feat: add provenance-aware worker history

crates/session-store/src/history.rs

@@ -0,0 +1,180 @@
+//! Serializable history entries with restore-authoritative logical identity and origin.
+
+use serde::{Deserialize, Serialize};
+
+use crate::{LoggedItem, SessionId};
+
+/// Stable logical identity of one model-visible history entry.
+///
+/// This value is generated at the trusted Worker session boundary and copied
+/// unchanged across fork, rewind, compaction retention, restore, and reboot.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct LoggedSessionHistoryEntryId(pub String);
+
+impl LoggedSessionHistoryEntryId {
+    pub fn new() -> Self {
+        Self(uuid::Uuid::now_v7().to_string())
+    }
+}
+
+impl Default for LoggedSessionHistoryEntryId {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Bounded subject snapshot. It is evidence, not a live authorization handle.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct LoggedWorkerSubject {
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub workspace_id: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub runtime_id: Option<String>,
+    pub worker_id: String,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+pub enum LoggedSessionHistoryOrigin {
+    HumanInput {
+        account_id: String,
+    },
+    WorkerInput {
+        actor: LoggedWorkerSubject,
+    },
+    FlowInstruction {
+        selector: String,
+        definition_id: String,
+        definition_revision: u64,
+        instance_id: String,
+        state_id: String,
+    },
+    BackendInstruction {
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        operation_id: Option<String>,
+    },
+    ModelOutput {
+        worker: LoggedWorkerSubject,
+    },
+    ToolOutput {
+        worker: LoggedWorkerSubject,
+    },
+    DerivedSummary,
+    LegacyUnknown,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct LoggedHistoryDerivation {
+    pub sources: Vec<LoggedSessionHistoryEntryId>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct LoggedSessionHistoryMetadata {
+    pub entry_id: LoggedSessionHistoryEntryId,
+    pub origin: LoggedSessionHistoryOrigin,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub derivation: Option<LoggedHistoryDerivation>,
+}
+
+impl LoggedSessionHistoryMetadata {
+    pub fn legacy_unknown() -> Self {
+        Self {
+            entry_id: LoggedSessionHistoryEntryId::new(),
+            origin: LoggedSessionHistoryOrigin::LegacyUnknown,
+            derivation: None,
+        }
+    }
+}
+
+/// Persisted item and metadata are one value so transforms cannot reorder or
+/// truncate one without the other.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct LoggedHistoryEntry {
+    pub item: LoggedItem,
+    pub metadata: LoggedSessionHistoryMetadata,
+}
+
+/// 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)]
+pub struct LoggedSystemHistoryEntry {
+    pub item: crate::SystemItem,
+    pub metadata: LoggedSessionHistoryMetadata,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::LoggedRole;
+    use agen::llm_client::RequestConfig;
+
+    #[test]
+    fn logged_history_entry_round_trip_preserves_id_origin_and_derivation() {
+        let source_id = LoggedSessionHistoryEntryId::new();
+        let entry = LoggedHistoryEntry {
+            item: LoggedItem::Message {
+                role: LoggedRole::User,
+                content: vec![crate::LoggedContentPart::Text {
+                    text: "preference".into(),
+                }],
+            },
+            metadata: LoggedSessionHistoryMetadata {
+                entry_id: LoggedSessionHistoryEntryId::new(),
+                origin: LoggedSessionHistoryOrigin::HumanInput {
+                    account_id: "account-1".into(),
+                },
+                derivation: Some(LoggedHistoryDerivation {
+                    sources: vec![source_id.clone()],
+                }),
+            },
+        };
+        let encoded = serde_json::to_vec(&entry).unwrap();
+        let decoded: LoggedHistoryEntry = serde_json::from_slice(&encoded).unwrap();
+        assert_eq!(decoded, entry);
+        assert_eq!(
+            decoded.metadata.derivation.unwrap().sources,
+            vec![source_id]
+        );
+    }
+
+    #[test]
+    fn annotated_segment_start_is_restore_visible_without_projecting_metadata() {
+        let session_id = uuid::Uuid::now_v7();
+        let history_entry = legacy_logged_history(LoggedItem::Message {
+            role: LoggedRole::Assistant,
+            content: vec![crate::LoggedContentPart::Text {
+                text: "answer".into(),
+            }],
+        });
+        let state = crate::collect_state(&[crate::LogEntry::AnnotatedSegmentStart {
+            ts: 1,
+            session_id,
+            system_prompt: None,
+            config: RequestConfig::default(),
+            history: vec![history_entry],
+            forked_from: None,
+            compacted_from: None,
+        }]);
+        assert_eq!(state.history[0].as_text(), Some("answer"));
+    }
+}
+
+/// Legacy Session Logs did not persist annotations. Decode helpers explicitly
+/// create `LegacyUnknown`; they never infer Human/System authority from role or
+/// plaintext.
+pub fn legacy_logged_history(item: LoggedItem) -> LoggedHistoryEntry {
+    LoggedHistoryEntry {
+        item,
+        metadata: LoggedSessionHistoryMetadata::legacy_unknown(),
+    }
+}
+
+pub fn legacy_segment_history(
+    session_id: SessionId,
+    items: impl IntoIterator<Item = LoggedItem>,
+) -> Vec<LoggedHistoryEntry> {
+    let _ = session_id;
+    items.into_iter().map(legacy_logged_history).collect()
+}

crates/session-store/src/lib.rs

@@ -32,6 +32,7 @@
 
 pub mod event_trace;
 pub mod fs_store;
+pub mod history;
 pub mod logged_item;
 pub mod segment;
 pub mod segment_log;
@@ -44,6 +45,11 @@ pub use agen::UsageRecord;
 pub use agen::llm_client::types::{ContentPart, Item, Role};
 pub use event_trace::{TraceEntry, TracePayload};
 pub use fs_store::FsStore;
+pub use history::{
+    LoggedHistoryDerivation, LoggedHistoryEntry, LoggedSessionHistoryEntryId,
+    LoggedSessionHistoryMetadata, LoggedSessionHistoryOrigin, LoggedSystemHistoryEntry,
+    LoggedWorkerSubject, legacy_logged_history, legacy_segment_history,
+};
 pub use logged_item::{LoggedContentPart, LoggedItem, LoggedRole, from_logged, to_logged};
 pub use segment::{
     SegmentStartState, append_entry, append_system_item, classify_history_item,

crates/session-store/src/segment_log.rs

@@ -14,6 +14,7 @@ use agen::{EngineResult, UsageRecord};
 use protocol::{InvokeKind, Segment};
 use serde::{Deserialize, Serialize};
 
+use crate::history::{LoggedHistoryEntry, LoggedSystemHistoryEntry};
 use crate::logged_item::LoggedItem;
 use crate::system_item::SystemItem;
 
@@ -70,6 +71,20 @@ pub enum LogEntry {
         compacted_from: Option<SegmentOrigin>,
     },
 
+    /// Schema-v2 segment seed. Retained entries keep their stable logical
+    /// identity and origin across fork/compaction/restore.
+    AnnotatedSegmentStart {
+        ts: u64,
+        session_id: crate::SessionId,
+        system_prompt: Option<String>,
+        config: RequestConfig,
+        history: Vec<LoggedHistoryEntry>,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        forked_from: Option<SegmentOrigin>,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        compacted_from: Option<SegmentOrigin>,
+    },
+
     /// IDLE → active marker. Records the start of a new self-driving
     /// cycle (Invoke range). The range extends implicitly until the
     /// next `Invoke` entry; this entry carries the trigger only — the
@@ -105,14 +120,37 @@ pub enum LogEntry {
         extensions: Vec<SessionExtension>,
     },
 
+    /// Schema-v2 user submission with its exact model-visible entries. Typed
+    /// Flow instructions and caller-attributed input remain separate entries.
+    AnnotatedUserInput {
+        ts: u64,
+        segments: Vec<Segment>,
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        extensions: Vec<SessionExtension>,
+        history: Vec<LoggedHistoryEntry>,
+    },
+
+    /// Schema-v2 model output and metadata committed as one journal record.
+    AnnotatedAssistantItem { ts: u64, entry: LoggedHistoryEntry },
+
     /// One assistant-side item appended to history — assistant message,
     /// reasoning, or tool call. Singular: one entry per history item so
     /// the wire-side `Event::*` lane and on-disk LogEntry stay 1:1.
     AssistantItem { ts: u64, item: LoggedItem },
 
+    /// Schema-v2 tool output and metadata committed as one journal record.
+    AnnotatedToolResult { ts: u64, entry: LoggedHistoryEntry },
+
     /// One tool-execution result appended to history.
     ToolResult { ts: u64, item: LoggedItem },
 
+    /// Schema-v2 typed system event and model-visible metadata committed
+    /// together.
+    AnnotatedSystemItem {
+        ts: u64,
+        entry: LoggedSystemHistoryEntry,
+    },
+
     /// One typed agent-injected system item: notification, child-Worker
     /// lifecycle event, `@<path>` / `/<slug>` resolution payload. Each
     /// `SystemItem` carries kind metadata that the LLM
@@ -278,6 +316,22 @@ pub fn collect_state(entries: &[LogEntry]) -> RestoredState {
                 state.config = config.clone();
                 state.history = history.iter().cloned().map(Item::from).collect();
             }
+            LogEntry::AnnotatedSegmentStart {
+                session_id,
+                system_prompt,
+                config,
+                history,
+                ..
+            } => {
+                state.session_id = Some(*session_id);
+                state.system_prompt = system_prompt.clone();
+                state.config = config.clone();
+                state.history = history
+                    .iter()
+                    .cloned()
+                    .map(|entry| Item::from(entry.item))
+                    .collect();
+            }
             LogEntry::Invoke { .. } => {
                 // A terminal run record below clears or refines this. If the
                 // log ends first, restore must treat the turn as interrupted.
@@ -298,6 +352,29 @@ pub fn collect_state(entries: &[LogEntry]) -> RestoredState {
                         .map(|extension| (extension.domain.clone(), extension.payload.clone())),
                 );
             }
+            LogEntry::AnnotatedUserInput {
+                segments,
+                extensions,
+                history,
+                ..
+            } => {
+                state
+                    .history
+                    .extend(history.iter().cloned().map(|entry| Item::from(entry.item)));
+                state.user_segments.push(segments.clone());
+                state.extensions.extend(
+                    extensions
+                        .iter()
+                        .map(|extension| (extension.domain.clone(), extension.payload.clone())),
+                );
+            }
+            LogEntry::AnnotatedAssistantItem { entry, .. }
+            | LogEntry::AnnotatedToolResult { entry, .. } => {
+                state.history.push(Item::from(entry.item.clone()));
+            }
+            LogEntry::AnnotatedSystemItem { entry, .. } => {
+                state.history.push(entry.item.to_history_item());
+            }
             LogEntry::AssistantItem { item, .. } => {
                 state.history.push(Item::from(item.clone()));
             }

crates/session-store/src/worker_session_store.rs

@@ -20,7 +20,8 @@ use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 use std::time::SystemTime;
 
-const SESSION_SCHEMA_VERSION: u32 = 1;
+const SESSION_SCHEMA_VERSION: u32 = 2;
+const LEGACY_SESSION_SCHEMA_VERSION: u32 = 1;
 const SESSION_FILE: &str = "session.json";
 const SEGMENTS_DIR: &str = "segments";
 
@@ -44,15 +45,22 @@ impl WorkerSessionStore {
         fs::create_dir_all(root.join(SEGMENTS_DIR))?;
         let session_id = match fs::read(root.join(SESSION_FILE)) {
             Ok(bytes) => {
-                let manifest: SessionManifest = serde_json::from_slice(&bytes)?;
-                if manifest.schema_version != SESSION_SCHEMA_VERSION {
-                    return Err(StoreError::Corrupt {
-                        line: 0,
-                        message: format!(
-                            "unsupported Worker Session schema version {}, expected {}",
-                            manifest.schema_version, SESSION_SCHEMA_VERSION
-                        ),
-                    });
+                let mut manifest: SessionManifest = serde_json::from_slice(&bytes)?;
+                match manifest.schema_version {
+                    SESSION_SCHEMA_VERSION => {}
+                    LEGACY_SESSION_SCHEMA_VERSION => {
+                        validate_legacy_segment_logs(&root)?;
+                        manifest.schema_version = SESSION_SCHEMA_VERSION;
+                        atomic_write_json(&root.join(SESSION_FILE), &manifest)?;
+                    }
+                    version => {
+                        return Err(StoreError::Corrupt {
+                            line: 0,
+                            message: format!(
+                                "unsupported Worker Session schema version {version}, expected {SESSION_SCHEMA_VERSION}"
+                            ),
+                        });
+                    }
                 }
                 Some(manifest.session_id)
             }
@@ -278,6 +286,37 @@ impl Store for WorkerSessionStore {
     }
 }
 
+fn validate_legacy_segment_logs(root: &Path) -> Result<(), StoreError> {
+    let segments = root.join(SEGMENTS_DIR);
+    if !segments.exists() {
+        return Ok(());
+    }
+    for entry in fs::read_dir(&segments)? {
+        let entry = entry?;
+        let path = entry.path();
+        let Some(name) = path.file_name().and_then(|name| name.to_str()) else {
+            continue;
+        };
+        if !name.ends_with(".jsonl") || name.ends_with(".trace.jsonl") {
+            continue;
+        }
+        let contents = fs::read_to_string(&path)?;
+        for (line_index, line) in contents.lines().enumerate() {
+            if line.trim().is_empty() {
+                continue;
+            }
+            serde_json::from_str::<LogEntry>(line).map_err(|error| StoreError::Corrupt {
+                line: line_index + 1,
+                message: format!(
+                    "cannot migrate legacy Worker Session log {}: {error}",
+                    path.display()
+                ),
+            })?;
+        }
+    }
+    Ok(())
+}
+
 fn atomic_write_json<T: Serialize>(path: &Path, value: &T) -> Result<(), StoreError> {
     let mut bytes = serde_json::to_vec_pretty(value)?;
     bytes.push(b'\n');
@@ -405,6 +444,54 @@ mod tests {
         assert_eq!(store.list_sessions().unwrap(), vec![session_id]);
     }
 
+    #[test]
+    fn schema_v1_logs_are_validated_and_promoted_to_v2() {
+        let root = tempfile::tempdir().unwrap();
+        let session_id = new_session_id();
+        let segment_id = new_segment_id();
+        WorkerSessionStore::new(root.path())
+            .unwrap()
+            .create_segment(session_id, segment_id, &[])
+            .unwrap();
+        let manifest_path = root.path().join(SESSION_FILE);
+        let mut manifest: SessionManifest =
+            serde_json::from_slice(&fs::read(&manifest_path).unwrap()).unwrap();
+        manifest.schema_version = LEGACY_SESSION_SCHEMA_VERSION;
+        atomic_write_json(&manifest_path, &manifest).unwrap();
+
+        let reopened = WorkerSessionStore::new(root.path()).unwrap();
+        assert_eq!(reopened.session_id().unwrap(), Some(session_id));
+        let migrated: SessionManifest =
+            serde_json::from_slice(&fs::read(&manifest_path).unwrap()).unwrap();
+        assert_eq!(migrated.schema_version, SESSION_SCHEMA_VERSION);
+    }
+
+    #[test]
+    fn schema_v1_migration_rejects_corrupt_log_before_manifest_update() {
+        let root = tempfile::tempdir().unwrap();
+        let session_id = new_session_id();
+        let manifest = SessionManifest {
+            schema_version: LEGACY_SESSION_SCHEMA_VERSION,
+            session_id,
+        };
+        atomic_write_json(&root.path().join(SESSION_FILE), &manifest).unwrap();
+        fs::create_dir_all(root.path().join(SEGMENTS_DIR)).unwrap();
+        fs::write(
+            root.path().join(SEGMENTS_DIR).join("broken.jsonl"),
+            "{not-json}\n",
+        )
+        .unwrap();
+
+        let error = match WorkerSessionStore::new(root.path()) {
+            Ok(_) => panic!("corrupt legacy Session log must reject migration"),
+            Err(error) => error,
+        };
+        assert!(matches!(error, StoreError::Corrupt { .. }));
+        let persisted: SessionManifest =
+            serde_json::from_slice(&fs::read(root.path().join(SESSION_FILE)).unwrap()).unwrap();
+        assert_eq!(persisted.schema_version, LEGACY_SESSION_SCHEMA_VERSION);
+    }
+
     #[test]
     fn reopen_preserves_session_and_segment_ids() {
         let root = tempfile::tempdir().unwrap();

crates/session-store/tests/session_test.rs

@@ -1,12 +1,13 @@
 mod common;
 
+use std::ops::{Deref, DerefMut};
 use std::sync::Arc;
 
-use agen::Engine;
 use agen::interceptor::{Interceptor, TurnEndAction};
 use agen::llm_client::event::{Event, ResponseStatus, StatusEvent};
 use agen::llm_client::types::{Item, RequestConfig};
 use agen::tool::{Tool, ToolDefinition, ToolError, ToolMeta, ToolOutput};
+use agen::{Engine, History};
 use async_trait::async_trait;
 use common::MockLlmClient;
 use session_store::{FsStore, LogEntry, SegmentStartState, Store, collect_state};
@@ -94,15 +95,47 @@ fn make_store() -> (tempfile::TempDir, FsStore) {
     (dir, store)
 }
 
+struct TestWorker {
+    engine: Engine<MockLlmClient>,
+    history: History,
+}
+
+impl TestWorker {
+    fn new(engine: Engine<MockLlmClient>) -> Self {
+        Self {
+            engine,
+            history: History::new(),
+        }
+    }
+
+    fn history(&self) -> Vec<Item> {
+        self.history.items_cloned()
+    }
+}
+
+impl Deref for TestWorker {
+    type Target = Engine<MockLlmClient>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.engine
+    }
+}
+
+impl DerefMut for TestWorker {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.engine
+    }
+}
+
 /// Run a worker turn and persist via session-store functions.
 /// Takes ownership of the worker (needed for lock/unlock) and returns it.
 async fn run_and_persist(
-    worker: Engine<MockLlmClient>,
+    mut worker: TestWorker,
     store: &FsStore,
     session_id: session_store::SessionId,
     segment_id: session_store::SegmentId,
     input: &str,
-) -> (Engine<MockLlmClient>, agen::EngineRunExit) {
+) -> (TestWorker, agen::EngineResult) {
     // Mirror Worker's run-entry contract: log the user input as segments
     // before the worker pushes its flattened user_message; save_delta
     // skips the resulting user_message item to avoid double-write.
@@ -114,13 +147,14 @@ async fn run_and_persist(
     )
     .unwrap();
 
-    let history_before = worker.history().len();
+    let history_before = worker.history.len();
 
-    let mut locked = worker.lock();
-    let result = locked.run(input).await;
-    let worker = locked.unlock();
+    let mut locked = worker.engine.lock(&worker.history);
+    let result = locked.run(&mut worker.history, input).await;
+    worker.engine = locked.unlock();
 
-    let new_items = &worker.history()[history_before..];
+    let projected = worker.history();
+    let new_items = &projected[history_before..];
     session_store::save_delta(store, session_id, segment_id, new_items).unwrap();
     session_store::save_turn_end(store, session_id, segment_id, worker.turn_count()).unwrap();
 
@@ -178,14 +212,14 @@ async fn run_and_persist(
 async fn session_run_logs_entries() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(simple_text_events());
-    let worker = Engine::new(client);
+    let worker = TestWorker::new(Engine::new(client));
 
     let (sid, segid) = session_store::create_segment(
         &store,
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -222,7 +256,7 @@ async fn session_run_logs_entries() {
 async fn session_restore_round_trip() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(simple_text_events());
-    let mut worker = Engine::new(client);
+    let mut worker = TestWorker::new(Engine::new(client));
     worker.set_system_prompt("You are helpful.");
 
     let (sid, segid) = session_store::create_segment(
@@ -230,7 +264,7 @@ async fn session_restore_round_trip() {
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -261,7 +295,7 @@ async fn session_restore_round_trip() {
 async fn session_run_with_tool_call() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::with_responses(tool_call_events());
-    let mut worker = Engine::new(client);
+    let mut worker = TestWorker::new(Engine::new(client));
     worker.register_tool(weather_tool_definition());
 
     let (sid, segid) = session_store::create_segment(
@@ -269,7 +303,7 @@ async fn session_run_with_tool_call() {
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -295,7 +329,7 @@ async fn session_resume_after_pause() {
 
     // First run: tool call with pause policy → Paused
     let client = MockLlmClient::with_responses(tool_call_events());
-    let mut worker = Engine::new(client);
+    let mut worker = TestWorker::new(Engine::new(client));
     worker.register_tool(weather_tool_definition());
     worker.set_interceptor(PausePolicy);
 
@@ -304,7 +338,7 @@ async fn session_resume_after_pause() {
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -335,7 +369,7 @@ async fn session_resume_after_pause() {
 async fn session_fork_creates_new_session() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(simple_text_events());
-    let mut worker = Engine::new(client);
+    let mut worker = TestWorker::new(Engine::new(client));
     worker.set_system_prompt("System prompt");
 
     let (sid, segid) = session_store::create_segment(
@@ -343,7 +377,7 @@ async fn session_fork_creates_new_session() {
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -356,7 +390,7 @@ async fn session_fork_creates_new_session() {
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -377,14 +411,14 @@ async fn session_fork_creates_new_session() {
 async fn session_fork_at_truncates_within_session() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(simple_text_events());
-    let worker = Engine::new(client);
+    let worker = TestWorker::new(Engine::new(client));
 
     let (sid, segid) = session_store::create_segment(
         &store,
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -422,14 +456,14 @@ async fn session_fork_at_truncates_within_session() {
 async fn session_config_changed_logged() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(vec![]);
-    let mut worker = Engine::new(client);
+    let mut worker = TestWorker::new(Engine::new(client));
 
     let (sid, segid) = session_store::create_segment(
         &store,
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();
@@ -455,14 +489,14 @@ async fn session_auto_forks_on_conflict() {
 
     // Create a segment
     let client_a = MockLlmClient::new(simple_text_events());
-    let worker_a = Engine::new(client_a);
+    let worker_a = TestWorker::new(Engine::new(client_a));
 
     let (sid, original_segid) = session_store::create_segment(
         &store,
         SegmentStartState {
             system_prompt: worker_a.get_system_prompt(),
             config: worker_a.request_config(),
-            history: worker_a.history(),
+            history: &worker_a.history(),
         },
     )
     .unwrap();
@@ -488,7 +522,7 @@ async fn session_auto_forks_on_conflict() {
         SegmentStartState {
             system_prompt: worker_a.get_system_prompt(),
             config: worker_a.request_config(),
-            history: worker_a.history(),
+            history: &worker_a.history(),
         },
     )
     .unwrap();
@@ -540,14 +574,14 @@ async fn session_auto_forks_on_conflict() {
 async fn nested_past_fork_leaves_ancestors_immutable() {
     let (_dir, store) = make_store();
     let client = MockLlmClient::new(simple_text_events());
-    let worker = Engine::new(client);
+    let worker = TestWorker::new(Engine::new(client));
 
     let (sid, root_segid) = session_store::create_segment(
         &store,
         SegmentStartState {
             system_prompt: worker.get_system_prompt(),
             config: worker.request_config(),
-            history: worker.history(),
+            history: &worker.history(),
         },
     )
     .unwrap();