",
+        "pre-schema-v11-backup",
     ] {
         let earlier = migration_sibling(root, suffix)?;
         if earlier.exists() {
-            return Err(runtime_store_corrupt(root, "unfinished earlier Runtime migration requires explicit recovery before schema-v11 startup".into()));
+            return Err(runtime_store_corrupt(root, "unfinished earlier Runtime migration requires explicit recovery before schema-v12 startup".into()));
         }
     }
-    let staging = migration_sibling(root, "schema-v11-staging")?;
-    let backup = migration_sibling(root, "pre-schema-v11-backup")?;
+    let staging = migration_sibling(root, "schema-v12-staging")?;
+    let backup = migration_sibling(root, "pre-schema-v12-backup")?;
     let root_exists = migration_directory_exists(root)?;
     let staging_exists = migration_directory_exists(&staging)?;
     let backup_exists = migration_directory_exists(&backup)?;
@@ -1732,8 +1764,8 @@ fn migrate_runtime_store(
     if !plan.migration_required {
         return Ok(plan);
     }
-    let staging = migration_sibling(root, "schema-v11-staging")?;
-    let backup = migration_sibling(root, "pre-schema-v11-backup")?;
+    let staging = migration_sibling(root, "schema-v12-staging")?;
+    let backup = migration_sibling(root, "pre-schema-v12-backup")?;
     if staging.exists() || backup.exists() {
         return Err(runtime_store_corrupt(
             root,
@@ -1790,7 +1822,9 @@ fn migrate_runtime_store(
     Ok(plan)
 }
 
-fn archive_orphaned_worker_directories(root: &Path) -> Result<usize, RuntimeError> {
+fn orphaned_worker_directories(
+    root: &Path,
+) -> Result<Vec<(std::ffi::OsString, PathBuf)>, RuntimeError> {
     let workers_dir = root.join(WORKERS_DIR);
     let mut orphaned = fs::read_dir(&workers_dir)
         .map_err(|source| runtime_io_error("read Worker records", &workers_dir, source))?
@@ -1803,6 +1837,11 @@ fn archive_orphaned_worker_directories(root: &Path) -> Result<usize, RuntimeErro
         })
         .collect::<Vec<_>>();
     orphaned.sort_by(|(left, _), (right, _)| left.cmp(right));
+    Ok(orphaned)
+}
+
+fn archive_orphaned_worker_directories(root: &Path) -> Result<usize, RuntimeError> {
+    let orphaned = orphaned_worker_directories(root)?;
     if orphaned.is_empty() {
         return Ok(0);
     }
@@ -1837,6 +1876,21 @@ fn migrate_runtime_store_in_place(
     if !plan.migration_required {
         return Ok(plan);
     }
+    if plan.current_schema_version == SCHEMA_VERSION {
+        // Session-only migration: do not reserialize Runtime/Worker identity,
+        // Restore guards, recovery fences, or retained execution receipts.
+        // As in a Runtime schema migration, retain orphan trees outside the
+        // Worker catalog before validating the completed staging tree.
+        let archived = archive_orphaned_worker_directories(root)?;
+        if archived != plan.archived_orphan_worker_count {
+            return Err(runtime_store_corrupt(
+                root,
+                "orphan count changed during Session migration".into(),
+            ));
+        }
+        crate::retention::migrate_staged_sessions(root)?;
+        return Ok(plan);
+    }
     let runtime_path = root.join(RUNTIME_FILE);
     let bytes =
         fs::read(&runtime_path).map_err(|error| runtime_io_error("read", &runtime_path, error))?;
@@ -1908,7 +1962,10 @@ fn migrate_runtime_store_in_place(
                 ));
             }
         }
-        if let Some(metadata) = metadata {
+        // Schema 11 metadata was validated above but needs no conversion.
+        if let Some(metadata) = metadata
+            && plan.current_schema_version != SOURCE_SCHEMA_VERSION
+        {
             atomic_write_json(
                 &migrated_dir.join(WORKER_METADATA_FILE),
                 &metadata,
@@ -1927,6 +1984,8 @@ fn migrate_runtime_store_in_place(
             ),
         ));
     }
+    // A Runtime schema bump says nothing about the retained Session schema.
+    // Session Store owns versioned conversion, including v4 -> generic v5.
     crate::retention::migrate_staged_sessions(root)?;
     let (document, _) = migrate_runtime_document(
         document,
@@ -1944,6 +2003,8 @@ fn migrate_runtime_store_in_place(
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
 struct RuntimeSnapshot {
+    #[serde(default)]
+    subject_create_recovery_fences: BTreeMap<WorkerId, crate::runtime::SubjectCreateRecoveryFence>,
     #[serde(default)]
     subject_releases: Vec<(
         runtime_api::SubjectReleaseRequest,
@@ -1980,6 +2041,7 @@ fn record_worker_load_diagnostic(
 impl RuntimeSnapshot {
     fn from_persisted(state: &PersistedRuntimeState) -> Self {
         Self {
+            subject_create_recovery_fences: state.subject_create_recovery_fences.clone(),
             subject_releases: state.subject_releases.clone(),
             schema_version: SCHEMA_VERSION,
             display_name: state.display_name.clone(),
@@ -2003,6 +2065,33 @@ impl RuntimeSnapshot {
                 ),
             });
         }
+        for (worker_id, fence) in &self.subject_create_recovery_fences {
+            let request = &fence.request;
+            let response_matches = fence.response.as_ref().is_none_or(|response| {
+                response.worker_id == request.worker_id
+                    && response.workspace_id == request.workspace_id
+                    && response.create_fingerprint == request.create_fingerprint
+                    && response.operation_id == request.operation_id
+            });
+            if *worker_id != request.worker_id
+                || request.workspace_id.trim().is_empty()
+                || request.create_fingerprint.trim().is_empty()
+                || request.create_fingerprint.len() > 512
+                || request.operation_id.trim().is_empty()
+                || request.operation_id.len() > 512
+                || self
+                    .workspace_owners
+                    .get(&request.workspace_id)
+                    .is_none_or(|owner| owner.trim().is_empty())
+                || !response_matches
+            {
+                return Err(RuntimeError::StoreCorrupt {
+                    operation: "read Subject create recovery fence",
+                    path: path.to_path_buf(),
+                    message: "invalid recovery identity, receipt or Workspace owner".into(),
+                });
+            }
+        }
         if self.backend != RuntimeBackendKind::FsStore {
             return Err(RuntimeError::StoreCorrupt {
                 operation: "read runtime snapshot",
@@ -2018,6 +2107,7 @@ impl RuntimeSnapshot {
         workers: BTreeMap<WorkerId, PersistedWorkerRecord>,
     ) -> PersistedRuntimeState {
         PersistedRuntimeState {
+            subject_create_recovery_fences: self.subject_create_recovery_fences,
             subject_releases: self.subject_releases,
             display_name: self.display_name,
             status: self.status,
@@ -2708,6 +2798,199 @@ mod tests {
         document["schema_version"].as_u64().unwrap()
     }
 
+    #[test]
+    fn schema_v11_migration_preserves_identity_history_and_recovery_fences_on_reopen() {
+        // Cover the released schema (no field) and intermediate writers with
+        // either a pending fence or a completed recovery receipt.
+        for fence_state in ["absent", "pending", "completed"] {
+            let temp = tempfile::tempdir().unwrap();
+            let root = temp.path().join("runtime");
+            let worker_id = WorkerId::now_v7();
+            let fenced_worker_id = WorkerId::now_v7();
+            let worker_dir = root.join(WORKERS_DIR).join(worker_id.to_string());
+            fs::create_dir_all(worker_dir.join("session")).unwrap();
+            let runtime_path = root.join(RUNTIME_FILE);
+            let worker_path = worker_dir.join(WORKER_FILE);
+            let metadata_path = worker_dir.join(WORKER_METADATA_FILE);
+            let history_path = worker_dir.join("session/history.json");
+            let history = b"[{\"role\":\"user\",\"content\":\"retained history\"}]\n";
+            fs::write(&history_path, history).unwrap();
+            let metadata = serde_json::to_vec(&serde_json::json!({
+                "worker_name": runtime_worker_name(worker_id),
+                "workspace_id": "workspace-a",
+                "retained_extension": {"history": "must not be rewritten"}
+            }))
+            .unwrap();
+            fs::write(&metadata_path, &metadata).unwrap();
+
+            let mut runtime = serde_json::json!({
+                "schema_version": 11,
+                "display_name": "schema-11 Runtime",
+                "backend": "fs_store",
+                "status": "running",
+                "next_diagnostic_id": 2,
+                "config_bundles": {},
+                "workspace_owners": {"workspace-a": "owner-a"},
+                "subject_releases": [],
+                "diagnostics": [{
+                    "id": 1, "worker_ref": {"worker_id": worker_id},
+                    "severity": "warning", "code": "retained_history",
+                    "message": "preserve diagnostic identity"
+                }]
+            });
+            let recovery_identity = serde_json::json!({
+                "workspace_id": "workspace-a", "worker_id": fenced_worker_id,
+                "create_fingerprint": "failed-create", "operation_id": "recover-a"
+            });
+            if fence_state != "absent" {
+                runtime["subject_create_recovery_fences"] = serde_json::json!({
+                    fenced_worker_id.to_string(): {
+                        "request": recovery_identity,
+                        "response": if fence_state == "completed" {
+                            recovery_identity.clone()
+                        } else {
+                            serde_json::Value::Null
+                        }
+                    }
+                });
+            }
+            atomic_write_json(&runtime_path, &runtime, "write schema-11 fixture").unwrap();
+            let runtime_before = fs::read(&runtime_path).unwrap();
+
+            let mut request = schema_v7_worker_document(worker_id)["request"].clone();
+            request["workspace_api"] = serde_json::json!({
+                "workspace_id": "workspace-a", "base_url": "https://workspace.invalid"
+            });
+            // Serialize defaults as a schema-11 writer would, without running
+            // a migration or generating a fresh Restore guard for the fixture.
+            let request: CreateWorkerRequest = serde_json::from_value(request).unwrap();
+            let worker: WorkerAggregateRecord = serde_json::from_value(serde_json::json!({
+                "schema_version": 11,
+                "restore_guard": {
+                    "observation_token": "retained-restore-token",
+                    "active_request_id": null, "owners": {}
+                },
+                "worker_ref": {"worker_id": worker_id}, "worker_id": worker_id,
+                "profile": request.profile,
+                "display_name": null,
+                "profile_source": request.profile_source.reference(),
+                "config_bundle": null,
+                "created_at_ms": 1234,
+                "status": "running",
+                "last_finished_submission_request_id": "finished-submission",
+                "workspace_id": "workspace-a",
+                "execution_state": {"state": "available", "execution": {
+                    "request": request, "binding": {}, "restore_intent": "automatic"
+                }}
+            }))
+            .unwrap();
+            let mut expected_worker = serde_json::to_value(&worker).unwrap();
+            atomic_write_json(&worker_path, &worker, "write schema-11 Worker").unwrap();
+            let worker_before = fs::read(&worker_path).unwrap();
+            let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-test");
+            let plan = FsRuntimeStore::migration_plan(&options).unwrap();
+            assert_eq!(plan.current_schema_version, 11);
+            assert_eq!(plan.target_schema_version, 12);
+            assert!(plan.migration_required);
+            assert_eq!(plan.worker_count, 1);
+            assert_eq!(plan.migrated_worker_aggregate_count, 0);
+            assert!(plan.mappings.is_empty());
+            assert_eq!(fs::read(&runtime_path).unwrap(), runtime_before);
+            assert_eq!(fs::read(&worker_path).unwrap(), worker_before);
+            // The direct reader still rejects a previous schema: migration is
+            // explicit, not permissive deserialization of a newer format.
+            let snapshot: RuntimeSnapshot = serde_json::from_value(runtime.clone()).unwrap();
+            assert!(snapshot.validate(&runtime_path).is_err());
+
+            let opened = FsRuntimeStore::open_or_create(root.clone(), "runtime-test").unwrap();
+            let state = opened.state.as_ref().unwrap();
+            let persisted_worker = state.workers.get(&worker_id).unwrap();
+            expected_worker["schema_version"] = serde_json::json!(12);
+            assert_eq!(
+                serde_json::to_value(WorkerAggregateRecord::from_persisted(persisted_worker))
+                    .unwrap(),
+                expected_worker
+            );
+            runtime["schema_version"] = serde_json::json!(12);
+            if fence_state == "absent" {
+                runtime["subject_create_recovery_fences"] = serde_json::json!({});
+            }
+            assert_eq!(
+                serde_json::to_value(&state.subject_create_recovery_fences).unwrap(),
+                runtime["subject_create_recovery_fences"]
+            );
+            assert_eq!(
+                read_json::<serde_json::Value>(&runtime_path, "read migrated Runtime").unwrap(),
+                runtime
+            );
+            assert_eq!(
+                read_json::<serde_json::Value>(&worker_path, "read migrated Worker").unwrap(),
+                expected_worker
+            );
+            // Exercise the normal writer too: it must retain intermediate fences.
+            opened.store.write_runtime_snapshot(state).unwrap();
+            drop(opened);
+            let runtime_once = fs::read(&runtime_path).unwrap();
+            let worker_once = fs::read(&worker_path).unwrap();
+            let reopened = FsRuntimeStore::open_or_create(root.clone(), "runtime-test").unwrap();
+            assert_eq!(
+                serde_json::to_value(
+                    &reopened
+                        .state
+                        .as_ref()
+                        .unwrap()
+                        .subject_create_recovery_fences
+                )
+                .unwrap(),
+                runtime["subject_create_recovery_fences"]
+            );
+            drop(reopened);
+            let plan = FsRuntimeStore::migrate(&options).unwrap();
+            assert!(!plan.migration_required);
+            assert_eq!(plan.current_schema_version, 12);
+            assert_eq!(plan.target_schema_version, 12);
+            assert!(
+                !FsRuntimeStore::migration_plan(&options)
+                    .unwrap()
+                    .migration_required
+            );
+            assert_eq!(fs::read(&runtime_path).unwrap(), runtime_once);
+            assert_eq!(fs::read(&worker_path).unwrap(), worker_once);
+            assert_eq!(fs::read(&metadata_path).unwrap(), metadata);
+            assert_eq!(fs::read(&history_path).unwrap(), history);
+            assert!(
+                !migration_sibling(&root, "schema-v12-staging")
+                    .unwrap()
+                    .exists()
+            );
+            assert!(
+                !migration_sibling(&root, "pre-schema-v12-backup")
+                    .unwrap()
+                    .exists()
+            );
+        }
+    }
+
+    #[test]
+    fn schema_v11_migration_rejects_invalid_fences_without_replacing_them() {
+        for fences in [
+            serde_json::Value::Null,
+            serde_json::json!({"invalid-worker": {}}),
+        ] {
+            let temp = tempfile::tempdir().unwrap();
+            let root = temp.path().join("runtime");
+            write_empty_schema_v8_store(&root);
+            let path = root.join(RUNTIME_FILE);
+            let mut runtime: serde_json::Value = read_json(&path, "read fixture").unwrap();
+            runtime["schema_version"] = serde_json::json!(11);
+            runtime["subject_create_recovery_fences"] = fences;
+            atomic_write_json(&path, &runtime, "write invalid fence fixture").unwrap();
+            let before = fs::read(&path).unwrap();
+            assert!(FsRuntimeStore::open_or_create(root, "runtime-test").is_err());
+            assert_eq!(fs::read(&path).unwrap(), before);
+        }
+    }
+
     #[test]
     fn schema_v10_startup_migrates_stopped_sessions_atomically() {
         for corrupt in [false, true] {
@@ -2761,10 +3044,9 @@ mod tests {
                 assert_eq!(record["schema_version"], 10);
             } else {
                 drop(result.unwrap());
-                assert_eq!(stored_schema_version(&root), 11);
-                let manifest: serde_json::Value =
-                    read_json(&session.join("session.json"), "test").unwrap();
-                assert_eq!(manifest["schema_version"], 4);
+                assert_eq!(stored_schema_version(&root), u64::from(SCHEMA_VERSION));
+                session_store::WorkerSessionStore::open_read_only(&session)
+                    .expect("startup migration must admit the current Session schema");
                 let once = fs::read(session.join("session.json")).unwrap();
                 drop(FsRuntimeStore::open_or_create(root.clone(), "runtime-test").unwrap());
                 assert_eq!(fs::read(session.join("session.json")).unwrap(), once);
@@ -3151,7 +3433,7 @@ mod tests {
         let temp = tempfile::tempdir().unwrap();
         let root = temp.path().join("runtime-store");
         write_empty_schema_v8_store(&root);
-        let staging = migration_sibling(&root, "schema-v11-staging").unwrap();
+        let staging = migration_sibling(&root, "schema-v12-staging").unwrap();
         fs::create_dir_all(&staging).unwrap();
         fs::write(staging.join("partial"), b"partial").unwrap();
         let store = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap();
@@ -3166,7 +3448,7 @@ mod tests {
         let temp = tempfile::tempdir().unwrap();
         let root = temp.path().join("runtime-store");
         write_empty_schema_v8_store(&root);
-        let backup = migration_sibling(&root, "pre-schema-v11-backup").unwrap();
+        let backup = migration_sibling(&root, "pre-schema-v12-backup").unwrap();
         fs::rename(&root, &backup).unwrap();
         let store = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap();
 
@@ -3180,10 +3462,10 @@ mod tests {
         let temp = tempfile::tempdir().unwrap();
         let root = temp.path().join("runtime-store");
         write_empty_schema_v8_store(&root);
-        let staging = migration_sibling(&root, "schema-v11-staging").unwrap();
+        let staging = migration_sibling(&root, "schema-v12-staging").unwrap();
         copy_runtime_tree(&root, &root, &staging).unwrap();
         migrate_runtime_store_in_place(&staging, "test-runtime").unwrap();
-        let backup = migration_sibling(&root, "pre-schema-v11-backup").unwrap();
+        let backup = migration_sibling(&root, "pre-schema-v12-backup").unwrap();
         fs::rename(&root, &backup).unwrap();
         let store = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap();
 
@@ -3198,10 +3480,10 @@ mod tests {
         let temp = tempfile::tempdir().unwrap();
         let root = temp.path().join("runtime-store");
         write_empty_schema_v8_store(&root);
-        let staging = migration_sibling(&root, "schema-v11-staging").unwrap();
+        let staging = migration_sibling(&root, "schema-v12-staging").unwrap();
         fs::create_dir_all(&staging).unwrap();
         fs::write(staging.join(RUNTIME_FILE), b"{\"schema_version\":8}").unwrap();
-        let backup = migration_sibling(&root, "pre-schema-v11-backup").unwrap();
+        let backup = migration_sibling(&root, "pre-schema-v12-backup").unwrap();
         fs::rename(&root, &backup).unwrap();
 
         let store = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap();
@@ -3218,7 +3500,7 @@ mod tests {
         let root = temp.path().join("runtime-store");
         write_empty_schema_v8_store(&root);
         migrate_runtime_store_in_place(&root, "test-runtime").unwrap();
-        let backup = migration_sibling(&root, "pre-schema-v11-backup").unwrap();
+        let backup = migration_sibling(&root, "pre-schema-v12-backup").unwrap();
         write_empty_schema_v8_store(&backup);
         let store = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap();
 
@@ -3228,14 +3510,21 @@ mod tests {
 
     #[test]
     fn earlier_migration_backup_cannot_be_mistaken_for_a_fresh_runtime() {
-        let temp = tempfile::tempdir().unwrap();
-        let root = temp.path().join("runtime-store");
-        let backup = migration_sibling(&root, "pre-schema-v9-backup").unwrap();
-        write_empty_schema_v8_store(&backup);
-        let error = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap_err();
-        assert!(error.to_string().contains("explicit recovery"));
-        assert!(!root.exists());
-        assert!(backup.join(RUNTIME_FILE).exists());
+        for suffix in [
+            "pre-schema-v9-backup",
+            "pre-schema-v10-backup",
+            "schema-v11-staging",
+            "pre-schema-v11-backup",
+        ] {
+            let temp = tempfile::tempdir().unwrap();
+            let root = temp.path().join("runtime-store");
+            let backup = migration_sibling(&root, suffix).unwrap();
+            write_empty_schema_v8_store(&backup);
+            let error = FsRuntimeStore::open_or_create(root.clone(), "test-runtime").unwrap_err();
+            assert!(error.to_string().contains("explicit recovery"));
+            assert!(!root.exists());
+            assert!(backup.join(RUNTIME_FILE).exists());
+        }
     }
 
     #[test]

crates/worker-runtime/src/http_server.rs

@@ -67,7 +67,7 @@ use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 use tokio::net::TcpListener;
 use workdir::{
-    CommandOutput, CommandStatus, WorkdirSessionHandle, dispatch_workdir_session_operation,
+    CommandOutput, WorkdirSessionHandle, dispatch_workdir_session_operation,
     http::{
         OpenWorkdirSessionRequest, OpenWorkdirSessionResponse, WorkdirSessionId,
         WorkdirSessionOperation, WorkdirSessionOperationRequest, WorkdirSessionOperationResult,
@@ -914,13 +914,9 @@ async fn run_workdir_session_operation(
             {
                 Ok(result) => result?,
                 Err(_) => CommandOutput {
-                    exit_code: None,
-                    timed_out: false,
-                    status: CommandStatus::Running,
-                    content: String::new(),
-                    next_cursor: Some(cursor),
-                    truncated: false,
-                    output_path: None,
+                    chunks: Vec::new(),
+                    next_cursor: cursor,
+                    terminal: None,
                 },
             };
             WorkdirSessionOperationResult::CommandOutput(output)
@@ -2102,6 +2098,9 @@ fn required_runtime_permission(method: &Method, path: &str) -> Option<&'static s
     {
         return Some("workers:input");
     }
+    if path == "/v1/subject-create-recovery" && *method == Method::POST {
+        return Some("workers:delete");
+    }
     if path.ends_with("/stop")
         || path.ends_with("/cancel")
         || (path == "/v1/subject-release" && *method == Method::POST)
@@ -2423,6 +2422,7 @@ pub enum RuntimeHttpServerError {
 
 #[cfg(test)]
 mod tests {
+    mod command_transport_tests;
     #[cfg(feature = "fs-store")]
     mod session_material_tests;
 
@@ -2973,6 +2973,19 @@ mod tests {
         }
     }
 
+    #[test]
+    fn subject_create_recovery_requires_worker_delete_permission() {
+        assert_eq!(
+            required_runtime_permission(&Method::POST, "/v1/subject-create-recovery"),
+            Some("workers:delete")
+        );
+        // Existing ordinary release authorization is unchanged.
+        assert_eq!(
+            required_runtime_permission(&Method::POST, "/v1/subject-release"),
+            Some("workers:stop")
+        );
+    }
+
     #[test]
     fn retention_routes_require_worker_delete_permission() {
         assert_eq!(
@@ -3197,6 +3210,14 @@ mod tests {
     struct AcceptingBackend;
 
     impl WorkerExecutionBackend for AcceptingBackend {
+        fn recover_subject_create(
+            &self,
+            _request: &runtime_api::SubjectCreateRecoveryRequest,
+        ) -> Result<(), String> {
+            // This test backend owns no real executions.
+            Ok(())
+        }
+
         fn backend_id(&self) -> &str {
             "http-test"
         }

crates/worker-runtime/src/http_server/runtime_management_api.rs

@@ -406,6 +406,18 @@ impl runtime_api::RuntimeApi for RuntimeManagementApi {
         }
     }
 
+    async fn recover_subject_create(
+        &self,
+        request: runtime_api::SubjectCreateRecoveryRequest,
+    ) -> Result<runtime_api::SubjectCreateRecoveryResponse, runtime_api::RuntimeApiError> {
+        let scope = material_scope(&self.state, &request.workspace_id)?;
+        self.state
+            .runtime
+            .recover_subject_create_scoped(&scope, request)
+            .map_err(RuntimeHttpRestError::runtime)
+            .map_err(api_error)
+    }
+
     async fn subject_release(
         &self,
         request: runtime_api::SubjectReleaseRequest,

crates/worker-runtime/src/http_server/tests/command_transport_tests.rs

@@ -0,0 +1,408 @@
+//! Loopback integration: production RemoteWorkdirSession, signed HTTP middleware,
+//! command operation handler, local process pipes, and JSON DTOs. Only opening the
+//! pre-seeded session is a fixture; no Runtime Worker/materializer is claimed here.
+
+use super::*;
+use std::time::Duration;
+use workdir::http::{
+    RemoteWorkdirSession, WorkdirHttpAuthorization, WorkdirHttpAuthorizationFuture,
+};
+use workdir::{CommandOutputRequest, CommandRequest, CommandStream, WorkdirSession};
+
+struct SignedAuthorization {
+    identity: RuntimeIdentityMaterial,
+    trust: WorkspaceIssuerTrustRecord,
+}
+impl std::fmt::Debug for SignedAuthorization {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("SignedAuthorization")
+    }
+}
+impl WorkdirHttpAuthorization for SignedAuthorization {
+    fn bearer_token(
+        &self,
+        method: String,
+        path: String,
+        body: Vec<u8>,
+    ) -> WorkdirHttpAuthorizationFuture {
+        let claims = signed_claims(&self.trust, &method, &path, &body);
+        let token =
+            issue_workspace_capability_token(&self.identity.signing_key().unwrap(), &claims)
+                .unwrap();
+        Box::pin(async move { Ok(token) })
+    }
+}
+
+struct Harness {
+    server: tokio::task::JoinHandle<()>,
+    session: WorkdirSessionHandle,
+    _root: tempfile::TempDir,
+    remote: RemoteWorkdirSession,
+    client: reqwest::Client,
+    operation_url: url::Url,
+    authorization: Arc<SignedAuthorization>,
+}
+impl Drop for Harness {
+    fn drop(&mut self) {
+        self.server.abort();
+    }
+}
+impl Harness {
+    async fn raw_operation(&self, operation: serde_json::Value) -> reqwest::Response {
+        let body = serde_json::to_vec(&serde_json::json!({"operation": operation})).unwrap();
+        let token = self
+            .authorization
+            .bearer_token(
+                "POST".into(),
+                self.operation_url.path().into(),
+                body.clone(),
+            )
+            .await
+            .unwrap();
+        self.client
+            .post(self.operation_url.clone())
+            .bearer_auth(token)
+            .header("content-type", "application/json")
+            .body(body)
+            .send()
+            .await
+            .unwrap()
+    }
+
+    async fn new() -> Self {
+        let root = tempfile::tempdir().unwrap();
+        let session: WorkdirSessionHandle = Arc::new(LocalWorkdirSession::materialized_bound(
+            Workdir::new("wd-transport"),
+            root.path().to_path_buf(),
+            root.path().to_path_buf(),
+            SharedScope::new(Scope::writable(root.path()).unwrap()),
+            WorkdirSessionCapabilities::ALL,
+        ));
+        let identity = RuntimeIdentityMaterial::generate("transport-key").unwrap();
+        let trust = workspace_trust(&identity);
+        let state = RuntimeHttpState {
+            runtime: Runtime::new_memory(),
+            local_token: None,
+            workspace_auth: Some(Arc::new(workspace_test_auth(vec![trust.clone()]))),
+            workdir_sessions: Arc::new(Mutex::new(HashMap::from([(
+                "session-transport".into(),
+                RuntimeHttpWorkdirSession {
+                    owner: RuntimeWorkspaceScope::new("workspace-a", "https://backend.test"),
+                    session: session.clone(),
+                },
+            )]))),
+            ssh_keyscan_program: Arc::new(PathBuf::from("ssh-keyscan")),
+        };
+        let app = Router::new()
+            .route(
+                "/v1/working-directories/{id}/sessions",
+                post(|| async {
+                    Json(OpenWorkdirSessionResponse {
+                        session_id: WorkdirSessionId::new("session-transport").unwrap(),
+                        workdir_id: Workdir::new("wd-transport").id().clone(),
+                        capabilities: WorkdirSessionCapabilities::ALL,
+                    })
+                }),
+            )
+            .route(
+                "/v1/workdir-sessions/{session_id}/operations",
+                post(run_workdir_session_operation),
+            )
+            .route(
+                "/v1/workdir-sessions/{session_id}",
+                delete(close_workdir_session),
+            )
+            .with_state(state.clone())
+            .layer(middleware::from_fn_with_state(state, require_runtime_auth));
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let base: url::Url = format!("http://{}", listener.local_addr().unwrap())
+            .parse()
+            .unwrap();
+        let server = tokio::spawn(async move {
+            axum::serve(listener, app).await.unwrap();
+        });
+        let mut headers = reqwest::header::HeaderMap::new();
+        headers.insert(
+            RUNTIME_WORKSPACE_SCOPE_HEADER,
+            "workspace-a".parse().unwrap(),
+        );
+        let client = reqwest::Client::builder()
+            .no_proxy()
+            .default_headers(headers)
+            .build()
+            .unwrap();
+        let authorization = Arc::new(SignedAuthorization { identity, trust });
+        let operation_url = base
+            .join("/v1/workdir-sessions/session-transport/operations")
+            .unwrap();
+        let remote = RemoteWorkdirSession::open_with_authorization(
+            client.clone(),
+            base,
+            authorization.clone(),
+            Workdir::new("wd-transport").id().clone(),
+            OpenWorkdirSessionRequest::default(),
+        )
+        .await
+        .unwrap();
+        Self {
+            server,
+            session,
+            _root: root,
+            remote,
+            client,
+            operation_url,
+            authorization,
+        }
+    }
+}
+
+#[tokio::test]
+async fn real_http_command_pages_preserve_binary_streams_replay_and_nonzero_exit() {
+    tokio::time::timeout(Duration::from_secs(20), async {
+        let harness = Harness::new().await;
+        let handle = harness.remote.start_command(CommandRequest {
+            transport_byte_budget: workdir::MAX_COMMAND_TRANSPORT_BYTES,
+            command: "head -c 2097152 /dev/zero | tr '\\0' x; printf '\\342\\202\\254\\377\\000'; printf 'stderr\\346\\227\\245' >&2; exit 9".into(),
+            timeout_secs: 15, cwd: WorkdirPath::root(), tool_call_id: Some("http-tool-call".into()),
+        }).await.unwrap();
+        let mut cursor = 0;
+        let mut stdout = Vec::new();
+        let mut stderr = Vec::new();
+        let terminal = loop {
+            let request = CommandOutputRequest { handle: handle.clone(), cursor, limit: 16384, wait: true };
+            let page = harness.remote.command_output(request.clone()).await.unwrap();
+            assert_eq!(harness.remote.command_output(request).await.unwrap(), page);
+            assert!(page.chunks.iter().map(|chunk| chunk.bytes.len()).sum::<usize>() <= 16384);
+            for chunk in page.chunks {
+                assert_eq!(chunk.sequence, cursor);
+                cursor += chunk.bytes.len() as u64;
+                let target = match chunk.stream { CommandStream::Stdout => &mut stdout, CommandStream::Stderr => &mut stderr };
+                assert_eq!(chunk.offset, target.len() as u64);
+                target.extend(chunk.bytes);
+            }
+            assert_eq!(cursor, page.next_cursor);
+            if let Some(terminal) = page.terminal { break terminal; }
+        };
+        let mut expected = vec![b'x'; 2097152];
+        expected.extend_from_slice(b"\xe2\x82\xac\xff\0");
+        assert_eq!(stdout, expected);
+        assert_eq!(stderr, b"stderr\xe6\x97\xa5");
+        assert_eq!(terminal.status, workdir::CommandStatus::Failed);
+        assert_eq!(terminal.exit_code, Some(9));
+        assert!(harness.remote.command_output(CommandOutputRequest { handle, cursor: 0, limit: 1, wait: false }).await.is_err());
+        harness.remote.close().await.unwrap();
+        assert!(harness.session.command_snapshot().is_empty());
+    }).await.expect("bounded HTTP command transport");
+}
+
+#[tokio::test]
+async fn real_http_cancel_drains_tail_before_terminal_and_timeout_is_distinct() {
+    tokio::time::timeout(Duration::from_secs(15), async {
+        let harness = Harness::new().await;
+        for (command, timeout, cancel, expected) in [
+            (
+                "printf ready; exec yes x",
+                10,
+                true,
+                workdir::CommandStatus::Cancelled,
+            ),
+            (
+                "printf ready; exec tail -f /dev/null",
+                1,
+                false,
+                workdir::CommandStatus::TimedOut,
+            ),
+        ] {
+            let handle = harness
+                .remote
+                .start_command(CommandRequest {
+                    transport_byte_budget: workdir::MAX_COMMAND_TRANSPORT_BYTES,
+                    command: command.into(),
+                    timeout_secs: timeout,
+                    cwd: WorkdirPath::root(),
+                    tool_call_id: None,
+                })
+                .await
+                .unwrap();
+            let mut cursor = 0;
+            let first = harness
+                .remote
+                .command_output(CommandOutputRequest {
+                    handle: handle.clone(),
+                    cursor,
+                    limit: 5,
+                    wait: true,
+                })
+                .await
+                .unwrap();
+            assert_eq!(
+                first
+                    .chunks
+                    .iter()
+                    .flat_map(|chunk| chunk.bytes.iter().copied())
+                    .collect::<Vec<_>>(),
+                b"ready"
+            );
+            cursor = first.next_cursor;
+            if cancel {
+                harness.remote.cancel_command(handle.clone()).await.unwrap();
+            }
+            loop {
+                let page = harness
+                    .remote
+                    .command_output(CommandOutputRequest {
+                        handle: handle.clone(),
+                        cursor,
+                        limit: workdir::MAX_COMMAND_READ_BYTES,
+                        wait: true,
+                    })
+                    .await
+                    .unwrap();
+                cursor = page.next_cursor;
+                if let Some(terminal) = page.terminal {
+                    assert_eq!(terminal.status, expected);
+                    break;
+                }
+            }
+        }
+        harness.remote.close().await.unwrap();
+    })
+    .await
+    .expect("bounded cancellation and timeout over HTTP");
+}
+
+#[tokio::test]
+async fn real_http_command_budget_bounds_unique_payload_and_reports_larger_seen_totals() {
+    tokio::time::timeout(Duration::from_secs(20), async {
+        let harness = Harness::new().await;
+        for budget in [0, 12345] {
+            let handle = harness
+                .remote
+                .start_command(CommandRequest {
+                    command: "head -c 1048576 /dev/zero; head -c 65536 /dev/zero >&2; exit 9"
+                        .into(),
+                    timeout_secs: 10,
+                    transport_byte_budget: budget,
+                    cwd: WorkdirPath::root(),
+                    tool_call_id: None,
+                })
+                .await
+                .unwrap();
+            let mut cursor = 0;
+            let mut delivered = [0_u64; 2];
+            let terminal = loop {
+                let request = CommandOutputRequest {
+                    handle: handle.clone(),
+                    cursor,
+                    limit: 997,
+                    wait: true,
+                };
+                let page = harness
+                    .remote
+                    .command_output(request.clone())
+                    .await
+                    .unwrap();
+                assert_eq!(harness.remote.command_output(request).await.unwrap(), page);
+                for chunk in page.chunks {
+                    assert_eq!(chunk.sequence, cursor);
+                    cursor += chunk.bytes.len() as u64;
+                    let index = match chunk.stream {
+                        CommandStream::Stdout => 0,
+                        CommandStream::Stderr => 1,
+                    };
+                    assert_eq!(chunk.offset, delivered[index]);
+                    delivered[index] += chunk.bytes.len() as u64;
+                }
+                assert_eq!(cursor, page.next_cursor);
+                assert!(
+                    cursor <= budget,
+                    "RemoteWorkdirSession must not receive bytes beyond budget"
+                );
+                if let Some(terminal) = page.terminal {
+                    break terminal;
+                }
+            };
+            assert_eq!(cursor, budget);
+            assert_eq!(terminal.stdout_bytes, 1048576);
+            assert_eq!(terminal.stderr_bytes, 65536);
+            assert_eq!(terminal.stdout_delivered_bytes, delivered[0]);
+            assert_eq!(terminal.stderr_delivered_bytes, delivered[1]);
+            assert_eq!(
+                terminal.truncation_reason,
+                Some(workdir::CommandOutputTruncation::ByteBudget)
+            );
+            assert_eq!(terminal.status, workdir::CommandStatus::Failed);
+            assert_eq!(terminal.exit_code, Some(9));
+            assert!(
+                harness
+                    .remote
+                    .command_output(CommandOutputRequest {
+                        handle: handle.clone(),
+                        cursor: budget + 1,
+                        limit: 1,
+                        wait: false,
+                    })
+                    .await
+                    .is_err()
+            );
+            if budget > 0 {
+                assert!(
+                    harness
+                        .remote
+                        .command_output(CommandOutputRequest {
+                            handle,
+                            cursor: 0,
+                            limit: 1,
+                            wait: false,
+                        })
+                        .await
+                        .is_err()
+                );
+            }
+        }
+        harness.remote.close().await.unwrap();
+    })
+    .await
+    .expect("bounded HTTP byte-budget transport");
+}
+
+#[tokio::test]
+async fn real_http_rejects_invalid_or_legacy_budget_requests_before_process_start() {
+    tokio::time::timeout(Duration::from_secs(10), async {
+        let harness = Harness::new().await;
+        let request = CommandRequest {
+            command: "touch must-not-exist".into(),
+            timeout_secs: 1,
+            transport_byte_budget: workdir::MAX_COMMAND_TRANSPORT_BYTES + 1,
+            cwd: WorkdirPath::root(),
+            tool_call_id: None,
+        };
+        let oversize =
+            serde_json::to_value(WorkdirSessionOperation::CommandStart(request)).unwrap();
+        assert_eq!(
+            harness.raw_operation(oversize.clone()).await.status(),
+            reqwest::StatusCode::BAD_REQUEST
+        );
+        let mut missing = oversize.clone();
+        // CommandStart is externally tagged by operation / request.
+        let object = missing.as_object_mut().unwrap();
+        let request = object.get_mut("request").unwrap().as_object_mut().unwrap();
+        request.remove("transport_byte_budget");
+        assert_eq!(
+            harness.raw_operation(missing).await.status(),
+            reqwest::StatusCode::BAD_REQUEST
+        );
+        let mut legacy = oversize;
+        let request = legacy["request"].as_object_mut().unwrap();
+        request.insert("transport_byte_budget".into(), serde_json::json!(0));
+        request.insert("spill_dir".into(), serde_json::json!("/private/host"));
+        assert_eq!(
+            harness.raw_operation(legacy).await.status(),
+            reqwest::StatusCode::BAD_REQUEST
+        );
+        assert!(!harness._root.path().join("must-not-exist").exists());
+        harness.remote.close().await.unwrap();
+    })
+    .await
+    .expect("bounded HTTP budget admission");
+}

crates/worker-runtime/src/http_server/tests/session_material_tests.rs

@@ -35,6 +35,7 @@ fn message(id: &str, role: LoggedRole, text: &str) -> LoggedHistoryEntry {
             content: vec![LoggedContentPart::Text { text: text.into() }],
         },
         metadata: LoggedSessionHistoryMetadata {
+            input_metadata: None,
             entry_id: LoggedSessionHistoryEntryId(id.into()),
             origin: LoggedSessionHistoryOrigin::LocalHumanInput,
             derivation: None,
@@ -1086,6 +1087,54 @@ async fn canonical_http_rejects_replay_tampered_body_and_workspace_mismatch() {
     assert_eq!(unsigned.status(), StatusCode::UNAUTHORIZED);
 }
 
+#[tokio::test]
+async fn subject_create_recovery_signed_http_requires_delete_and_matching_workspace() {
+    let f = Fixture::new();
+    let identity = RuntimeIdentityMaterial::generate("recovery-key").unwrap();
+    let trust = workspace_trust(&identity);
+    let app = runtime_http_router_with_workspace_auth(
+        f.runtime.clone(),
+        None,
+        workspace_test_auth(vec![trust.clone()]),
+    );
+    let path = "/v1/subject-create-recovery";
+    let mut request = runtime_api::SubjectCreateRecoveryRequest {
+        workspace_id: f.scope.workspace_id.clone(),
+        worker_id: WorkerId::now_v7(),
+        create_fingerprint: "unpublished-create".into(),
+        operation_id: "recovery-1".into(),
+    };
+    for operation in ["workers:read", "workers:stop", "workers:create"] {
+        let body = serde_json::to_vec(&request).unwrap();
+        let mut claims = signed_claims(&trust, "POST", path, &body);
+        claims.operation = operation.into();
+        let response = signed_request(app.clone(), &identity, &claims, body, "workspace-a").await;
+        assert_eq!(response.status(), StatusCode::UNAUTHORIZED);
+    }
+    request.workspace_id = "other-workspace".into();
+    let body = serde_json::to_vec(&request).unwrap();
+    let claims = signed_claims(&trust, "POST", path, &body);
+    let response = signed_request(app.clone(), &identity, &claims, body, "workspace-a").await;
+    assert_eq!(response.status(), StatusCode::FORBIDDEN);
+    request.workspace_id = f.scope.workspace_id.clone();
+    for _ in 0..2 {
+        let body = serde_json::to_vec(&request).unwrap();
+        let claims = signed_claims(&trust, "POST", path, &body);
+        assert_eq!(claims.operation, "workers:delete");
+        let response = signed_request(app.clone(), &identity, &claims, body, "workspace-a").await;
+        assert_eq!(response.status(), StatusCode::OK);
+        let bytes = axum::body::to_bytes(response.into_body(), 16384)
+            .await
+            .unwrap();
+        let receipt: runtime_api::SubjectCreateRecoveryResponse =
+            serde_json::from_slice(&bytes).unwrap();
+        assert_eq!(receipt.worker_id, request.worker_id);
+        assert_eq!(receipt.workspace_id, request.workspace_id);
+        assert_eq!(receipt.create_fingerprint, request.create_fingerprint);
+        assert_eq!(receipt.operation_id, request.operation_id);
+    }
+}
+
 #[tokio::test]
 async fn explicit_material_erasure_requires_delete_capability_and_matching_scope() {
     let f = Fixture::new();

crates/worker-runtime/src/retention.rs

@@ -641,6 +641,13 @@ impl FsWorkerRetentionProvider {
         let (manifest, session_root) = self.session_archive_identity(archive_id)?;
         let archive_dir = self.archive_dir(archive_id)?;
         let manifest = validate_existing_archive(&archive_dir, &manifest, false)?;
+        session_store::WorkerSessionStore::open_read_only(&session_root).map_err(|_| {
+            RuntimeError::StoreCorrupt {
+                operation: "read Worker Session archive",
+                path: session_root.clone(),
+                message: "archive Session is unavailable in the current schema".into(),
+            }
+        })?;
         Ok((manifest, session_root))
     }
 
@@ -653,13 +660,7 @@ impl FsWorkerRetentionProvider {
             &archive_dir.join("manifest.json"),
             "read Worker Session archive",
         )?;
-        if manifest.schema_version != ARCHIVE_SCHEMA_VERSION || manifest.archive_id != archive_id {
-            return Err(RuntimeError::StoreCorrupt {
-                operation: "read Worker Session archive",
-                path: archive_dir.join("manifest.json"),
-                message: "archive manifest identity mismatch".to_string(),
-            });
-        }
+        validate_archive_identity(&archive_dir, &manifest)?;
         Ok((manifest, archive_dir.join("session")))
     }
 
@@ -1204,9 +1205,14 @@ fn archive_storage(
     }
 }
 
-/// Called only on the private Runtime migration staging tree under its owner
-/// lock. Failure discards the whole tree, including manifests and attestations.
-pub(crate) fn migrate_staged_sessions(root: &Path) -> Result<(), RuntimeError> {
+// Share discovery and erasure fencing between Runtime preflight and staging.
+// Unreadable archives are retained but excluded before any conversion writes;
+// one historical archive must not block the live Runtime's startup. Session
+// Store owns conversion admission, including the current resource limits.
+fn for_each_live_session(
+    root: &Path,
+    mut visit: impl FnMut(&Path, bool) -> Result<(), RuntimeError>,
+) -> Result<(), RuntimeError> {
     for directory in ["workers", "orphaned-workers", "archives/workers"] {
         let directory = root.join(directory);
         let entries = match fs::read_dir(&directory) {
@@ -1228,69 +1234,232 @@ pub(crate) fn migrate_staged_sessions(root: &Path) -> Result<(), RuntimeError> {
             })?;
             let aggregate = entry.path();
             let session = aggregate.join("session");
-            if !session
-                .join("session.json")
-                .try_exists()
-                .map_err(|source| RuntimeError::StoreIo {
-                    operation: "inspect Session migration",
-                    path: session.clone(),
-                    source,
-                })?
-            {
-                continue;
-            }
-            let identity: CanonicalSessionManifest = read_json(
-                &session.join("session.json"),
-                "read Session migration identity",
-            )?;
-            let session_id = identity.session_id.parse().map_err(|_| {
-                RuntimeError::InvalidRequest("Session migration identity is invalid".into())
-            })?;
+            let is_archive = directory == root.join("archives/workers");
+            let identity = (|| {
+                if !session
+                    .join("session.json")
+                    .try_exists()
+                    .map_err(|source| RuntimeError::StoreIo {
+                        operation: "inspect Session migration",
+                        path: session.clone(),
+                        source,
+                    })?
+                {
+                    return Ok(None);
+                }
+                let identity: CanonicalSessionManifest = read_json(
+                    &session.join("session.json"),
+                    "read Session migration identity",
+                )?;
+                identity.session_id.parse().map(Some).map_err(|_| {
+                    RuntimeError::InvalidRequest("Session migration identity is invalid".into())
+                })
+            })();
+            let session_id = match identity {
+                Ok(Some(session_id)) => session_id,
+                Ok(None) => continue,
+                Err(error) if is_archive => {
+                    warn_unavailable_archive(
+                        &aggregate,
+                        ArchiveMigrationFailure::runtime("session_identity", &error),
+                    );
+                    continue;
+                }
+                Err(error) => return Err(error),
+            };
             match runtime_session_retention(root).ensure_live(session_id) {
                 Ok(()) => {}
-                // Erasure fences remain authoritative even if physical removal
-                // was interrupted. Do not inspect or migrate fenced originals.
+                // Retention-ledger failures are not archive-local. Never bypass
+                // erasure authority while isolating an unreadable archive.
                 Err(session_store::StoreError::SessionErased(_)) => continue,
                 Err(error) => return Err(retention_error(error)),
             }
-            let archive = if directory == root.join("archives/workers") {
-                let manifest: WorkerSessionArchiveManifest = read_json(
-                    &aggregate.join("manifest.json"),
-                    "read archive before Session migration",
-                )?;
-                Some(validate_existing_archive(&aggregate, &manifest, false)?)
-            } else {
-                None
-            };
-            session_store::WorkerSessionStore::new(&session).map_err(|error| {
-                RuntimeError::StoreCorrupt {
-                    operation: "migrate Session schema",
-                    path: session.clone(),
-                    message: error.to_string(),
+            if is_archive {
+                if let Err(failure) = validate_archive_migration(&aggregate) {
+                    warn_unavailable_archive(&aggregate, failure);
+                    continue;
                 }
-            })?;
-            if let Some(ingestion) = archive {
-                let (checksum_sha256, bytes, file_count) = checksum_files(
-                    &collect_files(&session, "migrate archive storage")?,
-                    "migrate archive storage",
-                )?;
-                atomic_write_json(
-                    &aggregate.join(ARCHIVE_STORAGE_FILE),
-                    &MigratedArchiveStorage {
-                        schema_version: 1,
-                        ingestion,
-                        checksum_sha256,
-                        bytes,
-                        file_count,
-                    },
-                    "commit migrated archive storage",
-                )?;
             }
+            // Publication failures still abort the outer staging transaction.
+            visit(&aggregate, is_archive)?;
         }
     }
     Ok(())
 }
 
+struct ArchiveMigrationFailure {
+    stage: &'static str,
+    reason: &'static str,
+}
+
+impl ArchiveMigrationFailure {
+    fn runtime(stage: &'static str, error: &RuntimeError) -> Self {
+        let reason = match error {
+            RuntimeError::StoreIo { source, .. } => safe_io_reason(source),
+            RuntimeError::StoreCorrupt { message, .. } => match message.as_str() {
+                "archive manifest identity mismatch" => "archive_identity_mismatch",
+                "archive id collision or manifest mismatch" => "archive_manifest_mismatch",
+                "archive checksum or content summary mismatch" => "archive_checksum_mismatch",
+                "archive storage attestation does not match ingestion receipt" => {
+                    "archive_storage_attestation_mismatch"
+                }
+                _ => "invalid_stored_data",
+            },
+            RuntimeError::InvalidRequest(_) => "invalid_identity",
+            _ => "archive_validation_failed",
+        };
+        Self { stage, reason }
+    }
+
+    fn conversion(error: session_store::StoreError) -> Self {
+        use session_store::StoreError;
+        let reason = match error {
+            StoreError::Io(error) => safe_io_reason(&error),
+            StoreError::Serde(_) => "invalid_session_manifest",
+            StoreError::Corrupt { message, .. }
+                if message.starts_with("unsupported Worker Session schema version ") =>
+            {
+                "unsupported_session_schema"
+            }
+            // The legacy decoder wraps InputMetadataError in a path-bearing Corrupt
+            // message. Recognize only its fixed cause; never publish that wrapper.
+            StoreError::Corrupt { message, .. }
+                if message.ends_with(&format!(
+                    ": {}",
+                    session_store::InputMetadataError::ResourceLimit
+                )) =>
+            {
+                "input_resource_limit_exceeded"
+            }
+            StoreError::Corrupt { .. } => "invalid_session_log",
+            StoreError::InvalidInputMetadata(session_store::InputMetadataError::ResourceLimit) => {
+                "input_resource_limit_exceeded"
+            }
+            StoreError::InvalidInputMetadata(_) => "invalid_input_metadata",
+            StoreError::ReadLimitExceeded => "read_limit_exceeded",
+            _ => "session_conversion_failed",
+        };
+        Self {
+            stage: "session_conversion",
+            reason,
+        }
+    }
+}
+
+fn safe_io_reason(error: &std::io::Error) -> &'static str {
+    match error.kind() {
+        std::io::ErrorKind::NotFound => "not_found",
+        std::io::ErrorKind::PermissionDenied => "permission_denied",
+        std::io::ErrorKind::InvalidData => "invalid_data",
+        _ => "io_error",
+    }
+}
+
+fn validate_archive_migration(aggregate: &Path) -> Result<(), ArchiveMigrationFailure> {
+    let session = aggregate.join("session");
+    // Current archives need no conversion. Their payload integrity is checked
+    // on access, not by scanning every retained byte during Runtime startup.
+    if session_store::WorkerSessionStore::open_read_only(&session).is_ok() {
+        return Ok(());
+    }
+    let manifest: WorkerSessionArchiveManifest = read_json(
+        &aggregate.join("manifest.json"),
+        "read archive before Session migration",
+    )
+    .map_err(|error| ArchiveMigrationFailure::runtime("archive_manifest", &error))?;
+    validate_existing_archive(aggregate, &manifest, false)
+        .map_err(|error| ArchiveMigrationFailure::runtime("archive_integrity", &error))?;
+    session_store::WorkerSessionStore::validate_migration(&session)
+        .map_err(ArchiveMigrationFailure::conversion)
+}
+
+fn warn_unavailable_archive(aggregate: &Path, failure: ArchiveMigrationFailure) {
+    let archive_id = aggregate.file_name().unwrap_or_default().to_string_lossy();
+    tracing::warn!(
+        archive_id = %bounded_diagnostic_id(&archive_id),
+        code = "session_archive_unavailable",
+        stage = failure.stage,
+        reason = failure.reason,
+        "Retained Session archive could not be admitted for migration; original bytes retained"
+    );
+}
+
+/// Read-only admission probe. Only convertible archives request a staged pass;
+/// unreadable originals remain available for archive-local diagnostics/recovery.
+/// Never create a writable Session store or rewrite archive attestations here.
+pub(crate) fn sessions_require_migration(root: &Path) -> Result<bool, RuntimeError> {
+    let mut required = false;
+    for_each_live_session(root, |aggregate, _| {
+        required |=
+            session_store::WorkerSessionStore::open_read_only(aggregate.join("session")).is_err();
+        Ok(())
+    })?;
+    Ok(required)
+}
+
+/// Called only on the private Runtime migration staging tree under its owner
+/// lock. Failure discards the whole tree, including manifests and attestations.
+pub(crate) fn migrate_staged_sessions(root: &Path) -> Result<(), RuntimeError> {
+    for_each_live_session(root, |aggregate, is_archive| {
+        let session = aggregate.join("session");
+        // Current Sessions need no writable admission, and their storage
+        // attestations must remain byte-for-byte unchanged.
+        if session_store::WorkerSessionStore::open_read_only(&session).is_ok() {
+            return Ok(());
+        }
+        let archive = if is_archive {
+            let manifest: WorkerSessionArchiveManifest = read_json(
+                &aggregate.join("manifest.json"),
+                "read archive before Session migration",
+            )?;
+            Some(validate_existing_archive(aggregate, &manifest, false)?)
+        } else {
+            None
+        };
+        session_store::WorkerSessionStore::new(&session).map_err(|error| {
+            RuntimeError::StoreCorrupt {
+                operation: "migrate Session schema",
+                path: session.clone(),
+                message: error.to_string(),
+            }
+        })?;
+        if let Some(ingestion) = archive {
+            let (checksum_sha256, bytes, file_count) = checksum_files(
+                &collect_files(&session, "migrate archive storage")?,
+                "migrate archive storage",
+            )?;
+            atomic_write_json(
+                &aggregate.join(ARCHIVE_STORAGE_FILE),
+                &MigratedArchiveStorage {
+                    schema_version: 1,
+                    ingestion,
+                    checksum_sha256,
+                    bytes,
+                    file_count,
+                },
+                "commit migrated archive storage",
+            )?;
+        }
+        Ok(())
+    })
+}
+
+fn validate_archive_identity(
+    archive_dir: &Path,
+    manifest: &WorkerSessionArchiveManifest,
+) -> Result<(), RuntimeError> {
+    if manifest.schema_version != ARCHIVE_SCHEMA_VERSION
+        || archive_dir.file_name().and_then(|name| name.to_str()) != Some(&manifest.archive_id)
+    {
+        return Err(RuntimeError::StoreCorrupt {
+            operation: "read Worker Session archive",
+            path: archive_dir.join("manifest.json"),
+            message: "archive manifest identity mismatch".into(),
+        });
+    }
+    Ok(())
+}
+
 fn validate_existing_archive(
     archive_dir: &Path,
     expected: &WorkerSessionArchiveManifest,
@@ -1300,6 +1469,7 @@ fn validate_existing_archive(
         &archive_dir.join("manifest.json"),
         "verify Worker Session archive",
     )?;
+    validate_archive_identity(archive_dir, &existing)?;
     let storage = archive_storage(archive_dir, &existing)?;
     let mut comparable_expected = expected.clone();
     comparable_expected.archived_at_unix_seconds = existing.archived_at_unix_seconds;
@@ -1753,12 +1923,16 @@ fn temporary_path(path: &Path) -> PathBuf {
     path.with_file_name(format!(".{name}.tmp-{}-{sequence}", std::process::id()))
 }
 
+#[cfg(all(test, feature = "fs-store"))]
+#[path = "retention/runtime_v5_tests.rs"]
+mod runtime_v5_tests;
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use std::sync::{Arc, Barrier};
 
-    fn write_json(path: &Path, value: &impl Serialize) {
+    pub(super) fn write_json(path: &Path, value: &impl Serialize) {
         fs::create_dir_all(path.parent().unwrap()).unwrap();
         fs::write(path, serde_json::to_vec_pretty(value).unwrap()).unwrap();
     }
@@ -1786,7 +1960,7 @@ mod tests {
         fs::write(worker.join("runs/attempt-a/worker.sock"), b"not retained").unwrap();
     }
 
-    fn request(
+    pub(super) fn request(
         worker_id: WorkerId,
         disposition: SessionDisposition,
     ) -> WorkerRetentionExecutionRequest {
@@ -1831,6 +2005,7 @@ mod tests {
                 }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId("original".into()),
                 origin: LoggedSessionHistoryOrigin::LocalHumanInput,
                 derivation: None,
@@ -1844,6 +2019,7 @@ mod tests {
                 }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId("summary".into()),
                 origin: LoggedSessionHistoryOrigin::DerivedSummary,
                 derivation: Some(session_store::LoggedHistoryDerivation {
@@ -2002,7 +2178,7 @@ mod tests {
     }
 
     #[test]
-    fn session_migration_rejects_corrupt_archive_before_replacing_its_bytes() {
+    fn session_migration_preserves_corrupt_archive_without_blocking_other_sessions() {
         let temp = tempfile::tempdir().unwrap();
         let worker = WorkerId::now_v7();
         let compact = old_compacted_source(temp.path(), worker);
@@ -2014,11 +2190,165 @@ mod tests {
             .join("session/segments")
             .join(format!("{compact}.jsonl"));
         fs::write(&path, b"corrupt\n").unwrap();
-        assert!(migrate_staged_sessions(temp.path()).is_err());
+        migrate_staged_sessions(temp.path()).unwrap();
         assert_eq!(fs::read(&path).unwrap(), b"corrupt\n");
         assert!(!archive.join(ARCHIVE_STORAGE_FILE).exists());
     }
 
+    #[cfg(feature = "fs-store")]
+    #[test]
+    fn archive_admission_logs_safe_causes_and_startup_preserves_original_bytes() {
+        // Exercise FsRuntimeStore startup, real archive admission and Session conversion;
+        // only the tracing sink is substituted, and all storage is temporary.
+        #[derive(Clone)]
+        struct Capture(Arc<std::sync::Mutex<Vec<u8>>>);
+        impl std::io::Write for Capture {
+            fn write(&mut self, bytes: &[u8]) -> std::io::Result<usize> {
+                self.0.lock().unwrap().extend_from_slice(bytes);
+                Ok(bytes.len())
+            }
+            fn flush(&mut self) -> std::io::Result<()> {
+                Ok(())
+            }
+        }
+        use crate::fs_store::FsRuntimeStore;
+        const PRIVATE: &str = "private-session-content-token=/private/host/session";
+        for (case, stage, reason) in [
+            ("identity_json", "session_identity", "invalid_stored_data"),
+            ("identity_value", "session_identity", "invalid_identity"),
+            ("manifest_json", "archive_manifest", "invalid_stored_data"),
+            (
+                "manifest_identity",
+                "archive_integrity",
+                "archive_identity_mismatch",
+            ),
+            ("storage_json", "archive_integrity", "invalid_stored_data"),
+            ("checksum", "archive_integrity", "archive_checksum_mismatch"),
+            ("schema", "session_conversion", "unsupported_session_schema"),
+            ("log", "session_conversion", "invalid_session_log"),
+            (
+                "resource_limit",
+                "session_conversion",
+                "input_resource_limit_exceeded",
+            ),
+        ] {
+            let temp = tempfile::tempdir().unwrap();
+            let root = temp.path().join("private-runtime-root");
+            drop(
+                crate::Runtime::with_fs_store(
+                    crate::fs_store::FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a"),
+                )
+                .unwrap(),
+            );
+            let worker = WorkerId::now_v7();
+            let segment = old_compacted_source(&root, worker);
+            let provider = FsWorkerRetentionProvider::new(&root);
+            let worker_dir = provider.worker_dir(worker);
+            let log = worker_dir
+                .join("session/segments")
+                .join(format!("{segment}.jsonl"));
+            if case == "log" {
+                fs::write(&log, format!("{{\"type\":\"{PRIVATE}\"}}\n")).unwrap();
+            } else if case == "schema" {
+                let path = worker_dir.join("session/session.json");
+                let mut manifest: serde_json::Value = read_json(&path, "test").unwrap();
+                manifest["schema_version"] = serde_json::json!(999);
+                write_json(&path, &manifest);
+            } else if case == "resource_limit" {
+                let mut bytes = fs::read_to_string(&log).unwrap();
+                for line in include_str!("retention/fixtures/system-input-v4.jsonl").lines() {
+                    let mut entry: serde_json::Value = serde_json::from_str(line).unwrap();
+                    if let Some(item) = entry.pointer_mut("/entry/item")
+                        && item.get("snapshot").is_some()
+                    {
+                        item["snapshot"] = serde_json::json!({
+                            "private": PRIVATE.repeat(128 * 1024 / PRIVATE.len() + 1)
+                        });
+                    }
+                    bytes.push_str(&serde_json::to_string(&entry).unwrap());
+                    bytes.push('\n');
+                }
+                fs::write(&log, bytes).unwrap();
+            }
+            commit_session_archive(
+                &provider,
+                &request(worker, SessionDisposition::Archive),
+                &worker_dir,
+            )
+            .unwrap();
+            fs::remove_dir_all(worker_dir).unwrap();
+            let archive = provider.archive_dir("archive-a").unwrap();
+            match case {
+                "identity_json" => write_json(
+                    &archive.join("session/session.json"),
+                    &serde_json::json!({"session_id": [PRIVATE]}),
+                ),
+                "identity_value" => write_json(
+                    &archive.join("session/session.json"),
+                    &serde_json::json!({"session_id": PRIVATE}),
+                ),
+                "manifest_json" => write_json(
+                    &archive.join("manifest.json"),
+                    &serde_json::json!({"schema_version": PRIVATE}),
+                ),
+                "manifest_identity" => {
+                    let path = archive.join("manifest.json");
+                    let mut manifest: WorkerSessionArchiveManifest =
+                        read_json(&path, "test").unwrap();
+                    manifest.archive_id = PRIVATE.into();
+                    write_json(&path, &manifest);
+                }
+                "storage_json" => write_json(
+                    &archive.join(ARCHIVE_STORAGE_FILE),
+                    &serde_json::json!({"schema_version": PRIVATE}),
+                ),
+                "checksum" => fs::write(
+                    archive
+                        .join("session/segments")
+                        .join(format!("{segment}.jsonl")),
+                    PRIVATE,
+                )
+                .unwrap(),
+                _ => {}
+            }
+            let snapshot = || {
+                collect_files(&archive, "test")
+                    .unwrap()
+                    .into_iter()
+                    .map(|(relative, path)| (relative, fs::read(path).unwrap()))
+                    .collect::<Vec<_>>()
+            };
+            let before = snapshot();
+            for _ in 0..2 {
+                let output = Arc::new(std::sync::Mutex::new(Vec::new()));
+                let writer = Capture(output.clone());
+                let subscriber = tracing_subscriber::fmt()
+                    .with_ansi(false)
+                    .without_time()
+                    .with_writer(move || writer.clone())
+                    .finish();
+                tracing::subscriber::with_default(subscriber, || {
+                    tracing::callsite::rebuild_interest_cache();
+                    drop(FsRuntimeStore::open_or_create(root.clone(), "runtime-a").unwrap());
+                });
+                let log = String::from_utf8(output.lock().unwrap().clone()).unwrap();
+                assert!(log.contains("session_archive_unavailable"), "{case}: {log}");
+                assert!(log.contains("archive_id=archive-a"), "{case}: {log}");
+                assert!(log.contains(&format!("stage=\"{stage}\"")), "{case}: {log}");
+                assert!(
+                    log.contains(&format!("reason=\"{reason}\"")),
+                    "{case}: {log}"
+                );
+                assert!(log.contains("original bytes retained"), "{case}: {log}");
+                assert!(!log.contains("private-session-content"), "{case}: {log}");
+                assert!(!log.contains("/private"), "{case}: {log}");
+                assert!(!log.contains("private-runtime-root"), "{case}: {log}");
+                assert_eq!(snapshot(), before, "{case}");
+                assert!(!archive.join(ARCHIVE_STORAGE_FILE).exists() || case == "storage_json");
+            }
+        }
+    }
+
     #[test]
     fn session_migration_does_not_read_or_upgrade_erased_originals() {
         let temp = tempfile::tempdir().unwrap();

crates/worker-runtime/src/retention/fixtures/system-input-v4.jsonl

@@ -0,0 +1,2 @@
+{"kind":"annotated_system_item","ts":101,"entry":{"item":{"kind":"journal_startup","body":"journal body\nunchanged","snapshot":{"entries":[{"text":"private snapshot"}]},"snapshot_sha256":"snapshot-digest","prompt_provenance":{"workspace_id":"workspace","source_digest":"source","projection_digest":"projection","logical_name":"journal_startup"}},"metadata":{"entry_id":"journal-id","origin":{"kind":"legacy_unknown"},"derivation":{"sources":["source-id"]}}},"extensions":[{"domain":"migration-fixture","payload":{"kept":true}}]}
+{"kind":"annotated_system_item","ts":103,"entry":{"item":{"kind":"subject_behavior_refresh","body":"rendered subject body","behavior_md":"exact behavior","prompt_provenance":{"source_digest":"subject-source","projection_digest":"subject-projection","logical_name":"subject_behavior"}},"metadata":{"entry_id":"subject-id","origin":{"kind":"backend_instruction","operation_id":"op"}}}}

crates/worker-runtime/src/retention/runtime_v5_tests.rs

@@ -0,0 +1,774 @@
+//! Runtime integration, not a second implementation of Session migration.
+//! The Feature records are frozen v4 wire copied from the Session Store fixture;
+//! only the empty segment envelope is built with current APIs.
+use super::tests::{request, write_json};
+use super::*;
+use crate::fs_store::{FsRuntimeStore, FsRuntimeStoreOptions};
+use serde_json::{Value, json};
+use session_store::{LogEntry, SegmentId, SessionId, Store, WorkerSessionStore};
+use std::collections::BTreeMap;
+
+const V4_SYSTEM_INPUTS: &str = include_str!("fixtures/system-input-v4.jsonl");
+
+fn write_v4_session(aggregate: &Path) -> (SessionId, SegmentId) {
+    let root = aggregate.join("session");
+    let session = session_store::new_session_id();
+    let segment = session_store::new_segment_id();
+    let store = WorkerSessionStore::new(&root).unwrap();
+    store
+        .create_segment(
+            session,
+            segment,
+            &[LogEntry::AnnotatedSegmentStart {
+                ts: 1,
+                session_id: session,
+                system_prompt: None,
+                config: Default::default(),
+                history: vec![],
+                forked_from: None,
+                compacted_from: None,
+            }],
+        )
+        .unwrap();
+    let path = root.join("segments").join(format!("{segment}.jsonl"));
+    let mut bytes = fs::read(&path).unwrap();
+    bytes.extend_from_slice(V4_SYSTEM_INPUTS.as_bytes());
+    fs::write(path, bytes).unwrap();
+    write_json(
+        &root.join("session.json"),
+        &json!({
+            "schema_version": 4, "session_id": session,
+        }),
+    );
+    (session, segment)
+}
+
+fn stopped_worker(root: &Path, schema: u32) -> (WorkerId, SessionId, SegmentId) {
+    let worker = WorkerId::now_v7();
+    let aggregate = root.join("workers").join(worker.to_string());
+    // Serialize request defaults just as a production aggregate writer does.
+    let request: crate::catalog::CreateWorkerRequest = serde_json::from_value(json!({
+        "worker_id": worker,
+        "workspace_api": {"workspace_id": "workspace-a", "base_url": "https://workspace.invalid"},
+        "create_fingerprint": "runtime-v5-fixture",
+        "profile": {"kind": "builtin", "value": "builtin:coder"},
+        "profile_source": {"kind": "workspace_config", "archive": {
+            "id": "archive-1", "digest": "sha256:archive", "size_bytes": 0,
+            "source_graph": {"source_count": 0, "total_source_bytes": 0,
+                "entrypoints": {}, "import_count": 0}
+        }}
+    }))
+    .unwrap();
+    write_json(
+        &aggregate.join("worker.json"),
+        &json!({
+            "schema_version": schema,
+            "worker_ref": {"worker_id": worker}, "worker_id": worker,
+            "profile": request.profile,
+            "profile_source": request.profile_source.reference(),
+            "display_name": null, "config_bundle": null,
+            "created_at_ms": 1234, "status": "stopped", "workspace_id": "workspace-a",
+            "last_finished_submission_request_id": "retained-submission",
+            "restore_guard": {"observation_token": "retained-token",
+                "active_request_id": null, "owners": {}},
+            "execution_state": {"state": "available", "execution": {
+                "request": request, "binding": {}, "restore_intent": "explicit"
+            }}
+        }),
+    );
+    let (session, segment) = write_v4_session(&aggregate);
+    let mut metadata = session_store::WorkerMetadata::new(
+        format!("worker-runtime-{worker}"),
+        Some(session_store::WorkerActiveSegmentRef::active_segment(
+            session, segment,
+        )),
+    );
+    metadata.workspace_id = Some("workspace-a".into());
+    write_json(&aggregate.join("metadata.json"), &metadata);
+    (worker, session, segment)
+}
+
+fn runtime_fixture(root: &Path, schema: u32) -> (WorkerId, SessionId, SegmentId) {
+    fs::create_dir_all(root.join("workers")).unwrap();
+    let fenced_worker = WorkerId::now_v7();
+    write_json(
+        &root.join("runtime.json"),
+        &json!({
+            "schema_version": schema, "display_name": "retained Runtime",
+            "backend": "fs_store", "status": "running", "next_diagnostic_id": 1,
+            "config_bundles": {}, "workspace_owners": {"workspace-a": "owner-a"},
+            "diagnostics": [], "subject_releases": [],
+            "subject_create_recovery_fences": {fenced_worker.to_string(): {
+                "request": {"workspace_id": "workspace-a", "worker_id": fenced_worker,
+                    "create_fingerprint": "retained-create", "operation_id": "retained-recovery"},
+                "response": null
+            }}
+        }),
+    );
+    stopped_worker(root, schema)
+}
+
+// Include every file, not just schema markers: failures must preserve original
+// history, metadata, archive receipts, checksums and retention evidence together.
+fn tree_bytes(root: &Path) -> BTreeMap<PathBuf, Vec<u8>> {
+    fn walk(root: &Path, at: &Path, result: &mut BTreeMap<PathBuf, Vec<u8>>) {
+        for entry in fs::read_dir(at).unwrap() {
+            let entry = entry.unwrap();
+            if entry.file_type().unwrap().is_dir() {
+                walk(root, &entry.path(), result);
+            } else {
+                result.insert(
+                    entry.path().strip_prefix(root).unwrap().to_path_buf(),
+                    fs::read(entry.path()).unwrap(),
+                );
+            }
+        }
+    }
+    let mut result = BTreeMap::new();
+    walk(root, root, &mut result);
+    result
+}
+
+fn assert_generic(root: &Path, session: SessionId, segment: SegmentId) {
+    use session_store::{InputCompactionUse, InputEvidenceUse, InputObservationUse};
+    let store = WorkerSessionStore::open_read_only(root).unwrap();
+    let entries = store.read_all_read_only(session, segment).unwrap();
+    assert_eq!(entries.len(), 3);
+    let originals: Vec<Value> = V4_SYSTEM_INPUTS
+        .lines()
+        .map(|line| serde_json::from_str(line).unwrap())
+        .collect();
+    for (log, old) in entries[1..].iter().zip(originals) {
+        let LogEntry::AnnotatedSystemItem { entry, .. } = log else {
+            panic!("lost System record: {log:?}");
+        };
+        let current = serde_json::to_value(log).unwrap();
+        assert_eq!(current["ts"], old["ts"]);
+        for field in ["entry_id", "origin", "derivation"] {
+            assert_eq!(
+                current["entry"]["metadata"][field],
+                old["entry"]["metadata"][field]
+            );
+        }
+        assert_eq!(current["entry"]["item"]["kind"], "input");
+        assert_eq!(
+            entry.item.history_text(),
+            old["entry"]["item"]["body"].as_str().unwrap()
+        );
+        let input = entry.metadata.input_metadata.as_ref().unwrap();
+        let usage = input.usage();
+        assert_eq!(usage.recording_material, InputEvidenceUse::Exclude);
+        assert_eq!(usage.memory_evidence, InputEvidenceUse::Exclude);
+        assert_eq!(usage.observation, InputObservationUse::Hidden);
+        let kind = old["entry"]["item"]["kind"].as_str().unwrap();
+        let schema = if kind == "journal_startup" {
+            assert_eq!(usage.compaction, InputCompactionUse::ReferenceInput);
+            assert_eq!(current["extensions"], old["extensions"]);
+            "journal:startup"
+        } else {
+            assert_eq!(usage.compaction, InputCompactionUse::Retain);
+            "subject:behavior"
+        };
+        let payload = input.feature_payload().unwrap();
+        assert_eq!(payload.schema(), schema);
+        assert_eq!(payload.version(), 1);
+        let mut expected_payload = old["entry"]["item"].clone();
+        expected_payload.as_object_mut().unwrap().remove("kind");
+        expected_payload.as_object_mut().unwrap().remove("body");
+        assert_eq!(
+            payload.decode::<Value>(schema, 1).unwrap(),
+            expected_payload
+        );
+        let public = serde_json::to_value(input.public_item().unwrap()).unwrap();
+        assert_eq!(public["kind"], kind);
+        assert_eq!(public["body"], old["entry"]["item"]["body"]);
+        assert_eq!(public["presentation"], json!({"kind": "context"}));
+    }
+}
+
+fn completed_v4_archive(
+    root: &Path,
+    schema: u32,
+) -> (
+    SessionId,
+    SegmentId,
+    WorkerRetentionExecutionRequest,
+    WorkerRetentionExecutionResult,
+) {
+    let (worker, session, segment) = stopped_worker(root, schema);
+    let provider = FsWorkerRetentionProvider::new(root);
+    let request = request(worker, SessionDisposition::Archive);
+    // Frozen old-runtime receipt: ingestion and removal completed before the
+    // current strict decoder existed. Do not ask the v5 reader to mint it.
+    let manifest =
+        commit_session_archive(&provider, &request, &provider.worker_dir(worker)).unwrap();
+    let completed = WorkerRetentionExecutionResult {
+        operation_id: request.operation_id.clone(),
+        input_fingerprint: request.input_fingerprint.clone(),
+        worker_id: worker,
+        session_disposition: SessionDisposition::Archive,
+        diagnostics_disposition: DiagnosticsDisposition::Purge,
+        archive: Some(manifest),
+        source_removed: true,
+        diagnostics_retained: false,
+    };
+    write_json(
+        &provider.operation_path(&request.operation_id).unwrap(),
+        &RetentionOperationReceipt {
+            schema_version: OPERATION_SCHEMA_VERSION,
+            request: request.clone(),
+            result: completed.clone(),
+        },
+    );
+    fs::remove_dir_all(provider.worker_dir(worker)).unwrap();
+    (session, segment, request, completed)
+}
+
+#[test]
+fn runtime_v11_and_current_route_v4_stopped_orphan_archive_through_staging() {
+    for runtime_schema in [11, 12] {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("runtime");
+        let (worker, session, segment) = runtime_fixture(&root, runtime_schema);
+        let orphan = root
+            .join("orphaned-workers")
+            .join(WorkerId::now_v7().to_string());
+        let (orphan_session, orphan_segment) = write_v4_session(&orphan);
+        // Include an unregistered tree still under workers, not just an
+        // already-archived orphan. Both Runtime source schemas must fence it
+        // out of the live catalog without discarding its Session.
+        let loose_id = WorkerId::now_v7();
+        let loose = root.join("workers").join(loose_id.to_string());
+        let (loose_session, loose_segment) = write_v4_session(&loose);
+        let retained_loose = root.join("orphaned-workers").join(loose_id.to_string());
+        let (archived_session, archived_segment, request, completed) =
+            completed_v4_archive(&root, runtime_schema);
+        let provider = FsWorkerRetentionProvider::new(&root);
+        let archive = provider.archive_dir("archive-a").unwrap();
+        // Also cover an archive which already has a local storage attestation
+        // from an earlier schema migration. Keep ingestion bytes immutable;
+        // harmless marker whitespace makes current storage differ from them.
+        if runtime_schema == 12 {
+            let marker = archive.join("session/session.json");
+            let mut bytes = fs::read(&marker).unwrap();
+            bytes.push(b'\n');
+            fs::write(marker, bytes).unwrap();
+            let ingestion = completed.archive.clone().unwrap();
+            let (checksum_sha256, bytes, file_count) = checksum_files(
+                &collect_files(&archive.join("session"), "test").unwrap(),
+                "test",
+            )
+            .unwrap();
+            write_json(
+                &archive.join(ARCHIVE_STORAGE_FILE),
+                &MigratedArchiveStorage {
+                    schema_version: 1,
+                    ingestion,
+                    checksum_sha256,
+                    bytes,
+                    file_count,
+                },
+            );
+        }
+        let storage_before = fs::read(archive.join(ARCHIVE_STORAGE_FILE)).ok();
+        let manifest_before = fs::read(archive.join("manifest.json")).unwrap();
+        let receipt_path = provider.operation_path(&request.operation_id).unwrap();
+        let receipt_before = fs::read(&receipt_path).unwrap();
+        let stopped = root.join("workers").join(worker.to_string());
+        assert!(WorkerSessionStore::open_read_only(stopped.join("session")).is_err());
+        // Current decode itself must not be made permissive to fix routing.
+        for line in V4_SYSTEM_INPUTS.lines() {
+            assert!(serde_json::from_str::<LogEntry>(line).is_err());
+        }
+        let before = tree_bytes(&root);
+        let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+        let plan = FsRuntimeStore::migration_plan(&options).unwrap();
+        assert!(plan.migration_required);
+        assert_eq!(plan.archived_orphan_worker_count, 1);
+        assert_eq!(plan.current_schema_version, runtime_schema);
+        assert_eq!(tree_bytes(&root), before, "preflight mutated source");
+        // Exercise normal startup, not just the private migration helper.
+        let opened = FsRuntimeStore::open_or_create(root.clone(), "runtime-a").unwrap();
+        assert!(
+            matches!(
+                FsRuntimeStore::migrate(&options),
+                Err(RuntimeError::RuntimeStoreAlreadyOpen { .. })
+            ),
+            "owner lock not fenced"
+        );
+        drop(opened);
+        assert_generic(&stopped.join("session"), session, segment);
+        assert_generic(&orphan.join("session"), orphan_session, orphan_segment);
+        assert!(!loose.exists());
+        assert_generic(
+            &retained_loose.join("session"),
+            loose_session,
+            loose_segment,
+        );
+        assert_generic(&archive.join("session"), archived_session, archived_segment);
+        assert_eq!(
+            fs::read(archive.join("manifest.json")).unwrap(),
+            manifest_before
+        );
+        assert_eq!(fs::read(&receipt_path).unwrap(), receipt_before);
+        let (manifest, archive_session) = provider.session_archive("archive-a").unwrap();
+        assert_eq!(completed.archive.as_ref(), Some(&manifest));
+        assert_eq!(provider.execute(&request).unwrap(), completed);
+        if let Some(storage_before) = storage_before {
+            assert_ne!(
+                fs::read(archive.join(ARCHIVE_STORAGE_FILE)).unwrap(),
+                storage_before
+            );
+        }
+        let storage: MigratedArchiveStorage =
+            read_json(&archive.join(ARCHIVE_STORAGE_FILE), "test").unwrap();
+        assert_eq!(storage.ingestion, manifest);
+        let (checksum, bytes, count) =
+            checksum_files(&collect_files(&archive_session, "test").unwrap(), "test").unwrap();
+        assert_eq!(
+            (storage.checksum_sha256, storage.bytes, storage.file_count),
+            (checksum, bytes, count)
+        );
+        if runtime_schema == 12 {
+            for name in [
+                PathBuf::from("runtime.json"),
+                PathBuf::from(format!("workers/{worker}/worker.json")),
+                PathBuf::from(format!("workers/{worker}/metadata.json")),
+            ] {
+                assert_eq!(fs::read(root.join(&name)).unwrap(), before[&name]);
+            }
+        }
+        let once = tree_bytes(&root);
+        assert!(
+            !FsRuntimeStore::migrate(&options)
+                .unwrap()
+                .migration_required
+        );
+        drop(FsRuntimeStore::open_or_create(root.clone(), "runtime-a").unwrap());
+        assert_eq!(tree_bytes(&root), once, "retry rewrote migrated evidence");
+        assert!(!temp.path().join(".runtime.schema-v12-staging").exists());
+        assert!(!temp.path().join(".runtime.pre-schema-v12-backup").exists());
+        // session-storage, not the immutable receipt's old checksum, attests
+        // current bytes. Tampering with those bytes must remain detectable.
+        let path = archive_session
+            .join("segments")
+            .join(format!("{archived_segment}.jsonl"));
+        fs::write(path, b"tampered\n").unwrap();
+        assert!(provider.session_archive("archive-a").is_err());
+    }
+}
+
+#[test]
+fn corrupt_archive_does_not_block_startup_or_healthy_session_migration_and_repair_converges() {
+    for runtime_schema in [11, 12] {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("runtime");
+        let (worker, session, segment) = runtime_fixture(&root, runtime_schema);
+        let (archived_session, archived_segment, request, completed) =
+            completed_v4_archive(&root, runtime_schema);
+        let provider = FsWorkerRetentionProvider::new(&root);
+        let archive = provider.archive_dir("archive-a").unwrap();
+        let path = archive
+            .join("session/segments")
+            .join(format!("{archived_segment}.jsonl"));
+        let original = fs::read(&path).unwrap();
+        fs::write(&path, b"corrupt archive\n").unwrap();
+        let (healthy_worker, healthy_session, healthy_segment) =
+            stopped_worker(&root, runtime_schema);
+        let mut healthy_request =
+            super::tests::request(healthy_worker, SessionDisposition::Archive);
+        healthy_request.operation_id = "healthy-operation".into();
+        healthy_request.archive_id = Some("healthy-archive".into());
+        let healthy_manifest = commit_session_archive(
+            &provider,
+            &healthy_request,
+            &provider.worker_dir(healthy_worker),
+        )
+        .unwrap();
+        fs::remove_dir_all(provider.worker_dir(healthy_worker)).unwrap();
+        let before = tree_bytes(&archive);
+        let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+        assert!(
+            FsRuntimeStore::migration_plan(&options)
+                .unwrap()
+                .migration_required
+        );
+        drop(FsRuntimeStore::open_or_create(root.clone(), "runtime-a").unwrap());
+        assert_eq!(tree_bytes(&archive), before);
+        assert!(provider.session_archive("archive-a").is_err());
+        let (manifest, healthy_root) = provider.session_archive("healthy-archive").unwrap();
+        assert_eq!(manifest, healthy_manifest);
+        assert_generic(&healthy_root, healthy_session, healthy_segment);
+        assert!(!archive.join(ARCHIVE_STORAGE_FILE).exists());
+        assert_generic(
+            &root
+                .join("workers")
+                .join(worker.to_string())
+                .join("session"),
+            session,
+            segment,
+        );
+        assert!(
+            !FsRuntimeStore::migration_plan(&options)
+                .unwrap()
+                .migration_required
+        );
+        drop(FsRuntimeStore::open_or_create(root.clone(), "runtime-a").unwrap());
+        assert_eq!(tree_bytes(&archive), before);
+        fs::write(&path, original).unwrap();
+        FsRuntimeStore::migrate(&options).unwrap();
+        assert_generic(
+            &root
+                .join("workers")
+                .join(worker.to_string())
+                .join("session"),
+            session,
+            segment,
+        );
+        assert_generic(&archive.join("session"), archived_session, archived_segment);
+        assert_eq!(provider.execute(&request).unwrap(), completed);
+    }
+}
+
+#[test]
+fn unmigratable_archive_preserves_evidence_across_startup_and_reopen() {
+    for (field, value) in [
+        ("snapshot_sha256", json!(42)),
+        ("behavior_md", json!([])),
+        ("snapshot", json!({"large": "x".repeat(128 * 1024 + 1)})),
+        ("body", json!("x".repeat(256 * 1024 + 1))),
+    ] {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("runtime");
+        let (live_worker, live_session, live_segment) = runtime_fixture(&root, 12);
+        let (worker, _, segment) = stopped_worker(&root, 12);
+        let provider = FsWorkerRetentionProvider::new(&root);
+        let path = provider
+            .worker_dir(worker)
+            .join("session/segments")
+            .join(format!("{segment}.jsonl"));
+        let source = fs::read_to_string(&path).unwrap();
+        let mut replaced = false;
+        let mut altered = String::new();
+        for line in source.lines() {
+            let mut entry: Value = serde_json::from_str(line).unwrap();
+            if let Some(item) = entry.pointer_mut("/entry/item")
+                && item.get(field).is_some()
+            {
+                item[field] = value.clone();
+                replaced = true;
+            }
+            altered.push_str(&serde_json::to_string(&entry).unwrap());
+            altered.push('\n');
+        }
+        assert!(replaced);
+        fs::write(&path, altered).unwrap();
+        let request = request(worker, SessionDisposition::Archive);
+        let manifest =
+            commit_session_archive(&provider, &request, &provider.worker_dir(worker)).unwrap();
+        fs::remove_dir_all(provider.worker_dir(worker)).unwrap();
+        let archive = provider.archive_dir("archive-a").unwrap();
+        validate_existing_archive(&archive, &manifest, false).unwrap();
+        let before = tree_bytes(&archive);
+        let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+        for _ in 0..2 {
+            let runtime = crate::Runtime::with_fs_store(options.clone()).unwrap();
+            assert_eq!(runtime.summary().unwrap().worker_count, 1);
+            runtime.bind_runtime_identity("runtime-a").unwrap();
+            let search = runtime_api::SessionPublicSearchRequest {
+                workspace_id: "workspace-a".into(),
+                source: runtime_api::SessionPublicSource::Archived {
+                    archive_id: "archive-a".into(),
+                },
+                expected_session_id: manifest.source_session_id.clone(),
+                expected_generation: None,
+                query: None,
+                kind: None,
+                tool_name: None,
+                tool_part: runtime_api::SessionPublicToolPart::Both,
+                scan_cursor: None,
+                limit: 10,
+                max_scan_bytes: 1024 * 1024,
+                max_segments: 10,
+                max_entries: 100,
+            };
+            let availability = runtime
+                .session_public_search_scoped(
+                    &crate::runtime::RuntimeWorkspaceScope::new("workspace-a", "owner-a"),
+                    &search,
+                )
+                .unwrap();
+            assert!(matches!(
+                availability,
+                runtime_api::SessionPublicSearchAvailability::Unavailable {
+                    reason: runtime_api::SessionPublicUnavailableReason::ArchiveIncomplete,
+                    ..
+                }
+            ));
+            drop(runtime);
+            assert_eq!(tree_bytes(&archive), before);
+            validate_existing_archive(&archive, &manifest, false).unwrap();
+            assert!(matches!(
+                provider.session_archive("archive-a"),
+                Err(RuntimeError::StoreCorrupt { .. })
+            ));
+            assert!(
+                !FsRuntimeStore::migration_plan(&options)
+                    .unwrap()
+                    .migration_required
+            );
+            assert_generic(
+                &provider.worker_dir(live_worker).join("session"),
+                live_session,
+                live_segment,
+            );
+        }
+    }
+}
+
+#[test]
+fn unreadable_archive_metadata_does_not_block_archive_only_runtime_startup() {
+    for (path, field, value) in [
+        ("session/session.json", None, Value::Null),
+        ("manifest.json", None, Value::Null),
+        (ARCHIVE_STORAGE_FILE, None, Value::Null),
+        ("session/session.json", Some("schema_version"), json!(999)),
+        ("manifest.json", Some("schema_version"), json!(999)),
+        (
+            "manifest.json",
+            Some("archive_id"),
+            json!("another-archive"),
+        ),
+    ] {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("runtime");
+        let (worker, _, _) = runtime_fixture(&root, 12);
+        completed_v4_archive(&root, 12);
+        let provider = FsWorkerRetentionProvider::new(&root);
+        fs::remove_dir_all(provider.worker_dir(worker)).unwrap();
+        let archive = provider.archive_dir("archive-a").unwrap();
+        if let Some(field) = field {
+            let mut record: Value = read_json(&archive.join(path), "test").unwrap();
+            record[field] = value;
+            write_json(&archive.join(path), &record);
+        } else {
+            fs::write(archive.join(path), b"{broken\n").unwrap();
+        }
+        let before = tree_bytes(&archive);
+        let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+        for _ in 0..2 {
+            assert!(
+                !FsRuntimeStore::migration_plan(&options)
+                    .unwrap()
+                    .migration_required
+            );
+            let runtime = crate::Runtime::with_fs_store(options.clone()).unwrap();
+            assert_eq!(runtime.summary().unwrap().worker_count, 0);
+            drop(runtime);
+            assert!(provider.session_archive("archive-a").is_err());
+            assert_eq!(tree_bytes(&archive), before);
+        }
+    }
+}
+
+#[test]
+fn archive_isolation_does_not_bypass_corrupt_erasure_authority() {
+    let temp = tempfile::tempdir().unwrap();
+    let root = temp.path().join("runtime");
+    runtime_fixture(&root, 12);
+    let (session, _, _, _) = completed_v4_archive(&root, 12);
+    let ledger = root.join("retention/session-sources");
+    fs::create_dir_all(&ledger).unwrap();
+    fs::write(ledger.join(format!("{session}.json")), b"{broken\n").unwrap();
+    let before = tree_bytes(&root);
+    let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+    assert!(FsRuntimeStore::migration_plan(&options).is_err());
+    assert!(crate::Runtime::with_fs_store(options).is_err());
+    assert_eq!(tree_bytes(&root), before);
+}
+
+#[test]
+fn runtime_v5_probe_and_staging_skip_erased_originals() {
+    let temp = tempfile::tempdir().unwrap();
+    let root = temp.path().join("runtime");
+    let (worker, live_session, live_segment) = runtime_fixture(&root, 12);
+    let erased = root
+        .join("orphaned-workers")
+        .join(WorkerId::now_v7().to_string());
+    let (session, segment) = write_v4_session(&erased);
+    runtime_session_retention(&root)
+        .delete(
+            session,
+            session_store::retention::SessionDeletionIntent::ErasePermanently,
+            || Ok(()),
+        )
+        .unwrap();
+    fs::write(
+        erased
+            .join("session/segments")
+            .join(format!("{segment}.jsonl")),
+        b"fenced malformed JSON\n",
+    )
+    .unwrap();
+    let before = tree_bytes(&erased);
+    let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+    assert!(
+        FsRuntimeStore::migration_plan(&options)
+            .unwrap()
+            .migration_required
+    );
+    FsRuntimeStore::migrate(&options).unwrap();
+    assert_generic(
+        &root
+            .join("workers")
+            .join(worker.to_string())
+            .join("session"),
+        live_session,
+        live_segment,
+    );
+    assert_eq!(tree_bytes(&erased), before);
+    assert!(
+        !FsRuntimeStore::migration_plan(&options)
+            .unwrap()
+            .migration_required
+    );
+    assert!(matches!(
+        runtime_session_retention(&root).ensure_live(session),
+        Err(session_store::StoreError::SessionErased(_))
+    ));
+}
+
+#[test]
+fn runtime_v5_rejects_broken_or_future_source_without_rewriting_evidence() {
+    for corruption in ["broken-json", "future-schema"] {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("runtime");
+        let (worker, session, segment) = runtime_fixture(&root, 12);
+        let session_root = root
+            .join("workers")
+            .join(worker.to_string())
+            .join("session");
+        if corruption == "broken-json" {
+            fs::write(
+                session_root
+                    .join("segments")
+                    .join(format!("{segment}.jsonl")),
+                b"{not valid JSON\n",
+            )
+            .unwrap();
+        } else {
+            write_json(
+                &session_root.join("session.json"),
+                &json!({
+                    "schema_version": 999, "session_id": session,
+                }),
+            );
+        }
+        let before = tree_bytes(&root);
+        let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+        assert!(
+            FsRuntimeStore::migration_plan(&options)
+                .unwrap()
+                .migration_required
+        );
+        assert_eq!(tree_bytes(&root), before);
+        assert!(FsRuntimeStore::migrate(&options).is_err());
+        assert_eq!(tree_bytes(&root), before);
+        assert!(!temp.path().join(".runtime.schema-v12-staging").exists());
+        assert!(!temp.path().join(".runtime.pre-schema-v12-backup").exists());
+    }
+}
+
+#[cfg(unix)]
+#[test]
+fn current_runtime_session_migration_still_rejects_live_worker_sockets() {
+    let temp = tempfile::tempdir().unwrap();
+    let root = temp.path().join("runtime");
+    let (worker, _, _) = runtime_fixture(&root, 12);
+    let before = tree_bytes(&root);
+    let runs = root.join("workers").join(worker.to_string()).join("runs");
+    fs::create_dir_all(runs.join("1")).unwrap();
+    let listener = std::os::unix::net::UnixListener::bind(runs.join("1/worker.sock")).unwrap();
+    let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+    let error = FsRuntimeStore::migrate(&options).unwrap_err();
+    assert!(error.to_string().contains("active Worker socket"));
+    drop(listener);
+    fs::remove_dir_all(runs).unwrap();
+    assert_eq!(tree_bytes(&root), before);
+    assert!(!temp.path().join(".runtime.schema-v12-staging").exists());
+}
+
+#[test]
+fn current_runtime_upgrades_v5_role_metadata_through_staging_without_reserializing_owner_evidence()
+{
+    let temp = tempfile::tempdir().unwrap();
+    let root = temp.path().join("runtime");
+    let (worker, session, segment) = runtime_fixture(&root, 12);
+    let aggregate = root.join("workers").join(worker.to_string());
+    let path = aggregate
+        .join("session/segments")
+        .join(format!("{segment}.jsonl"));
+    let old = fs::read_to_string(&path).unwrap();
+    let header = old.lines().next().unwrap();
+    let source = include_str!(
+        "../../../session-store/src/legacy_session_log/tests/fixtures/v5-role-metadata.jsonl"
+    );
+    fs::write(&path, format!("{header}\n{source}")).unwrap();
+    write_json(
+        &aggregate.join("session/session.json"),
+        &json!({"schema_version":5, "session_id": session}),
+    );
+    let owner_before = fs::read(root.join("runtime.json")).unwrap();
+    let worker_before = fs::read(aggregate.join("worker.json")).unwrap();
+    let metadata_before = fs::read(aggregate.join("metadata.json")).unwrap();
+    assert!(WorkerSessionStore::open_read_only(aggregate.join("session")).is_err());
+    let options = FsRuntimeStoreOptions::new(&root).with_runtime_id("runtime-a");
+    assert!(
+        FsRuntimeStore::migration_plan(&options)
+            .unwrap()
+            .migration_required
+    );
+    FsRuntimeStore::migrate(&options).unwrap();
+    let store = WorkerSessionStore::open_read_only(aggregate.join("session")).unwrap();
+    let entries = store.read_all_read_only(session, segment).unwrap();
+    assert_eq!(entries.len(), 6);
+    for (current, old) in entries[1..].iter().zip(source.lines()) {
+        let current = serde_json::to_value(current).unwrap();
+        let old: Value = serde_json::from_str(old).unwrap();
+        assert_eq!(current["ts"], old["ts"]);
+        assert_eq!(current["entry"]["item"], old["entry"]["item"]);
+        for field in ["entry_id", "origin", "derivation"] {
+            assert_eq!(
+                current["entry"]["metadata"][field],
+                old["entry"]["metadata"][field]
+            );
+        }
+        if current["entry"]["metadata"]["origin"]["kind"] == "derived_summary" {
+            assert_eq!(
+                current["entry"]["metadata"]["input_metadata"]["usage"]["recording_material"],
+                "exclude"
+            );
+            assert_eq!(
+                current["entry"]["metadata"]["input_metadata"]["usage"]["memory_evidence"],
+                "exclude"
+            );
+        }
+    }
+    assert_eq!(fs::read(root.join("runtime.json")).unwrap(), owner_before);
+    assert_eq!(
+        fs::read(aggregate.join("worker.json")).unwrap(),
+        worker_before
+    );
+    assert_eq!(
+        fs::read(aggregate.join("metadata.json")).unwrap(),
+        metadata_before
+    );
+    let once = tree_bytes(&aggregate.join("session"));
+    assert!(
+        !FsRuntimeStore::migration_plan(&options)
+            .unwrap()
+            .migration_required
+    );
+    FsRuntimeStore::migrate(&options).unwrap();
+    assert_eq!(tree_bytes(&aggregate.join("session")), once);
+}

crates/worker-runtime/src/session_public.rs

@@ -398,6 +398,7 @@ mod tests {
                 content: vec![LoggedContentPart::Text { text: text.into() }],
             },
             metadata: LoggedSessionHistoryMetadata {
+                input_metadata: None,
                 entry_id: LoggedSessionHistoryEntryId(id.to_string()),
                 origin: LoggedSessionHistoryOrigin::HumanInput {
                     account_id: "account-1".to_string(),

crates/worker-runtime/src/worker_backend/deferred_workdir.rs

@@ -0,0 +1,256 @@
+//! Restore retains attachment identity without opening a provider. Failed opens
+//! are retryable at operation time; closing an unopened session never opens it.
+
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use tokio::sync::{Mutex, broadcast};
+use workdir::*;
+
+type OpenSession = dyn Fn() -> Result<WorkdirSessionHandle, String> + Send + Sync;
+
+pub(super) struct DeferredWorkdirSession {
+    workdir: Workdir,
+    capabilities: WorkdirSessionCapabilities,
+    open: Arc<OpenSession>,
+    state: Mutex<State>,
+    events: broadcast::Sender<CommandEvent>,
+}
+
+#[derive(Default)]
+struct State {
+    session: Option<WorkdirSessionHandle>,
+    event_bridge: Option<tokio::task::JoinHandle<()>>,
+    closed: bool,
+}
+
+impl Drop for State {
+    fn drop(&mut self) {
+        if let Some(task) = &self.event_bridge {
+            task.abort();
+        }
+    }
+}
+
+impl std::fmt::Debug for DeferredWorkdirSession {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("DeferredWorkdirSession")
+            .field("workdir", &self.workdir)
+            .finish_non_exhaustive()
+    }
+}
+
+impl DeferredWorkdirSession {
+    pub(super) fn handle(
+        workdir_id: &str,
+        capabilities: WorkdirSessionCapabilities,
+        open: impl Fn() -> Result<WorkdirSessionHandle, String> + Send + Sync + 'static,
+    ) -> WorkdirSessionHandle {
+        Arc::new(Self {
+            workdir: Workdir::new(workdir_id),
+            capabilities,
+            open: Arc::new(open),
+            state: Mutex::new(State::default()),
+            events: broadcast::channel(1024).0,
+        })
+    }
+
+    async fn session(&self) -> Result<WorkdirSessionHandle, WorkdirError> {
+        let mut state = self.state.lock().await;
+        if state.closed {
+            return Err(WorkdirError::SessionClosed);
+        }
+        if let Some(session) = &state.session {
+            return Ok(session.clone());
+        }
+        let open = self.open.clone();
+        let session = tokio::task::spawn_blocking(move || open())
+            .await
+            .map_err(|_| WorkdirError::Unavailable("Workdir session opener failed".into()))?
+            .map_err(WorkdirError::Unavailable)?;
+        if session.workdir().id() != self.workdir.id() {
+            session.close().await?;
+            return Err(WorkdirError::Unavailable(
+                "Workdir session identity mismatch".into(),
+            ));
+        }
+        if let Some(mut source) = session.subscribe_command_events() {
+            let events = self.events.clone();
+            state.event_bridge = Some(tokio::spawn(async move {
+                loop {
+                    match source.recv().await {
+                        Ok(event) => {
+                            let _ = events.send(event);
+                        }
+                        Err(broadcast::error::RecvError::Lagged(_)) => continue,
+                        Err(broadcast::error::RecvError::Closed) => break,
+                    }
+                }
+            }));
+        }
+        state.session = Some(session.clone());
+        Ok(session)
+    }
+}
+
+macro_rules! impl_deferred_session {
+    ($( $method:ident($request:ident: $request_type:ty) -> $result:ty; )*) => {
+        #[async_trait]
+        impl WorkdirSession for DeferredWorkdirSession {
+            fn workdir(&self) -> &Workdir {
+                &self.workdir
+            }
+
+            fn capabilities(&self) -> WorkdirSessionCapabilities {
+                self.capabilities
+            }
+
+            $(
+                async fn $method(&self, $request: $request_type) -> Result<$result, WorkdirError> {
+                    self.session().await?.$method($request).await
+                }
+            )*
+
+            fn subscribe_command_events(&self) -> Option<broadcast::Receiver<CommandEvent>> {
+                Some(self.events.subscribe())
+            }
+
+            fn command_snapshot(&self) -> Vec<CommandSnapshot> {
+                self.state.try_lock().ok().and_then(|state| {
+                    state.session.as_ref().map(|session| session.command_snapshot())
+                }).unwrap_or_default()
+            }
+
+            async fn close(&self) -> Result<(), WorkdirError> {
+                let mut state = self.state.lock().await;
+                state.closed = true;
+                if let Some(session) = &state.session {
+                    session.close().await?;
+                }
+                if let Some(task) = state.event_bridge.take() {
+                    task.abort();
+                    let _ = task.await;
+                }
+                Ok(())
+            }
+        }
+    };
+}
+
+impl_deferred_session! {
+    authorize_scope_path(request: WorkdirScopeAuthorizationRequest) -> ();
+    scope_rules_overlap(request: WorkdirScopeOverlapRequest) -> bool;
+    checkout_search(request: CheckoutSearchRequest) -> CheckoutSearchResult;
+    checkout_observe(path: WorkdirPath) -> CheckoutObservation;
+    checkout_execute(request: CheckoutRequest) -> CheckoutResult;
+    stat(request: StatRequest) -> StatResult;
+    read(request: ReadRequest) -> ReadResult;
+    read_bytes(request: ReadBytesRequest) -> ReadBytesResult;
+    write(request: WriteRequest) -> WriteResult;
+    edit(request: EditRequest) -> EditResult;
+    list(request: ListRequest) -> ListResult;
+    glob(request: GlobRequest) -> GlobResult;
+    grep(request: GrepRequest) -> GrepResult;
+    start_command(request: CommandRequest) -> CommandHandle;
+    command_status(handle: CommandHandle) -> CommandStatus;
+    command_output(request: CommandOutputRequest) -> CommandOutput;
+    cancel_command(handle: CommandHandle) -> ();
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    fn read_request() -> ReadRequest {
+        ReadRequest {
+            path: WorkdirPath::new("README.md").unwrap(),
+            offset: 0,
+            limit: 10,
+            max_bytes: 1024,
+        }
+    }
+
+    #[tokio::test]
+    async fn unopened_session_close_does_not_connect_and_is_terminal() {
+        let attempts = Arc::new(AtomicUsize::new(0));
+        let observed = attempts.clone();
+        let session = DeferredWorkdirSession::handle(
+            "offline",
+            WorkdirSessionCapabilities::READ_ONLY,
+            move || {
+                observed.fetch_add(1, Ordering::SeqCst);
+                Err("offline".into())
+            },
+        );
+        assert_eq!(session.workdir().id().as_str(), "offline");
+        assert!(session.subscribe_command_events().is_some());
+        session.close().await.unwrap();
+        session.close().await.unwrap();
+        assert!(matches!(
+            session.read(read_request()).await,
+            Err(WorkdirError::SessionClosed)
+        ));
+        assert_eq!(attempts.load(Ordering::SeqCst), 0);
+    }
+
+    #[tokio::test]
+    async fn failed_open_retries_on_use_and_keeps_read_only_capabilities() {
+        let temp = tempfile::tempdir().unwrap();
+        std::fs::write(temp.path().join("README.md"), "restored").unwrap();
+        let root = temp.path().to_path_buf();
+        let attempts = Arc::new(AtomicUsize::new(0));
+        let observed = attempts.clone();
+        let session = DeferredWorkdirSession::handle(
+            "saved",
+            WorkdirSessionCapabilities::READ_ONLY,
+            move || {
+                if observed.fetch_add(1, Ordering::SeqCst) == 0 {
+                    return Err("offline".into());
+                }
+                let scope = super::super::runtime_attachment_scope(
+                    &root,
+                    WorkdirSessionCapabilities::READ_ONLY,
+                )?;
+                Ok(super::super::runtime_local_workdir_session(
+                    "saved",
+                    &root,
+                    &root,
+                    scope,
+                    WorkdirSessionCapabilities::READ_ONLY,
+                    Default::default(),
+                    Vec::new(),
+                ))
+            },
+        );
+        assert_eq!(attempts.load(Ordering::SeqCst), 0);
+        assert!(matches!(
+            session.read(read_request()).await,
+            Err(WorkdirError::Unavailable(_))
+        ));
+        assert_eq!(
+            session.read(read_request()).await.unwrap().bytes,
+            b"restored"
+        );
+        assert_eq!(
+            session.read(read_request()).await.unwrap().bytes,
+            b"restored"
+        );
+        assert_eq!(attempts.load(Ordering::SeqCst), 2);
+        assert!(
+            session
+                .write(WriteRequest {
+                    path: WorkdirPath::new("README.md").unwrap(),
+                    content: b"forbidden".to_vec(),
+                    expected_hash: None
+                })
+                .await
+                .is_err()
+        );
+        assert_eq!(
+            std::fs::read(temp.path().join("README.md")).unwrap(),
+            b"restored"
+        );
+        session.close().await.unwrap();
+    }
+}

crates/worker/examples/worker_protocol.rs

@@ -47,9 +47,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let worker = worker::Worker::from_manifest_toml(&toml, store).await?;
 
     let runtime_tmp = tempfile::tempdir()?;
-    let bash_output_dir = runtime_tmp.path().join("bash-output");
-    let (handle, _shutdown_rx) =
-        WorkerController::spawn(worker, runtime_tmp.path(), &bash_output_dir).await?;
+    let (handle, _shutdown_rx) = WorkerController::spawn(worker, runtime_tmp.path()).await?;
 
     // Check initial status via shared state
     println!("[shared_state] {}", handle.shared_state.status_json());

crates/worker/src/bootstrap.rs

@@ -17,28 +17,9 @@ use manifest::WorkerManifest;
 #[derive(Debug, Clone)]
 pub enum WorkerBootstrapLayout {
     /// A direct Worker rooted below the supplied runtime base directory.
-    Direct {
-        runtime_base: PathBuf,
-        bash_output_dir: PathBuf,
-    },
+    Direct { runtime_base: PathBuf },
     /// A runtime-managed Worker with an exact persisted run directory.
-    RuntimeManagedRun {
-        run_dir: PathBuf,
-        bash_output_dir: PathBuf,
-    },
-}
-
-/// Return the temporary Bash spill directory owned by a stable Worker identity.
-///
-/// The directory deliberately lives outside session/run-generation storage so a
-/// restarted controller for the same Worker keeps the same readable artifact
-/// boundary.
-pub fn bash_output_dir_for_worker_id(worker_id: impl std::fmt::Display) -> PathBuf {
-    std::env::temp_dir()
-        .join("yoi")
-        .join("workers")
-        .join(worker_id.to_string())
-        .join("bash-output")
+    RuntimeManagedRun { run_dir: PathBuf },
 }
 
 /// Construction and controller inputs that are stable for one Worker launch.
@@ -145,6 +126,13 @@ where
     pub async fn prepare(
         self,
     ) -> Result<PreparedWorker<Box<dyn LlmClient>, St>, WorkerBootstrapError> {
+        crate::feature::authorize_requested_manifest(
+            self.workspace_context.client_handle().as_ref(),
+            &self.manifest,
+        )
+        .map_err(|error| {
+            WorkerBootstrapError::Worker(WorkerError::FeatureLifecycle(error.to_string()))
+        })?;
         let mut worker = Worker::from_manifest_with_context_and_model_client(
             self.manifest,
             self.store,
@@ -272,27 +260,12 @@ where
 {
     let cleanup_sessions = worker.workdir_sessions();
     let controller = match layout {
-        WorkerBootstrapLayout::Direct {
-            runtime_base,
-            bash_output_dir,
-        } => {
-            WorkerController::spawn_with_transport_owned(
-                worker,
-                &runtime_base,
-                &bash_output_dir,
-                transport,
-            )
-            .await
+        WorkerBootstrapLayout::Direct { runtime_base } => {
+            WorkerController::spawn_with_transport_owned(worker, &runtime_base, transport).await
         }
-        WorkerBootstrapLayout::RuntimeManagedRun {
-            run_dir,
-            bash_output_dir,
-        } => {
+        WorkerBootstrapLayout::RuntimeManagedRun { run_dir } => {
             WorkerController::spawn_runtime_managed_run_with_transport_owned(
-                worker,
-                &run_dir,
-                &bash_output_dir,
-                transport,
+                worker, &run_dir, transport,
             )
             .await
         }
@@ -313,22 +286,3 @@ where
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::bash_output_dir_for_worker_id;
-
-    #[test]
-    fn bash_output_directory_is_stable_per_worker_below_system_temp() {
-        let path = bash_output_dir_for_worker_id("019c1234-worker");
-
-        assert_eq!(
-            path,
-            std::env::temp_dir()
-                .join("yoi")
-                .join("workers")
-                .join("019c1234-worker")
-                .join("bash-output")
-        );
-    }
-}

crates/worker/src/checkout.rs

@@ -7,7 +7,7 @@
 //! empty children mean "no indexable children", not "empty directory". List/Glob/Grep discover
 //! content; Inspect checks selected coordinates.
 //!
-//! Interfaces/validators bind the projection incarnation, attachment generation, and provider state
+//! Object validators bind the projection incarnation, attachment generation, and provider state
 //! so alias reuse after restore or detach cannot transfer old observations to a new connection.
 //! Publication also checks the generation recorded at acquisition. Possessing an Interface grants
 //! no authority: route-reconstructed permission inputs and current provider capability/scope are
@@ -28,9 +28,8 @@ use manifest::{ToolPermissionAction, ToolPermissionConfig};
 use serde_json::{Value as Json, json};
 use sha2::{Digest, Sha256};
 use wip_protocol::{
-    Documentation, FieldDeclaration, INTERFACE_FORMAT_V1, InterfaceDescriptor, Object,
-    OperationDeclaration, ParameterDeclaration, ProtocolError, ProtocolErrorCode,
-    ReturnDeclaration, TypeExpr, Value,
+    Documentation, INTERFACE_FORMAT_V1, InterfaceDescriptor, Object, OperationDeclaration,
+    ParameterDeclaration, ProtocolError, ProtocolErrorCode, ReturnDeclaration, TypeExpr, Value,
 };
 use workdir::{
     CheckoutObservation, EntryKind, WorkdirPath, WorkdirSessionCapability as Cap,
@@ -117,13 +116,23 @@ impl Provider {
         }
         Some((decode_identity(slug)?, WorkdirPath::new(tail).ok()?))
     }
-    fn wrap_validator(&self, alias: &str, generation: u64, workdir: &str, raw: &[u8]) -> Vec<u8> {
+    fn wrap_validator(
+        &self,
+        alias: &str,
+        generation: u64,
+        workdir: &str,
+        target: &WorkdirPath,
+        capabilities: workdir::WorkdirSessionCapabilities,
+        raw: &[u8],
+    ) -> Vec<u8> {
         let mut hash = Sha256::new();
         for value in [
             self.incarnation.as_bytes(),
             alias.as_bytes(),
             &generation.to_be_bytes(),
             workdir.as_bytes(),
+            target.as_str().as_bytes(),
+            format!("{capabilities:?}").as_bytes(),
             raw,
         ] {
             hash.update(value.len().to_be_bytes());
@@ -236,45 +245,17 @@ impl Provider {
             return Ok(None);
         }
         let workdir = selected.session.workdir().id().as_str().to_owned();
-        let root = checkout_root(&alias);
-        // The router guard pins this connection across both observations. Root
-        // lifetime is attachment lifetime, not directory-content validator state.
-        let scope = if target.is_root() {
-            None
-        } else {
-            let root_observation =
-                match selected.session.checkout_observe(WorkdirPath::root()).await {
-                    Ok(o) => o,
-                    Err(_) => return Ok(None),
-                };
-            self.entry_projection(
-                &root,
-                &alias,
-                selected.generation,
-                &workdir,
-                WorkdirPath::root(),
-                root_observation,
-            )
-        };
-        let Some(projection) = self.entry_projection(
+        let projection = self.entry_projection(
             path,
             &alias,
             selected.generation,
             &workdir,
             target,
             observation,
-        ) else {
-            return Ok(None);
-        };
-        if path == root {
-            return WipPublication::self_scoped(projection).map(Some);
-        }
-        let Some(scope) = scope else {
-            return Ok(None);
-        };
-        Ok(Some(WipPublication {
+        );
+        Ok(projection.map(|projection| WipPublication {
             projection,
-            scope: Some(scope.object),
+            scope: None,
         }))
     }
     fn entry_projection(
@@ -286,16 +267,44 @@ impl Provider {
         target: WorkdirPath,
         observation: CheckoutObservation,
     ) -> Option<WipProjection> {
-        let ops = self.operations(&observation);
-        if ops.is_empty() {
-            return None;
-        }
+        use crate::file_operation::Contract as C;
+        let has = |cap, name| observation.capabilities.supports(cap) && self.may_allow(name);
+        let mut contracts = Vec::new();
         let kind = if observation.kind == EntryKind::File {
+            if has(Cap::Read, "Read") {
+                contracts.extend([C::ReadLines, C::SearchText, C::ReadBytes]);
+            }
+            if has(Cap::Edit, "Edit") {
+                contracts.push(C::Edit);
+            }
+            if has(Cap::Write, "Write") {
+                contracts.push(C::Write);
+            }
             "file"
         } else {
+            if has(Cap::Read, "List") {
+                contracts.push(C::List);
+            }
+            if has(Cap::Glob, "Glob") {
+                contracts.push(C::Glob);
+            }
+            if has(Cap::Grep, "Grep") {
+                contracts.push(C::Grep);
+            }
+            if has(Cap::Write, "Write") {
+                contracts.push(C::CreateFile);
+            }
             "directory"
         };
-        let validator = self.wrap_validator(alias, generation, workdir, &observation.validator);
+        let primary = *contracts.first()?;
+        let validator = self.wrap_validator(
+            alias,
+            generation,
+            workdir,
+            &target,
+            observation.capabilities,
+            &observation.validator,
+        );
         let handler = Arc::new(FileHandler {
             provider: self.clone(),
             alias: alias.into(),
@@ -304,86 +313,17 @@ impl Provider {
             target,
             observation,
         });
-        let family = format!("{kind}-g{generation}");
-        let mut projection = self.project(path, descriptor(ops), validator, &family, handler);
-        // Keep path-qualified local names (permissions/capabilities may differ
-        // per target) while binding every content Interface to its live entrance.
-        projection.interface.scope = checkout_root(alias);
-        projection.interface.name.push_str("#target/");
-        projection.interface.name.push_str(&encode_identity(path));
-        projection.object.interfaces = vec![projection.interface.clone()];
+        let mut projection = self.project(path, primary.descriptor(), validator, kind, handler);
+        projection.interface = primary.reference();
+        projection.interface_validator = Some(primary.validator());
+        projection.object.interfaces = Vec::new();
+        crate::file_operation::expose(&mut projection, contracts);
         Some(projection)
     }
-
-    fn operations(&self, o: &CheckoutObservation) -> Vec<OperationDeclaration> {
-        let mut ops = Vec::new();
-        let has = |cap, name| o.capabilities.supports(cap) && self.may_allow(name);
-        if o.kind == EntryKind::File {
-            if has(Cap::Read, "Read") {
-                ops.push(operation(
-                    "read",
-                    "Read text with line offsets and numbered output",
-                    crate::file_operation::parameters("read", true).unwrap(),
-                ));
-            }
-            if has(Cap::Edit, "Edit") {
-                ops.push(operation(
-                    "edit",
-                    "Replace a unique string (requires prior Read)",
-                    crate::file_operation::parameters("edit", true).unwrap(),
-                ));
-            }
-            if has(Cap::Write, "Write") {
-                ops.push(operation(
-                    "write",
-                    "Overwrite this existing file (requires prior Read)",
-                    crate::file_operation::parameters("write", true).unwrap(),
-                ));
-            }
-        } else {
-            if has(Cap::Read, "List") {
-                ops.push(operation(
-                    "list",
-                    "List direct contents, directories first then lexical path. Bounded live pages, not a snapshot; pass returned after to continue. Limit defaults to 100, maximum 1000. List permission and provider Read/enumeration authority apply. Includes hidden/ignored names per provider List policy, unlike Glob/Grep.",
-                    vec![parameter("limit", false, TypeExpr::Integer), parameter("after", false, cursor_type())],
-                ));
-            }
-            if has(Cap::Glob, "Glob") {
-                ops.push(operation(
-                    "glob",
-                    "Glob within this directory",
-                    vec![
-                        parameter("pattern", true, TypeExpr::String),
-                        parameter("path", false, TypeExpr::String),
-                    ],
-                ));
-            }
-            if has(Cap::Grep, "Grep") {
-                ops.push(operation(
-                    "grep",
-                    "Search within this directory with the existing Grep contract",
-                    grep_parameters(),
-                ));
-            }
-            if has(Cap::Write, "Write") {
-                ops.push(operation("create_file", "Create a new relative file, creating permitted missing parents; never overwrite", vec![parameter("path",true,TypeExpr::String),parameter("content",true,TypeExpr::String)]));
-            }
-        }
-        ops
-    }
 }
 
 #[async_trait]
 impl WipSubtreeProvider for Arc<Provider> {
-    fn interface_target(&self, reference: &wip_protocol::InterfaceReference) -> Option<String> {
-        if reference.scope == ROOT {
-            return Some(ROOT.into());
-        }
-        let (_, encoded) = reference.name.rsplit_once("#target/")?;
-        let path = decode_identity(encoded)?;
-        let (alias, _) = self.parse(&path)?;
-        (reference.scope == checkout_root(&alias)).then_some(path)
-    }
     async fn publication(&self, path: &str) -> Result<Option<WipPublication>, ProtocolError> {
         let _permit = tokio::time::timeout(self.deadline, self.permits.acquire())
             .await
@@ -588,8 +528,14 @@ impl FileHandler {
         if let Some(raw) = result.validator {
             Ok(WipOperationOutput::native_with_validator(
                 value,
-                self.provider
-                    .wrap_validator(&self.alias, self.generation, &self.workdir, &raw),
+                self.provider.wrap_validator(
+                    &self.alias,
+                    self.generation,
+                    &self.workdir,
+                    &self.target,
+                    self.observation.capabilities,
+                    &raw,
+                ),
             ))
         } else {
             Ok(WipOperationOutput::native(value))
@@ -604,6 +550,127 @@ impl WipOperationHandler for FileHandler {
         arguments: &BTreeMap<String, Value>,
         context: WipCallContext,
     ) -> Result<WipOperationOutput, WipOperationError> {
+        if operation == "read_bytes" {
+            let (offset, limit) = crate::file_operation::byte_range(arguments)?;
+            if !self.provider.allowed("Read",&json!({"target_workdir":self.alias,"file_path":self.target.as_str(),"offset":offset,"limit":limit})) {return Err(protocol(ProtocolErrorCode::PermissionDenied,"byte read denied"));}
+            let _permit =
+                tokio::time::timeout(self.provider.deadline, self.provider.permits.acquire())
+                    .await
+                    .map_err(|_| {
+                        protocol(
+                            ProtocolErrorCode::ResourceLimitExceeded,
+                            "byte read capacity deadline",
+                        )
+                    })?
+                    .map_err(|_| protocol(ProtocolErrorCode::Internal, "byte read unavailable"))?;
+            let (read, raw) = tokio::time::timeout(
+                self.provider.deadline,
+                tools::checkout::read_checkout_bytes(
+                    self.provider.router.clone(),
+                    &self.alias,
+                    self.generation,
+                    self.target.clone(),
+                    self.observation.validator.clone(),
+                    offset,
+                    limit,
+                ),
+            )
+            .await
+            .map_err(|_| {
+                protocol(
+                    ProtocolErrorCode::ResourceLimitExceeded,
+                    "byte read deadline",
+                )
+            })?
+            .map_err(map_tool_error)?;
+            self.check_connection()?;
+            let value = crate::file_operation::bytes_result(arguments, &read.bytes, read.eof)?;
+            return Ok(WipOperationOutput::native_with_validator(
+                value,
+                self.provider.wrap_validator(
+                    &self.alias,
+                    self.generation,
+                    &self.workdir,
+                    &self.target,
+                    self.observation.capabilities,
+                    &raw,
+                ),
+            ));
+        }
+        if matches!(operation, "read_lines" | "search_text") {
+            let (offset, limit) =
+                crate::file_operation::window(arguments, operation == "search_text")?;
+            if !self.provider.allowed("Read",&json!({"target_workdir":self.alias,"file_path":self.target.as_str(),"offset":offset,"limit":limit})) {
+                return Err(protocol(ProtocolErrorCode::PermissionDenied,"text read denied"));
+            }
+            let _permit =
+                tokio::time::timeout(self.provider.deadline, self.provider.permits.acquire())
+                    .await
+                    .map_err(|_| {
+                        protocol(
+                            ProtocolErrorCode::ResourceLimitExceeded,
+                            "text read capacity deadline",
+                        )
+                    })?
+                    .map_err(|_| protocol(ProtocolErrorCode::Internal, "text read unavailable"))?;
+            let result = tokio::time::timeout(
+                self.provider.deadline,
+                tools::checkout::read_checkout_text(
+                    self.provider.router.clone(),
+                    self.provider.tracker.clone(),
+                    &self.alias,
+                    self.generation,
+                    self.target.clone(),
+                    self.observation.validator.clone(),
+                    offset,
+                    limit,
+                    crate::file_operation::MAX_BYTES,
+                ),
+            )
+            .await
+            .map_err(|_| {
+                protocol(
+                    ProtocolErrorCode::ResourceLimitExceeded,
+                    "text read deadline",
+                )
+            })?
+            .map_err(map_tool_error)?;
+            let (read, validator, record_read) = result;
+            self.check_connection()?;
+            if read.byte_truncated {
+                return Err(protocol(
+                    ProtocolErrorCode::ResourceLimitExceeded,
+                    "text line window exceeds the provider byte budget; use byte ranges",
+                ));
+            }
+            let text = String::from_utf8_lossy(&read.bytes);
+            let value = crate::file_operation::page_result(
+                operation,
+                arguments,
+                &text,
+                offset,
+                read.truncated,
+            )?;
+            // Only a successfully rendered Read can establish mutation authority.
+            // Search and failed result budgets must leave prior-Read history unchanged.
+            if operation == "read_lines" {
+                record_read();
+            }
+            return Ok(match validator {
+                Some(raw) => WipOperationOutput::native_with_validator(
+                    value,
+                    self.provider.wrap_validator(
+                        &self.alias,
+                        self.generation,
+                        &self.workdir,
+                        &self.target,
+                        self.observation.capabilities,
+                        &raw,
+                    ),
+                ),
+                None => WipOperationOutput::native(value),
+            });
+        }
         let tool = match operation {
             "list" => "List",
             "read" => "Read",
@@ -752,14 +819,6 @@ fn join_under(parent: &WorkdirPath, relative: &str) -> Result<String, WipOperati
         format!("{}/{}", parent.as_str(), child.as_str())
     })
 }
-fn parameter(name: &str, required: bool, r#type: TypeExpr) -> ParameterDeclaration {
-    ParameterDeclaration {
-        name: name.into(),
-        required,
-        documentation: None,
-        r#type,
-    }
-}
 fn operation(
     name: &str,
     summary: &str,
@@ -774,53 +833,10 @@ fn operation(
         parameters,
         returns: ReturnDeclaration {
             documentation: None,
-            r#type: result_type(name == "list"),
+            r#type: TypeExpr::Json,
         },
     }
 }
-fn field(name: &str, required: bool, r#type: TypeExpr) -> FieldDeclaration {
-    FieldDeclaration {
-        name: name.into(),
-        required,
-        documentation: None,
-        r#type,
-    }
-}
-fn cursor_type() -> TypeExpr {
-    TypeExpr::Record {
-        fields: vec![
-            field("kind", true, TypeExpr::String),
-            field("entry", true, TypeExpr::Entry),
-        ],
-    }
-}
-fn result_type(list: bool) -> TypeExpr {
-    let mut item = vec![field("entry", true, TypeExpr::Entry)];
-    if list {
-        item.extend([
-            field("kind", true, TypeExpr::String),
-            field("size", true, TypeExpr::Integer),
-        ]);
-    }
-    let mut fields = vec![
-        field("summary", true, TypeExpr::String),
-        field("content", false, TypeExpr::String),
-        field(
-            "items",
-            true,
-            TypeExpr::List {
-                items: Box::new(TypeExpr::Record { fields: item }),
-            },
-        ),
-    ];
-    if list {
-        fields.extend([
-            field("truncated", true, TypeExpr::Boolean),
-            field("after", false, cursor_type()),
-        ]);
-    }
-    TypeExpr::Record { fields }
-}
 fn kind_name(kind: EntryKind) -> &'static str {
     match kind {
         EntryKind::Directory => "directory",
@@ -841,19 +857,6 @@ fn cursor_value(alias: &str, cursor: &workdir::ListCursor) -> Value {
 fn descriptor(operations: Vec<OperationDeclaration>) -> InterfaceDescriptor {
     InterfaceDescriptor{format:INTERFACE_FORMAT_V1.into(),documentation:Some(Documentation{summary:"AI-oriented attached Workdir operations".into(),details:Some("The route binds attachment and target. Line offsets are zero-based; text output numbers lines from one. Read-before-write and provider validators are both required. Paths are Worldspace references, never host paths.".into())}),types:Vec::new(),operations}
 }
-fn grep_parameters() -> Vec<ParameterDeclaration> {
-    let mut p = vec![parameter("pattern", true, TypeExpr::String)];
-    for name in ["path", "glob", "type", "output_mode"] {
-        p.push(parameter(name, false, TypeExpr::String));
-    }
-    for name in ["-A", "-B", "-C", "head_limit", "offset"] {
-        p.push(parameter(name, false, TypeExpr::Integer));
-    }
-    for name in ["case_insensitive", "multiline"] {
-        p.push(parameter(name, false, TypeExpr::Boolean));
-    }
-    p
-}
 fn error(code: ProtocolErrorCode, message: &str) -> ProtocolError {
     ProtocolError {
         code,

crates/worker/src/checkout_http_tests.rs

@@ -31,11 +31,18 @@ enum WriteResponseFault {
     LostBody,
 }
 
+#[derive(Clone, Copy)]
+enum CommandResponseFault {
+    LostTerminal,
+    EmptyWaiting,
+}
+
 struct ProviderState {
     session: WorkdirSessionHandle,
     requests: Mutex<Vec<(String, String)>>,
     operations: Mutex<Vec<WorkdirSessionOperation>>,
     write_fault: Mutex<Option<WriteResponseFault>>,
+    command_fault: Mutex<Option<CommandResponseFault>>,
     observe_refusal: Mutex<bool>,
 }
 
@@ -152,6 +159,21 @@ async fn operate(
             source: Box::new(WorkdirError::OutOfScope("/private/provider/path".into())),
         });
     }
+    if let WorkdirSessionOperation::CommandOutput(output) = &request.operation {
+        if matches!(
+            *state.command_fault.lock().unwrap(),
+            Some(CommandResponseFault::EmptyWaiting)
+        ) {
+            return AxumJson(workdir::http::WorkdirSessionOperationResult::CommandOutput(
+                workdir::CommandOutput {
+                    chunks: vec![],
+                    next_cursor: output.cursor,
+                    terminal: None,
+                },
+            ))
+            .into_response();
+        }
+    }
     let result =
         dispatch_workdir_session_operation(state.session.as_ref(), request.operation).await;
     match result {
@@ -159,6 +181,15 @@ async fn operate(
         Ok(result) => {
             let fault = if is_write {
                 state.write_fault.lock().unwrap().take()
+            } else if matches!(&result, workdir::http::WorkdirSessionOperationResult::CommandOutput(output) if output.terminal.is_some())
+            {
+                let mut command_fault = state.command_fault.lock().unwrap();
+                if matches!(*command_fault, Some(CommandResponseFault::LostTerminal)) {
+                    command_fault.take();
+                    Some(WriteResponseFault::LostBody)
+                } else {
+                    None
+                }
             } else {
                 None
             };
@@ -237,6 +268,7 @@ impl HttpFixture {
             requests: Mutex::new(Vec::new()),
             operations: Mutex::new(Vec::new()),
             write_fault: Mutex::new(None),
+            command_fault: Mutex::new(None),
             observe_refusal: Mutex::new(false),
         });
         let app = Router::new()
@@ -358,7 +390,8 @@ async fn observe_interface(runtime: &WipRuntime, path: &str) -> wip_protocol::In
 }
 
 async fn native_call(runtime: &WipRuntime, path: &str, operation: &str, args: Json) -> Value {
-    let interface = observe_interface(runtime, path).await;
+    observe_interface(runtime, path).await;
+    let interface = super::checkout_wip_tests::contract(operation).reference();
     runtime
         .call(
             path.into(),
@@ -620,7 +653,8 @@ async fn committed_write_unknown(fault: WriteResponseFault) {
     let (runtime, router) = native_runtime(remote);
     let file = "/checkouts/main/src/deep/a.txt";
     native_call(&runtime, file, "read", json!({})).await;
-    let interface = observe_interface(&runtime, file).await;
+    observe_interface(&runtime, file).await;
+    let interface = super::checkout_wip_tests::contract("write").reference();
     *fixture.state.write_fault.lock().unwrap() = Some(fault);
     let error = runtime
         .call(
@@ -798,3 +832,175 @@ async fn remote_checkout_diagnostic_context_keeps_wip_refusal_classification_wit
         "refusal was retried"
     );
 }
+
+// Full collection/projection integration: production HTTP client, local process pipes,
+// Bash collector/store, WIP codec and common file dispatch. Only HTTP response loss is injected.
+#[tokio::test]
+async fn remote_native_bash_retains_streams_quota_and_replays_lost_terminal_through_common_files() {
+    watchdog(async {
+        let f = HttpFixture::new(WorkdirSessionCapabilities::ALL).await;
+        let remote = Arc::new(f.open(TOKEN).await.unwrap());
+        let router = Arc::new(WorkdirSessionRouter::new());
+        router.attach(WorkdirAttachmentAlias::new("main").unwrap(), remote.clone()).unwrap();
+        let mut registry = WipMountRegistry::new();
+        crate::checkout::mount_checkouts(&mut registry, router.clone(), tools::Tracker::new(), None).unwrap();
+        let view = tools::bash_output::BashOutputView::new();
+        crate::feature::builtin::bash::mount(&mut registry, router.clone(), view, None).unwrap();
+        let runtime = WipRuntime::new(WipHost::new(registry), SecurityContext::new("remote-bash"), 0).unwrap();
+        *f.state.command_fault.lock().unwrap() = Some(CommandResponseFault::LostTerminal);
+        let run = runtime.invoke("/bash-output".into(), contextual_reference("yoi.bash/command/v1", "/bash-output"), "run".into(), json!({"input":{"command":r"printf 'first\nneedle\n'; printf '%200000s' ''; printf '\377€' >&2; exit 7","cwd":"."}}), Default::default()).await.unwrap();
+        f.public_output(run.content.as_ref().unwrap());
+        let result: Json = serde_json::from_str(&run.content.unwrap()).unwrap();
+        assert_eq!(result["metadata"]["stdout_saved"], 200013);
+        assert_eq!(result["metadata"]["stderr_saved"], 4);
+        assert_eq!(result["metadata"]["terminal"]["exit_code"], 7);
+        assert_eq!(result["metadata"]["terminal"]["transport_complete"], true);
+        assert_eq!(result["metadata"]["storage_truncated"], false);
+        assert_eq!(result["preview_omitted"], true);
+        for name in ["stdout_entry", "stderr_entry", "order_entry"] {
+            runtime.inspect(result[name].as_str().unwrap().into(), false).await.unwrap();
+        }
+        let stdout = result["stdout_entry"].as_str().unwrap();
+        let search = runtime.invoke(stdout.into(), crate::file_operation::Contract::SearchText.reference(), "search".into(), json!({"pattern":"needle","limit":2}), Default::default()).await.unwrap();
+        assert!(search.content.unwrap().contains("needle"));
+        let stderr = runtime.invoke(result["stderr_entry"].as_str().unwrap().into(), crate::file_operation::Contract::ReadBytes.reference(), "read".into(), json!({"limit":4}), Default::default()).await.unwrap();
+        let stderr: Json = serde_json::from_str(&stderr.content.unwrap()).unwrap();
+        use base64::Engine as _;
+        assert_eq!(base64::engine::general_purpose::STANDARD.decode(stderr["data"].as_str().unwrap()).unwrap(), [vec![255], "€".as_bytes().to_vec()].concat());
+        let run = runtime.invoke("/bash-output".into(), contextual_reference("yoi.bash/command/v1", "/bash-output"), "run".into(), json!({"input":{"command":"printf '%4194303s' ''; printf '€'","cwd":"."}}), Default::default()).await.unwrap();
+        let result: Json = serde_json::from_str(&run.content.unwrap()).unwrap();
+        assert_eq!(result["metadata"]["stdout_saved"], 4194304);
+        assert_eq!(result["metadata"]["stdout_seen"], 4194306);
+        assert_eq!(result["metadata"]["transport_truncation"], "byte_budget");
+        assert_eq!(result["metadata"]["storage_truncated"], true);
+        let tail = runtime.invoke(result["stdout_entry"].as_str().unwrap().into(), crate::file_operation::Contract::ReadBytes.reference(), "read".into(), json!({"offset":4194303,"limit":4}), Default::default()).await.unwrap();
+        let tail: Json = serde_json::from_str(&tail.content.unwrap()).unwrap();
+        assert_eq!(base64::engine::general_purpose::STANDARD.decode(tail["data"].as_str().unwrap()).unwrap(), vec![0xe2]);
+        assert_eq!(tail["eof"], true);
+        assert_eq!(f.state.operations.lock().unwrap().iter().filter(|op| matches!(op, WorkdirSessionOperation::CommandStart(_))).count(), 2);
+        assert!(f.state.command_fault.lock().unwrap().is_none());
+        router.close_all().await.unwrap();
+        f.assert_endpoints();
+    }).await;
+}
+
+#[tokio::test]
+async fn waiting_remote_command_rejects_empty_response_without_http_busy_loop() {
+    watchdog(async {
+        let f = HttpFixture::new(WorkdirSessionCapabilities::ALL).await;
+        let remote = f.open(TOKEN).await.unwrap();
+        *f.state.command_fault.lock().unwrap() = Some(CommandResponseFault::EmptyWaiting);
+        let error = remote
+            .command_output(workdir::CommandOutputRequest {
+                handle: workdir::CommandHandle("unused".into()),
+                cursor: 0,
+                limit: 1024,
+                wait: true,
+            })
+            .await
+            .unwrap_err();
+        assert!(matches!(error, WorkdirError::Unavailable(_)));
+        assert_eq!(
+            f.state
+                .operations
+                .lock()
+                .unwrap()
+                .iter()
+                .filter(|op| matches!(op, WorkdirSessionOperation::CommandOutput(_)))
+                .count(),
+            1
+        );
+        remote.close().await.unwrap();
+    })
+    .await;
+}
+
+#[tokio::test]
+async fn remote_checked_byte_read_uses_common_contract_and_keeps_binary_boundaries() {
+    use base64::Engine as _;
+    let fixture = HttpFixture::new(WorkdirSessionCapabilities::READ_ONLY).await;
+    let remote = Arc::new(fixture.open(TOKEN).await.unwrap());
+    let (runtime, _) = native_runtime(remote);
+    let path = "/checkouts/main/src/deep/a.txt";
+    observe_interface(&runtime, path).await;
+    let output = runtime
+        .invoke(
+            path.into(),
+            crate::file_operation::Contract::ReadBytes.reference(),
+            "read".into(),
+            json!({"offset":1,"limit":3}),
+            Default::default(),
+        )
+        .await
+        .unwrap();
+    let json: Json = serde_json::from_str(output.content.as_deref().unwrap()).unwrap();
+    assert_eq!(json["encoding"], "base64");
+    assert_eq!(json["offset"], 1);
+    assert_eq!(json["next_offset"], 4);
+    let source = fixture
+        .state
+        .session
+        .read_bytes(workdir::ReadBytesRequest {
+            path: WorkdirPath::new("src/deep/a.txt").unwrap(),
+            offset: 1,
+            max_bytes: 3,
+            expected_hash: None,
+        })
+        .await
+        .unwrap();
+    assert_eq!(
+        base64::engine::general_purpose::STANDARD
+            .decode(json["data"].as_str().unwrap())
+            .unwrap(),
+        source.bytes
+    );
+}
+
+#[tokio::test]
+async fn http_failed_text_read_does_not_authorize_mutations() {
+    for operation in ["write", "edit"] {
+        for oversized in ["\"".repeat(50_000), "x".repeat(65_530)] {
+            let fixture = HttpFixture::new(WorkdirSessionCapabilities::READ_WRITE).await;
+            let remote = fixture.open(TOKEN).await.unwrap();
+            checkout_wip_tests::failed_text_read_cannot_authorize_mutation(
+                Arc::new(remote),
+                &fixture.dir.path().join("text"),
+                &oversized,
+                operation,
+            )
+            .await;
+            let mutations = fixture
+                .state
+                .operations
+                .lock()
+                .unwrap()
+                .iter()
+                .filter(|op| {
+                    matches!(
+                        op,
+                        WorkdirSessionOperation::CheckoutExecute(CheckoutRequest {
+                            operation: CheckoutOperation::Write { .. }
+                                | CheckoutOperation::Edit { .. },
+                            ..
+                        })
+                    )
+                })
+                .count();
+            assert_eq!(
+                mutations, 1,
+                "only the mutation after a successful Read may reach the provider"
+            );
+        }
+    }
+}
+
+#[tokio::test]
+async fn http_long_utf8_search_refuses_incomplete_line_and_preserves_line_pagination() {
+    let fixture = HttpFixture::new(WorkdirSessionCapabilities::READ_WRITE).await;
+    let remote = fixture.open(TOKEN).await.unwrap();
+    checkout_wip_tests::assert_long_utf8_search_refuses_incomplete_line(
+        Arc::new(remote),
+        fixture.dir.path(),
+    )
+    .await;
+}

crates/worker/src/checkout_race_tests.rs

@@ -683,7 +683,12 @@ async fn committed_checkout_mutation_losing_connection_is_unknown_not_rejected_o
         let calls = Arc::new(AtomicUsize::new(0));
         let route = object_path("main", &file.target);
         let mut projection = p.node(&route).await.unwrap().unwrap();
-        let interface = projection.interface.clone();
+        let interface = match operation {
+            "write" => crate::file_operation::Contract::Write,
+            "edit" => crate::file_operation::Contract::Edit,
+            _ => crate::file_operation::Contract::CreateFile,
+        }
+        .reference();
         projection.handler = Arc::new(DetachBeforePublication {
             file,
             calls: calls.clone(),

crates/worker/src/checkout_wip_tests.rs

@@ -41,13 +41,28 @@ async fn interface(r: &WipRuntime, path: &str) -> wip_protocol::InterfaceReferen
         .unwrap();
     p.interface
 }
+pub(super) fn contract(operation: &str) -> crate::file_operation::Contract {
+    use crate::file_operation::Contract as C;
+    match operation {
+        "read" => C::ReadLines,
+        "search" => C::SearchText,
+        "edit" => C::Edit,
+        "write" => C::Write,
+        "list" => C::List,
+        "glob" => C::Glob,
+        "grep" => C::Grep,
+        "create_file" => C::CreateFile,
+        _ => panic!("unknown file operation {operation}"),
+    }
+}
 async fn call(
     r: &WipRuntime,
     path: &str,
     operation: &str,
     args: Json,
 ) -> Result<ToolOutput, ToolError> {
-    let i = interface(r, path).await;
+    interface(r, path).await;
+    let i = contract(operation).reference();
     r.call(path.into(), i, operation.into(), args, Default::default())
         .await
 }
@@ -336,12 +351,26 @@ async fn checkout_wip_detach_alias_reuse_and_restore_fence_old_references() {
     let old = r.host.projection_live(path).await.unwrap().unwrap();
     router.detach(&alias).await.unwrap();
     assert!(r.host.projection_live(path).await.unwrap().is_none());
-    assert!(r.host.fetch_interface_live(&old.interface).await.is_err());
+    assert_eq!(
+        r.host
+            .fetch_interface_live(&old.interface)
+            .await
+            .unwrap()
+            .validator,
+        old.interface_validator
+    );
     router.attach(alias, session(&b, false)).unwrap();
     let new = r.host.projection_live(path).await.unwrap().unwrap();
-    assert_ne!(old.interface, new.interface);
+    assert_eq!(old.interface, new.interface);
     assert_ne!(old.object.validator, new.object.validator);
-    assert!(r.host.fetch_interface_live(&old.interface).await.is_err());
+    assert_eq!(
+        r.host
+            .fetch_interface_live(&old.interface)
+            .await
+            .unwrap()
+            .validator,
+        old.interface_validator
+    );
     assert!(
         call(
             &r,
@@ -354,14 +383,16 @@ async fn checkout_wip_detach_alias_reuse_and_restore_fence_old_references() {
     );
     let restored = runtime(router, None);
     let next = restored.host.projection_live(path).await.unwrap().unwrap();
-    assert_ne!(new.interface, next.interface);
+    assert_eq!(new.interface, next.interface);
     assert_ne!(new.object.validator, next.object.validator);
-    assert!(
+    assert_eq!(
         restored
             .host
             .fetch_interface_live(&new.interface)
             .await
-            .is_err()
+            .unwrap()
+            .validator,
+        new.interface_validator
     );
     assert_eq!(
         std::fs::read_to_string(b.path().join("file.txt")).unwrap(),
@@ -446,7 +477,11 @@ async fn checkout_wip_policy_is_not_feature_authority_and_compatibility_is_repla
     let mut registry = WipMountRegistry::new();
     crate::checkout::mount_checkouts(&mut registry, router.clone(), tools::Tracker::new(), None)
         .unwrap();
-    for def in tools::routed_builtin_tools(router, tools::Tracker::new(), dir.path().join("bash")) {
+    for def in tools::routed_builtin_tools(
+        router,
+        tools::Tracker::new(),
+        tools::bash_output::BashOutputView::new(),
+    ) {
         let (meta, tool) = def();
         let p = compatibility_projection(meta, tool, None).unwrap();
         registry.mount(p).unwrap();
@@ -497,7 +532,7 @@ async fn checkout_wip_post_operation_validators_support_cached_chains() {
         .unwrap();
     let r = runtime(router, None);
     let path = "/checkouts/main/file.txt";
-    let i = interface(&r, path).await;
+    interface(&r, path).await;
     // No rediscovery or Interface refresh between any of these operations.
     for (op, args) in [
         ("read", json!({})),
@@ -505,16 +540,23 @@ async fn checkout_wip_post_operation_validators_support_cached_chains() {
         ("write", json!({"content":"saved\n"})),
         ("read", json!({})),
     ] {
-        r.call(path.into(), i.clone(), op.into(), args, Default::default())
-            .await
-            .unwrap();
+        r.call(
+            path.into(),
+            contract(op).reference(),
+            op.into(),
+            args,
+            Default::default(),
+        )
+        .await
+        .unwrap();
     }
     assert_eq!(
         std::fs::read_to_string(dir.path().join("file.txt")).unwrap(),
         "saved\n"
     );
     let parent = "/checkouts/main";
-    let i = interface(&r, parent).await;
+    interface(&r, parent).await;
+    let i = contract("create_file").reference();
     for name in ["one.txt", "nested/two.txt"] {
         r.call(
             parent.into(),
@@ -617,11 +659,12 @@ async fn checkout_wip_scoped_child_search_and_revoke_cannot_expose_siblings() {
             .is_none()
     );
     let file = "/checkouts/child/a.txt";
-    let i = interface(&child, file).await;
+    interface(&child, file).await;
+    let i = contract("write").reference();
     child
         .call(
             file.into(),
-            i.clone(),
+            contract("read").reference(),
             "read".into(),
             json!({}),
             Default::default(),
@@ -686,7 +729,21 @@ pub(super) async fn model_invoke(
     operation: &str,
     arguments: Json,
 ) -> Result<ToolOutput, ToolError> {
-    model_operation(r, "Invoke", json!({"path":inspected["path"], "interface":inspected["interfaces"][0]["reference"], "operation":operation, "arguments":arguments})).await
+    let reference = inspected["interfaces"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|item| &item["reference"])
+        .find(|r| {
+            Some(wip_protocol::InterfaceReference {
+                scope: r["scope"].as_str().unwrap().into(),
+                name: r["name"].as_str().unwrap().into(),
+            })
+            .and_then(|r| crate::file_operation::Contract::from_reference(&r))
+            .is_some_and(|c| c.operation() == operation)
+        })
+        .unwrap_or(&inspected["interfaces"][0]["reference"]);
+    model_operation(r, "Invoke", json!({"path":inspected["path"], "interface":reference, "operation":operation, "arguments":arguments})).await
 }
 
 #[tokio::test]
@@ -752,10 +809,7 @@ async fn checkout_model_list_glob_grep_entries_are_lazy_and_never_become_tree_ed
     let r = Arc::new(runtime(router, None));
     let entrance = model_inspect(r.clone(), "/checkouts/main").await;
     assert_eq!(entrance["path"], "/checkouts/main");
-    assert_eq!(
-        entrance["interfaces"][0]["reference"]["scope"],
-        "/checkouts/main"
-    );
+    assert_eq!(entrance["interfaces"][0]["reference"]["scope"], "/");
     let projection = r
         .host
         .projection_live("/checkouts/main")
@@ -829,10 +883,7 @@ async fn checkout_model_list_glob_grep_entries_are_lazy_and_never_become_tree_ed
         json!([])
     );
     let deep = model_inspect(r.clone(), "/checkouts/main/nested/deep").await;
-    assert_eq!(
-        deep["interfaces"][0]["reference"]["scope"],
-        "/checkouts/main"
-    );
+    assert_eq!(deep["interfaces"][0]["reference"]["scope"], "/");
     for (operation, args) in [
         ("list", json!({})),
         ("glob", json!({"pattern":"*.txt"})),
@@ -926,7 +977,7 @@ async fn checkout_list_permission_cannot_be_bypassed_with_glob_or_command_identi
 }
 
 #[tokio::test]
-async fn checkout_ancestor_scope_rejects_siblings_prefixes_refs_and_old_connection_before_read() {
+async fn common_scope_rejects_wrong_namespace_scope_ref_and_old_target_authority() {
     let dir = TempDir::new().unwrap();
     std::fs::write(dir.path().join("a.txt"), "same\n").unwrap();
     let router = Arc::new(WorkdirSessionRouter::new());
@@ -943,8 +994,8 @@ async fn checkout_ancestor_scope_rejects_siblings_prefixes_refs_and_old_connecti
     let p = r.host.projection_live(path).await.unwrap().unwrap();
     let fetched = r.host.fetch_interface_live(&p.interface).await.unwrap();
     assert!(
-        fetched.scope_ref.is_none(),
-        "ref-less publication is legitimate"
+        fetched.scope_ref.is_some(),
+        "common namespace uses the Host root scope"
     );
     // Ordinary content changes do not terminate the entrance's Interface lifetime.
     std::fs::write(dir.path().join("new.txt"), "fixture").unwrap();
@@ -959,12 +1010,12 @@ async fn checkout_ancestor_scope_rejects_siblings_prefixes_refs_and_old_connecti
     let request = |reference, scope_ref| CallOperationRequest {
         target: wip_protocol::Target {
             path: path.into(),
-            validator: None,
+            validator: p.object.validator.clone(),
         },
         interface: wip_protocol::InterfaceTarget {
             reference,
             scope_ref,
-            validator: None,
+            validator: fetched.validator.clone(),
         },
         operation: "read".into(),
         arguments: BTreeMap::new(),
@@ -996,6 +1047,654 @@ async fn checkout_ancestor_scope_rejects_siblings_prefixes_refs_and_old_connecti
     router.attach(main, session(&dir, true)).unwrap();
     let forged = request(p.interface.clone(), None);
     assert!(
-        matches!(r.host.call(forged, WipCallContext { execution:Default::default(),security_context:"fixture".into() }).await, Err(WipOperationError::Protocol(e)) if e.code == ProtocolErrorCode::InterfaceMismatch)
+        matches!(r.host.call(forged, WipCallContext { execution:Default::default(),security_context:"fixture".into() }).await, Err(WipOperationError::Protocol(e)) if e.code == ProtocolErrorCode::ValidatorMismatch)
     );
 }
+
+fn observed_common_request(
+    path: &str,
+    validator: Option<Vec<u8>>,
+    fetched: &FetchInterfaceResponse,
+    operation: &str,
+) -> CallOperationRequest {
+    CallOperationRequest {
+        target: wip_protocol::Target {
+            path: path.into(),
+            validator,
+        },
+        interface: wip_protocol::InterfaceTarget {
+            reference: fetched.interface.clone(),
+            scope_ref: fetched.scope_ref.clone(),
+            validator: fetched.validator.clone(),
+        },
+        operation: operation.into(),
+        arguments: BTreeMap::new(),
+    }
+}
+fn file_context() -> WipCallContext {
+    WipCallContext {
+        execution: Default::default(),
+        security_context: "file-contract-test".into(),
+    }
+}
+
+#[tokio::test]
+async fn shared_contract_survives_one_attachment_update_but_old_object_authority_never_transfers() {
+    let left = TempDir::new().unwrap();
+    let right = TempDir::new().unwrap();
+    for root in [&left, &right] {
+        std::fs::write(root.path().join("a.txt"), "same\n").unwrap();
+    }
+    std::fs::write(left.path().join("b.txt"), "same\n").unwrap();
+    let router = Arc::new(WorkdirSessionRouter::new());
+    let alias = WorkdirAttachmentAlias::new("left").unwrap();
+    router.attach(alias.clone(), session(&left, false)).unwrap();
+    router
+        .attach(
+            WorkdirAttachmentAlias::new("right").unwrap(),
+            session(&right, true),
+        )
+        .unwrap();
+    let r = runtime(router.clone(), None);
+    let path = "/checkouts/left/a.txt";
+    let other = "/checkouts/right/a.txt";
+    let first = r.host.projection_live(path).await.unwrap().unwrap();
+    let same_bytes = r
+        .host
+        .projection_live("/checkouts/left/b.txt")
+        .await
+        .unwrap()
+        .unwrap();
+    let independent = r.host.projection_live(other).await.unwrap().unwrap();
+    assert_eq!(first.interface, independent.interface);
+    assert_eq!(first.descriptor, independent.descriptor);
+    assert_ne!(first.object.validator, same_bytes.object.validator);
+    let definition = r.host.fetch_interface_live(&first.interface).await.unwrap();
+    let request =
+        observed_common_request(path, first.object.validator.clone(), &definition, "read");
+    assert!(r.host.call(request.clone(), file_context()).await.is_ok());
+    // Replace the same path with a different inode containing exactly the same bytes.
+    std::fs::write(left.path().join("replacement"), "same\n").unwrap();
+    std::fs::rename(left.path().join("replacement"), left.path().join("a.txt")).unwrap();
+    assert!(
+        matches!(r.host.call(request.clone(),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::ValidatorMismatch)
+    );
+    assert_eq!(
+        r.host
+            .fetch_interface_live(&first.interface)
+            .await
+            .unwrap()
+            .validator,
+        definition.validator
+    );
+    assert!(
+        r.host
+            .call(
+                observed_common_request(
+                    other,
+                    independent.object.validator.clone(),
+                    &definition,
+                    "read"
+                ),
+                file_context()
+            )
+            .await
+            .is_ok()
+    );
+    call(&r, path, "read", json!({})).await.unwrap();
+    router.detach(&alias).await.unwrap();
+    router.attach(alias, session(&left, false)).unwrap();
+    assert!(
+        matches!(r.host.call(request,file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::ValidatorMismatch)
+    );
+    assert!(
+        r.host
+            .call(
+                observed_common_request(other, independent.object.validator, &definition, "read"),
+                file_context()
+            )
+            .await
+            .is_ok()
+    );
+    call(&r, path, "read", json!({})).await.unwrap();
+    let before_restore = r.host.projection_live(path).await.unwrap().unwrap();
+    let restored = runtime(router, None);
+    let restored_definition = restored
+        .host
+        .fetch_interface_live(&first.interface)
+        .await
+        .unwrap();
+    assert_eq!(definition.descriptor, restored_definition.descriptor);
+    assert_eq!(definition.validator, restored_definition.validator);
+    assert!(
+        matches!(restored.host.call(observed_common_request(path,before_restore.object.validator,&restored_definition,"read"),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::ValidatorMismatch)
+    );
+    call(&restored, path, "read", json!({})).await.unwrap();
+}
+
+#[tokio::test]
+async fn shared_readonly_contract_rejects_wrong_membership_operation_and_interface_validator() {
+    let dir = TempDir::new().unwrap();
+    std::fs::write(dir.path().join("a.txt"), "雪.*\r\nother\n").unwrap();
+    let router = Arc::new(WorkdirSessionRouter::new());
+    router
+        .attach(
+            WorkdirAttachmentAlias::new("main").unwrap(),
+            session(&dir, true),
+        )
+        .unwrap();
+    let r = Arc::new(runtime(router, None));
+    let path = "/checkouts/main/a.txt";
+    let observed = model_inspect(r.clone(), path).await;
+    let read = json_content(
+        model_invoke(r.clone(), &observed, "read", json!({"limit":1}))
+            .await
+            .unwrap(),
+    );
+    assert_eq!(
+        read,
+        json!({"content":"     1\t雪.*\n","next_offset":1,"truncated":true})
+    );
+    let searched = json_content(
+        model_invoke(
+            r.clone(),
+            &observed,
+            "search",
+            json!({"pattern":".*","limit":1}),
+        )
+        .await
+        .unwrap(),
+    );
+    assert_eq!(
+        searched,
+        json!({"matches":[{"line":1,"text":"雪.*"}],"next_offset":1,"truncated":true})
+    );
+    let p = r.host.projection_live(path).await.unwrap().unwrap();
+    let read = r
+        .host
+        .fetch_interface_live(&contract("read").reference())
+        .await
+        .unwrap();
+    let write = r
+        .host
+        .fetch_interface_live(&contract("write").reference())
+        .await
+        .unwrap();
+    assert!(
+        matches!(r.host.call(observed_common_request(path,p.object.validator.clone(),&write,"write"),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::InterfaceMismatch)
+    );
+    assert!(
+        matches!(r.host.call(observed_common_request(path,p.object.validator.clone(),&read,"missing"),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::OperationNotFound)
+    );
+    let mut stale = observed_common_request(path, p.object.validator.clone(), &read, "read");
+    stale.interface.validator = Some(vec![0]);
+    assert!(
+        matches!(r.host.call(stale,file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::InterfaceValidatorMismatch)
+    );
+    let mut legacy = observed_common_request(path, p.object.validator, &read, "read");
+    legacy.interface.reference = InterfaceReference {
+        scope: "/checkouts/main".into(),
+        name: "yoi.checkout/old/file/v1#target/old".into(),
+    };
+    assert!(
+        matches!(r.host.call(legacy,file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::InterfaceMismatch)
+    );
+    assert_eq!(
+        std::fs::read_to_string(dir.path().join("a.txt")).unwrap(),
+        "雪.*\r\nother\n"
+    );
+}
+
+// The fixture substitutes only a binary source. Real Host/Client/model tools, fixed common
+// descriptors, membership, validators and output decoding stay on their production path.
+struct ReadonlyBytes {
+    bytes: Arc<Vec<u8>>,
+    version: Arc<std::sync::atomic::AtomicU64>,
+    captured: u64,
+}
+impl ReadonlyBytes {
+    fn projection(&self) -> WipProjection {
+        let contract = crate::file_operation::Contract::ReadBytes;
+        WipProjection {
+            route: "/virtual".into(),
+            capability: "virtual:bytes".into(),
+            kind: WipProjectionKind::Native,
+            object: Object {
+                name: "virtual".into(),
+                description: None,
+                interfaces: vec![contract.reference()],
+                r#ref: None,
+                validator: Some(self.captured.to_be_bytes().to_vec()),
+            },
+            interface: contract.reference(),
+            descriptor: contract.descriptor(),
+            interface_validator: Some(contract.validator()),
+            handler: Arc::new(Self {
+                bytes: self.bytes.clone(),
+                version: self.version.clone(),
+                captured: self.captured,
+            }),
+        }
+    }
+}
+#[async_trait]
+impl WipOperationHandler for ReadonlyBytes {
+    async fn call(
+        &self,
+        op: &str,
+        args: &BTreeMap<String, Value>,
+        _: WipCallContext,
+    ) -> Result<WipOperationOutput, WipOperationError> {
+        if op != "read_bytes" {
+            return Err(WipOperationError::Protocol(protocol_error(
+                ProtocolErrorCode::OperationNotFound,
+                "readonly bytes",
+            )));
+        }
+        if self.captured != self.version.load(Ordering::SeqCst) {
+            return Err(WipOperationError::Protocol(protocol_error(
+                ProtocolErrorCode::ValidatorMismatch,
+                "virtual source replaced",
+            )));
+        }
+        let (offset, limit) = crate::file_operation::byte_range(args)?;
+        if offset > self.bytes.len() as u64 {
+            return Err(WipOperationError::Protocol(protocol_error(
+                ProtocolErrorCode::InvalidArguments,
+                "past EOF",
+            )));
+        }
+        let end = (offset as usize + limit).min(self.bytes.len());
+        Ok(WipOperationOutput::native(
+            crate::file_operation::bytes_result(
+                args,
+                &self.bytes[offset as usize..end],
+                end == self.bytes.len(),
+            )?,
+        ))
+    }
+}
+#[async_trait]
+impl WipSubtreeProvider for ReadonlyBytes {
+    async fn publication(&self, path: &str) -> Result<Option<WipPublication>, ProtocolError> {
+        Ok((path == "/virtual").then(|| {
+            let current = Self {
+                bytes: self.bytes.clone(),
+                version: self.version.clone(),
+                captured: self.version.load(Ordering::SeqCst),
+            };
+            WipPublication {
+                projection: current.projection(),
+                scope: None,
+            }
+        }))
+    }
+    async fn children(&self, _: &str) -> Result<Vec<String>, ProtocolError> {
+        Ok(vec![])
+    }
+}
+#[tokio::test]
+async fn common_bytes_read_long_lines_invalid_utf8_arbitrary_boundaries_and_eof_without_write_authority()
+ {
+    use base64::Engine as _;
+    let mut bytes = "雪".as_bytes().to_vec();
+    bytes.extend_from_slice(&[0xff, 0, 0xc0]);
+    bytes.extend(vec![b'x'; 100_000]);
+    let bytes = Arc::new(bytes);
+    let dir = TempDir::new().unwrap();
+    std::fs::write(dir.path().join("raw"), bytes.as_ref()).unwrap();
+    let router = Arc::new(WorkdirSessionRouter::new());
+    router
+        .attach(
+            WorkdirAttachmentAlias::new("main").unwrap(),
+            session(&dir, true),
+        )
+        .unwrap();
+    let source = Arc::new(ReadonlyBytes {
+        bytes: bytes.clone(),
+        version: Arc::new(std::sync::atomic::AtomicU64::new(1)),
+        captured: 1,
+    });
+    let mut registry = WipMountRegistry::new();
+    crate::checkout::mount_checkouts(&mut registry, router, tools::Tracker::new(), None).unwrap();
+    registry.allocate_namespace("virtual", "virtual").unwrap();
+    registry.mount(source.projection()).unwrap();
+    registry
+        .mount_subtree(WipSubtreeMount {
+            root: "/virtual".into(),
+            provider: source.clone(),
+        })
+        .unwrap();
+    let r = Arc::new(WipRuntime::from_mounts(registry, "bytes-test".into()).unwrap());
+    let virtual_inspect = model_inspect(r.clone(), "/virtual").await;
+    let reference = virtual_inspect["interfaces"][0]["reference"].clone();
+    let checkout = model_inspect(r.clone(), "/checkouts/main/raw").await;
+    assert!(
+        checkout["interfaces"]
+            .as_array()
+            .unwrap()
+            .iter()
+            .any(|i| i["reference"] == reference)
+    );
+    for path in ["/virtual", "/checkouts/main/raw"] {
+        for offset in [0, 1, 2, 3, 5, 80_000, bytes.len()] {
+            let output=json_content(model_operation(r.clone(),"Invoke",json!({"path":path,"interface":reference,"operation":"read","arguments":{"offset":offset,"limit":17}})).await.unwrap());
+            let end = (offset + 17).min(bytes.len());
+            assert_eq!(output["encoding"], "base64");
+            assert_eq!(output["offset"], offset);
+            assert_eq!(output["next_offset"], end);
+            assert_eq!(output["eof"], end == bytes.len());
+            assert_eq!(
+                base64::engine::general_purpose::STANDARD
+                    .decode(output["data"].as_str().unwrap())
+                    .unwrap(),
+                bytes[offset..end]
+            );
+        }
+        for arguments in [
+            json!({"limit":0}),
+            json!({"limit":32769}),
+            json!({"offset":-1}),
+            json!({"offset":9_007_199_254_740_991i64}),
+            json!({"offset":bytes.len()+1}),
+            json!({"file_path":"other"}),
+        ] {
+            assert!(model_operation(r.clone(),"Invoke",json!({"path":path,"interface":reference,"operation":"read","arguments":arguments})).await.is_err());
+        }
+        assert!(model_operation(r.clone(),"Invoke",json!({"path":path,"interface":{"scope":"/","name":"yoi.file/write-text/v1"},"operation":"write","arguments":{"content":"lost"}})).await.is_err());
+    }
+    let fetched = r
+        .host
+        .fetch_interface_live(&crate::file_operation::Contract::ReadBytes.reference())
+        .await
+        .unwrap();
+    let mut request = observed_common_request(
+        "/virtual",
+        Some(1u64.to_be_bytes().to_vec()),
+        &fetched,
+        "read",
+    );
+    source.version.store(2, Ordering::SeqCst);
+    assert!(
+        matches!(r.host.call(request.clone(),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::ValidatorMismatch)
+    );
+    request.target.validator = Some(2u64.to_be_bytes().to_vec());
+    assert!(r.host.call(request, file_context()).await.is_ok());
+    assert_eq!(
+        std::fs::read(dir.path().join("raw")).unwrap(),
+        bytes.as_ref().clone()
+    );
+}
+
+#[tokio::test]
+async fn scope_downgrade_changes_object_membership_not_common_contract_and_read_remains_available()
+{
+    let dir = TempDir::new().unwrap();
+    std::fs::write(dir.path().join("a"), "same").unwrap();
+    let scope = manifest::SharedScope::new(manifest::Scope::writable(dir.path()).unwrap());
+    let session = Arc::new(LocalWorkdirSession::materialized(
+        dir.path().into(),
+        dir.path().into(),
+        scope.clone(),
+        WorkdirSessionCapabilities::READ_WRITE,
+    ));
+    let router = Arc::new(WorkdirSessionRouter::new());
+    router
+        .attach(WorkdirAttachmentAlias::new("main").unwrap(), session)
+        .unwrap();
+    let r = Arc::new(runtime(router, None));
+    let path = "/checkouts/main/a";
+    let old = model_inspect(r.clone(), path).await;
+    let current = r.host.projection_live(path).await.unwrap().unwrap();
+    let definition = r
+        .host
+        .fetch_interface_live(&contract("read").reference())
+        .await
+        .unwrap();
+    scope
+        .update(|_| {
+            manifest::Scope::from_config(&manifest::ScopeConfig {
+                allow: vec![manifest::ScopeRule {
+                    target: dir.path().into(),
+                    permission: manifest::Permission::Read,
+                    recursive: true,
+                    symlink_policy: manifest::SymlinkPolicy::Resolved,
+                }],
+                deny: vec![],
+            })
+        })
+        .unwrap();
+    assert!(model_operation(r.clone(),"Invoke",json!({"path":path,"interface":contract_json("write"),"operation":"write","arguments":{"content":"lost"}})).await.is_err());
+    let new = json_content(
+        model_operation(r.clone(), "Inspect", json!({"path":path,"refresh":true}))
+            .await
+            .unwrap(),
+    );
+    assert_ne!(old["object_signature"], new["object_signature"]);
+    assert!(
+        !new["interfaces"]
+            .as_array()
+            .unwrap()
+            .iter()
+            .any(|i| i["reference"]["name"] == "yoi.file/write-text/v1")
+    );
+    assert_eq!(
+        r.host
+            .fetch_interface_live(&contract("read").reference())
+            .await
+            .unwrap()
+            .validator,
+        definition.validator
+    );
+    assert!(
+        matches!(r.host.call(observed_common_request(path,current.object.validator,&definition,"read"),file_context()).await,Err(WipOperationError::Protocol(e)) if e.code==ProtocolErrorCode::ValidatorMismatch)
+    );
+    assert_eq!(
+        json_content(
+            model_invoke(r.clone(), &new, "read", json!({}))
+                .await
+                .unwrap()
+        )["content"],
+        "     1\tsame\n"
+    );
+}
+fn contract_json(operation: &str) -> Json {
+    let r = contract(operation).reference();
+    json!({"scope":r.scope,"name":r.name})
+}
+
+#[test]
+fn common_contract_registration_rejects_descriptor_redefinition_and_domain_operation_injection() {
+    let source = ReadonlyBytes {
+        bytes: Arc::new(vec![]),
+        version: Arc::new(std::sync::atomic::AtomicU64::new(1)),
+        captured: 1,
+    };
+    let mut registry = WipMountRegistry::new();
+    registry.allocate_namespace("virtual", "virtual").unwrap();
+    let mut invalid = source.projection();
+    invalid.descriptor.operations[0]
+        .parameters
+        .push(ParameterDeclaration {
+            name: "target_override".into(),
+            required: false,
+            documentation: None,
+            r#type: TypeExpr::String,
+        });
+    assert!(matches!(
+        registry.mount(invalid),
+        Err(WipMountError::InvalidProjection { .. })
+    ));
+    let projection = source.projection();
+    registry.mount(projection.clone()).unwrap();
+    let mut extension = projection.descriptor.clone();
+    extension.operations[0].name = "erase".into();
+    assert!(matches!(
+        registry.contribute_operations(WipOperationContribution {
+            route: "/virtual".into(),
+            contributor: "other".into(),
+            interface: projection.interface,
+            descriptor: extension,
+            handler: projection.handler
+        }),
+        Err(WipMountError::InterfaceCollision { .. })
+    ));
+}
+
+pub(super) async fn failed_text_read_cannot_authorize_mutation(
+    source: WorkdirSessionHandle,
+    disk_file: &std::path::Path,
+    oversized: &str,
+    operation: &str,
+) {
+    let original = format!("{oversized}\nknown\n");
+    std::fs::write(disk_file, &original).unwrap();
+    let router = Arc::new(WorkdirSessionRouter::new());
+    router
+        .attach(WorkdirAttachmentAlias::new("main").unwrap(), source)
+        .unwrap();
+    let r = Arc::new(runtime(router, None));
+    let inspected = model_inspect(r.clone(), "/checkouts/main/text").await;
+    let arguments = if operation == "write" {
+        json!({"content":"changed"})
+    } else {
+        json!({"old_string":"known","new_string":"changed"})
+    };
+    let failure = model_invoke(r.clone(), &inspected, "read", json!({"limit":1}))
+        .await
+        .unwrap_err();
+    assert!(
+        failure.to_string().contains("ResourceLimitExceeded"),
+        "{failure}"
+    );
+    let denied = model_invoke(r.clone(), &inspected, operation, arguments.clone()).await;
+    assert!(denied.is_err(), "failed read authorized {operation}");
+    let denied = denied.unwrap_err();
+    assert!(denied.to_string().contains("InvalidArguments"), "{denied}");
+    assert_eq!(std::fs::read_to_string(disk_file).unwrap(), original);
+    model_invoke(r.clone(), &inspected, "read", json!({"offset":1,"limit":1}))
+        .await
+        .unwrap();
+    // A failed read must neither grant new authority nor erase an earlier successful Read.
+    assert!(
+        model_invoke(r.clone(), &inspected, "read", json!({"limit":1}))
+            .await
+            .is_err()
+    );
+    model_invoke(r, &inspected, operation, arguments)
+        .await
+        .unwrap();
+    let expected = if operation == "write" {
+        "changed".to_string()
+    } else {
+        original.replace("known", "changed")
+    };
+    assert_eq!(std::fs::read_to_string(disk_file).unwrap(), expected);
+}
+
+#[tokio::test]
+async fn failed_text_read_does_not_authorize_write() {
+    for oversized in ["\"".repeat(50_000), "x".repeat(65_530)] {
+        let dir = TempDir::new().unwrap();
+        failed_text_read_cannot_authorize_mutation(
+            session(&dir, false),
+            &dir.path().join("text"),
+            &oversized,
+            "write",
+        )
+        .await;
+    }
+}
+
+#[tokio::test]
+async fn failed_text_read_does_not_authorize_edit() {
+    for oversized in ["\"".repeat(50_000), "x".repeat(65_530)] {
+        let dir = TempDir::new().unwrap();
+        failed_text_read_cannot_authorize_mutation(
+            session(&dir, false),
+            &dir.path().join("text"),
+            &oversized,
+            "edit",
+        )
+        .await;
+    }
+}
+
+pub(super) async fn assert_long_utf8_search_refuses_incomplete_line(
+    source: WorkdirSessionHandle,
+    directory: &std::path::Path,
+) {
+    let original = format!("{}needle\nnext\n", "雪".repeat(22_000));
+    std::fs::write(directory.join("text"), &original).unwrap();
+    for (name, text) in [
+        ("normal", "雪\nneedle\nnext\n"),
+        ("unterminated", "雪\nneedle\nnext"),
+    ] {
+        std::fs::write(directory.join(name), text).unwrap();
+    }
+    let router = Arc::new(WorkdirSessionRouter::new());
+    router
+        .attach(WorkdirAttachmentAlias::new("main").unwrap(), source)
+        .unwrap();
+    let r = Arc::new(runtime(router, None));
+    let inspected = model_inspect(r.clone(), "/checkouts/main/text").await;
+    let result = model_invoke(
+        r.clone(),
+        &inspected,
+        "search",
+        json!({"pattern":"needle","limit":1}),
+    )
+    .await;
+    assert!(
+        result.is_err(),
+        "search advanced over a byte-truncated UTF-8 line: {result:?}"
+    );
+    let failure = result.unwrap_err();
+    assert!(
+        failure.to_string().contains("ResourceLimitExceeded"),
+        "{failure}"
+    );
+    let read = model_invoke(r.clone(), &inspected, "read", json!({"limit":1}))
+        .await
+        .unwrap_err();
+    assert!(read.to_string().contains("ResourceLimitExceeded"), "{read}");
+    let write = model_invoke(r.clone(), &inspected, "write", json!({"content":"lost"}))
+        .await
+        .unwrap_err();
+    assert!(write.to_string().contains("InvalidArguments"), "{write}");
+    assert_eq!(
+        std::fs::read_to_string(directory.join("text")).unwrap(),
+        original
+    );
+    for name in ["normal", "unterminated"] {
+        let inspected = model_inspect(r.clone(), &format!("/checkouts/main/{name}")).await;
+        for offset in 0..=3 {
+            let page = json_content(
+                model_invoke(
+                    r.clone(),
+                    &inspected,
+                    "search",
+                    json!({"pattern":"needle","offset":offset,"limit":1}),
+                )
+                .await
+                .unwrap(),
+            );
+            assert_eq!(page["next_offset"], (offset + 1).min(3));
+            assert_eq!(page["truncated"], offset < 2);
+            assert_eq!(
+                page["matches"],
+                if offset == 1 {
+                    json!([{"line":2,"text":"needle"}])
+                } else {
+                    json!([])
+                }
+            );
+        }
+    }
+}
+
+#[tokio::test]
+async fn long_utf8_search_refuses_incomplete_line_and_preserves_line_pagination() {
+    let dir = TempDir::new().unwrap();
+    assert_long_utf8_search_refuses_incomplete_line(session(&dir, false), dir.path()).await;
+}

crates/worker/src/controller.rs

@@ -692,7 +692,6 @@ impl WorkerController {
     pub async fn spawn<C, St>(
         worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
     ) -> Result<(WorkerHandle, ShutdownReceiver), std::io::Error>
     where
         C: LlmClient + Clone + 'static,
@@ -701,7 +700,6 @@ impl WorkerController {
         let (handle, shutdown, _task) = Self::spawn_inner(
             worker,
             runtime_base,
-            bash_output_dir,
             false,
             None,
             WorkerControllerTransport::UnixSocket,
@@ -715,7 +713,7 @@ impl WorkerController {
     pub async fn spawn_with_transport<C, St>(
         worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
+
         transport: WorkerControllerTransport,
     ) -> Result<(WorkerHandle, ShutdownReceiver), std::io::Error>
     where
@@ -723,42 +721,32 @@ impl WorkerController {
         St: Store + WorkerMetadataStore + Clone + Send + Sync + 'static,
     {
         let (handle, shutdown, _task) =
-            Self::spawn_with_transport_owned(worker, runtime_base, bash_output_dir, transport)
-                .await?;
+            Self::spawn_with_transport_owned(worker, runtime_base, transport).await?;
         Ok((handle, shutdown))
     }
 
     pub(crate) async fn spawn_with_transport_owned<C, St>(
         worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
+
         transport: WorkerControllerTransport,
     ) -> Result<(WorkerHandle, ShutdownReceiver, tokio::task::JoinHandle<()>), std::io::Error>
     where
         C: LlmClient + Clone + 'static,
         St: Store + WorkerMetadataStore + Clone + Send + Sync + 'static,
     {
-        Self::spawn_inner(
-            worker,
-            runtime_base,
-            bash_output_dir,
-            false,
-            None,
-            transport,
-        )
-        .await
+        Self::spawn_inner(worker, runtime_base, false, None, transport).await
     }
 
     /// Spawn a Worker owned by `worker-runtime`.
     ///
-    /// The controller uses an ephemeral directory for Unix sockets while tool
-    /// spill artifacts use the separately supplied Worker-owned temporary path.
+    /// The controller uses an ephemeral directory for Unix sockets. Bash output is
+    /// owned by its live Feature instance, independently of filesystem layout.
     /// Runtime-managed Workers do not write legacy pid/status/manifest liveness
     /// projections.
     pub async fn spawn_runtime_managed<C, St>(
         worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
     ) -> Result<(WorkerHandle, ShutdownReceiver), std::io::Error>
     where
         C: LlmClient + Clone + 'static,
@@ -767,7 +755,6 @@ impl WorkerController {
         let (handle, shutdown, _task) = Self::spawn_inner(
             worker,
             runtime_base,
-            bash_output_dir,
             true,
             None,
             WorkerControllerTransport::UnixSocket,
@@ -780,7 +767,6 @@ impl WorkerController {
     pub async fn spawn_runtime_managed_run<C, St>(
         worker: Worker<C, St>,
         run_dir: &Path,
-        bash_output_dir: &Path,
     ) -> Result<(WorkerHandle, ShutdownReceiver), std::io::Error>
     where
         C: LlmClient + Clone + 'static,
@@ -789,7 +775,6 @@ impl WorkerController {
         Self::spawn_runtime_managed_run_with_transport(
             worker,
             run_dir,
-            bash_output_dir,
             WorkerControllerTransport::UnixSocket,
         )
         .await
@@ -800,27 +785,23 @@ impl WorkerController {
     pub async fn spawn_runtime_managed_run_with_transport<C, St>(
         worker: Worker<C, St>,
         run_dir: &Path,
-        bash_output_dir: &Path,
+
         transport: WorkerControllerTransport,
     ) -> Result<(WorkerHandle, ShutdownReceiver), std::io::Error>
     where
         C: LlmClient + Clone + 'static,
         St: Store + WorkerMetadataStore + Clone + Send + Sync + 'static,
     {
-        let (handle, shutdown, _task) = Self::spawn_runtime_managed_run_with_transport_owned(
-            worker,
-            run_dir,
-            bash_output_dir,
-            transport,
-        )
-        .await?;
+        let (handle, shutdown, _task) =
+            Self::spawn_runtime_managed_run_with_transport_owned(worker, run_dir, transport)
+                .await?;
         Ok((handle, shutdown))
     }
 
     pub(crate) async fn spawn_runtime_managed_run_with_transport_owned<C, St>(
         worker: Worker<C, St>,
         run_dir: &Path,
-        bash_output_dir: &Path,
+
         transport: WorkerControllerTransport,
     ) -> Result<(WorkerHandle, ShutdownReceiver, tokio::task::JoinHandle<()>), std::io::Error>
     where
@@ -830,21 +811,13 @@ impl WorkerController {
         let parent = run_dir
             .parent()
             .ok_or_else(|| std::io::Error::other("run path has no parent"))?;
-        Self::spawn_inner(
-            worker,
-            parent,
-            bash_output_dir,
-            true,
-            Some(run_dir),
-            transport,
-        )
-        .await
+        Self::spawn_inner(worker, parent, true, Some(run_dir), transport).await
     }
 
     async fn spawn_inner<C, St>(
         worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
+
         runtime_managed: bool,
         runtime_run: Option<&Path>,
         transport: WorkerControllerTransport,
@@ -857,7 +830,6 @@ impl WorkerController {
         let result = Self::spawn_initialized(
             worker,
             runtime_base,
-            bash_output_dir,
             runtime_managed,
             runtime_run,
             transport,
@@ -874,7 +846,7 @@ impl WorkerController {
     async fn spawn_initialized<C, St>(
         mut worker: Worker<C, St>,
         runtime_base: &Path,
-        bash_output_dir: &Path,
+
         runtime_managed: bool,
         runtime_run: Option<&Path>,
         transport: WorkerControllerTransport,
@@ -888,8 +860,7 @@ impl WorkerController {
             .map_err(std::io::Error::other)?;
 
         // === 1. Initialization (channels / RuntimeDir / worker-immutable
-        //         snapshots / SpawnedWorkerRegistry / alerter attach /
-        //         bash-output scope) ===
+        //         snapshots / SpawnedWorkerRegistry / alerter attach) ===
         let (shutdown_tx, shutdown_rx) = oneshot::channel::<()>();
         let (method_tx, method_rx) = mpsc::channel::<Method>(32);
         let (working_event_tx, _) = broadcast::channel::<Event>(256);
@@ -897,8 +868,8 @@ impl WorkerController {
         let in_flight = InFlightEvents::new(working_event_tx.clone());
         worker.attach_in_flight_events(in_flight.clone());
 
-        // Runtime directory is created before tool registration because it owns
-        // bounded tool artifacts, and before initial status/history writes consume
+        // Runtime directory is created before tool registration and before
+        // initial status/history writes consume
         // the greeting we build after registration is complete.
         let runtime_dir = Arc::new(if let Some(run_dir) = runtime_run {
             RuntimeDir::create_worker_run(run_dir).await?
@@ -935,26 +906,6 @@ impl WorkerController {
         worker.attach_internal_worker_registry(spawned_registry.clone());
         worker.attach_working_event_tx(working_event_tx.clone());
 
-        // Bash spill artifacts are owned by the stable Worker identity rather
-        // than a controller session/run generation. Push a recursive
-        // `allow(Read)` for the exact tool output path into the Worker's shared
-        // runtime scope so the Workdir session and system prompt stay aligned.
-        let bash_output_dir = bash_output_dir.to_path_buf();
-        std::fs::create_dir_all(&bash_output_dir).map_err(|e| {
-            std::io::Error::other(format!(
-                "create bash output dir {}: {e}",
-                bash_output_dir.display()
-            ))
-        })?;
-        worker
-            .add_scope_rules([manifest::ScopeRule {
-                target: bash_output_dir.clone(),
-                permission: manifest::Permission::Read,
-                recursive: true,
-                symlink_policy: Default::default(),
-            }])
-            .map_err(std::io::Error::other)?;
-
         // === 1.5. Direct writer wiring ===
         //
         // Engine callbacks fire `on_history_append` for each assistant
@@ -974,7 +925,6 @@ impl WorkerController {
         // === 3. Tool registration (builtin / memory / spawn-orchestration) ===
         let fs_for_view = register_worker_tools(
             &mut worker,
-            bash_output_dir,
             runtime_base.to_path_buf(),
             spawned_registry.clone(),
             Some(method_tx.downgrade()),
@@ -1440,7 +1390,7 @@ fn validate_memory_lifecycle_targets(
 /// the shared state.
 pub(crate) async fn register_worker_tools<C, St>(
     worker: &mut Worker<C, St>,
-    bash_output_dir: PathBuf,
+
     runtime_base: PathBuf,
     spawned_registry: Arc<SpawnedWorkerRegistry>,
     parent_method_tx: Option<mpsc::WeakSender<Method>>,
@@ -1453,6 +1403,11 @@ where
     // Worker-immutable snapshots taken before the mutable worker borrow
     // below so the worker borrow doesn't conflict with reads on `worker`.
     let feature_config = worker.manifest().feature.clone();
+    // New activation requires admission before any initialization side effect.
+    // Restore reconstructs saved composition; operation authority stays live.
+    worker
+        .authorize_feature_configuration()
+        .map_err(|error| std::io::Error::new(std::io::ErrorKind::PermissionDenied, error))?;
     let workdir_sessions = worker.workdir_sessions();
     let restrict_workdir_tools_to_current_capabilities = inherited_workdir_tool_broker.is_some();
     let workdir_tool_broker = Some(
@@ -1485,6 +1440,7 @@ where
     let lifecycle_enabled = worker.manifest_lifecycle_features_enabled() && backend_job.is_none();
     let prompts = worker.prompts().clone();
     let tracker = tools::Tracker::new();
+    let bash_output = spawned_registry.bash_output();
     {
         let paste_store = worker.store().clone();
         let paste_session_id = worker.session_id();
@@ -1507,13 +1463,13 @@ where
             tools::routed_builtin_tools_for_current_capabilities(
                 workdir_sessions.clone(),
                 tracker.clone(),
-                bash_output_dir.clone(),
+                bash_output.clone(),
             )
         } else {
             tools::routed_builtin_tools(
                 workdir_sessions.clone(),
                 tracker.clone(),
-                bash_output_dir.clone(),
+                bash_output.clone(),
             )
         };
         worker.engine_mut().register_tools(workdir_tools);
@@ -1656,10 +1612,10 @@ where
     if ordinary_subjektiv_features_enabled
         && lifecycle_enabled
         && let Some(host) = subjektiv_host.as_ref()
-        && host.host.journal_startup_granted()
+        && (host.host.journal_startup_granted() || host.host.journal_compaction_granted())
     {
-        worker.install_initial_context_source(Arc::new(
-            crate::feature::builtin::journal::JournalStartupContextSource::new(
+        worker.install_session_context_source(Arc::new(
+            crate::feature::builtin::journal::JournalContextSource::new(
                 host.clone(),
                 worker.prompts(),
             ),
@@ -1910,6 +1866,20 @@ where
             )
         })?;
     }
+    if wip_mode {
+        crate::feature::builtin::bash::mount(
+            &mut wip_mount_registry,
+            worker.workdir_sessions(),
+            bash_output.clone(),
+            wip_permissions.clone(),
+        )
+        .map_err(|error| {
+            std::io::Error::new(
+                std::io::ErrorKind::InvalidInput,
+                format!("mount Bash output WIP projection: {error}"),
+            )
+        })?;
+    }
     if wip_mode && let Some(feature) = &workdir_wip_feature {
         crate::feature::builtin::manage_workdir::wip::mount_workspace_workdir_wip(
             &mut wip_mount_registry,
@@ -2040,7 +2010,6 @@ where
                 spawner_workspace_context,
                 parent_notifications,
                 runtime_base.clone(),
-                bash_output_dir.clone(),
                 spawner_workspace_root,
                 workdir_tool_broker,
                 spawned_registry.clone(),
@@ -3326,6 +3295,8 @@ async fn controller_loop<C, St>(
         }
     }
 
+    spawned_registry.bash_output().revoke();
+
     if let Some(observer) = command_observer.take() {
         observer.abort();
         let _ = observer.await;
@@ -4139,7 +4110,21 @@ mod tests {
                 request: crate::worker::WorkspaceRequest,
             ) -> Result<crate::worker::WorkspaceResponse, crate::worker::WorkspaceClientError>
             {
-                // Native discovery must not enumerate or perform any mutation.
+                if request.path == "/api/w/workspace-1/authorization/check" {
+                    assert_eq!(request.method, crate::worker::WorkspaceRequestMethod::Post);
+                    return Ok(crate::worker::WorkspaceResponse {
+                        status: 200,
+                        body: serde_json::json!({"scope":null}).to_string(),
+                    });
+                }
+                // Native discovery reads metadata and the current caller's ceiling, never inventory or mutations.
+                assert_eq!(request.method, crate::worker::WorkspaceRequestMethod::Get);
+                if request.path == "/api/w/workspace-1/drive/capabilities" {
+                    return Ok(crate::worker::WorkspaceResponse {
+                        status: 200,
+                        body: serde_json::json!({"write":true}).to_string(),
+                    });
+                }
                 assert_eq!(request.path, "/api/w/workspace-1/drive/root");
                 Ok(crate::worker::WorkspaceResponse { status: 200, body: serde_json::json!({
                     "entry": {"workspace_id": "workspace-1", "node_id": "1"},
@@ -4210,16 +4195,23 @@ mod tests {
                         worker.workdir_sessions(),
                     )
                     .descriptor();
-                    register_worker_tools(
+                    let registered = register_worker_tools(
                         &mut worker,
-                        root.path().join("bash-output"),
                         root.path().join("runtime"),
                         SpawnedWorkerRegistry::new_for_internal_services(),
                         None,
                         None,
                     )
-                    .await
-                    .unwrap();
+                    .await;
+                    if enabled && (!available || workspace.is_none()) {
+                        assert_eq!(
+                            registered.unwrap_err().kind(),
+                            std::io::ErrorKind::PermissionDenied
+                        );
+                        assert!(requests.lock().unwrap().is_empty());
+                        continue;
+                    }
+                    registered.unwrap();
                     let configured = enabled && available && workspace.is_some();
                     let tools = worker.engine().tool_server_handle();
                     tools.flush_pending();

crates/worker/src/controller_subject_release_tests.rs

@@ -64,7 +64,6 @@ async fn prepared(
         WorkerFilesystemAuthority::None,
         WorkerBootstrapLayout::Direct {
             runtime_base: temp.path().join("runtime"),
-            bash_output_dir: temp.path().join("bash"),
         },
         WorkerControllerTransport::InProcess,
     )

crates/worker/src/entrypoint.rs

@@ -635,12 +635,11 @@ async fn run_cli_inner(cli: Cli) -> ExitCode {
             return ExitCode::FAILURE;
         }
     };
-    let bash_output_dir = crate::bash_output_dir_for_worker_id(&worker_name);
+
     let started = match start_worker_controller(
         worker,
         WorkerBootstrapLayout::Direct {
             runtime_base: runtime_base.clone(),
-            bash_output_dir,
         },
         WorkerControllerTransport::UnixSocket,
     )

crates/worker/src/feature.rs

@@ -1534,8 +1534,18 @@ impl ProtocolProviderRegistrar<'_> {
     }
 }
 
+/// Restore preserves the saved Feature composition; only new activation asks
+/// for admission. Neither mode grants authority for protected operations.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub(crate) enum FeatureInstallation {
+    #[default]
+    Activate,
+    Restore,
+}
+
 /// Install-time context provided to a feature module.
 pub struct FeatureInstallContext<'a> {
+    installation: FeatureInstallation,
     feature_id: &'a FeatureId,
     declarations: &'a FeatureContributionDeclarations,
     pending_tools: &'a mut Vec<ToolDefinition>,
@@ -1548,6 +1558,10 @@ pub struct FeatureInstallContext<'a> {
 }
 
 impl FeatureInstallContext<'_> {
+    pub(crate) fn is_restoring(&self) -> bool {
+        self.installation == FeatureInstallation::Restore
+    }
+
     pub fn feature_id(&self) -> &FeatureId {
         self.feature_id
     }
@@ -1751,6 +1765,60 @@ pub enum FeaturePlanError {
 /// Builder/installer for enabled feature modules.
 pub struct FeatureRegistryBuilder {
     modules: Vec<Arc<dyn FeatureModule>>,
+    installation: FeatureInstallation,
+    activation_guard: Option<Arc<dyn Fn() -> Result<(), String> + Send + Sync>>,
+}
+
+/// Profile switches request activation, not authority. Names are the actual
+/// public config keys (not internal module ids such as `builtin:sub-worker-control`).
+/// Check even switches whose runtime prerequisites will later make them inert.
+/// No parent/child permission inheritance is performed here.
+pub(crate) fn authorize_requested_features(
+    client: &dyn crate::worker::WorkspaceClient,
+    config: &manifest::FeatureConfig,
+) -> Result<(), crate::worker::WorkspaceClientError> {
+    for (name, enabled) in [
+        ("task", config.task.enabled),
+        ("memory", config.memory.enabled()),
+        ("subjektiv", config.subjektiv.enabled()),
+        ("web", config.web.enabled),
+        ("image", config.image.enabled),
+        ("sub_worker", config.sub_worker.enabled),
+        ("flow", config.flow.enabled),
+        ("worker", config.worker.enabled),
+        (
+            "workspace_worker_discovery",
+            config.workspace_worker_discovery.enabled,
+        ),
+        ("objective", config.objective.enabled),
+        ("manage_workdir", config.manage_workdir.enabled),
+        ("workdir_catalog", config.workdir_catalog.enabled),
+        ("workspace_config", config.workspace_config.enabled),
+        ("drive", config.drive.enabled),
+        ("ticket", config.ticket.enabled),
+        ("merge_request", config.merge_request.any()),
+        ("orchestration", config.orchestration.enabled),
+    ] {
+        if enabled {
+            client.authorize_feature_activation(name).map_err(|error| {
+                crate::worker::WorkspaceClientError::Request(format!(
+                    "Feature `{name}` activation rejected: {error}"
+                ))
+            })?;
+        }
+    }
+    Ok(())
+}
+
+pub(crate) fn authorize_requested_manifest(
+    client: &dyn crate::worker::WorkspaceClient,
+    manifest: &manifest::WorkerManifest,
+) -> Result<(), crate::worker::WorkspaceClientError> {
+    authorize_requested_features(client, &manifest.feature)?;
+    if !manifest.mcp.stdio_servers.is_empty() {
+        client.authorize_feature_activation("mcp")?;
+    }
+    Ok(())
 }
 
 fn build_feature_install_plan(
@@ -1945,6 +2013,8 @@ impl Default for FeatureRegistryBuilder {
     fn default() -> Self {
         Self {
             modules: Vec::new(),
+            installation: FeatureInstallation::Activate,
+            activation_guard: None,
         }
     }
 }
@@ -1954,6 +2024,28 @@ impl FeatureRegistryBuilder {
         Self::default()
     }
 
+    pub(crate) fn with_installation(mut self, installation: FeatureInstallation) -> Self {
+        self.installation = installation;
+        self
+    }
+
+    /// Add a trusted, live preflight that runs before *any* new module activation.
+    /// Restoring saved composition does not repeat admission checks. Worker
+    /// hosts use this in addition to the earlier pre-construction preflight.
+    pub fn with_activation_guard(
+        mut self,
+        guard: impl Fn() -> Result<(), String> + Send + Sync + 'static,
+    ) -> Self {
+        let previous = self.activation_guard.take();
+        self.activation_guard = Some(Arc::new(move || {
+            if let Some(previous) = &previous {
+                previous()?;
+            }
+            guard()
+        }));
+        self
+    }
+
     pub fn add_module<M>(&mut self, module: M) -> &mut Self
     where
         M: FeatureModule + 'static,
@@ -2025,6 +2117,43 @@ impl FeatureRegistryBuilder {
         hook_builder: &mut HookRegistryBuilder,
         mut installed_tool_names: HashMap<String, FeatureId>,
     ) -> FeatureRegistryInstallReport {
+        if self.installation == FeatureInstallation::Activate
+            && let Some(error) = self
+                .activation_guard
+                .as_ref()
+                .and_then(|guard| guard().err())
+        {
+            return FeatureRegistryInstallReport {
+                reports: {
+                    let mut descriptors = self.descriptors();
+                    if descriptors.is_empty() {
+                        descriptors.push(FeatureDescriptor::builtin(
+                            "activation",
+                            "Feature activation",
+                        ));
+                    }
+                    descriptors
+                        .iter()
+                        .map(|descriptor| {
+                            let mut report = FeatureInstallReport::new(descriptor);
+                            report
+                                .diagnostics
+                                .push(FeatureDiagnostic::error(error.clone()));
+                            report.mark_skipped(
+                                FeatureContributionKind::Diagnostic,
+                                descriptor.id.to_string(),
+                                "Feature activation rejected before installation",
+                            );
+                            report
+                        })
+                        .collect()
+                },
+                services: FeatureServiceRegistry::default(),
+                background_tasks: FeatureBackgroundTaskRegistry::default(),
+                chat_invocations: FeatureInvocationRegistry::default(),
+                plan_error: None,
+            };
+        }
         let descriptors: Vec<_> = self
             .modules
             .iter()
@@ -2125,6 +2254,7 @@ impl FeatureRegistryBuilder {
 
             let install_result = {
                 let mut context = FeatureInstallContext {
+                    installation: self.installation,
                     feature_id: &descriptor.id,
                     declarations: &declarations,
                     pending_tools,
@@ -2300,6 +2430,170 @@ mod tests {
     use serde_json::json;
     use std::sync::atomic::{AtomicUsize, Ordering};
 
+    #[derive(Debug)]
+    struct ActivationClient {
+        allowed: Vec<String>,
+        requested: std::sync::Mutex<Vec<String>>,
+    }
+
+    impl crate::worker::WorkspaceClient for ActivationClient {
+        fn workspace_id(&self) -> Option<&str> {
+            Some("workspace")
+        }
+        fn kind(&self) -> &str {
+            "activation-fixture"
+        }
+        fn is_available(&self) -> bool {
+            true
+        }
+        fn execute(
+            &self,
+            request: crate::worker::WorkspaceRequest,
+        ) -> Result<crate::worker::WorkspaceResponse, crate::worker::WorkspaceClientError> {
+            use server_api::authorization::{OperationAuthorizationRequest, PermissionResource};
+            assert_eq!(request.path, "/api/w/workspace/authorization/check");
+            let input: OperationAuthorizationRequest =
+                serde_json::from_str(request.body.as_deref().unwrap()).unwrap();
+            assert_eq!(input.resource, PermissionResource::Feature);
+            self.requested.lock().unwrap().push(input.operation.clone());
+            Ok(crate::worker::WorkspaceResponse {
+                status: if self.allowed.contains(&input.operation) {
+                    200
+                } else {
+                    403
+                },
+                body: "{}".into(),
+            })
+        }
+    }
+
+    #[test]
+    fn requested_activation_uses_exact_public_config_names_before_install() {
+        let mut config = manifest::FeatureConfig::default();
+        config.workdir_catalog.enabled = false;
+        // Enabling each config key independently also detects default-on flags.
+        for name in [
+            "task",
+            "memory",
+            "subjektiv",
+            "web",
+            "image",
+            "sub_worker",
+            "flow",
+            "worker",
+            "workspace_worker_discovery",
+            "objective",
+            "manage_workdir",
+            "workdir_catalog",
+            "workspace_config",
+            "drive",
+            "ticket",
+            "merge_request",
+            "orchestration",
+        ] {
+            let mut value = serde_json::to_value(&config).unwrap();
+            if name == "memory" || name == "subjektiv" {
+                value[name]["profile"]["enabled"] = json!(true);
+            } else if name == "merge_request" {
+                value[name]["show"] = json!(true);
+            } else {
+                value[name]["enabled"] = json!(true);
+            }
+            let requested: manifest::FeatureConfig = serde_json::from_value(value).unwrap();
+            let client = ActivationClient {
+                allowed: vec![name.into()],
+                requested: Default::default(),
+            };
+            authorize_requested_features(&client, &requested).unwrap();
+            assert_eq!(*client.requested.lock().unwrap(), [name], "{name}");
+        }
+    }
+
+    #[test]
+    fn ticket_operation_permission_does_not_enable_feature_or_install_services() {
+        let mut config = manifest::FeatureConfig::default();
+        config.workdir_catalog.enabled = false;
+        config.ticket.enabled = true;
+        for allowed in [vec![], vec!["ticket.create"], vec!["ticket"]] {
+            let client = Arc::new(ActivationClient {
+                allowed: allowed.iter().map(|name| name.to_string()).collect(),
+                requested: Default::default(),
+            });
+            let module = PlannedServiceFeature::new(
+                FeatureDescriptor::builtin("ticket", "Ticket")
+                    .with_provided_service(provided_service("ticket.test", "1")),
+            );
+            let calls = module.install_calls.clone();
+            let config = config.clone();
+            let registry = FeatureRegistryBuilder::new()
+                .with_module(module)
+                .with_activation_guard(move || {
+                    authorize_requested_features(client.as_ref(), &config)
+                        .map_err(|error| error.to_string())
+                });
+            let mut tools = Vec::new();
+            let report = registry.install_into_pending(&mut tools, &mut HookRegistryBuilder::new());
+            let permitted = allowed == ["ticket"];
+            assert_eq!(report.has_errors(), !permitted);
+            assert_eq!(calls.load(Ordering::SeqCst), usize::from(permitted));
+            assert!(tools.is_empty());
+            if !permitted {
+                assert!(report.error_message().contains("ticket"));
+            }
+        }
+    }
+
+    #[test]
+    fn local_compatibility_is_explicit_and_never_grants_workspace_operations() {
+        use crate::worker::{WorkspaceClient, unavailable_workspace_client};
+        use server_api::authorization::PermissionResource;
+        let local = unavailable_workspace_client(None, "standalone");
+        assert!(local.authorize_feature_activation("task").is_ok());
+        assert!(
+            local
+                .authorize_operation(
+                    "ticket.create",
+                    &PermissionResource::Workspace {
+                        workspace_id: "workspace".into()
+                    }
+                )
+                .is_err()
+        );
+        let unbound = ActivationClient {
+            allowed: vec!["ticket".into()],
+            requested: Default::default(),
+        };
+        assert!(unbound.authorize_feature_activation("ticket").is_ok());
+        let local_files = crate::worker::WorkerWorkspaceContext::local_filesystem(None);
+        assert!(
+            local_files
+                .client_handle()
+                .authorize_feature_activation("task")
+                .is_ok()
+        );
+        assert!(
+            local_files
+                .client_handle()
+                .authorize_operation(
+                    "ticket.create",
+                    &PermissionResource::Workspace {
+                        workspace_id: "workspace".into()
+                    }
+                )
+                .is_err()
+        );
+        let marker = crate::worker::marker_workspace_client(None, "local-filesystem");
+        assert!(
+            marker.authorize_feature_activation("task").is_err(),
+            "display kind is not authority"
+        );
+        let missing = unavailable_workspace_client(
+            Some(&crate::worker::WorkspaceId::new("workspace").unwrap()),
+            "Host unavailable",
+        );
+        assert!(missing.authorize_feature_activation("ticket").is_err());
+    }
+
     #[test]
     fn worker_feature_composition_has_no_dynamic_plugin_install_path() {
         let feature_source = include_str!("feature.rs")

crates/worker/src/feature/builtin.rs

@@ -5,6 +5,17 @@
 //! an external plugin-loading surface.
 
 pub mod backend_job_result;
+pub(crate) mod bash;
+
+/// Host metadata participants are independent of model-facing Tool enablement.
+/// Disabling a Feature must not preserve stale Session-bound authority evidence.
+pub(crate) fn session_metadata_lifecycles()
+-> Vec<std::sync::Arc<dyn crate::metadata_lifecycle::SessionMetadataLifecycle>> {
+    vec![std::sync::Arc::new(
+        crate::subjektiv_metadata::SessionAttributionMetadata,
+    )]
+}
+
 pub mod chat_invocation;
 pub mod drive;
 pub mod flow_transition;

crates/worker/src/feature/builtin/bash.rs

@@ -0,0 +1,451 @@
+//! Bash Feature projection. The view is instance-owned and shared only by explicit parent
+//! routing. No output is indexable; committed result entries directly address immutable files.
+//! Root namespace knowledge grants nothing: every publication and read checks the current view.
+
+use crate::{
+    file_operation::{self, Contract},
+    permission::permission_action_for,
+    wip::{
+        WipCallContext, WipMountError, WipMountRegistry, WipOperationError, WipOperationHandler,
+        WipOperationOutput, WipProjection, WipProjectionKind, WipPublication, WipSubtreeMount,
+        WipSubtreeProvider, contextual_reference, json_to_wip, wip_to_json,
+    },
+};
+use agen::tool::{Tool, ToolError};
+use async_trait::async_trait;
+use manifest::{ToolPermissionAction, ToolPermissionConfig};
+use serde_json::{Value as Json, json};
+use sha2::{Digest, Sha256};
+use std::{collections::BTreeMap, sync::Arc};
+use tools::{BashTool, bash_output::BashOutputView};
+use wip_protocol::{
+    Documentation, FieldDeclaration, INTERFACE_FORMAT_V1, InterfaceDescriptor, Object,
+    OperationDeclaration, ParameterDeclaration, ProtocolError, ProtocolErrorCode,
+    ReturnDeclaration, TypeExpr, Value,
+};
+use workdir::{CommandStream, WorkdirSessionRouter};
+
+const ROOT: &str = "/bash-output";
+
+pub(crate) fn mount(
+    registry: &mut WipMountRegistry,
+    router: Arc<WorkdirSessionRouter>,
+    view: BashOutputView,
+    permissions: Option<ToolPermissionConfig>,
+) -> Result<(), WipMountError> {
+    registry.allocate_namespace("bash", "bash-output")?;
+    let provider = Arc::new(Provider {
+        service: BashTool::new(router, view.clone()),
+        view,
+        permissions,
+        incarnation: uuid::Uuid::now_v7().to_string(),
+    });
+    registry.mount(provider.root())?;
+    registry.replace_compatibility_tools(ROOT, ["Bash"])?;
+    registry.mount_subtree(WipSubtreeMount {
+        root: ROOT.into(),
+        provider: Arc::new(provider),
+    })
+}
+
+struct Provider {
+    service: BashTool,
+    view: BashOutputView,
+    permissions: Option<ToolPermissionConfig>,
+    incarnation: String,
+}
+impl Provider {
+    fn allowed(&self, tool: &str, args: &Json) -> bool {
+        self.view.is_active()
+            && self
+                .permissions
+                .as_ref()
+                .is_none_or(|p| permission_action_for(p, tool, args) == ToolPermissionAction::Allow)
+    }
+    fn may_allow(&self, tool: &str) -> bool {
+        if !self.view.is_active() {
+            return false;
+        }
+        let Some(p) = &self.permissions else {
+            return true;
+        };
+        for rule in p.rules.iter().filter(|r| r.tool.eq_ignore_ascii_case(tool)) {
+            if rule.action == ToolPermissionAction::Allow {
+                return true;
+            }
+            if rule.pattern == "*" {
+                return false;
+            }
+        }
+        p.default_action == ToolPermissionAction::Allow
+    }
+    fn root(self: &Arc<Self>) -> WipProjection {
+        let interface = contextual_reference("yoi.bash/command/v1", ROOT);
+        let descriptor = InterfaceDescriptor {
+            format: INTERFACE_FORMAT_V1.into(),
+            documentation: Some(Documentation {
+                summary: "Run Bash with bounded ephemeral output; retained bytes are accessed via result entries, not listed".into(),
+                details: None,
+            }),
+            types: vec![],
+            operations: vec![OperationDeclaration {
+                name: "run".into(),
+                documentation: None,
+                parameters: vec![ParameterDeclaration {
+                    name: "input".into(),
+                    required: true,
+                    documentation: Some(Documentation {
+                        summary: "Bash input, validated by the existing Tool argument contract".into(),
+                        details: Some(BashTool::input_schema().to_string()),
+                    }),
+                    r#type: TypeExpr::Json,
+                }],
+                returns: ReturnDeclaration {
+                    documentation: None,
+                    r#type: TypeExpr::Record {
+                        fields: vec![
+                            field("summary", TypeExpr::String),
+                            field("stdout_preview", TypeExpr::String),
+                            field("stderr_preview", TypeExpr::String),
+                            field("preview_omitted", TypeExpr::Boolean),
+                            field("metadata", TypeExpr::Json),
+                            field("stdout_entry", TypeExpr::Entry),
+                            field("stderr_entry", TypeExpr::Entry),
+                            field("order_entry", TypeExpr::Entry),
+                        ],
+                    },
+                },
+            }],
+        };
+        WipProjection {
+            route: ROOT.into(),
+            capability: "bash:command".into(),
+            kind: WipProjectionKind::Native,
+            object: Object {
+                name: "bash-output".into(),
+                description: Some("Bash command and nonindexable retained output".into()),
+                interfaces: vec![interface.clone()],
+                r#ref: Some(format!("bash:{}", self.incarnation)),
+                validator: Some(self.incarnation.as_bytes().to_vec()),
+            },
+            interface,
+            interface_validator: Some(Sha256::digest(format!("{descriptor:?}")).to_vec()),
+            descriptor,
+            handler: Arc::new(Run {
+                provider: self.clone(),
+            }),
+        }
+    }
+    fn parse(&self, path: &str) -> Option<(String, Option<CommandStream>)> {
+        let rest = path.strip_prefix("/bash-output/")?;
+        let (id, stream) = rest.split_once('/')?;
+        if uuid::Uuid::parse_str(id).ok()?.to_string() != id {
+            return None;
+        }
+        let stream = match stream {
+            "stdout" => Some(CommandStream::Stdout),
+            "stderr" => Some(CommandStream::Stderr),
+            "order" => None,
+            _ => return None,
+        };
+        Some((id.into(), stream))
+    }
+}
+
+#[async_trait]
+impl WipSubtreeProvider for Arc<Provider> {
+    async fn publication(&self, path: &str) -> Result<Option<WipPublication>, ProtocolError> {
+        if !self.view.is_active() {
+            return Ok(None);
+        }
+        if path == ROOT {
+            let projection = self.root();
+            return Ok(Some(WipPublication {
+                scope: Some(projection.object.clone()),
+                projection,
+            }));
+        }
+        let Some((id, stream)) = self.parse(path) else {
+            return Ok(None);
+        };
+        let Some(metadata) = self.view.metadata(&id) else {
+            return Ok(None);
+        };
+        if !self.may_allow("Read") && !self.may_allow("Grep") {
+            return Ok(None);
+        }
+        let mut contracts = vec![];
+        if self.may_allow("Read") {
+            contracts.extend([Contract::ReadLines, Contract::ReadBytes]);
+        }
+        if self.may_allow("Grep") {
+            contracts.push(Contract::SearchText);
+        }
+        let primary = contracts[0];
+        let interface = primary.reference();
+        let descriptor = primary.descriptor();
+        let validator = Sha256::digest(format!("{}:{id}:{stream:?}", self.incarnation)).to_vec();
+        let mut projection = WipProjection {
+            route: path.into(),
+            capability: "bash:output".into(),
+            kind: WipProjectionKind::Native,
+            object: Object {
+                name: path.rsplit('/').next().unwrap().into(),
+                description: Some(format!(
+                    "Read-only output component (stdout={} bytes, stderr={} bytes); text is UTF-8 lossy; storage_truncated={}",
+                    metadata.stdout_saved, metadata.stderr_saved, metadata.storage_truncated
+                )),
+                interfaces: vec![interface.clone()],
+                r#ref: Some(format!("bash:{}:{id}:{stream:?}", self.incarnation)),
+                validator: Some(validator.clone()),
+            },
+            interface,
+            descriptor: descriptor.clone(),
+            interface_validator: Some(primary.validator()),
+            handler: Arc::new(File {
+                provider: self.clone(),
+                id,
+                stream,
+                path: path.into(),
+                validator,
+            }),
+        };
+        file_operation::expose(&mut projection, contracts);
+        Ok(Some(WipPublication {
+            projection,
+            scope: None,
+        }))
+    }
+    async fn children(&self, _: &str) -> Result<Vec<String>, ProtocolError> {
+        Ok(vec![])
+    }
+}
+
+struct Run {
+    provider: Arc<Provider>,
+}
+#[async_trait]
+impl WipOperationHandler for Run {
+    fn is_visible(&self) -> bool {
+        self.provider.view.is_active()
+    }
+    fn operation_available(&self, op: &str) -> bool {
+        op == "run" && self.provider.may_allow("Bash")
+    }
+    async fn call(
+        &self,
+        op: &str,
+        args: &BTreeMap<String, Value>,
+        ctx: WipCallContext,
+    ) -> Result<WipOperationOutput, WipOperationError> {
+        if op != "run" {
+            return Err(fail(
+                ProtocolErrorCode::OperationNotFound,
+                "unknown Bash operation",
+            ));
+        }
+        let input = args
+            .get("input")
+            .ok_or_else(|| fail(ProtocolErrorCode::InvalidArguments, "input is required"))?;
+        let input =
+            wip_to_json(input).map_err(|e| fail(ProtocolErrorCode::InvalidArguments, &e))?;
+        if !self.provider.allowed("Bash", &input) {
+            return Err(fail(
+                ProtocolErrorCode::PermissionDenied,
+                "Bash not permitted",
+            ));
+        }
+        let result = self
+            .provider
+            .service
+            .execute_result(&input.to_string(), ctx.execution)
+            .await
+            .map_err(tool_error)?;
+        if result.cancelled {
+            return Err(WipOperationError::Cancelled(result.tool_output()));
+        }
+        if result.metadata.terminal.status == Some(workdir::CommandStatus::TimedOut) {
+            return Err(WipOperationError::Interrupted(result.tool_output()));
+        }
+        // Entry fields are typed by the native Descriptor. No display-string parsing is involved.
+        Ok(WipOperationOutput::native(Value::Record(BTreeMap::from([
+            ("summary".into(), Value::String(result.summary.clone())),
+            (
+                "stdout_preview".into(),
+                Value::String(result.stdout_preview.clone()),
+            ),
+            (
+                "stderr_preview".into(),
+                Value::String(result.stderr_preview.clone()),
+            ),
+            (
+                "preview_omitted".into(),
+                Value::Boolean(result.preview_omitted),
+            ),
+            ("stdout_entry".into(), Value::String(result.stdout_entry())),
+            ("stderr_entry".into(), Value::String(result.stderr_entry())),
+            ("order_entry".into(), Value::String(result.order_entry())),
+            (
+                "metadata".into(),
+                json_to_wip(&serde_json::to_value(result.metadata).unwrap())
+                    .map_err(|e| fail(ProtocolErrorCode::Internal, &e))?,
+            ),
+        ]))))
+    }
+    async fn cancel(&self, ctx: &agen::tool::ToolExecutionContext) -> Result<(), ToolError> {
+        self.provider.service.cancel_execution(ctx).await
+    }
+}
+
+struct File {
+    provider: Arc<Provider>,
+    id: String,
+    stream: Option<CommandStream>,
+    path: String,
+    validator: Vec<u8>,
+}
+impl File {
+    fn order_text(&self) -> Result<String, WipOperationError> {
+        use std::fmt::Write;
+        let ranges = self
+            .provider
+            .view
+            .order(&self.id)
+            .ok_or_else(|| fail(ProtocolErrorCode::NotFound, "output expired or revoked"))?;
+        let mut text = String::new();
+        for r in ranges {
+            writeln!(&mut text, "{:?} {} {}", r.stream, r.start, r.end).unwrap();
+        }
+        Ok(text)
+    }
+}
+#[async_trait]
+impl WipOperationHandler for File {
+    fn is_visible(&self) -> bool {
+        self.provider.view.metadata(&self.id).is_some()
+    }
+    fn object_validator(&self) -> Option<Vec<u8>> {
+        self.is_visible().then(|| self.validator.clone())
+    }
+    fn operation_available(&self, op: &str) -> bool {
+        match op {
+            "read_lines" | "read_bytes" | "read" => self.provider.may_allow("Read"),
+            "search_text" | "search" => self.provider.may_allow("Grep"),
+            _ => false,
+        }
+    }
+    async fn call(
+        &self,
+        op: &str,
+        args: &BTreeMap<String, Value>,
+        _: WipCallContext,
+    ) -> Result<WipOperationOutput, WipOperationError> {
+        if !self.operation_available(op) {
+            return Err(fail(
+                ProtocolErrorCode::PermissionDenied,
+                "output operation not permitted",
+            ));
+        }
+        let mut input = wip_to_json(&Value::Record(args.clone()))
+            .map_err(|e| fail(ProtocolErrorCode::InvalidArguments, &e))?;
+        let tool = if op == "search_text" {
+            input["path"] = json!(self.path);
+            "Grep"
+        } else {
+            input["file_path"] = json!(self.path);
+            "Read"
+        };
+        if !self.provider.allowed(tool, &input) {
+            return Err(fail(
+                ProtocolErrorCode::PermissionDenied,
+                "output operation not permitted",
+            ));
+        }
+        let metadata = self
+            .provider
+            .view
+            .metadata(&self.id)
+            .ok_or_else(|| fail(ProtocolErrorCode::NotFound, "output expired or revoked"))?;
+        if op == "read_bytes" {
+            let (offset, limit) = file_operation::byte_range(args)?;
+            let (bytes, total) = if let Some(stream) = self.stream {
+                let total = if stream == CommandStream::Stdout {
+                    metadata.stdout_saved
+                } else {
+                    metadata.stderr_saved
+                };
+                if offset > total as u64 {
+                    return Err(fail(
+                        ProtocolErrorCode::InvalidArguments,
+                        "byte offset exceeds output length",
+                    ));
+                }
+                let bytes = self
+                    .provider
+                    .view
+                    .read(&self.id, stream, offset as usize, limit)
+                    .ok_or_else(|| {
+                        fail(ProtocolErrorCode::NotFound, "output expired or revoked")
+                    })?;
+                (bytes, total)
+            } else {
+                let text = self.order_text()?;
+                if offset > text.len() as u64 {
+                    return Err(fail(
+                        ProtocolErrorCode::InvalidArguments,
+                        "byte offset exceeds output length",
+                    ));
+                }
+                (
+                    text.as_bytes()[offset as usize..(offset as usize + limit).min(text.len())]
+                        .to_vec(),
+                    text.len(),
+                )
+            };
+            let eof = offset + bytes.len() as u64 == total as u64;
+            return Ok(WipOperationOutput::native_with_validator(
+                file_operation::bytes_result(args, &bytes, eof)?,
+                self.validator.clone(),
+            ));
+        }
+        let (offset, limit) = file_operation::window(args, op == "search_text")?;
+        let value = if let Some(stream) = self.stream {
+            let (text, more) = self
+                .provider
+                .view
+                .line_window(&self.id, stream, offset, limit)
+                .ok_or_else(|| fail(ProtocolErrorCode::NotFound, "output expired or revoked"))?
+                .map_err(|e| fail(ProtocolErrorCode::ResourceLimitExceeded, &e))?;
+            file_operation::page_result(op, args, &text, offset, more)?
+        } else {
+            file_operation::text_result(op, args, &self.order_text()?)?
+        };
+        Ok(WipOperationOutput::native_with_validator(
+            value,
+            self.validator.clone(),
+        ))
+    }
+}
+
+fn fail(code: ProtocolErrorCode, message: &str) -> WipOperationError {
+    WipOperationError::Protocol(ProtocolError {
+        code,
+        message: message.into(),
+    })
+}
+fn tool_error(error: ToolError) -> WipOperationError {
+    match error {
+        ToolError::InvalidArgument(_) => fail(ProtocolErrorCode::InvalidArguments, "invalid Bash arguments"),
+        ToolError::Cancelled(output) => WipOperationError::Cancelled(output),
+        ToolError::Interrupted(output) => WipOperationError::Interrupted(output),
+        _ => WipOperationError::OutcomeUnknown("Bash execution failed; effects or process termination may be unconfirmed; do not automatically restart the command".into()),
+    }
+}
+fn field(name: &str, r#type: TypeExpr) -> FieldDeclaration {
+    FieldDeclaration {
+        name: name.into(),
+        required: true,
+        documentation: None,
+        r#type,
+    }
+}

crates/worker/src/feature/builtin/drive/backend.rs

@@ -138,6 +138,9 @@ impl DriveBackend {
         )
         .await
     }
+    pub async fn capabilities(&self) -> Result<DriveCapabilities, DriveError> {
+        self.get("/capabilities", &serde_json::json!({})).await
+    }
     pub async fn root(&self) -> Result<DriveEntry, DriveError> {
         let entry: DriveEntry = self
             .json(

crates/worker/src/feature/builtin/drive/delegation.rs

@@ -102,6 +102,26 @@ impl WorkspaceClient for InternalChildWorkspaceClient {
         self.inner.is_available()
     }
 
+    fn authorize_operation(
+        &self,
+        operation: &str,
+        resource: &server_api::authorization::PermissionResource,
+    ) -> Result<(), WorkspaceClientError> {
+        self.inner.authorize_operation(operation, resource)
+    }
+
+    fn authorize_operation_scope(
+        &self,
+        operation: &str,
+        resource: &server_api::authorization::PermissionResource,
+    ) -> Result<Option<server_api::authorization::PermissionResource>, WorkspaceClientError> {
+        self.inner.authorize_operation_scope(operation, resource)
+    }
+
+    fn authorize_feature_activation(&self, feature: &str) -> Result<(), WorkspaceClientError> {
+        self.inner.authorize_feature_activation(feature)
+    }
+
     fn execute(
         &self,
         request: WorkspaceRequest,

crates/worker/src/feature/builtin/drive/tests.rs

@@ -7,12 +7,14 @@ use std::collections::VecDeque;
 struct Client {
     responses: Mutex<VecDeque<Result<WorkspaceResponse, WorkspaceClientError>>>,
     requests: Mutex<Vec<WorkspaceRequest>>,
+    capabilities: Mutex<WorkspaceResponse>,
 }
 impl Client {
     fn new(responses: Vec<WorkspaceResponse>) -> Arc<Self> {
         Arc::new(Self {
             responses: Mutex::new(responses.into_iter().map(Ok).collect()),
             requests: Mutex::new(Vec::new()),
+            capabilities: Mutex::new(response(DriveCapabilities { write: false })),
         })
     }
 }
@@ -30,7 +32,15 @@ impl WorkspaceClient for Client {
         &self,
         request: WorkspaceRequest,
     ) -> Result<WorkspaceResponse, WorkspaceClientError> {
+        let capabilities = request.path == "/api/w/workspace/drive/capabilities";
         self.requests.lock().unwrap().push(request);
+        if capabilities {
+            let response = self.capabilities.lock().unwrap();
+            return Ok(WorkspaceResponse {
+                status: response.status,
+                body: response.body.clone(),
+            });
+        }
         self.responses
             .lock()
             .unwrap()
@@ -479,7 +489,7 @@ async fn drive_native_entry_is_directly_resolvable_but_never_indexable_and_binds
     let feature = feature(client.clone());
     let mut mounts = crate::wip::WipMountRegistry::new();
     wip::mount_drive_wip(&mut mounts, &feature).unwrap();
-    let provider = wip::DriveProvider(feature);
+    let provider = wip::DriveProvider::new(feature);
     let path = entry_path(&entry.entry);
     let publication = provider.publication(&path).await.unwrap().unwrap();
     assert_eq!(publication.projection.route, path);
@@ -487,7 +497,8 @@ async fn drive_native_entry_is_directly_resolvable_but_never_indexable_and_binds
         publication.scope.as_ref().unwrap().r#ref,
         publication.projection.object.r#ref
     );
-    assert_eq!(publication.projection.object.validator, Some(b"3".to_vec()));
+    assert!(publication.projection.object.validator.is_some());
+    assert_ne!(publication.projection.object.validator, Some(b"3".to_vec()));
     assert!(provider.children("/drive").await.unwrap().is_empty());
     assert!(
         provider
@@ -504,7 +515,7 @@ async fn drive_native_entry_is_directly_resolvable_but_never_indexable_and_binds
             .flat_map(|op| &op.parameters)
             .any(|parameter| parameter.name == "expected_mutation_id")
     );
-    assert_eq!(client.requests.lock().unwrap().len(), 1);
+    assert_eq!(client.requests.lock().unwrap().len(), 2);
 }
 
 #[derive(Debug)]
@@ -656,3 +667,662 @@ async fn oversized_images_and_unknown_arguments_fail_before_binary_transfer() {
     );
     assert_eq!(client.json.requests.lock().unwrap().len(), 1);
 }
+
+fn native_context() -> crate::wip::WipCallContext {
+    crate::wip::WipCallContext {
+        execution: ToolExecutionContext::direct(),
+        security_context: "drive-test".into(),
+    }
+}
+fn native_args(value: Value) -> std::collections::BTreeMap<String, wip_protocol::Value> {
+    let wip_protocol::Value::Record(args) = crate::wip::json_to_wip(&value).unwrap() else {
+        panic!("named arguments required")
+    };
+    args
+}
+
+#[tokio::test]
+async fn drive_common_text_reads_use_bounded_complete_source_and_literal_window_search() {
+    use crate::file_operation::Contract;
+    use crate::wip::WipSubtreeProvider;
+    let text = "α\r\nneedle.*\nNeedle.*\nlast\n";
+    let mut entry = entry("2", "3");
+    entry.size = Some(text.len() as u32);
+    let read = DriveReadTextResponse {
+        entry: entry.clone(),
+        text: text.into(),
+        truncated: false,
+    };
+    let client = Client::new(vec![
+        response(entry.clone()),
+        response(&read),
+        response(&read),
+    ]);
+    let feature = feature(client.clone());
+    let publication = wip::DriveProvider::new(feature)
+        .publication(&entry_path(&entry.entry))
+        .await
+        .unwrap()
+        .unwrap();
+    let mut projection = publication.projection;
+    assert!(
+        projection
+            .object
+            .interfaces
+            .contains(&Contract::ReadLines.reference())
+    );
+    assert!(
+        projection
+            .object
+            .interfaces
+            .contains(&Contract::SearchText.reference())
+    );
+    assert!(
+        !projection
+            .object
+            .interfaces
+            .contains(&Contract::Write.reference())
+    );
+    assert!(
+        !projection
+            .object
+            .interfaces
+            .contains(&Contract::Edit.reference())
+    );
+    assert!(
+        projection
+            .descriptor
+            .operations
+            .iter()
+            .any(|op| op.name == "read" && op.parameters.iter().any(|p| p.name == "max_bytes"))
+    );
+    let original_handler = projection.handler.clone();
+    assert!(crate::file_operation::select(
+        &mut projection,
+        &Contract::ReadLines.reference()
+    ));
+    let read = projection
+        .handler
+        .call(
+            "read",
+            &native_args(json!({"offset":1,"limit":2})),
+            native_context(),
+        )
+        .await
+        .unwrap_or_else(|_| panic!("common read failed"));
+    let value = crate::wip::wip_to_json(&read.value).unwrap();
+    assert_eq!(value["next_offset"], 3);
+    assert_eq!(value["truncated"], true);
+    assert!(value["content"].as_str().unwrap().contains("needle.*"));
+    // The common selector wraps a provider handler once; reuse the original
+    // publication for the independent SearchText contract.
+    projection.handler = original_handler;
+    let request = client.requests.lock().unwrap().last().unwrap().clone();
+    assert!(request.path.contains("max_bytes=65536"));
+    assert!(crate::file_operation::select(
+        &mut projection,
+        &Contract::SearchText.reference()
+    ));
+    let search = projection
+        .handler
+        .call(
+            "search",
+            &native_args(json!({"pattern":"needle.*","limit":3})),
+            native_context(),
+        )
+        .await
+        .unwrap_or_else(|_| panic!("common search failed"));
+    let value = crate::wip::wip_to_json(&search.value).unwrap();
+    assert_eq!(value["matches"], json!([{"line":2,"text":"needle.*"}]));
+    assert_eq!(value["next_offset"], 3);
+    assert_eq!(value["truncated"], true);
+}
+
+fn read_response(entry: &DriveEntry, text: &str) -> DriveReadTextResponse {
+    DriveReadTextResponse {
+        entry: entry.clone(),
+        text: text.into(),
+        truncated: false,
+    }
+}
+
+#[tokio::test]
+async fn drive_common_text_refuses_truncated_mismatched_stale_and_denied_reads() {
+    use crate::wip::WipSubtreeProvider;
+    use wip_protocol::ProtocolErrorCode;
+    for (case, expected) in [
+        ("truncated", ProtocolErrorCode::ResourceLimitExceeded),
+        ("size", ProtocolErrorCode::ResourceLimitExceeded),
+        ("stale", ProtocolErrorCode::ValidatorMismatch),
+        ("denied", ProtocolErrorCode::PermissionDenied),
+    ] {
+        let entry = entry("2", "3");
+        let mut read = read_response(&entry, "hello");
+        match case {
+            "truncated" => read.truncated = true,
+            "size" => read.text = "hell".into(),
+            "stale" => read.entry.last_mutation_id = "4".into(),
+            _ => {}
+        }
+        let read = if case == "denied" {
+            WorkspaceResponse {
+                status: 403,
+                body: "denied".into(),
+            }
+        } else {
+            response(read)
+        };
+        let client = Client::new(vec![response(entry.clone()), read]);
+        let projection = wip::DriveProvider::new(feature(client.clone()))
+            .publication(&entry_path(&entry.entry))
+            .await
+            .unwrap()
+            .unwrap()
+            .projection;
+        let result = projection
+            .handler
+            .call("read_lines", &native_args(json!({})), native_context())
+            .await;
+        assert!(
+            matches!(result, Err(crate::wip::WipOperationError::Protocol(ref error)) if error.code == expected),
+            "{case}"
+        );
+        let requests = client.requests.lock().unwrap();
+        assert_eq!(requests.len(), 3, "{case}: no retries");
+        assert!(
+            requests
+                .iter()
+                .all(|request| request.method == crate::worker::WorkspaceRequestMethod::Get)
+        );
+    }
+}
+
+#[tokio::test]
+async fn drive_common_text_rejects_oversized_source_before_read_and_remount_changes_object_validator()
+ {
+    use crate::wip::WipSubtreeProvider;
+    let mut entry = entry("2", "3");
+    entry.size = Some(server_api::DRIVE_CHUNK_MAX_BYTES + 1);
+    let client = Client::new(vec![response(entry.clone()), response(entry.clone())]);
+    let first = feature(client.clone());
+    let second = first.clone();
+    let path = entry_path(&entry.entry);
+    let first = wip::DriveProvider::new(first)
+        .publication(&path)
+        .await
+        .unwrap()
+        .unwrap()
+        .projection;
+    let second = wip::DriveProvider::new(second)
+        .publication(&path)
+        .await
+        .unwrap()
+        .unwrap()
+        .projection;
+    assert_ne!(first.object.validator, second.object.validator);
+    assert_eq!(first.object.interfaces, second.object.interfaces);
+    let result = first
+        .handler
+        .call("read_lines", &native_args(json!({})), native_context())
+        .await;
+    assert!(
+        matches!(result, Err(crate::wip::WipOperationError::Protocol(error)) if error.code == wip_protocol::ProtocolErrorCode::ResourceLimitExceeded)
+    );
+    assert_eq!(client.requests.lock().unwrap().len(), 4);
+}
+
+#[tokio::test]
+async fn drive_common_text_reads_keep_tool_permission_denial_before_backend_read() {
+    use crate::wip::WipSubtreeProvider;
+    let entry = entry("2", "3");
+    let client = Client::new(vec![response(entry.clone())]);
+    let feature = feature(client.clone()).with_permissions(Some(manifest::ToolPermissionConfig {
+        default_action: manifest::ToolPermissionAction::Deny,
+        rules: Vec::new(),
+    }));
+    let projection = wip::DriveProvider::new(feature)
+        .publication(&entry_path(&entry.entry))
+        .await
+        .unwrap()
+        .unwrap()
+        .projection;
+    let result = projection
+        .handler
+        .call("read_lines", &native_args(json!({})), native_context())
+        .await;
+    assert!(
+        matches!(result, Err(crate::wip::WipOperationError::Protocol(error)) if error.code == wip_protocol::ProtocolErrorCode::PermissionDenied)
+    );
+    assert_eq!(client.requests.lock().unwrap().len(), 2);
+}
+
+#[tokio::test]
+async fn drive_read_only_capability_omits_file_and_folder_mutation_contracts() {
+    use crate::file_operation::Contract;
+    use crate::wip::WipSubtreeProvider;
+    for (kind, root) in [
+        (DriveEntryKind::File, false),
+        (DriveEntryKind::Folder, false),
+        (DriveEntryKind::Folder, true),
+    ] {
+        let mut entry = entry("2", "3");
+        entry.kind = kind;
+        if root {
+            entry.parent = None;
+        }
+        let path = if root {
+            "/drive".into()
+        } else {
+            entry_path(&entry.entry)
+        };
+        let client = Client::new(vec![response(entry.clone())]);
+        let projection = wip::DriveProvider::new(feature(client.clone()))
+            .publication(&path)
+            .await
+            .unwrap()
+            .unwrap()
+            .projection;
+        assert!(
+            !projection
+                .object
+                .interfaces
+                .contains(&Contract::Edit.reference())
+        );
+        assert!(
+            !projection
+                .object
+                .interfaces
+                .contains(&Contract::Write.reference())
+        );
+        assert!(!projection.descriptor.operations.iter().any(|op| matches!(
+            op.name.as_str(),
+            "write"
+                | "edit"
+                | "delete"
+                | "relocate"
+                | "create_folder"
+                | "create_text"
+                | "save_workdir"
+        )));
+        let result = projection
+            .handler
+            .call(
+                "write",
+                &native_args(json!({"content":"denied"})),
+                native_context(),
+            )
+            .await;
+        assert!(
+            matches!(result, Err(crate::wip::WipOperationError::Protocol(error)) if error.code == wip_protocol::ProtocolErrorCode::OperationNotFound)
+        );
+        let requests = client.requests.lock().unwrap();
+        assert_eq!(requests.len(), 2);
+        assert_eq!(requests[1].path, "/api/w/workspace/drive/capabilities");
+        assert_eq!(
+            requests[1].method,
+            crate::worker::WorkspaceRequestMethod::Get
+        );
+        assert!(requests[1].body.is_none());
+    }
+}
+
+#[tokio::test]
+async fn drive_capability_failure_never_publishes_an_assumed_write_ceiling() {
+    use crate::wip::WipSubtreeProvider;
+    for (status, body) in [
+        (403, "denied"),
+        (500, "unavailable"),
+        (200, "{}"),
+        (200, "{\"write\":true,\"grant_id\":\"spoof\"}"),
+    ] {
+        let entry = entry("2", "3");
+        let client = Client::new(vec![response(entry.clone())]);
+        *client.capabilities.lock().unwrap() = WorkspaceResponse {
+            status,
+            body: body.into(),
+        };
+        let result = wip::DriveProvider::new(feature(client.clone()))
+            .publication(&entry_path(&entry.entry))
+            .await;
+        assert!(!matches!(result, Ok(Some(_))), "{status}: {body}");
+        assert_eq!(client.requests.lock().unwrap().len(), 2);
+    }
+}
+
+#[tokio::test]
+async fn drive_common_mutation_publication_intersects_tool_permission_ceiling() {
+    use crate::file_operation::Contract;
+    use crate::wip::WipSubtreeProvider;
+    let entry = entry("2", "3");
+    let client = Client::new(vec![response(entry.clone())]);
+    *client.capabilities.lock().unwrap() = response(DriveCapabilities { write: true });
+    let feature = feature(client).with_permissions(Some(manifest::ToolPermissionConfig {
+        default_action: manifest::ToolPermissionAction::Allow,
+        rules: vec![manifest::ToolPermissionRule {
+            tool: "DriveWrite".into(),
+            pattern: "*".into(),
+            action: manifest::ToolPermissionAction::Deny,
+        }],
+    }));
+    let projection = wip::DriveProvider::new(feature)
+        .publication(&entry_path(&entry.entry))
+        .await
+        .unwrap()
+        .unwrap()
+        .projection;
+    assert!(
+        !projection
+            .object
+            .interfaces
+            .contains(&Contract::Write.reference())
+    );
+    assert!(
+        projection
+            .object
+            .interfaces
+            .contains(&Contract::Edit.reference())
+    );
+    assert!(
+        !projection
+            .descriptor
+            .operations
+            .iter()
+            .any(|op| matches!(op.name.as_str(), "write" | "edit"))
+    );
+}
+
+/// Narrow transport fixture for native mutation chaining. The real provider,
+/// Client/Host, permission checks and Backend CAS adapter remain in the path;
+/// only canonical Drive persistence is replaced by an entry and text value.
+#[derive(Debug)]
+struct NativeMutations(Mutex<(DriveEntry, String, Vec<DriveMutationRequest>)>);
+impl WorkspaceClient for NativeMutations {
+    fn workspace_id(&self) -> Option<&str> {
+        Some("workspace")
+    }
+    fn kind(&self) -> &str {
+        "drive-native-mutations"
+    }
+    fn is_available(&self) -> bool {
+        true
+    }
+    fn execute(
+        &self,
+        request: WorkspaceRequest,
+    ) -> Result<WorkspaceResponse, WorkspaceClientError> {
+        let mut state = self.0.lock().unwrap();
+        let suffix = request
+            .path
+            .strip_prefix("/api/w/workspace/drive/")
+            .unwrap();
+        Ok(if suffix == "capabilities" {
+            response(DriveCapabilities { write: true })
+        } else if suffix.starts_with("metadata?") {
+            response(&state.0)
+        } else if suffix.starts_with("read-text?") {
+            response(read_response(&state.0, &state.1))
+        } else if suffix == "mutate" {
+            let request: DriveMutationRequest =
+                serde_json::from_str(request.body.as_deref().unwrap()).unwrap();
+            let DriveMutation::UpdateText {
+                id,
+                expected_mutation_id,
+                text,
+                ..
+            } = &request.mutation
+            else {
+                panic!("unexpected mutation")
+            };
+            assert_eq!(id, &state.0.entry);
+            assert_eq!(expected_mutation_id, &state.0.last_mutation_id);
+            state.1 = text.clone();
+            state.0.size = Some(text.len() as u32);
+            state.0.last_mutation_id = request.request_id.clone();
+            let output = response(DriveMutationResponse {
+                request_id: request.request_id.clone(),
+                entry: Some(state.0.clone()),
+            });
+            state.2.push(request);
+            output
+        } else {
+            panic!("unexpected request: {}", request.path)
+        })
+    }
+}
+
+#[tokio::test]
+async fn drive_common_edit_then_write_reuses_exact_post_operation_object_validator() {
+    use crate::file_operation::Contract;
+    use crate::wip::{WipMountRegistry, WipRuntime};
+    let entry = entry("2", "3");
+    let path = entry_path(&entry.entry);
+    let client = Arc::new(NativeMutations(Mutex::new((
+        entry,
+        "hello".into(),
+        Vec::new(),
+    ))));
+    let feature = DriveFeature::new(client.clone(), Arc::new(WorkdirSessionRouter::new()));
+    let mut mounts = WipMountRegistry::new();
+    wip::mount_drive_wip(&mut mounts, &feature).unwrap();
+    let runtime = WipRuntime::from_mounts(mounts, "drive-test".into()).unwrap();
+    runtime
+        .prepare_call_observations(path.clone(), true)
+        .await
+        .unwrap();
+    let edit = runtime
+        .call(
+            path.clone(),
+            Contract::Edit.reference(),
+            "edit".into(),
+            json!({"old_string":"hello","new_string":"updated"}),
+            ToolExecutionContext::direct(),
+        )
+        .await
+        .unwrap();
+    let edit: Value = serde_json::from_str(edit.content.as_deref().unwrap()).unwrap();
+    assert!(edit["metadata"]["entry"]["metadata"]["last_mutation_id"].is_string());
+    assert_eq!(client.0.lock().unwrap().1, "updated");
+    // No intervening Inspect/prepare_call_observations: success depends on the
+    // exact nonce-bound post-commit validator returned by the first operation.
+    let write = runtime
+        .call(
+            path,
+            Contract::Write.reference(),
+            "write".into(),
+            json!({"content":"final"}),
+            ToolExecutionContext::direct(),
+        )
+        .await
+        .unwrap();
+    let write: Value = serde_json::from_str(write.content.as_deref().unwrap()).unwrap();
+    assert!(write["metadata"]["entry"]["metadata"]["last_mutation_id"].is_string());
+    let state = client.0.lock().unwrap();
+    assert_eq!(state.1, "final");
+    assert_eq!(state.2.len(), 2);
+}
+
+#[tokio::test]
+async fn drive_argument_dependent_write_policy_is_rechecked_and_ask_is_not_published() {
+    use crate::file_operation::Contract;
+    use crate::wip::WipSubtreeProvider;
+    for (default_action, pattern, action, published, code) in [
+        (
+            manifest::ToolPermissionAction::Deny,
+            "*permitted*",
+            manifest::ToolPermissionAction::Allow,
+            true,
+            wip_protocol::ProtocolErrorCode::PermissionDenied,
+        ),
+        (
+            manifest::ToolPermissionAction::Allow,
+            "*",
+            manifest::ToolPermissionAction::Ask,
+            false,
+            wip_protocol::ProtocolErrorCode::OperationNotFound,
+        ),
+    ] {
+        let entry = entry("2", "3");
+        let client = Client::new(vec![response(entry.clone())]);
+        *client.capabilities.lock().unwrap() = response(DriveCapabilities { write: true });
+        let feature =
+            feature(client.clone()).with_permissions(Some(manifest::ToolPermissionConfig {
+                default_action,
+                rules: vec![manifest::ToolPermissionRule {
+                    tool: "DriveWrite".into(),
+                    pattern: pattern.into(),
+                    action,
+                }],
+            }));
+        let projection = wip::DriveProvider::new(feature)
+            .publication(&entry_path(&entry.entry))
+            .await
+            .unwrap()
+            .unwrap()
+            .projection;
+        assert_eq!(
+            projection
+                .object
+                .interfaces
+                .contains(&Contract::Write.reference()),
+            published
+        );
+        let result = projection
+            .handler
+            .call(
+                "write",
+                &native_args(json!({"content":"denied"})),
+                native_context(),
+            )
+            .await;
+        assert!(
+            matches!(result, Err(crate::wip::WipOperationError::Protocol(error)) if error.code == code)
+        );
+        assert_eq!(client.requests.lock().unwrap().len(), 2);
+    }
+}
+
+// A single retained Object observation models a restored Client cache. All later
+// publication and execution use the real new-mount provider; the new Host supplies
+// the common contract's root scope independently, without replaying its old ref.
+struct RetainedObjectOnce {
+    current: wip::DriveProvider,
+    retained: Mutex<Option<wip_protocol::Object>>,
+}
+#[async_trait]
+impl crate::wip::WipSubtreeProvider for RetainedObjectOnce {
+    async fn publication(
+        &self,
+        path: &str,
+    ) -> Result<Option<crate::wip::WipPublication>, wip_protocol::ProtocolError> {
+        let Some(mut publication) = self.current.publication(path).await? else {
+            return Ok(None);
+        };
+        if let Some(retained) = self.retained.lock().unwrap().take() {
+            publication.projection.object = retained;
+            publication = crate::wip::WipPublication::self_scoped(publication.projection)?;
+        }
+        Ok(Some(publication))
+    }
+    async fn children(&self, _: &str) -> Result<Vec<String>, wip_protocol::ProtocolError> {
+        Ok(Vec::new())
+    }
+}
+
+#[tokio::test]
+async fn drive_same_feature_remount_rejects_retained_object_with_fresh_common_scope_then_reobservation_succeeds()
+ {
+    use crate::file_operation::Contract;
+    use crate::wip::{WipMountRegistry, WipRuntime, WipSubtreeMount, WipSubtreeProvider};
+    let entry = entry("2", "3");
+    let path = entry_path(&entry.entry);
+    let client = Arc::new(NativeMutations(Mutex::new((
+        entry,
+        "hello".into(),
+        Vec::new(),
+    ))));
+    let feature = DriveFeature::new(client.clone(), Arc::new(WorkdirSessionRouter::new()));
+    // mount_drive_wip constructs exactly one of these providers per mount. Reuse
+    // the same Feature, whose mutation request identity deliberately does not rotate.
+    let first = wip::DriveProvider::new(feature.clone());
+    let old = first.publication(&path).await.unwrap().unwrap().projection;
+    let cloned = first
+        .clone()
+        .publication(&path)
+        .await
+        .unwrap()
+        .unwrap()
+        .projection;
+    assert_eq!(old.object.validator, cloned.object.validator);
+    let second = wip::DriveProvider::new(feature.clone());
+    let current = second.publication(&path).await.unwrap().unwrap().projection;
+    assert_ne!(old.object.validator, current.object.validator);
+    let mut old_contract = old.clone();
+    let mut current_contract = current.clone();
+    assert!(crate::file_operation::select(
+        &mut old_contract,
+        &Contract::ReadLines.reference()
+    ));
+    assert!(crate::file_operation::select(
+        &mut current_contract,
+        &Contract::ReadLines.reference()
+    ));
+    assert_eq!(old_contract.interface, current_contract.interface);
+    assert_eq!(old_contract.descriptor, current_contract.descriptor);
+    assert_eq!(
+        old_contract.interface_validator,
+        current_contract.interface_validator
+    );
+
+    // Mount only the selected entry for this cache-restoration fixture. The real
+    // Host still selects the root common contract and validates target membership,
+    // scope_ref and Object/Interface validators before running the Drive handler.
+    let mut mounts = WipMountRegistry::new();
+    mounts.allocate_namespace("drive", "drive").unwrap();
+    mounts.mount(current).unwrap();
+    mounts
+        .mount_subtree(WipSubtreeMount {
+            root: path.clone(),
+            provider: Arc::new(RetainedObjectOnce {
+                current: second,
+                retained: Mutex::new(Some(old.object)),
+            }),
+        })
+        .unwrap();
+    let runtime = WipRuntime::from_mounts(mounts, "drive-remount".into()).unwrap();
+    runtime.inspect(path.clone(), true).await.unwrap();
+    let interface_path = format!(
+        "{}::{}",
+        serde_json::to_string("/").unwrap(),
+        serde_json::to_string(&Contract::ReadLines.reference().name).unwrap()
+    );
+    // This fetch obtains the *new* Host's root scope_ref and the unchanged common
+    // Interface validator; only the retained target observation remains stale.
+    runtime.inspect(interface_path, true).await.unwrap();
+    let error = runtime
+        .call(
+            path.clone(),
+            Contract::ReadLines.reference(),
+            "read".into(),
+            json!({}),
+            ToolExecutionContext::direct(),
+        )
+        .await
+        .unwrap_err()
+        .to_string();
+    assert!(error.contains("ValidatorMismatch"), "{error}");
+    assert!(!error.contains("InterfaceMismatch"), "{error}");
+    runtime.inspect(path.clone(), true).await.unwrap();
+    let result = runtime
+        .call(
+            path,
+            Contract::ReadLines.reference(),
+            "read".into(),
+            json!({}),
+            ToolExecutionContext::direct(),
+        )
+        .await
+        .unwrap();
+    let result: Value = serde_json::from_str(result.content.as_deref().unwrap()).unwrap();
+    assert!(result["content"].as_str().unwrap().contains("hello"));
+    assert!(client.0.lock().unwrap().2.is_empty());
+}