feat: promote workers to Workspace-owned UUIDv7 identities

crates/workdir/src/workspace.rs

@@ -126,7 +126,7 @@ pub struct WorkingDirectoryCurrentObservation {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub cleanliness: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub primary_worker_id: Option<u64>,
+    pub primary_worker_id: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
@@ -151,7 +151,7 @@ pub struct WorkingDirectorySummary {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub cleanliness: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub primary_worker_id: Option<u64>,
+    pub primary_worker_id: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
@@ -177,7 +177,7 @@ impl WorkingDirectorySummary {
             current_ref: self.current_ref.clone(),
             status: self.status.clone(),
             cleanliness: self.cleanliness.clone(),
-            primary_worker_id: self.primary_worker_id,
+            primary_worker_id: self.primary_worker_id.clone(),
             occupied_by: self.occupied_by.clone(),
         }
     }

crates/worker-runtime/src/catalog.rs

@@ -148,10 +148,10 @@ impl std::fmt::Debug for WorkspaceApiRef {
 /// summarized without exposing raw host paths.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct CreateWorkerRequest {
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub idempotency_key: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub idempotency_fingerprint: Option<String>,
+    /// Workspace-owned stable identity reserved before this request reaches a Runtime.
+    pub worker_id: WorkerId,
+    /// Canonical create-intent fingerprint bound to `worker_id` for retry recovery.
+    pub create_fingerprint: String,
     pub profile: ProfileSelector,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub display_name: Option<String>,

crates/worker-runtime/src/fs_store.rs

@@ -11,7 +11,7 @@ use std::io::{BufReader, Write};
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicU64, Ordering};
 
-const SCHEMA_VERSION: u32 = 1;
+const SCHEMA_VERSION: u32 = 2;
 const RUNTIME_FILE: &str = "runtime.json";
 const WORKERS_DIR: &str = "workers";
 const WORKER_FILE: &str = "worker.json";
@@ -24,6 +24,7 @@ static NEXT_TMP_SEQUENCE: AtomicU64 = AtomicU64::new(1);
 pub struct FsRuntimeStoreOptions {
     /// Root directory containing this Runtime's store data.
     pub root: PathBuf,
+    pub runtime_id: String,
     pub display_name: Option<String>,
 }
 
@@ -31,14 +32,19 @@ impl FsRuntimeStoreOptions {
     pub fn new(root: impl Into<PathBuf>) -> Self {
         Self {
             root: root.into(),
+            runtime_id: "local".to_string(),
             display_name: None,
         }
     }
+    pub fn with_runtime_id(mut self, runtime_id: impl Into<String>) -> Self {
+        self.runtime_id = runtime_id.into();
+        self
+    }
 }
 
 /// Filesystem persistence boundary for one Worker Runtime state.
 ///
-/// Authority is Runtime-local typed Worker identity. Legacy pod paths, socket
+/// Authority is the Workspace-owned typed Worker identity. Legacy pod paths, socket
 /// paths, and session paths are deliberately not part of the layout or lookup API.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct FsRuntimeStore {
@@ -54,7 +60,10 @@ impl FsRuntimeStore {
         &self.root
     }
 
-    pub(crate) fn open_or_create(root: PathBuf) -> Result<OpenedFsRuntimeStore, RuntimeError> {
+    pub(crate) fn open_or_create(
+        root: PathBuf,
+        runtime_id: &str,
+    ) -> Result<OpenedFsRuntimeStore, RuntimeError> {
         let existed = root.exists();
         if existed && !root.is_dir() {
             return Err(RuntimeError::StoreCorrupt {
@@ -82,6 +91,9 @@ impl FsRuntimeStore {
             }
         }
 
+        if existed {
+            migrate_v1_worker_identity(&root, runtime_id)?;
+        }
         let store = Self { root };
         let state = if existed {
             Some(store.load_runtime_state()?)
@@ -241,7 +253,6 @@ pub(crate) struct OpenedFsRuntimeStore {
 pub(crate) struct PersistedRuntimeState {
     pub(crate) display_name: Option<String>,
     pub(crate) status: RuntimeStatus,
-    pub(crate) next_worker_sequence: u64,
     pub(crate) next_diagnostic_id: u64,
     pub(crate) workers: BTreeMap<WorkerId, PersistedWorkerRecord>,
     pub(crate) workspace_owners: BTreeMap<String, String>,
@@ -259,13 +270,151 @@ pub(crate) struct PersistedWorkerRecord {
     pub(crate) working_directory: Option<WorkingDirectoryStatus>,
 }
 
+fn runtime_io_error(operation: &'static str, path: &Path, source: std::io::Error) -> RuntimeError {
+    RuntimeError::StoreIo {
+        operation,
+        path: path.to_path_buf(),
+        source,
+    }
+}
+
+fn runtime_store_corrupt(path: &Path, message: String) -> RuntimeError {
+    RuntimeError::StoreCorrupt {
+        operation: "migrate Worker identity",
+        path: path.to_path_buf(),
+        message,
+    }
+}
+
+fn migrate_v1_worker_identity(root: &Path, runtime_id: &str) -> Result<(), RuntimeError> {
+    let runtime_path = root.join(RUNTIME_FILE);
+    let bytes =
+        fs::read(&runtime_path).map_err(|error| runtime_io_error("read", &runtime_path, error))?;
+    let mut document: serde_json::Value = serde_json::from_slice(&bytes).map_err(|error| {
+        runtime_store_corrupt(
+            &runtime_path,
+            format!("decode Runtime state {}: {error}", runtime_path.display()),
+        )
+    })?;
+    let schema_version = document
+        .get("schema_version")
+        .and_then(serde_json::Value::as_u64)
+        .ok_or_else(|| {
+            runtime_store_corrupt(
+                &runtime_path,
+                "Runtime state is missing schema_version".to_string(),
+            )
+        })?;
+    if schema_version == u64::from(SCHEMA_VERSION) {
+        return Ok(());
+    }
+    if schema_version != 1 {
+        return Err(runtime_store_corrupt(
+            &runtime_path,
+            format!(
+                "unsupported Runtime store schema version {schema_version}; expected 1 or {SCHEMA_VERSION}"
+            ),
+        ));
+    }
+
+    let legacy_ids = document
+        .get("workers")
+        .and_then(serde_json::Value::as_array)
+        .ok_or_else(|| {
+            runtime_store_corrupt(
+                &runtime_path,
+                "Runtime state workers must be an array".to_string(),
+            )
+        })?
+        .iter()
+        .map(|value| {
+            value.as_u64().ok_or_else(|| {
+                runtime_store_corrupt(
+                    &runtime_path,
+                    "legacy Worker id must be unsigned".to_string(),
+                )
+            })
+        })
+        .collect::<Result<Vec<_>, _>>()?;
+
+    let mut migrated_ids = Vec::with_capacity(legacy_ids.len());
+    for legacy_id in legacy_ids {
+        let legacy_dir = root.join("workers").join(legacy_id.to_string());
+        let legacy_snapshot_path = legacy_dir.join(WORKER_FILE);
+        let bytes = fs::read(&legacy_snapshot_path)
+            .map_err(|error| runtime_io_error("read", &legacy_snapshot_path, error))?;
+        let mut snapshot: serde_json::Value = serde_json::from_slice(&bytes).map_err(|error| {
+            runtime_store_corrupt(
+                &runtime_path,
+                format!(
+                    "decode Worker snapshot {}: {error}",
+                    legacy_snapshot_path.display()
+                ),
+            )
+        })?;
+        let workspace_id = snapshot
+            .get("workspace_id")
+            .and_then(serde_json::Value::as_str)
+            .unwrap_or("local")
+            .to_string();
+        let worker_id = WorkerId::from_legacy_binding(&workspace_id, runtime_id, legacy_id);
+        let worker_id_text = worker_id.to_string();
+        snapshot["schema_version"] = serde_json::Value::from(SCHEMA_VERSION);
+        snapshot["worker_id"] = serde_json::Value::String(worker_id_text.clone());
+        snapshot["worker_ref"]["worker_id"] = serde_json::Value::String(worker_id_text.clone());
+        let request = snapshot
+            .get_mut("request")
+            .and_then(serde_json::Value::as_object_mut)
+            .ok_or_else(|| {
+                runtime_store_corrupt(
+                    &runtime_path,
+                    "Worker snapshot request must be an object".to_string(),
+                )
+            })?;
+        let fingerprint = request
+            .remove("idempotency_fingerprint")
+            .and_then(|value| value.as_str().map(ToOwned::to_owned))
+            .unwrap_or_else(|| format!("legacy:{workspace_id}:{runtime_id}:{legacy_id}"));
+        request.remove("idempotency_key");
+        request.insert(
+            "worker_id".to_string(),
+            serde_json::Value::String(worker_id_text.clone()),
+        );
+        request.insert(
+            "create_fingerprint".to_string(),
+            serde_json::Value::String(fingerprint),
+        );
+
+        let migrated_dir = root.join("workers").join(&worker_id_text);
+        fs::rename(&legacy_dir, &migrated_dir)
+            .map_err(|error| runtime_io_error("rename", &legacy_dir, error))?;
+        let migrated_snapshot_path = migrated_dir.join(WORKER_FILE);
+        atomic_write_json(
+            &migrated_snapshot_path,
+            &snapshot,
+            "migrate Worker identity",
+        )?;
+        migrated_ids.push(serde_json::Value::String(worker_id_text));
+    }
+
+    document["schema_version"] = serde_json::Value::from(SCHEMA_VERSION);
+    document["workers"] = serde_json::Value::Array(migrated_ids);
+    if let Some(object) = document.as_object_mut() {
+        object.remove("next_worker_sequence");
+    }
+    atomic_write_json(
+        &runtime_path,
+        &document,
+        "migrate Runtime Worker identities",
+    )
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize)]
 struct RuntimeSnapshot {
     schema_version: u32,
     display_name: Option<String>,
     backend: RuntimeBackendKind,
     status: RuntimeStatus,
-    next_worker_sequence: u64,
     next_diagnostic_id: u64,
     #[serde(default)]
     config_bundles: BTreeMap<String, ConfigBundle>,
@@ -297,7 +446,6 @@ impl RuntimeSnapshot {
             display_name: state.display_name.clone(),
             backend: RuntimeBackendKind::FsStore,
             status: state.status,
-            next_worker_sequence: state.next_worker_sequence,
             next_diagnostic_id: state.next_diagnostic_id,
             config_bundles: BTreeMap::new(),
             workspace_owners: state.workspace_owners.clone(),
@@ -333,7 +481,6 @@ impl RuntimeSnapshot {
         PersistedRuntimeState {
             display_name: self.display_name,
             status: self.status,
-            next_worker_sequence: self.next_worker_sequence,
             next_diagnostic_id: self.next_diagnostic_id,
             workers,
             workspace_owners: self.workspace_owners,

crates/worker-runtime/src/http_server.rs

@@ -2162,8 +2162,8 @@ mod tests {
         let profile = ProfileSelector::Builtin("builtin:coder".to_string());
         let bundle = test_bundle(profile.clone());
         CreateWorkerRequest {
-            idempotency_key: None,
-            idempotency_fingerprint: None,
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "test-create".to_string(),
             profile,
             display_name: None,
             profile_source: crate::catalog::ProfileSourceArchiveSource::Http {
@@ -2659,12 +2659,14 @@ mod tests {
     async fn runtime_errors_use_typed_rest_error_shape() {
         let token = "local-token";
         let app = runtime_http_router(Runtime::new_memory(), token.to_string());
-        let response = authed_empty_request(app, Method::GET, "/v1/workers/999", token).await;
+        let missing = crate::identity::WorkerId::from_legacy_u64(999);
+        let response =
+            authed_empty_request(app, Method::GET, &format!("/v1/workers/{missing}"), token).await;
 
         assert_eq!(response.status(), StatusCode::NOT_FOUND);
         let error: RuntimeHttpErrorResponse = read_json(response).await;
         assert_eq!(error.error.code, "worker_not_found");
-        assert!(error.error.message.contains("999"));
+        assert!(error.error.message.contains(&missing.to_string()));
     }
 
     #[tokio::test]
@@ -2795,8 +2797,8 @@ mod ws_tests {
     fn ws_create_request() -> CreateWorkerRequest {
         let bundle = ws_test_bundle(ProfileSelector::Builtin("builtin:companion".to_string()));
         CreateWorkerRequest {
-            idempotency_key: None,
-            idempotency_fingerprint: None,
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "test-create".to_string(),
             profile: ProfileSelector::Builtin("builtin:companion".to_string()),
             display_name: None,
             profile_source: crate::catalog::ProfileSourceArchiveSource::Http {

crates/worker-runtime/src/identity.rs

@@ -1,50 +1,108 @@
-use serde::{Deserialize, Serialize};
-use std::fmt;
+use serde::{Deserialize, Deserializer, Serialize, Serializer, de};
+use std::{fmt, str::FromStr};
+use uuid::{Uuid, Version};
+
 pub use workdir::workspace::RuntimeWorkerRef;
 
-/// Runtime-local Worker identity.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct WorkerId(u64);
+/// Stable Workspace-owned Worker identity.
+///
+/// Runtime placement is deliberately not part of this value. New identities are
+/// allocated by Workspace authority before a Runtime create request is sent.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct WorkerId(Uuid);
 
 impl WorkerId {
-    pub fn new(value: u64) -> Self {
-        Self(value)
+    pub fn now_v7() -> Self {
+        Self(Uuid::now_v7())
+    }
+
+    /// Converts a legacy Runtime-local numeric id into a syntactically valid
+    /// migration-only UUIDv7 value. New Worker allocation must use `now_v7`.
+    pub fn from_legacy_u64(value: u64) -> Self {
+        let mut bytes = [0_u8; 16];
+        bytes[8..].copy_from_slice(&value.to_be_bytes());
+        bytes[6] = 0x70;
+        bytes[8] = (bytes[8] & 0x3f) | 0x80;
+        Self(Uuid::from_bytes(bytes))
+    }
+
+    pub fn from_legacy_binding(workspace_id: &str, runtime_id: &str, value: u64) -> Self {
+        use sha2::{Digest, Sha256};
+
+        let mut hasher = Sha256::new();
+        hasher.update(b"yoi.workspace-worker-id.v1\0");
+        hasher.update(workspace_id.as_bytes());
+        hasher.update([0]);
+        hasher.update(runtime_id.as_bytes());
+        hasher.update([0]);
+        hasher.update(value.to_be_bytes());
+        let digest = hasher.finalize();
+        let mut bytes = [0_u8; 16];
+        bytes.copy_from_slice(&digest[..16]);
+        // Migrated ids sort before normally allocated UUIDv7 values while retaining
+        // deterministic collision-resistant payload bits.
+        bytes[..6].fill(0);
+        bytes[6] = (bytes[6] & 0x0f) | 0x70;
+        bytes[8] = (bytes[8] & 0x3f) | 0x80;
+        Self(Uuid::from_bytes(bytes))
     }
 
     pub fn parse(value: &str) -> Option<Self> {
-        value.parse::<u64>().ok().map(Self)
+        let value = Uuid::parse_str(value).ok()?;
+        (value.get_version() == Some(Version::SortRand)).then_some(Self(value))
     }
 
-    pub(crate) fn generated(sequence: u64) -> Self {
-        Self(sequence)
-    }
-
-    pub fn as_u64(&self) -> u64 {
+    pub const fn as_uuid(self) -> Uuid {
         self.0
     }
 }
 
 impl fmt::Display for WorkerId {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.fmt(f)
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(formatter)
     }
 }
 
-/// Convert an opaque Workspace Worker reference only at the Runtime-local boundary.
-impl TryFrom<&RuntimeWorkerRef> for WorkerRef {
-    type Error = std::num::ParseIntError;
+impl FromStr for WorkerId {
+    type Err = WorkerIdParseError;
 
-    fn try_from(value: &RuntimeWorkerRef) -> Result<Self, Self::Error> {
-        value
-            .worker_id
-            .parse::<u64>()
-            .map(WorkerId::new)
-            .map(Self::new)
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        Self::parse(value).ok_or(WorkerIdParseError)
     }
 }
 
-/// Runtime-local authority reference for Worker operations.
+impl Serialize for WorkerId {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for WorkerId {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value = String::deserialize(deserializer)?;
+        Self::parse(&value).ok_or_else(|| de::Error::custom("Worker id must be a UUIDv7"))
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct WorkerIdParseError;
+
+impl fmt::Display for WorkerIdParseError {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        formatter.write_str("Worker id must be a UUIDv7")
+    }
+}
+
+impl std::error::Error for WorkerIdParseError {}
+
+/// Runtime-local authority reference for Worker operations. The contained id is
+/// nevertheless the Workspace-owned stable identity; the Runtime does not mint it.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
 pub struct WorkerRef {
     pub worker_id: WorkerId,
@@ -56,28 +114,43 @@ impl WorkerRef {
     }
 }
 
+impl TryFrom<&RuntimeWorkerRef> for WorkerRef {
+    type Error = WorkerIdParseError;
+
+    fn try_from(value: &RuntimeWorkerRef) -> Result<Self, Self::Error> {
+        value.worker_id.parse().map(Self::new)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
-    fn runtime_worker_ref_preserves_structured_identity_and_json_fields() {
-        let worker = RuntimeWorkerRef::new("arcadia", "30");
-        assert_eq!(worker.runtime_id, "arcadia");
-        assert_eq!(worker.worker_id, "30");
+    fn worker_id_accepts_only_uuid_v7() {
+        let worker_id = WorkerId::now_v7();
+        assert_eq!(WorkerId::parse(&worker_id.to_string()), Some(worker_id));
+        assert!(WorkerId::parse("30").is_none());
+        assert!(WorkerId::parse(&Uuid::nil().to_string()).is_none());
+    }
+
+    #[test]
+    fn runtime_worker_ref_preserves_stable_worker_identity() {
+        let worker_id = WorkerId::now_v7();
+        let worker = RuntimeWorkerRef::new("arcadia", worker_id.to_string());
         assert_eq!(
             WorkerRef::try_from(&worker).unwrap(),
-            WorkerRef::new(WorkerId::new(30))
+            WorkerRef::new(worker_id)
         );
         assert_eq!(
             serde_json::to_value(&worker).unwrap(),
-            serde_json::json!({"runtime_id": "arcadia", "worker_id": "30"})
+            serde_json::json!({"runtime_id": "arcadia", "worker_id": worker_id.to_string()})
         );
     }
 
     #[test]
-    fn runtime_worker_ref_does_not_treat_composite_text_as_local_worker_id() {
-        let worker = RuntimeWorkerRef::new("arcadia", "embedded-worker-runtime-5");
+    fn runtime_worker_ref_rejects_legacy_numeric_identity() {
+        let worker = RuntimeWorkerRef::new("arcadia", "30");
         assert!(WorkerRef::try_from(&worker).is_err());
     }
 }

crates/worker-runtime/src/main.rs

@@ -112,7 +112,14 @@ fn build_runtime(config: &ProcessConfig) -> Result<Runtime, ProcessError> {
                 .map_err(ProcessError::Runtime)
         }
         RuntimeHttpStoreSelection::Fs { root } => {
-            let mut options = FsRuntimeStoreOptions::new(root.clone());
+            let mut options = FsRuntimeStoreOptions::new(root.clone()).with_runtime_id(
+                config
+                    .http
+                    .auth
+                    .as_ref()
+                    .map(|auth| auth.runtime_id.as_str())
+                    .unwrap_or("local"),
+            );
             options.display_name = config.http.display_name.clone();
             Runtime::with_fs_store_and_execution_backend(options, backend)
                 .map_err(ProcessError::Runtime)

crates/worker-runtime/src/retention.rs

@@ -275,14 +275,13 @@ impl FsWorkerRetentionProvider {
                 ));
                 continue;
             }
-            let Ok(worker_number) = raw_id.parse::<u64>() else {
+            let Ok(worker_id) = raw_id.parse::<WorkerId>() else {
                 diagnostics.push(runtime_aggregate_diagnostic(
                     &bounded_id,
                     "aggregate_worker_id_invalid",
                 ));
                 continue;
             };
-            let worker_id = WorkerId::new(worker_number);
             let worker_dir = self.worker_dir(worker_id);
             let snapshot: WorkerGenerationSnapshot = match read_json(
                 &worker_dir.join("worker.json"),
@@ -1315,7 +1314,7 @@ mod tests {
     #[test]
     fn archive_is_verified_before_source_removal_and_retry_converges() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(7);
+        let worker_id = WorkerId::from_legacy_u64(7);
         source(temp.path(), worker_id, 4);
         let provider = FsWorkerRetentionProvider::new(temp.path());
         let request = request(worker_id, 4, SessionDisposition::Archive);
@@ -1325,7 +1324,7 @@ mod tests {
         let archive = first.archive.as_ref().unwrap();
         assert_eq!(archive.source_session_id, "session-a");
         assert_eq!(archive.segment_ids, vec!["segment-a"]);
-        assert!(!temp.path().join("workers/7").exists());
+        assert!(!temp.path().join(format!("workers/{worker_id}")).exists());
         assert!(
             temp.path()
                 .join("archives/workers/archive-a/session/segments/segment-a.jsonl")
@@ -1346,7 +1345,7 @@ mod tests {
     #[test]
     fn archive_failure_keeps_live_source_for_retry() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(8);
+        let worker_id = WorkerId::from_legacy_u64(8);
         source(temp.path(), worker_id, 2);
         let collision = temp.path().join("archives/workers/archive-a");
         fs::create_dir_all(&collision).unwrap();
@@ -1358,7 +1357,11 @@ mod tests {
                 .execute(&request(worker_id, 2, SessionDisposition::Archive))
                 .is_err()
         );
-        assert!(temp.path().join("workers/8/session").is_dir());
+        assert!(
+            temp.path()
+                .join(format!("workers/{worker_id}/session"))
+                .is_dir()
+        );
         assert!(
             !temp
                 .path()
@@ -1370,7 +1373,7 @@ mod tests {
     #[test]
     fn target_inventory_and_execute_reject_cross_workspace_aggregate() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(16);
+        let worker_id = WorkerId::from_legacy_u64(16);
         source(temp.path(), worker_id, 3);
         let provider = FsWorkerRetentionProvider::new(temp.path());
         assert!(matches!(
@@ -1383,7 +1386,11 @@ mod tests {
             provider.execute(&request),
             Err(RuntimeError::WorkerNotFound { .. })
         ));
-        assert!(temp.path().join("workers/16/session").is_dir());
+        assert!(
+            temp.path()
+                .join(format!("workers/{worker_id}/session"))
+                .is_dir()
+        );
         assert!(
             !temp
                 .path()
@@ -1401,18 +1408,22 @@ mod tests {
     fn purge_removes_aggregate_and_rejects_stale_generation() {
         let temp = tempfile::tempdir().unwrap();
         let provider = FsWorkerRetentionProvider::new(temp.path());
-        let worker_id = WorkerId::new(9);
+        let worker_id = WorkerId::from_legacy_u64(9);
         source(temp.path(), worker_id, 5);
         let stale = request(worker_id, 4, SessionDisposition::Purge);
         assert!(provider.execute(&stale).is_err());
-        assert!(temp.path().join("workers/9/session").is_dir());
+        assert!(
+            temp.path()
+                .join(format!("workers/{worker_id}/session"))
+                .is_dir()
+        );
 
         let mut current = request(worker_id, 5, SessionDisposition::Purge);
         current.operation_id = "operation-current".to_string();
         current.input_fingerprint = "fingerprint-current".to_string();
         let result = provider.execute(&current).unwrap();
         assert!(result.archive.is_none());
-        assert!(!temp.path().join("workers/9").exists());
+        assert!(!temp.path().join(format!("workers/{worker_id}")).exists());
         assert!(
             temp.path()
                 .join("retention/operations/operation-current.json")
@@ -1423,7 +1434,7 @@ mod tests {
     #[test]
     fn pending_receipt_recovers_delete_to_receipt_crash_window() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(11);
+        let worker_id = WorkerId::from_legacy_u64(11);
         source(temp.path(), worker_id, 1);
         let provider = FsWorkerRetentionProvider::new(temp.path());
         let request = request(worker_id, 1, SessionDisposition::Archive);
@@ -1442,10 +1453,15 @@ mod tests {
     #[test]
     fn provider_snapshot_scans_aggregate_storage_independent_of_runtime_catalog() {
         let temp = tempfile::tempdir().unwrap();
-        source(temp.path(), WorkerId::new(13), 2);
-        source(temp.path(), WorkerId::new(14), 1);
+        source(temp.path(), WorkerId::from_legacy_u64(13), 2);
+        let other_worker = WorkerId::from_legacy_u64(14);
+        source(temp.path(), other_worker, 1);
         write_json(
-            &temp.path().join("workers/14/worker.json"),
+            &temp
+                .path()
+                .join("workers")
+                .join(other_worker.to_string())
+                .join("worker.json"),
             &serde_json::json!({"workspace_id": "other-workspace", "run_generation": 1}),
         );
         fs::create_dir_all(temp.path().join("workers/not-a-worker")).unwrap();
@@ -1454,15 +1470,20 @@ mod tests {
             b"not-json",
         )
         .unwrap();
-        fs::create_dir_all(temp.path().join("workers/15")).unwrap();
-        fs::write(temp.path().join("workers/15/worker.json"), b"not-json").unwrap();
+        let corrupt_worker = WorkerId::from_legacy_u64(15);
+        let corrupt_worker_dir = temp.path().join("workers").join(corrupt_worker.to_string());
+        fs::create_dir_all(&corrupt_worker_dir).unwrap();
+        fs::write(corrupt_worker_dir.join("worker.json"), b"not-json").unwrap();
         let provider = FsWorkerRetentionProvider::new(temp.path());
 
         let snapshot = provider.snapshot("workspace-a", "runtime-a").unwrap();
         assert_eq!(snapshot.workers().len(), 1);
-        assert_eq!(snapshot.workers()[0].worker_id, WorkerId::new(13));
+        assert_eq!(
+            snapshot.workers()[0].worker_id,
+            WorkerId::from_legacy_u64(13)
+        );
         assert!(snapshot.diagnostics().iter().any(|diagnostic| {
-            diagnostic.worker_id() == "14"
+            diagnostic.worker_id() == other_worker.to_string()
                 && diagnostic.category() == "aggregate_workspace_mismatch"
         }));
         assert!(snapshot.diagnostics().iter().any(|diagnostic| {
@@ -1470,7 +1491,7 @@ mod tests {
                 && diagnostic.category() == "aggregate_worker_id_invalid"
         }));
         assert!(snapshot.diagnostics().iter().any(|diagnostic| {
-            diagnostic.worker_id() == "15"
+            diagnostic.worker_id() == corrupt_worker.to_string()
                 && diagnostic.category() == "aggregate_worker_record_corrupt"
         }));
     }
@@ -1478,7 +1499,7 @@ mod tests {
     #[test]
     fn diagnostics_retry_rejects_corrupt_existing_archive_before_source_delete() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(12);
+        let worker_id = WorkerId::from_legacy_u64(12);
         source(temp.path(), worker_id, 1);
         let provider = FsWorkerRetentionProvider::new(temp.path());
         let mut request = request(worker_id, 1, SessionDisposition::Archive);
@@ -1499,14 +1520,18 @@ mod tests {
         .unwrap();
 
         assert!(provider.execute(&request).is_err());
-        assert!(temp.path().join("workers/12/session").is_dir());
+        assert!(
+            temp.path()
+                .join(format!("workers/{worker_id}/session"))
+                .is_dir()
+        );
         assert!(provider.completed_for(&request).unwrap().is_none());
     }
 
     #[test]
     fn concurrent_retry_produces_one_archive() {
         let temp = tempfile::tempdir().unwrap();
-        let worker_id = WorkerId::new(10);
+        let worker_id = WorkerId::from_legacy_u64(10);
         source(temp.path(), worker_id, 1);
         let provider = Arc::new(FsWorkerRetentionProvider::new(temp.path()));
         let request = Arc::new(request(worker_id, 1, SessionDisposition::Archive));

crates/worker-runtime/src/runtime.rs

@@ -196,7 +196,7 @@ impl Runtime {
         options: FsRuntimeStoreOptions,
         execution_backend: Option<WorkerExecutionBackendRef>,
     ) -> Result<Self, RuntimeError> {
-        let opened = FsRuntimeStore::open_or_create(options.root)?;
+        let opened = FsRuntimeStore::open_or_create(options.root, &options.runtime_id)?;
         let mut state = if let Some(persisted) = opened.state {
             RuntimeState::from_persisted(persisted, opened.store)?
         } else {
@@ -492,7 +492,7 @@ impl Runtime {
         let state = self.lock()?;
         status.summary.primary_worker_id = state
             .primary_worker_id_for_workdir(status.summary.working_directory_id.as_str())
-            .map(|worker_id| worker_id.as_u64());
+            .map(|worker_id| worker_id.to_string());
         Ok(status)
     }
 
@@ -518,11 +518,6 @@ impl Runtime {
         request: CreateWorkerRequest,
         scope: Option<&RuntimeWorkspaceScope>,
     ) -> Result<WorkerDetail, RuntimeError> {
-        if request.idempotency_key.is_some() != request.idempotency_fingerprint.is_some() {
-            return Err(RuntimeError::InvalidRequest(
-                "idempotency_key and idempotency_fingerprint must be provided together".to_string(),
-            ));
-        }
         let (backend, worker_ref, spawn_request) = {
             let mut state = self.lock()?;
             state.ensure_running()?;
@@ -534,19 +529,21 @@ impl Runtime {
             if let Some(scope) = scope {
                 state.ensure_workspace_owner(scope, true)?;
             };
-            if let Some(idempotency_key) = request.idempotency_key.as_deref() {
-                let workspace_id = scope.map(|scope| scope.workspace_id.as_str());
-                if let Some(existing) = state.workers.values().find(|record| {
-                    record.workspace_id.as_deref() == workspace_id
-                        && record.request.idempotency_key.as_deref() == Some(idempotency_key)
-                }) {
-                    if existing.request.idempotency_fingerprint != request.idempotency_fingerprint {
-                        return Err(RuntimeError::InvalidRequest(format!(
-                            "worker creation idempotency key {idempotency_key} was already used with different input"
-                        )));
-                    }
-                    return Ok(existing.detail());
+            let workspace_id = scope.map(|scope| scope.workspace_id.as_str());
+            if let Some(existing) = state.workers.get(&request.worker_id) {
+                if existing.workspace_id.as_deref() != workspace_id {
+                    return Err(RuntimeError::InvalidRequest(format!(
+                        "worker {} already belongs to another Workspace scope",
+                        request.worker_id
+                    )));
                 }
+                if existing.request.create_fingerprint != request.create_fingerprint {
+                    return Err(RuntimeError::InvalidRequest(format!(
+                        "worker {} was already created with a different fingerprint",
+                        request.worker_id
+                    )));
+                }
+                return Ok(existing.detail());
             }
             state.validate_worker_config_boundary(&request)?;
             if let Some(working_directory_id) = requested_primary_workdir_id(&request) {
@@ -565,9 +562,8 @@ impl Runtime {
             })?;
             let config_bundle = state.resolve_config_bundle_ref(request.config_bundle.as_ref())?;
 
-            let worker_id = WorkerId::generated(state.next_worker_sequence);
-            state.next_worker_sequence += 1;
-            let worker_ref = WorkerRef::new(worker_id.clone());
+            let worker_id = request.worker_id;
+            let worker_ref = WorkerRef::new(worker_id);
 
             let record = WorkerRecord {
                 worker_ref: worker_ref.clone(),
@@ -1850,7 +1846,6 @@ struct RuntimeState {
     persistence: RuntimePersistence,
     status: RuntimeStatus,
     execution_backend: Option<WorkerExecutionBackendRef>,
-    next_worker_sequence: u64,
     #[cfg(feature = "fs-store")]
     next_diagnostic_id: u64,
     workers: BTreeMap<WorkerId, WorkerRecord>,
@@ -1878,7 +1873,6 @@ impl RuntimeState {
             persistence: RuntimePersistence::Memory,
             status: RuntimeStatus::Running,
             execution_backend: None,
-            next_worker_sequence: 1,
             #[cfg(feature = "fs-store")]
             next_diagnostic_id: 1,
             workers: BTreeMap::new(),
@@ -1907,7 +1901,6 @@ impl RuntimeState {
             persistence: RuntimePersistence::Fs(store),
             status: RuntimeStatus::Running,
             execution_backend: None,
-            next_worker_sequence: 1,
             #[cfg(feature = "fs-store")]
             next_diagnostic_id: 1,
             workers: BTreeMap::new(),
@@ -1958,7 +1951,6 @@ impl RuntimeState {
             persistence: RuntimePersistence::Fs(store),
             status: persisted.status,
             execution_backend: None,
-            next_worker_sequence: persisted.next_worker_sequence,
             next_diagnostic_id,
             workers,
             config_bundles: BTreeMap::new(),
@@ -1982,7 +1974,6 @@ impl RuntimeState {
         PersistedRuntimeState {
             display_name: self.display_name.clone(),
             status: self.status,
-            next_worker_sequence: self.next_worker_sequence,
             next_diagnostic_id: self.next_diagnostic_id,
             workers: self
                 .workers
@@ -2589,6 +2580,11 @@ fn requested_primary_workdir_id(request: &CreateWorkerRequest) -> Option<&str> {
 }
 
 fn validate_create_worker_request(request: &CreateWorkerRequest) -> Result<(), RuntimeError> {
+    if request.create_fingerprint.trim().is_empty() {
+        return Err(RuntimeError::InvalidRequest(
+            "create_fingerprint must not be empty".to_string(),
+        ));
+    }
     match &request.profile_source {
         crate::catalog::ProfileSourceArchiveSource::Embedded { archive } => {
             archive.verify().map_err(|err| {
@@ -2791,8 +2787,8 @@ mod tests {
         let profile = ProfileSelector::Builtin("builtin:coder".to_string());
         let bundle = test_bundle_for_profile(profile.clone());
         CreateWorkerRequest {
-            idempotency_key: None,
-            idempotency_fingerprint: None,
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "test-create".to_string(),
             profile,
             display_name: None,
             profile_source: crate::catalog::ProfileSourceArchiveSource::Http {
@@ -3570,8 +3566,7 @@ mod tests {
     fn create_worker_idempotency_reuses_worker_and_rejects_different_input() {
         let runtime = runtime_with_backend();
         let mut request = task_request("idempotent");
-        request.idempotency_key = Some("operation-1".to_string());
-        request.idempotency_fingerprint = Some("sha256:input-1".to_string());
+        request.create_fingerprint = "sha256:input-1".to_string();
         request.working_directory = Some(WorkingDirectoryClaim {
             working_directory_id: "workdir-idempotent".to_string(),
             relative_cwd: None,
@@ -3587,7 +3582,7 @@ mod tests {
             workdir_count_after_first
         );
 
-        request.idempotency_fingerprint = Some("sha256:different".to_string());
+        request.create_fingerprint = "sha256:different".to_string();
         let error = runtime.create_worker(request).unwrap_err();
         assert!(matches!(error, RuntimeError::InvalidRequest(_)));
         assert_eq!(runtime.list_workers().unwrap().len(), 1);
@@ -4141,6 +4136,85 @@ mod tests {
         }
     }
 
+    #[cfg(feature = "fs-store")]
+    #[test]
+    fn fs_store_migrates_legacy_numeric_worker_identity_to_workspace_uuid() {
+        let root = fs_store_root("worker-id-v1");
+        let runtime_id = "arcadia";
+        let runtime = Runtime::with_fs_store_and_execution_backend(
+            crate::fs_store::FsRuntimeStoreOptions {
+                root: root.clone(),
+                runtime_id: runtime_id.to_string(),
+                display_name: None,
+            },
+            Arc::new(TestExecutionBackend::default()),
+        )
+        .unwrap();
+        runtime.store_config_bundle(test_bundle()).unwrap();
+        let worker = runtime
+            .create_worker_scoped(
+                &RuntimeWorkspaceScope::new("workspace-a", "server"),
+                task_request("legacy"),
+            )
+            .unwrap();
+        drop(runtime);
+
+        let current_dir = root.join("workers").join(worker.worker_id.to_string());
+        let legacy_dir = root.join("workers").join("7");
+        std::fs::rename(&current_dir, &legacy_dir).unwrap();
+        let worker_path = legacy_dir.join("worker.json");
+        let mut worker_json: serde_json::Value =
+            serde_json::from_slice(&std::fs::read(&worker_path).unwrap()).unwrap();
+        worker_json["schema_version"] = serde_json::json!(1);
+        worker_json["worker_id"] = serde_json::json!(7);
+        worker_json["worker_ref"]["worker_id"] = serde_json::json!(7);
+        let request = worker_json["request"].as_object_mut().unwrap();
+        request.remove("worker_id");
+        request.remove("create_fingerprint");
+        request.insert("idempotency_key".to_string(), serde_json::Value::Null);
+        request.insert(
+            "idempotency_fingerprint".to_string(),
+            serde_json::Value::Null,
+        );
+        std::fs::write(
+            &worker_path,
+            serde_json::to_vec_pretty(&worker_json).unwrap(),
+        )
+        .unwrap();
+
+        let runtime_path = root.join("runtime.json");
+        let mut runtime_json: serde_json::Value =
+            serde_json::from_slice(&std::fs::read(&runtime_path).unwrap()).unwrap();
+        runtime_json["schema_version"] = serde_json::json!(1);
+        runtime_json["workers"] = serde_json::json!([7]);
+        runtime_json["next_worker_sequence"] = serde_json::json!(8);
+        std::fs::write(
+            &runtime_path,
+            serde_json::to_vec_pretty(&runtime_json).unwrap(),
+        )
+        .unwrap();
+
+        let restored = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
+            root: root.clone(),
+            runtime_id: runtime_id.to_string(),
+            display_name: None,
+        })
+        .unwrap();
+        let expected = WorkerId::from_legacy_binding("workspace-a", runtime_id, 7);
+        let detail = restored.worker_detail(&WorkerRef::new(expected)).unwrap();
+        assert_eq!(detail.worker_id, expected);
+        assert_eq!(detail.worker_ref.worker_id, expected);
+        assert!(root.join("workers").join(expected.to_string()).exists());
+        assert!(!legacy_dir.exists());
+        let migrated_runtime: serde_json::Value =
+            serde_json::from_slice(&std::fs::read(runtime_path).unwrap()).unwrap();
+        assert_eq!(migrated_runtime["schema_version"], serde_json::json!(2));
+        assert!(migrated_runtime.get("next_worker_sequence").is_none());
+
+        drop(restored);
+        let _ = std::fs::remove_dir_all(root);
+    }
+
     #[cfg(feature = "fs-store")]
     #[test]
     fn fs_store_restores_workers_without_legacy_event_or_protocol_observation_logs() {
@@ -4148,6 +4222,7 @@ mod tests {
         let runtime = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: Some("filesystem runtime".to_string()),
             },
             Arc::new(TestExecutionBackend::default()),
@@ -4189,6 +4264,7 @@ mod tests {
 
         let restored = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .unwrap();
@@ -4239,6 +4315,7 @@ mod tests {
         let runtime = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             Arc::new(TestExecutionBackend::default()),
@@ -4264,6 +4341,7 @@ mod tests {
 
         let restored = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .unwrap();
@@ -4313,6 +4391,7 @@ mod tests {
         let runtime = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             Arc::new(TestExecutionBackend::default()),
@@ -4326,6 +4405,7 @@ mod tests {
 
         let backendless = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .unwrap();
@@ -4337,6 +4417,7 @@ mod tests {
         let restored = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             restoring_backend.clone(),
@@ -4360,6 +4441,7 @@ mod tests {
         let runtime = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             Arc::new(TestExecutionBackend::default()),
@@ -4379,6 +4461,7 @@ mod tests {
         let restored = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             restoring_backend.clone(),
@@ -4415,6 +4498,7 @@ mod tests {
         let corrupt_root = fs_store_root("corrupt");
         let corrupt_runtime = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: corrupt_root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .unwrap();
@@ -4427,6 +4511,7 @@ mod tests {
         drop(corrupt_runtime);
         let err = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: corrupt_root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .unwrap_err();
@@ -4437,6 +4522,7 @@ mod tests {
         let missing_runtime = Runtime::with_fs_store_and_execution_backend(
             crate::fs_store::FsRuntimeStoreOptions {
                 root: missing_root.clone(),
+                runtime_id: "test-runtime".to_string(),
                 display_name: None,
             },
             Arc::new(TestExecutionBackend::default()),
@@ -4456,6 +4542,7 @@ mod tests {
         drop(missing_runtime);
         let loaded = Runtime::with_fs_store(crate::fs_store::FsRuntimeStoreOptions {
             root: missing_root.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: None,
         })
         .expect("invalid worker snapshot should not make runtime store unreadable");

crates/worker-runtime/src/worker_backend.rs

@@ -1998,6 +1998,7 @@ mod tests {
         WorkingDirectoryRequest,
     };
     use crate::execution::WorkerExecutionContext;
+    use crate::identity::WorkerId;
     use crate::identity::WorkerRef;
     use crate::management::RuntimeOptions;
     use crate::observation::WorkerObservationCursor;
@@ -2119,7 +2120,7 @@ mod tests {
     #[test]
     fn restart_restore_reconstructs_runtime_owned_worker_mutation_client() {
         let identity = RuntimeIdentityMaterial::generate("runtime-source").unwrap();
-        let worker_ref = WorkerRef::new(crate::identity::WorkerId::new(17));
+        let worker_ref = WorkerRef::new(crate::identity::WorkerId::from_legacy_u64(17));
         let backend = RuntimeWorkspaceBackendRef::Http {
             workspace_id: "workspace-a".to_string(),
             base_url: "https://server.invalid".to_string(),
@@ -2486,8 +2487,8 @@ mod tests {
     fn create_request(_name: &str) -> CreateWorkerRequest {
         let bundle = test_bundle();
         CreateWorkerRequest {
-            idempotency_key: None,
-            idempotency_fingerprint: None,
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "test-create".to_string(),
             profile: ProfileSelector::Builtin("builtin:companion".to_string()),
             display_name: None,
             profile_source: crate::catalog::ProfileSourceArchiveSource::Embedded {
@@ -2590,7 +2591,8 @@ mod tests {
     #[tokio::test]
     async fn runtime_provider_projects_only_explicit_live_canonical_grants() {
         let hub = Arc::new(RuntimeWorkerObservationHub::default());
-        let worker_ref = WorkerRef::new(crate::identity::WorkerId::new(7));
+        let worker_id = crate::identity::WorkerId::from_legacy_u64(7);
+        let worker_ref = WorkerRef::new(worker_id);
         let shared_state = Arc::new(WorkerSharedState::new(
             "peer-worker".to_string(),
             session_store::new_segment_id(),
@@ -2614,7 +2616,7 @@ mod tests {
                 sink: SegmentLogSink::new(),
             },
         );
-        let grant = crate::identity::RuntimeWorkerRef::new("runtime-1", "7");
+        let grant = crate::identity::RuntimeWorkerRef::new("runtime-1", worker_id.to_string());
         let provider = RuntimeGrantedWorkerObservationProvider {
             runtime_id: "runtime-1".to_string(),
             workspace_id: "workspace-1".to_string(),
@@ -2628,7 +2630,7 @@ mod tests {
             listed[0].subject,
             WorkerObservationSubjectRef::RuntimeWorker {
                 runtime_id: "runtime-1".to_string(),
-                worker_id: "7".to_string(),
+                worker_id: worker_id.to_string(),
             }
         );
         provider
@@ -2668,8 +2670,9 @@ mod tests {
     }
 
     #[test]
-    fn runtime_worker_name_is_runtime_local() {
-        let worker_ref = crate::identity::WorkerRef::new(crate::identity::WorkerId::new(1));
+    fn runtime_worker_name_uses_workspace_worker_identity() {
+        let worker_ref =
+            crate::identity::WorkerRef::new(crate::identity::WorkerId::from_legacy_u64(1));
         let request = WorkerExecutionSpawnRequest {
             worker_ref: worker_ref.clone(),
             run_generation: 1,
@@ -2682,7 +2685,7 @@ mod tests {
 
         assert_eq!(
             ProfileRuntimeWorkerFactory::runtime_worker_name(&request),
-            "worker-runtime-1"
+            format!("worker-runtime-{}", request.worker_ref.worker_id)
         );
         assert_ne!(
             ProfileRuntimeWorkerFactory::runtime_worker_name(&request),
@@ -2765,8 +2768,10 @@ mod tests {
     async fn restore_pending_workspace_worker_without_system_prompt_fails_closed() {
         let root = tempfile::tempdir().unwrap();
         let runtime_store_dir = root.path().join("runtime");
-        let worker_ref = WorkerRef::new(crate::identity::WorkerId::new(1));
-        let worker_aggregate_dir = runtime_store_dir.join("workers/1");
+        let worker_ref = WorkerRef::new(crate::identity::WorkerId::from_legacy_u64(1));
+        let worker_aggregate_dir = runtime_store_dir
+            .join("workers")
+            .join(worker_ref.worker_id.to_string());
         let worker_name = ProfileRuntimeWorkerFactory::runtime_worker_name_for_ref(&worker_ref);
         let session_id = session_store::new_session_id();
         let manifest = manifest::WorkerManifest::from_toml(&format!(
@@ -2842,8 +2847,10 @@ mod tests {
         let root = tempfile::tempdir().unwrap();
         let long_component = "embedded-workspace-store-segment".repeat(4);
         let runtime_store_dir = root.path().join(long_component);
-        let worker_ref = WorkerRef::new(crate::identity::WorkerId::new(1));
-        let worker_aggregate_dir = runtime_store_dir.join("workers/1");
+        let worker_ref = WorkerRef::new(crate::identity::WorkerId::from_legacy_u64(1));
+        let worker_aggregate_dir = runtime_store_dir
+            .join("workers")
+            .join(worker_ref.worker_id.to_string());
         let worker_name = ProfileRuntimeWorkerFactory::runtime_worker_name_for_ref(&worker_ref);
         let session_id = session_store::new_session_id();
         let manifest = manifest::WorkerManifest::from_toml(&format!(
@@ -2880,7 +2887,10 @@ mod tests {
             )
             .unwrap();
 
-        let run_dir = runtime_store_dir.join("workers/1/runs/2");
+        let run_dir = runtime_store_dir
+            .join("workers")
+            .join(worker_ref.worker_id.to_string())
+            .join("runs/2");
         let socket_path = run_dir.join("worker.sock");
         assert!(
             socket_path.as_os_str().as_encoded_bytes().len() > 107,
@@ -2926,6 +2936,7 @@ mod tests {
         let runtime_store_dir = root.path().join(long_component);
         let runtime_options = crate::fs_store::FsRuntimeStoreOptions {
             root: runtime_store_dir.clone(),
+            runtime_id: "test-runtime".to_string(),
             display_name: Some("embedded".to_string()),
         };
 
@@ -2946,7 +2957,10 @@ mod tests {
         let mut request = create_request("embedded singleton");
         request.profile = ProfileSelector::Builtin("default".to_string());
         let worker = runtime.create_worker(request).unwrap();
-        let first_run_socket = runtime_store_dir.join("workers/1/runs/1/worker.sock");
+        let first_run_socket = runtime_store_dir
+            .join("workers")
+            .join(worker.worker_id.to_string())
+            .join("runs/1/worker.sock");
         assert!(
             first_run_socket.as_os_str().as_encoded_bytes().len() > 107,
             "test path must exceed Linux sockaddr_un.sun_path capacity: {}",
@@ -2998,7 +3012,10 @@ mod tests {
             diagnostic.code == "worker_execution_restore_failed"
                 && diagnostic.worker_ref.as_ref() == Some(&worker.worker_ref)
         }));
-        let restored_run = runtime_store_dir.join("workers/1/runs/2");
+        let restored_run = runtime_store_dir
+            .join("workers")
+            .join(worker.worker_id.to_string())
+            .join("runs/2");
         assert!(!restored_run.join("worker.sock").exists());
         assert!(restored_run.join("worker.out.log").is_file());
         assert!(restored_run.join("worker.err.log").is_file());

crates/worker-runtime/src/working_directory.rs

@@ -803,7 +803,7 @@ mod tests {
     }
 
     fn worker_ref(sequence: u64) -> WorkerRef {
-        WorkerRef::new(WorkerId::generated(sequence))
+        WorkerRef::new(WorkerId::from_legacy_u64(sequence))
     }
 
     #[test]

crates/workspace-server/src/hosts.rs

@@ -340,6 +340,14 @@ pub struct WorkerTicketAssignmentRequest {
     pub operation_id: String,
 }
 
+pub(crate) fn worker_spawn_create_fingerprint(
+    request: &WorkerSpawnRequest,
+) -> Result<String, String> {
+    let encoded = serde_json::to_vec(request)
+        .map_err(|error| format!("serialize Worker create input: {error}"))?;
+    Ok(format!("sha256:{}", digest_hex(&encoded, 64)))
+}
+
 pub(crate) fn worker_spawn_idempotency(
     request: &WorkerSpawnRequest,
 ) -> Result<Option<(String, String)>, String> {
@@ -366,6 +374,12 @@ pub struct WorkerControlOperation {
     pub input_fingerprint: String,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct WorkerCreateBinding {
+    pub worker_id: EmbeddedWorkerId,
+    pub create_fingerprint: String,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(deny_unknown_fields)]
 pub struct WorkerSpawnRequest {
@@ -763,7 +777,11 @@ pub trait WorkspaceWorkerRuntime: Send + Sync {
         }
     }
 
-    fn spawn_worker(&self, request: WorkerSpawnRequest) -> WorkerSpawnResult {
+    fn spawn_worker(
+        &self,
+        _binding: WorkerCreateBinding,
+        request: WorkerSpawnRequest,
+    ) -> WorkerSpawnResult {
         WorkerSpawnResult {
             state: WorkerOperationState::Unsupported,
             worker: None,
@@ -1226,6 +1244,7 @@ impl RuntimeRegistry {
     pub fn spawn_worker(
         &self,
         runtime_id: &str,
+        binding: WorkerCreateBinding,
         request: WorkerSpawnRequest,
     ) -> Result<WorkerSpawnResult, RuntimeRegistryError> {
         validate_backend_identifier("runtime_id", runtime_id)?;
@@ -1269,7 +1288,7 @@ impl RuntimeRegistry {
                 });
             }
         }
-        Ok(runtime.spawn_worker(request))
+        Ok(runtime.spawn_worker(binding, request))
     }
 
     pub fn create_working_directory(
@@ -1606,6 +1625,7 @@ impl EmbeddedWorkerRuntime {
         let runtime = worker_runtime::Runtime::with_fs_store_and_execution_backend(
             FsRuntimeStoreOptions {
                 root: store_root.into(),
+                runtime_id: EMBEDDED_RUNTIME_ID.to_string(),
                 display_name: Some("embedded".to_string()),
             },
             backend,
@@ -1948,7 +1968,11 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
         }
     }
 
-    fn spawn_worker(&self, request: WorkerSpawnRequest) -> WorkerSpawnResult {
+    fn spawn_worker(
+        &self,
+        binding: WorkerCreateBinding,
+        request: WorkerSpawnRequest,
+    ) -> WorkerSpawnResult {
         let mut diagnostics = Vec::new();
         if request.resolved_working_directory_request.is_some()
             || request.resolved_working_directory.is_some()
@@ -1981,7 +2005,7 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
             diagnostics.push(diagnostic(
                 "embedded_worker_name_display_only",
                 DiagnosticSeverity::Info,
-                "requested_worker_name is used only as display_name; embedded Runtime allocates opaque runtime-local worker ids".to_string(),
+                "requested_worker_name is used only as display_name; Worker identity is allocated by Workspace authority".to_string(),
             ));
         }
         if matches!(request.acceptance, WorkerSpawnAcceptanceRequirement::RunAccepted { expected_segments } if expected_segments > 0)
@@ -2010,11 +2034,6 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
                 };
             }
         };
-        let (idempotency_key, idempotency_fingerprint) = worker_spawn_idempotency(&request)
-            .expect("WorkerSpawnRequest serialization is infallible")
-            .map_or((None, None), |(key, fingerprint)| {
-                (Some(key), Some(fingerprint))
-            });
         let workspace_api = match required_worker_workspace_api(&request) {
             Ok(workspace_api) => workspace_api,
             Err(diagnostic) => {
@@ -2030,8 +2049,8 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
         let workspace_id = workspace_api.workspace_id.clone();
         let config_bundle = spawn_config_bundle_ref(&request);
         let create_request = CreateWorkerRequest {
-            idempotency_key,
-            idempotency_fingerprint,
+            worker_id: binding.worker_id,
+            create_fingerprint: binding.create_fingerprint,
             profile,
             display_name: request.requested_worker_name.clone(),
             config_bundle,
@@ -3113,7 +3132,11 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
         }
     }
 
-    fn spawn_worker(&self, request: WorkerSpawnRequest) -> WorkerSpawnResult {
+    fn spawn_worker(
+        &self,
+        binding: WorkerCreateBinding,
+        request: WorkerSpawnRequest,
+    ) -> WorkerSpawnResult {
         if matches!(
             request.acceptance,
             WorkerSpawnAcceptanceRequirement::SocketReady
@@ -3152,11 +3175,6 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
                 };
             }
         };
-        let (idempotency_key, idempotency_fingerprint) = worker_spawn_idempotency(&request)
-            .expect("WorkerSpawnRequest serialization is infallible")
-            .map_or((None, None), |(key, fingerprint)| {
-                (Some(key), Some(fingerprint))
-            });
         let workspace_api = match required_worker_workspace_api(&request) {
             Ok(workspace_api) => workspace_api,
             Err(diagnostic) => {
@@ -3170,8 +3188,8 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
         };
         let config_bundle = spawn_config_bundle_ref(&request);
         let create = CreateWorkerRequest {
-            idempotency_key,
-            idempotency_fingerprint,
+            worker_id: binding.worker_id,
+            create_fingerprint: binding.create_fingerprint,
             profile,
             display_name: request.requested_worker_name.clone(),
             config_bundle,
@@ -4245,6 +4263,13 @@ mod tests {
     use std::sync::{Arc, Mutex};
     use std::thread;
 
+    fn test_create_binding() -> WorkerCreateBinding {
+        WorkerCreateBinding {
+            worker_id: EmbeddedWorkerId::now_v7(),
+            create_fingerprint: "sha256:test-create".to_string(),
+        }
+    }
+
     fn test_workspace_api() -> WorkspaceApiRef {
         WorkspaceApiRef {
             workspace_id: "workspace-test".to_string(),
@@ -4899,11 +4924,16 @@ mod tests {
             digest: bundle.metadata.digest.clone(),
         };
         request.resolved_config_bundle = Some(bundle);
+        let binding = test_create_binding();
 
         let result = registry
-            .spawn_worker("embedded-worker-runtime", request)
+            .spawn_worker("embedded-worker-runtime", binding.clone(), request)
             .expect("spawn request");
         assert_eq!(result.state, WorkerOperationState::Accepted);
+        assert_eq!(
+            result.worker.as_ref().unwrap().worker.worker_id,
+            binding.worker_id.to_string()
+        );
         let check = registry
             .check_config_bundle("embedded-worker-runtime", bundle_ref)
             .expect("bundle check");
@@ -4921,7 +4951,7 @@ mod tests {
         let mut request = embedded_spawn_request();
         request.resolved_workspace_api = None;
 
-        let spawned = runtime.spawn_worker(request);
+        let spawned = runtime.spawn_worker(test_create_binding(), request);
 
         assert_eq!(spawned.state, WorkerOperationState::Rejected);
         assert!(
@@ -4939,7 +4969,7 @@ mod tests {
             Arc::new(FailingSpawnBackend),
         )
         .expect("test backend should connect");
-        let spawned = runtime.spawn_worker(embedded_spawn_request());
+        let spawned = runtime.spawn_worker(test_create_binding(), embedded_spawn_request());
         assert_eq!(spawned.state, WorkerOperationState::Rejected);
         assert!(spawned.acceptance_evidence.is_empty());
         assert!(spawned.diagnostics.iter().any(|diagnostic| {
@@ -5006,7 +5036,7 @@ mod tests {
             Arc::new(AcceptingExecutionBackend::default()),
         )
         .expect("test backend should connect");
-        let spawned = runtime.spawn_worker(embedded_spawn_request());
+        let spawned = runtime.spawn_worker(test_create_binding(), embedded_spawn_request());
         assert_eq!(spawned.state, WorkerOperationState::Accepted);
         let worker = spawned.worker.expect("created embedded worker");
         assert!(worker.capabilities.can_stop);
@@ -5064,6 +5094,7 @@ mod tests {
         let spawned = registry
             .spawn_worker(
                 EMBEDDED_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     intent: WorkerSpawnIntent::TicketRole {
                         ticket_id: "00001KVZSGT0Q".to_string(),
@@ -5162,6 +5193,7 @@ mod tests {
         let spawned = registry
             .spawn_worker(
                 EMBEDDED_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     intent: WorkerSpawnIntent::TicketRole {
                         ticket_id: "00001KVZSGT0Q".to_string(),
@@ -5204,6 +5236,7 @@ mod tests {
         let result = registry
             .spawn_worker(
                 EMBEDDED_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     intent: WorkerSpawnIntent::WorkspaceCompanion,
                     requested_worker_name: None,
@@ -5251,7 +5284,8 @@ mod tests {
 
     #[test]
     fn remote_runtime_registry_routes_commands_without_browser_secret_leaks() {
-        let worker_json = worker_json("remote:primary", "1");
+        let worker_id = EmbeddedWorkerId::from_legacy_u64(1).to_string();
+        let worker_json = worker_json("remote:primary", &worker_id);
         let (base_url, server) = serve_mock_http(vec![
             mock_response(
                 "GET",
@@ -5262,19 +5296,19 @@ mod tests {
             ),
             mock_response(
                 "GET",
-                "/v1/workers/1",
+                format!("/v1/workers/{worker_id}"),
                 true,
                 200,
                 json!({ "worker": worker_json.clone() }).to_string(),
             ),
             mock_response(
                 "POST",
-                "/v1/workers/1/input",
+                format!("/v1/workers/{worker_id}/input"),
                 true,
                 200,
                 json!({
                     "ack": {
-                        "worker_ref": { "runtime_id": "remote:primary", "worker_id": 1 },
+                        "worker_ref": { "runtime_id": "remote:primary", "worker_id": worker_id.clone() },
                         "status": "running"
                     }
                 })
@@ -5298,20 +5332,24 @@ mod tests {
         );
 
         let observation = registry
-            .observation_source(&RuntimeWorkerRef::new("remote:primary", "1"))
+            .observation_source(&RuntimeWorkerRef::new("remote:primary", &worker_id))
             .expect("remote runtime exposes backend-owned WS observation source");
         let crate::observation::RuntimeObservationSource::RemoteWs(observation) = observation
         else {
             panic!("remote runtime should expose a remote WS observation source");
         };
         assert!(observation.endpoint.starts_with("ws://127.0.0.1:"));
-        assert!(observation.endpoint.ends_with("/v1/workers/1/protocol/ws"));
+        assert!(
+            observation
+                .endpoint
+                .ends_with(&format!("/v1/workers/{worker_id}/protocol/ws"))
+        );
         assert_eq!(observation.bearer_token.as_deref(), Some(secret.as_str()));
 
         let workers = registry.list_workers(10);
         assert_eq!(workers.items.len(), 1);
         assert_eq!(workers.items[0].worker.runtime_id, "remote:primary");
-        assert_eq!(workers.items[0].worker.worker_id, "1");
+        assert_eq!(workers.items[0].worker.worker_id, worker_id.as_str());
         assert_eq!(
             workers.items[0].implementation.kind,
             "remote_worker_runtime"
@@ -5324,7 +5362,7 @@ mod tests {
 
         let input = registry
             .send_input(
-                &RuntimeWorkerRef::new("remote:primary", "1"),
+                &RuntimeWorkerRef::new("remote:primary", &worker_id),
                 WorkerInputRequest {
                     kind: WorkerInputKind::User,
                     content: "hello remote".to_string(),
@@ -5350,6 +5388,10 @@ mod tests {
 
     #[test]
     fn remote_runtime_projection_uses_canonical_worker_status_for_stop_capability() {
+        let worker_ids = (1..=4)
+            .map(|value| EmbeddedWorkerId::from_legacy_u64(value).to_string())
+            .collect::<Vec<_>>();
+        let worker_id = worker_ids[0].clone();
         let (base_url, server) = serve_mock_http(vec![
             mock_response(
                 "GET",
@@ -5358,21 +5400,26 @@ mod tests {
                 200,
                 json!({
                     "workers": [
-                    worker_json_with_status("remote:primary", "1", "stopped"),
-                    worker_json_with_status("remote:primary", "2", "cancelled"),
-                    worker_json_with_status("remote:primary", "3", "paused"),
-                    worker_json_with_status("remote:primary", "4", "idle")
+                        worker_json_with_status("remote:primary", &worker_ids[0], "stopped"),
+                        worker_json_with_status("remote:primary", &worker_ids[1], "cancelled"),
+                        worker_json_with_status("remote:primary", &worker_ids[2], "paused"),
+                        worker_json_with_status("remote:primary", &worker_ids[3], "idle")
                     ]
                 })
                 .to_string(),
             ),
             mock_response(
                 "GET",
-                "/v1/workers/1",
+                format!("/v1/workers/{worker_id}"),
                 true,
                 200,
                 json!({
-                    "worker": worker_json_with_status("remote:primary", "1", "stopped")})
+                    "worker": worker_json_with_status(
+                        "remote:primary",
+                        &worker_ids[0],
+                        "stopped"
+                    )
+                })
                 .to_string(),
             ),
         ]);
@@ -5402,7 +5449,7 @@ mod tests {
         assert_eq!(workers.items[3].state, "idle");
 
         let stopped_detail = registry
-            .worker(&RuntimeWorkerRef::new("remote:primary", "1"))
+            .worker(&RuntimeWorkerRef::new("remote:primary", &worker_id))
             .unwrap();
         assert!(!stopped_detail.capabilities.can_stop);
         assert_eq!(stopped_detail.state, "stopped");
@@ -5595,7 +5642,7 @@ mod tests {
     #[derive(Clone)]
     struct MockResponse {
         method: &'static str,
-        path: &'static str,
+        path: String,
         require_auth: bool,
         status: u16,
         body: String,
@@ -5603,14 +5650,14 @@ mod tests {
 
     fn mock_response(
         method: &'static str,
-        path: &'static str,
+        path: impl Into<String>,
         require_auth: bool,
         status: u16,
         body: String,
     ) -> MockResponse {
         MockResponse {
             method,
-            path,
+            path: path.into(),
             require_auth,
             status,
             body,
@@ -5667,7 +5714,6 @@ mod tests {
         worker_id: &str,
         status: &str,
     ) -> serde_json::Value {
-        let worker_id = worker_id.parse::<u64>().unwrap();
         json!({
             "worker_ref": { "runtime_id": runtime_id, "worker_id": worker_id },
             "runtime_id": runtime_id,

crates/workspace-server/src/retention.rs

@@ -285,7 +285,7 @@ impl SqliteWorkspaceStore {
             let worker=match load_worker(&tx,&req.workspace_id,&req.worker)? {
                 Some(v)=>v,
                 None=>{
-                    let other:bool=tx.query_row("SELECT EXISTS(SELECT 1 FROM worker_registry WHERE runtime_id=?1 AND runtime_worker_id=?2 AND workspace_id!=?3)",params![req.worker.runtime_id,req.worker.worker_id,req.workspace_id],|r|r.get(0))?;
+                    let other:bool=tx.query_row("SELECT EXISTS(SELECT 1 FROM worker_registry WHERE runtime_id=?1 AND worker_id=?2 AND workspace_id!=?3)",params![req.worker.runtime_id,req.worker.worker_id,req.workspace_id],|r|r.get(0))?;
                     return Err(StoreError::InvalidInput(if other{"cross-workspace".into()}else{"worker-missing".into()}));
                 }
             };
@@ -366,11 +366,13 @@ impl SqliteWorkspaceStore {
                 plan_id: plan.plan_id.clone(),
                 reason: "Worker disappeared after execution fence".to_string(),
             })?;
-        let worker_number = plan.worker.worker_id.parse::<u64>().map_err(|_| {
-            WorkerRetentionError::Invalid(
-                "Runtime Worker id is not a canonical unsigned integer".to_string(),
-            )
-        })?;
+        let worker_id = plan
+            .worker
+            .worker_id
+            .parse::<worker_runtime::identity::WorkerId>()
+            .map_err(|_| {
+                WorkerRetentionError::Invalid("Worker id must be a canonical UUIDv7".to_string())
+            })?;
         let removed_at = plan.created_at.clone();
         let prior_failure_category = plan.failure_category.clone();
         Ok(PreparedWorkerRemoval {
@@ -380,7 +382,7 @@ impl SqliteWorkspaceStore {
                 archive_id: plan.archive_id.clone(),
                 workspace_id: plan.workspace_id.clone(),
                 source_runtime_id: plan.worker.runtime_id.clone(),
-                worker_id: worker_runtime::identity::WorkerId::new(worker_number),
+                worker_id: worker_id,
                 expected_worker_revision: plan.worker_revision.clone(),
                 expected_run_generation: plan.run_generation,
                 source_created_at: worker.created_at,
@@ -435,11 +437,13 @@ impl SqliteWorkspaceStore {
             return Ok(None);
         };
         let prior_failure_category = plan.failure_category.clone();
-        let worker_number = plan.worker.worker_id.parse::<u64>().map_err(|_| {
-            WorkerRetentionError::Invalid(
-                "Runtime Worker id is not a canonical unsigned integer".to_string(),
-            )
-        })?;
+        let worker_id = plan
+            .worker
+            .worker_id
+            .parse::<worker_runtime::identity::WorkerId>()
+            .map_err(|_| {
+                WorkerRetentionError::Invalid("Worker id must be a canonical UUIDv7".to_string())
+            })?;
         let worker = if plan.state == WorkerRemovalPlanState::Succeeded {
             None
         } else {
@@ -455,7 +459,7 @@ impl SqliteWorkspaceStore {
                 archive_id: plan.archive_id.clone(),
                 workspace_id: plan.workspace_id.clone(),
                 source_runtime_id: plan.worker.runtime_id.clone(),
-                worker_id: worker_runtime::identity::WorkerId::new(worker_number),
+                worker_id: worker_id,
                 expected_worker_revision: plan.worker_revision.clone(),
                 expected_run_generation: plan.run_generation,
                 source_created_at: worker
@@ -544,7 +548,7 @@ impl SqliteWorkspaceStore {
             if plan.metadata_disposition==MetadataDisposition::Tombstone{
                 tx.execute("INSERT OR IGNORE INTO worker_tombstones(workspace_id,runtime_id,worker_id,display_name,profile,worker_created_at,removed_at,archive_id,policy_id,policy_revision,operation_id) VALUES(?1,?2,?3,?4,?5,?6,?7,?8,?9,?10,?11)",params![workspace_id,plan.worker.runtime_id,plan.worker.worker_id,worker.display_name,worker.profile,worker.created_at,now,plan.archive_id,plan.policy_id,plan.policy_revision,operation_id])?;
             }
-            let deleted=tx.execute("DELETE FROM worker_registry WHERE workspace_id=?1 AND runtime_id=?2 AND runtime_worker_id=?3 AND updated_at=?4",params![workspace_id,plan.worker.runtime_id,plan.worker.worker_id,plan.worker_revision])?;
+            let deleted=tx.execute("DELETE FROM worker_registry WHERE workspace_id=?1 AND runtime_id=?2 AND worker_id=?3 AND updated_at=?4",params![workspace_id,plan.worker.runtime_id,plan.worker.worker_id,plan.worker_revision])?;
             if deleted!=1{return Err(StoreError::InvalidInput(format!("stale:{}:removal fence changed",plan.plan_id)));}
             tx.execute("UPDATE worker_removal_operations SET state='succeeded',failure_category=NULL,updated_at=?1 WHERE operation_id=?2",params![now,operation_id])?;
             tx.execute("INSERT OR IGNORE INTO worker_retention_audit_events(event_id,operation_id,workspace_id,event_kind,detail,created_at) VALUES(?1,?2,?3,'worker_removed',?4,?5)",params![stable("wre",operation_id),operation_id,workspace_id,format!("runtime_id={} worker_id={} session={} metadata={} diagnostics={}",plan.worker.runtime_id,plan.worker.worker_id,sess(plan.session_disposition),meta(plan.metadata_disposition),diag(plan.diagnostics_disposition)),now])?;
@@ -593,7 +597,7 @@ impl SqliteWorkspaceStore {
             let tx = conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
             let policy_configured = load_policy(&tx, workspace_id)?.is_some();
             let mut statement = tx.prepare(
-                "SELECT CAST(runtime_worker_id AS TEXT), retention_state
+                "SELECT CAST(worker_id AS TEXT), retention_state
                  FROM worker_registry WHERE workspace_id=?1 AND runtime_id=?2",
             )?;
             let registry = statement
@@ -718,7 +722,7 @@ struct WorkerRow {
     updated_at: String,
 }
 fn load_worker(c: &Connection, w: &str, r: &RuntimeWorkerRef) -> crate::Result<Option<WorkerRow>> {
-    c.query_row("SELECT display_name,profile,retention_state,created_at,updated_at FROM worker_registry WHERE workspace_id=?1 AND runtime_id=?2 AND runtime_worker_id=?3",params![w,r.runtime_id,r.worker_id],|x|Ok(WorkerRow{display_name:x.get(0)?,profile:x.get(1)?,retention_state:x.get(2)?,created_at:x.get(3)?,updated_at:x.get(4)?})).optional().map_err(StoreError::from)
+    c.query_row("SELECT display_name,profile,retention_state,created_at,updated_at FROM worker_registry WHERE workspace_id=?1 AND runtime_id=?2 AND worker_id=?3",params![w,r.runtime_id,r.worker_id],|x|Ok(WorkerRow{display_name:x.get(0)?,profile:x.get(1)?,retention_state:x.get(2)?,created_at:x.get(3)?,updated_at:x.get(4)?})).optional().map_err(StoreError::from)
 }
 fn load_policy(c: &Connection, w: &str) -> crate::Result<Option<WorkerRetentionPolicy>> {
     c.query_row(
@@ -1042,16 +1046,33 @@ mod tests {
     use super::*;
     use crate::store::{ControlPlaneStore, TicketWorkerAssignmentRecord, WorkerRegistryRecord};
     use worker_runtime::identity::WorkerId;
+    fn worker_id() -> WorkerId {
+        WorkerId::from_legacy_u64(1)
+    }
     fn setup() -> SqliteWorkspaceStore {
         let s = SqliteWorkspaceStore::in_memory().unwrap();
-        s.with_conn(|c|{c.execute("INSERT INTO workspaces(workspace_id,display_name,state,created_at,updated_at)VALUES('w','W','active','t','t')",[])?;c.execute("INSERT INTO worker_registry(workspace_id,runtime_id,runtime_worker_id,display_name,profile,retention_state,created_at,updated_at)VALUES('w','r',1,'one','builtin:coder','normal','created','rev1')",[])?;Ok(())}).unwrap();
+        s.with_conn(|c| {
+            c.execute(
+                "INSERT INTO workspaces(workspace_id,display_name,state,created_at,updated_at) \
+                 VALUES('w','W','active','t','t')",
+                [],
+            )?;
+            c.execute(
+                "INSERT INTO worker_registry(\
+                    workspace_id,worker_id,runtime_id,display_name,profile,retention_state,created_at,updated_at\
+                 ) VALUES('w',?1,'r','one','builtin:coder','normal','created','rev1')",
+                [worker_id().to_string()],
+            )?;
+            Ok(())
+        })
+        .unwrap();
         s
     }
     fn inv() -> WorkerRetentionInventory {
         WorkerRetentionInventory {
             workspace_id: "w".into(),
             runtime_id: "r".into(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             run_generation: 2,
             session_id: Some("s".into()),
             segment_ids: vec!["a".into()],
@@ -1064,7 +1085,7 @@ mod tests {
             workspace_id: "w".into(),
             worker: RuntimeWorkerRef {
                 runtime_id: "r".into(),
-                worker_id: "1".into(),
+                worker_id: worker_id().to_string(),
             },
             expected_worker_revision: "rev1".into(),
             reason: "cleanup".into(),
@@ -1213,7 +1234,10 @@ mod tests {
             SessionDisposition::Archive
         );
         assert_eq!(prepared.runtime_request.policy_revision, 1);
-        assert_eq!(prepared.runtime_request.worker_id, WorkerId::new(1));
+        assert_eq!(
+            prepared.runtime_request.worker_id,
+            WorkerId::from_legacy_u64(1)
+        );
         let retry = s
             .prepare_worker_removal_execution("w", &plan.plan_id, &plan.input_fingerprint)
             .unwrap();
@@ -1234,7 +1258,7 @@ mod tests {
             operation_id: p.operation_id.clone(),
             input_fingerprint: p.input_fingerprint.clone(),
             expected_worker_revision: p.worker_revision.clone(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             session_disposition: p.session_disposition,
             diagnostics_disposition: p.diagnostics_disposition,
             archive: Some(worker_runtime::retention::WorkerSessionArchiveManifest {
@@ -1242,7 +1266,7 @@ mod tests {
                 archive_id: p.archive_id.clone().unwrap(),
                 workspace_id: "w".into(),
                 source_runtime_id: "r".into(),
-                source_worker_id: WorkerId::new(1),
+                source_worker_id: worker_id(),
                 source_session_id: "s".into(),
                 segment_ids: vec!["a".into()],
                 source_created_at: "created".into(),
@@ -1284,7 +1308,23 @@ mod tests {
     #[test]
     fn assignment_and_orphan_are_authoritative() {
         let s = setup();
-        s.with_conn(|c|{c.execute("INSERT INTO ticket_worker_assignments(workspace_id,ticket_id,assignment_id,runtime_id,worker_id,assigned_by,assigned_at)VALUES('w','ticket','assignment','r','1','test','t')",[])?;c.execute("INSERT INTO ticket_current_worker_assignments(workspace_id,ticket_id,assignment_id,runtime_id,worker_id,updated_at)VALUES('w','ticket','assignment','r','1','t')",[])?;Ok(())}).unwrap();
+        s.with_conn(|c| {
+            let stable_worker_id = worker_id().to_string();
+            c.execute(
+                "INSERT INTO ticket_worker_assignments(\
+                    workspace_id,ticket_id,assignment_id,runtime_id,worker_id,assigned_by,assigned_at\
+                 ) VALUES('w','ticket','assignment','r',?1,'test','t')",
+                [&stable_worker_id],
+            )?;
+            c.execute(
+                "INSERT INTO ticket_current_worker_assignments(\
+                    workspace_id,ticket_id,assignment_id,runtime_id,worker_id,updated_at\
+                 ) VALUES('w','ticket','assignment','r',?1,'t')",
+                [&stable_worker_id],
+            )?;
+            Ok(())
+        })
+        .unwrap();
         let p = s.plan_worker_removal(&req(), &inv()).unwrap();
         assert!(
             matches!(&p.blockers[..],[WorkerRemovalBlocker::CurrentAssignment{assignment_id,ticket_id}] if assignment_id=="assignment"&&ticket_id=="ticket")
@@ -1292,7 +1332,7 @@ mod tests {
         let runtime_only = WorkerRetentionInventory {
             workspace_id: "w".into(),
             runtime_id: "r".into(),
-            worker_id: WorkerId::new(2),
+            worker_id: WorkerId::from_legacy_u64(2),
             run_generation: 1,
             session_id: Some("orphan-session".into()),
             segment_ids: vec![],
@@ -1304,10 +1344,12 @@ mod tests {
             .unwrap();
         assert_eq!(diagnostics.len(), 2);
         assert!(diagnostics.iter().any(|item| {
-            item.worker_id == "2" && item.category == "runtime_aggregate_without_backend_registry"
+            item.worker_id == WorkerId::from_legacy_u64(2).to_string()
+                && item.category == "runtime_aggregate_without_backend_registry"
         }));
         assert!(diagnostics.iter().any(|item| {
-            item.worker_id == "1" && item.category == "backend_registry_without_runtime_aggregate"
+            item.worker_id == worker_id().to_string()
+                && item.category == "backend_registry_without_runtime_aggregate"
         }));
         let count: i64 = s
             .with_conn(|conn| {
@@ -1375,7 +1417,7 @@ mod tests {
             operation_id: p.operation_id.clone(),
             input_fingerprint: p.input_fingerprint.clone(),
             expected_worker_revision: p.worker_revision.clone(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             session_disposition: SessionDisposition::Purge,
             diagnostics_disposition: DiagnosticsDisposition::Purge,
             archive: None,
@@ -1394,7 +1436,7 @@ mod tests {
             operation_id: plan.operation_id.clone(),
             input_fingerprint: plan.input_fingerprint.clone(),
             expected_worker_revision: plan.worker_revision.clone(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             session_disposition: plan.session_disposition,
             diagnostics_disposition: plan.diagnostics_disposition,
             archive: None,
@@ -1408,15 +1450,15 @@ mod tests {
         store
             .begin_worker_removal("w", &plan.plan_id, &plan.input_fingerprint)
             .unwrap();
-        result.worker_id = WorkerId::new(2);
+        result.worker_id = WorkerId::from_legacy_u64(2);
         assert!(
             store
                 .commit_worker_removal("w", &plan.operation_id, &plan.input_fingerprint, &result)
                 .is_err()
         );
         let count: i64 = store.with_conn(|conn| conn.query_row(
-            "SELECT COUNT(*) FROM worker_registry WHERE workspace_id='w' AND runtime_id='r' AND runtime_worker_id=1",
-            [],
+            "SELECT COUNT(*) FROM worker_registry WHERE workspace_id='w' AND runtime_id='r' AND worker_id=?1",
+            [worker_id().to_string()],
             |row| row.get(0),
         ).map_err(StoreError::from)).unwrap();
         assert_eq!(count, 1);
@@ -1433,7 +1475,7 @@ mod tests {
             workspace_id: "w".into(),
             worker: RuntimeWorkerRef {
                 runtime_id: "r".into(),
-                worker_id: "1".into(),
+                worker_id: worker_id().to_string(),
             },
             display_name: "stale".into(),
             profile: None,
@@ -1447,8 +1489,8 @@ mod tests {
         };
         store.upsert_worker_registry(&stale).unwrap();
         let revision: String = store.with_conn(|conn| conn.query_row(
-            "SELECT updated_at FROM worker_registry WHERE workspace_id='w' AND runtime_id='r' AND runtime_worker_id=1",
-            [],
+            "SELECT updated_at FROM worker_registry WHERE workspace_id='w' AND runtime_id='r' AND worker_id=?1",
+            [worker_id().to_string()],
             |row| row.get(0),
         ).map_err(StoreError::from)).unwrap();
         assert_eq!(revision, "rev1");
@@ -1459,7 +1501,7 @@ mod tests {
             assignment_id: "new-assignment".into(),
             worker: RuntimeWorkerRef {
                 runtime_id: "r".into(),
-                worker_id: "1".into(),
+                worker_id: worker_id().to_string(),
             },
             assigned_by: "test".into(),
             assigned_at: "t".into(),
@@ -1488,7 +1530,7 @@ mod tests {
             operation_id: prepared.plan.operation_id.clone(),
             input_fingerprint: prepared.plan.input_fingerprint.clone(),
             expected_worker_revision: prepared.plan.worker_revision.clone(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             session_disposition: prepared.plan.session_disposition,
             diagnostics_disposition: prepared.plan.diagnostics_disposition,
             archive: None,
@@ -1522,7 +1564,7 @@ mod tests {
             operation_id: prepared.plan.operation_id.clone(),
             input_fingerprint: prepared.plan.input_fingerprint.clone(),
             expected_worker_revision: prepared.plan.worker_revision.clone(),
-            worker_id: WorkerId::new(1),
+            worker_id: worker_id(),
             session_disposition: prepared.plan.session_disposition,
             diagnostics_disposition: prepared.plan.diagnostics_disposition,
             archive: Some(worker_runtime::retention::WorkerSessionArchiveManifest {
@@ -1530,7 +1572,7 @@ mod tests {
                 archive_id: prepared.plan.archive_id.clone().unwrap(),
                 workspace_id: "w".into(),
                 source_runtime_id: "r".into(),
-                source_worker_id: WorkerId::new(1),
+                source_worker_id: worker_id(),
                 source_session_id: "s".into(),
                 segment_ids: vec!["a".into()],
                 source_created_at: "created".into(),

crates/workspace-server/src/runtime_subscription_tests.rs

@@ -8,6 +8,7 @@ use worker_runtime::execution::{
     WorkerExecutionBackend, WorkerExecutionHandle, WorkerExecutionOperation, WorkerExecutionResult,
     WorkerExecutionRunState, WorkerExecutionSpawnRequest, WorkerExecutionSpawnResult,
 };
+use worker_runtime::identity::WorkerId;
 use worker_runtime::profile_archive::{ProfileSourceArchiveRef, ProfileSourceGraphSummary};
 
 #[derive(Debug)]
@@ -57,8 +58,8 @@ const TOKEN: &str = "runtime-subscription-test-token";
 
 fn create_request(name: &str) -> CreateWorkerRequest {
     CreateWorkerRequest {
-        idempotency_key: None,
-        idempotency_fingerprint: None,
+        worker_id: WorkerId::now_v7(),
+        create_fingerprint: "test-create".to_string(),
         profile: ProfileSelector::Builtin("builtin:companion".to_string()),
         display_name: Some(name.to_string()),
         config_bundle: None,

crates/workspace-server/src/server.rs

@@ -76,11 +76,12 @@ use crate::hosts::{
     EmbeddedWorkerRuntime, HostSummary, RemoteRuntimeConfig, RemoteWorkerRuntime,
     RuntimeDiagnostic, RuntimeRegistry, RuntimeRegistryError, RuntimeRegistryUnregisterResult,
     RuntimeSummary, TicketWorkerRole, WorkerCapabilitySummary, WorkerCompletionsRequest,
-    WorkerCompletionsResult, WorkerControlOperation, WorkerImplementationSummary, WorkerInputKind,
-    WorkerInputRequest, WorkerInputResult, WorkerLifecycleRequest, WorkerLifecycleResult,
-    WorkerOperationState, WorkerRestoreResult, WorkerSpawnAcceptanceRequirement, WorkerSpawnIntent,
-    WorkerSpawnRequest, WorkerSpawnResult, WorkerSpawnWorkingDirectoryRequest, WorkerSummary,
-    WorkerTicketAssignmentRequest, WorkerWorkspaceSummary,
+    WorkerCompletionsResult, WorkerControlOperation, WorkerCreateBinding,
+    WorkerImplementationSummary, WorkerInputKind, WorkerInputRequest, WorkerInputResult,
+    WorkerLifecycleRequest, WorkerLifecycleResult, WorkerOperationState, WorkerRestoreResult,
+    WorkerSpawnAcceptanceRequirement, WorkerSpawnIntent, WorkerSpawnRequest, WorkerSpawnResult,
+    WorkerSpawnWorkingDirectoryRequest, WorkerSummary, WorkerTicketAssignmentRequest,
+    WorkerWorkspaceSummary, worker_spawn_create_fingerprint,
 };
 use crate::identity::WorkspaceIdentity;
 use crate::memory_backend::execute_memory_backend_operation_with_authority;
@@ -120,7 +121,7 @@ use worker_runtime::http_server::{
     RuntimeHttpConfigBundleAvailabilityResponse, RuntimeHttpConfigBundlesResponse,
     RuntimeHttpSummaryResponse, RuntimeHttpWorkerResponse, RuntimeHttpWorkersResponse,
 };
-use worker_runtime::identity::RuntimeWorkerRef;
+use worker_runtime::identity::{RuntimeWorkerRef, WorkerId};
 
 const EMBEDDED_WORKER_RUNTIME_ID: &str = "embedded-worker-runtime";
 
@@ -887,7 +888,40 @@ impl WorkspaceApi {
                 &now_registry_timestamp(),
             )?;
         }
-        let result = match self.runtime.spawn_worker(runtime_id, request) {
+        let create_fingerprint = worker_spawn_create_fingerprint(&request)
+            .map_err(|message| Error::Config(message.to_string()))?;
+        let allocation_key = request
+            .resolved_control_operation
+            .as_ref()
+            .map(|operation| operation.operation_id.clone())
+            .or_else(|| {
+                request
+                    .ticket_assignment
+                    .as_ref()
+                    .map(|assignment| assignment.operation_id.clone())
+            })
+            .unwrap_or_else(|| format!("manual:{}", WorkerId::now_v7()));
+        let worker_id = self
+            .config_store
+            .reserve_worker_create(
+                &self.config.workspace_id,
+                runtime_id,
+                &allocation_key,
+                &create_fingerprint,
+            )
+            .map_err(|error| Error::RuntimeOperationFailed {
+                runtime_id: runtime_id.to_string(),
+                code: "workspace_worker_allocation_conflict".to_string(),
+                message: error.to_string(),
+            })?;
+        let create_binding = WorkerCreateBinding {
+            worker_id,
+            create_fingerprint,
+        };
+        let result = match self
+            .runtime
+            .spawn_worker(runtime_id, create_binding, request)
+        {
             Ok(result) => result,
             Err(error) => {
                 if let Some((workdir_id, reservation_id)) = attachment_reservation.as_ref() {
@@ -911,6 +945,24 @@ impl WorkspaceApi {
             return Ok(result);
         };
         let worker_ref = worker.worker.clone();
+        if worker_ref.worker_id != worker_id.to_string() {
+            if let Some((workdir_id, reservation_id)) = attachment_reservation.as_ref() {
+                let _ = self.store.release_worker_workdir_attachment_reservation(
+                    &self.config.workspace_id,
+                    workdir_id,
+                    reservation_id,
+                );
+            }
+            return Err(Error::RuntimeOperationFailed {
+                runtime_id: runtime_id.to_string(),
+                code: "workspace_worker_identity_mismatch".to_string(),
+                message: format!(
+                    "Runtime returned Worker {} for reserved Workspace Worker {}",
+                    worker_ref.worker_id, worker_id
+                ),
+            }
+            .into());
+        }
         let replacement = match self
             .runtime
             .replace_worker_workspace_api(&worker_ref, workspace_api)
@@ -1017,6 +1069,9 @@ impl WorkspaceApi {
                 return Err(error);
             }
         }
+        self.config_store
+            .complete_worker_create_reservation(&self.config.workspace_id, worker_id)
+            .map_err(|error| Error::Config(error.to_string()))?;
         Ok(result)
     }
 
@@ -11889,11 +11944,11 @@ fn working_directory_request_for_browser(
     })
 }
 
-fn parse_runtime_worker_id_for_registry(worker_id: &str) -> ApiResult<u64> {
-    worker_id.parse::<u64>().map_err(|_| {
+fn parse_runtime_worker_id_for_registry(worker_id: &str) -> ApiResult<WorkerId> {
+    worker_id.parse::<WorkerId>().map_err(|_| {
         settings_bad_request(
             "workspace_worker_id_invalid",
-            "Runtime Worker id must be an unsigned integer",
+            "Workspace Worker id must be a UUIDv7",
         )
     })
 }
@@ -12420,6 +12475,13 @@ mod tests {
         ObjectiveTicketLinkRecord, SqliteWorkspaceStore, WorkspaceRecord,
     };
 
+    fn test_create_binding() -> WorkerCreateBinding {
+        WorkerCreateBinding {
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "sha256:test-create".to_string(),
+        }
+    }
+
     #[test]
     fn reopen_confirmation_rejects_api_token_actor_before_session_resolution() {
         let mut headers = HeaderMap::new();
@@ -14084,6 +14146,7 @@ mod tests {
             .runtime
             .spawn_worker(
                 EMBEDDED_WORKER_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     requested_worker_name: Some(MEMORY_CONSOLIDATION_PROFILE.to_string()),
                     intent: WorkerSpawnIntent::WorkspaceOrchestrator,
@@ -14313,6 +14376,7 @@ mod tests {
             .runtime
             .spawn_worker(
                 EMBEDDED_WORKER_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     requested_worker_name: Some("notification-source".to_string()),
                     intent: WorkerSpawnIntent::TicketRole {
@@ -14533,13 +14597,21 @@ mod tests {
         };
         let source_worker = api
             .runtime
-            .spawn_worker(EMBEDDED_WORKER_RUNTIME_ID, spawn("source-worker"))
+            .spawn_worker(
+                EMBEDDED_WORKER_RUNTIME_ID,
+                test_create_binding(),
+                spawn("source-worker"),
+            )
             .unwrap()
             .worker
             .unwrap();
         let recipient_worker = api
             .runtime
-            .spawn_worker(EMBEDDED_WORKER_RUNTIME_ID, spawn("recipient-worker"))
+            .spawn_worker(
+                EMBEDDED_WORKER_RUNTIME_ID,
+                test_create_binding(),
+                spawn("recipient-worker"),
+            )
             .unwrap()
             .worker
             .unwrap();
@@ -14727,6 +14799,7 @@ mod tests {
             .runtime
             .spawn_worker(
                 EMBEDDED_WORKER_RUNTIME_ID,
+                test_create_binding(),
                 WorkerSpawnRequest {
                     requested_worker_name: Some("orchestrator-source".to_string()),
                     intent: WorkerSpawnIntent::TicketRole {
@@ -15037,9 +15110,25 @@ mod tests {
                 TEST_CREATED_AT,
             )
             .unwrap();
+        let reserved_worker_id = api
+            .config_store
+            .reserve_worker_create(
+                TEST_WORKSPACE_ID,
+                EMBEDDED_WORKER_RUNTIME_ID,
+                "pending-spawn-operation",
+                &pending_fingerprint,
+            )
+            .unwrap();
         let spawned_before_backend_failure = api
             .runtime
-            .spawn_worker(EMBEDDED_WORKER_RUNTIME_ID, pending_request.clone())
+            .spawn_worker(
+                EMBEDDED_WORKER_RUNTIME_ID,
+                WorkerCreateBinding {
+                    worker_id: reserved_worker_id,
+                    create_fingerprint: pending_fingerprint.clone(),
+                },
+                pending_request.clone(),
+            )
             .unwrap()
             .worker
             .unwrap();
@@ -16632,8 +16721,8 @@ mod tests {
     fn runtime_create_request() -> worker_runtime::catalog::CreateWorkerRequest {
         let bundle = runtime_test_bundle();
         worker_runtime::catalog::CreateWorkerRequest {
-            idempotency_key: None,
-            idempotency_fingerprint: None,
+            worker_id: WorkerId::now_v7(),
+            create_fingerprint: "test-create".to_string(),
             profile: worker_runtime::catalog::ProfileSelector::Builtin(
                 "builtin:companion".to_string(),
             ),
@@ -17847,6 +17936,7 @@ mod tests {
             .runtime
             .spawn_worker(
                 "embedded-worker-runtime",
+                test_create_binding(),
                 WorkerSpawnRequest {
                     intent: WorkerSpawnIntent::TicketRole {
                         ticket_id: "00001KVZSGT0Q".to_string(),

crates/workspace-server/src/store.rs

@@ -8,7 +8,7 @@ use rusqlite::{Connection, OptionalExtension, TransactionBehavior, params};
 use serde::{Deserialize, Serialize};
 use uuid::Uuid;
 
-use worker_runtime::identity::RuntimeWorkerRef;
+use worker_runtime::identity::{RuntimeWorkerRef, WorkerId};
 
 use crate::{Error, Result};
 
@@ -201,6 +201,11 @@ const MIGRATIONS: &[Migration] = &[
         name: "add Objective query indexes",
         apply: add_objective_query_indexes,
     },
+    Migration {
+        version: 37,
+        name: "promote Workspace Worker UUIDv7 identity",
+        apply: promote_workspace_worker_uuid_identity,
+    },
 ];
 
 struct Migration {
@@ -968,6 +973,95 @@ impl SqliteWorkspaceStore {
         f(&mut conn)
     }
 
+    pub(crate) fn reserve_worker_create(
+        &self,
+        workspace_id: &str,
+        runtime_id: &str,
+        allocation_key: &str,
+        create_fingerprint: &str,
+    ) -> Result<WorkerId> {
+        if allocation_key.trim().is_empty() || create_fingerprint.trim().is_empty() {
+            return Err(Error::InvalidInput(
+                "Worker create allocation key and fingerprint must be non-empty".to_string(),
+            ));
+        }
+        self.with_conn_mut(|conn| {
+            let tx = conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
+            let existing = tx
+                .query_row(
+                    "SELECT worker_id, runtime_id, create_fingerprint \
+                     FROM worker_create_reservations \
+                     WHERE workspace_id = ?1 AND allocation_key = ?2",
+                    params![workspace_id, allocation_key],
+                    |row| {
+                        Ok((
+                            row.get::<_, String>(0)?,
+                            row.get::<_, String>(1)?,
+                            row.get::<_, String>(2)?,
+                        ))
+                    },
+                )
+                .optional()?;
+            if let Some((worker_id, reserved_runtime_id, reserved_fingerprint)) = existing {
+                if reserved_runtime_id != runtime_id || reserved_fingerprint != create_fingerprint {
+                    return Err(Error::InvalidInput(format!(
+                        "Worker create allocation `{allocation_key}` was already used with different input"
+                    )));
+                }
+                return worker_id.parse::<WorkerId>().map_err(|_| {
+                    Error::Store(format!(
+                        "Worker create allocation `{allocation_key}` has a non-UUIDv7 worker id"
+                    ))
+                });
+            }
+
+            let worker_id = WorkerId::now_v7();
+            let now = chrono::Utc::now().to_rfc3339();
+            tx.execute(
+                "INSERT INTO worker_create_reservations(\
+                    workspace_id, allocation_key, worker_id, runtime_id, create_fingerprint,\
+                    state, created_at, updated_at\
+                 ) VALUES (?1, ?2, ?3, ?4, ?5, 'reserved', ?6, ?6)",
+                params![
+                    workspace_id,
+                    allocation_key,
+                    worker_id.to_string(),
+                    runtime_id,
+                    create_fingerprint,
+                    now
+                ],
+            )?;
+            tx.commit()?;
+            Ok(worker_id)
+        })
+    }
+
+    pub(crate) fn complete_worker_create_reservation(
+        &self,
+        workspace_id: &str,
+        worker_id: WorkerId,
+    ) -> Result<()> {
+        self.with_conn(|conn| {
+            let changed = conn.execute(
+                "UPDATE worker_create_reservations \
+                 SET state = 'created', updated_at = ?3 \
+                 WHERE workspace_id = ?1 AND worker_id = ?2",
+                params![
+                    workspace_id,
+                    worker_id.to_string(),
+                    chrono::Utc::now().to_rfc3339()
+                ],
+            )?;
+            if changed != 1 {
+                return Err(Error::Store(format!(
+                    "Worker create reservation {} was not found",
+                    worker_id
+                )));
+            }
+            Ok(())
+        })
+    }
+
     fn materialize_workspace_config(&self, workspace_id: &str, created_at: &str) -> Result<()> {
         self.with_conn_mut(|conn| {
             let tx = conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
@@ -2276,7 +2370,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                 "SELECT EXISTS(
                     SELECT 1 FROM worker_removal_operations
                     WHERE workspace_id = ?1 AND runtime_id = ?2
-                      AND CAST(worker_id AS INTEGER) = ?3
+                      AND worker_id = ?3
                       AND state IN ('executing', 'failed', 'succeeded')
                 )",
                 params![
@@ -2291,11 +2385,12 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             conn.execute(
                 r#"INSERT INTO worker_registry (
-                    workspace_id, runtime_id, runtime_worker_id, display_name, profile,
+                    workspace_id, runtime_id, worker_id, display_name, profile,
                     retention_state, transcript_ref, session_ref, summary_ref,
                     diagnostics_ref, created_at, updated_at
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12)
-                ON CONFLICT(workspace_id, runtime_id, runtime_worker_id) DO UPDATE SET
+                ON CONFLICT(workspace_id, worker_id) DO UPDATE SET
+                    runtime_id = excluded.runtime_id,
                     display_name = excluded.display_name,
                     profile = excluded.profile,
                     retention_state = CASE
@@ -2312,7 +2407,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                     SELECT 1 FROM worker_removal_operations retention
                     WHERE retention.workspace_id = excluded.workspace_id
                       AND retention.runtime_id = excluded.runtime_id
-                      AND CAST(retention.worker_id AS INTEGER) = excluded.runtime_worker_id
+                      AND retention.worker_id = excluded.worker_id
                       AND retention.state IN ('executing', 'failed', 'succeeded')
                 )"#,
                 params![
@@ -2342,7 +2437,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
         self.with_conn(|conn| {
             conn.query_row(
                 worker_registry_select_sql(
-                    "WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3",
+                    "WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3",
                 )
                 .as_str(),
                 params![workspace_id, worker.runtime_id, worker.worker_id],
@@ -2383,11 +2478,11 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             let changed = conn.execute(
                 r#"UPDATE worker_registry
                    SET retention_state = ?4, updated_at = ?5
-                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3
+                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3
                      AND NOT EXISTS (
                        SELECT 1 FROM worker_removal_operations retention
                        WHERE retention.workspace_id = ?1 AND retention.runtime_id = ?2
-                         AND CAST(retention.worker_id AS INTEGER) = ?3
+                         AND retention.worker_id = ?3
                          AND retention.state IN ('executing', 'failed')
                      )"#,
                 params![
@@ -2412,11 +2507,11 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             tx.execute(
                 r#"UPDATE worker_workdir_links
                    SET unlinked_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')
-                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3 AND unlinked_at IS NULL"#,
+                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL"#,
                 params![workspace_id, worker.runtime_id, worker.worker_id],
             )?;
             let changed = tx.execute(
-                "DELETE FROM worker_registry WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3",
+                "DELETE FROM worker_registry WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3",
                 params![workspace_id, worker.runtime_id, worker.worker_id],
             )?;
             tx.commit()?;
@@ -2440,7 +2535,6 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12)
                 ON CONFLICT (
                     workspace_id,
-                    controller_runtime_id,
                     controller_worker_id,
                     operation_id
                 ) DO NOTHING"#,
@@ -3281,9 +3375,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             tx.execute(
                 r#"INSERT INTO worker_workdir_links (
-                    workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                    workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, NULL)
-                ON CONFLICT(workspace_id, runtime_id, runtime_worker_id, workdir_id, role) DO UPDATE SET
+                ON CONFLICT(workspace_id, worker_id, workdir_id, role) DO UPDATE SET
                     linked_at = excluded.linked_at,
                     unlinked_at = NULL"#,
                 params![
@@ -3365,9 +3459,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             let active_for_worker = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                        FROM worker_workdir_links
-                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3 AND unlinked_at IS NULL"#,
+                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL"#,
                     params![
                         record.workspace_id,
                         record.worker.runtime_id,
@@ -3388,7 +3482,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             let active_for_workdir = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                        FROM worker_workdir_links
                        WHERE workspace_id = ?1 AND workdir_id = ?2 AND unlinked_at IS NULL"#,
                     params![record.workspace_id, record.workdir_id],
@@ -3403,9 +3497,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             let write = tx.execute(
                 r#"INSERT INTO worker_workdir_links (
-                    workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                    workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, NULL)
-                ON CONFLICT(workspace_id, runtime_id, runtime_worker_id, workdir_id, role) DO UPDATE SET
+                ON CONFLICT(workspace_id, worker_id, workdir_id, role) DO UPDATE SET
                     linked_at = excluded.linked_at,
                     unlinked_at = NULL"#,
                 params![
@@ -3445,9 +3539,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             )?;
             let active = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                        FROM worker_workdir_links
-                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3 AND unlinked_at IS NULL"#,
+                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL"#,
                     params![workspace_id, worker.runtime_id, worker.worker_id],
                     read_worker_workdir_link_record,
                 )
@@ -3467,7 +3561,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             let changed = tx.execute(
                 r#"UPDATE worker_workdir_links
                    SET unlinked_at = ?4
-                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3 AND unlinked_at IS NULL"#,
+                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL"#,
                 params![workspace_id, worker.runtime_id, worker.worker_id, unlinked_at],
             )?;
             if changed != 1 {
@@ -3493,7 +3587,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             let exists = conn.query_row(
                 r#"SELECT EXISTS(
                     SELECT 1 FROM worker_workdir_links
-                    WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3
+                    WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3
                 )"#,
                 params![workspace_id, worker.runtime_id, worker.worker_id],
                 |row| row.get(0),
@@ -3509,9 +3603,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
     ) -> Result<Vec<WorkerWorkdirLinkRecord>> {
         self.with_conn(|conn| {
             let mut stmt = conn.prepare(
-                r#"SELECT workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                    FROM worker_workdir_links
-                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND runtime_worker_id = ?3 AND unlinked_at IS NULL
+                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL
                    ORDER BY linked_at DESC"#,
             )?;
             let rows = stmt.query_map(
@@ -3530,7 +3624,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
     ) -> Result<Vec<WorkerWorkdirLinkRecord>> {
         self.with_conn(|conn| {
             let mut stmt = conn.prepare(
-                r#"SELECT workspace_id, runtime_id, runtime_worker_id, workdir_id, role, linked_at, unlinked_at
+                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
                    FROM worker_workdir_links
                    WHERE workspace_id = ?1 AND workdir_id = ?2 AND unlinked_at IS NULL
                    ORDER BY linked_at DESC"#,
@@ -3797,7 +3891,7 @@ fn read_worker_workdir_link_record(
 ) -> rusqlite::Result<WorkerWorkdirLinkRecord> {
     Ok(WorkerWorkdirLinkRecord {
         workspace_id: row.get(0)?,
-        worker: RuntimeWorkerRef::new(row.get::<_, String>(1)?, row.get::<_, u64>(2)?.to_string()),
+        worker: RuntimeWorkerRef::new(row.get::<_, String>(1)?, row.get::<_, String>(2)?),
         workdir_id: row.get(3)?,
         role: row.get(4)?,
         linked_at: row.get(5)?,
@@ -3880,7 +3974,7 @@ fn read_memory_staging_resolution_record(
 
 fn worker_registry_select_sql(where_clause: &str) -> String {
     format!(
-        "SELECT workspace_id, runtime_id, runtime_worker_id, display_name, profile, \
+        "SELECT workspace_id, runtime_id, worker_id, display_name, profile, \
          retention_state, transcript_ref, session_ref, summary_ref, diagnostics_ref, \
          created_at, updated_at FROM worker_registry {where_clause}"
     )
@@ -3889,7 +3983,7 @@ fn worker_registry_select_sql(where_clause: &str) -> String {
 fn read_worker_registry_record(row: &rusqlite::Row<'_>) -> rusqlite::Result<WorkerRegistryRecord> {
     Ok(WorkerRegistryRecord {
         workspace_id: row.get(0)?,
-        worker: RuntimeWorkerRef::new(row.get::<_, String>(1)?, row.get::<_, u64>(2)?.to_string()),
+        worker: RuntimeWorkerRef::new(row.get::<_, String>(1)?, row.get::<_, String>(2)?),
         display_name: row.get(3)?,
         profile: row.get(4)?,
         retention_state: row.get(5)?,
@@ -3912,11 +4006,8 @@ fn read_worker_control_grant_record(
     Ok(WorkerControlGrantRecord {
         workspace_id: row.get(0)?,
         grant_id: row.get(1)?,
-        controller: RuntimeWorkerRef::new(
-            row.get::<_, String>(2)?,
-            row.get::<_, u64>(3)?.to_string(),
-        ),
-        subject: RuntimeWorkerRef::new(row.get::<_, String>(4)?, row.get::<_, u64>(5)?.to_string()),
+        controller: RuntimeWorkerRef::new(row.get::<_, String>(2)?, row.get::<_, String>(3)?),
+        subject: RuntimeWorkerRef::new(row.get::<_, String>(4)?, row.get::<_, String>(5)?),
         relation: row.get(6)?,
         origin: row.get(7)?,
         permissions,
@@ -5069,6 +5160,201 @@ fn add_objective_query_indexes(conn: &Connection) -> Result<()> {
     Ok(())
 }
 
+fn promote_workspace_worker_uuid_identity(conn: &Connection) -> Result<()> {
+    conn.execute_batch(
+        r#"
+        PRAGMA defer_foreign_keys = ON;
+        CREATE TEMP TABLE worker_identity_v37 (
+            workspace_id TEXT NOT NULL,
+            runtime_id TEXT NOT NULL,
+            runtime_worker_id INTEGER NOT NULL,
+            worker_id TEXT NOT NULL UNIQUE,
+            PRIMARY KEY (workspace_id, runtime_id, runtime_worker_id)
+        );
+        "#,
+    )?;
+
+    let legacy_workers = {
+        let mut statement = conn.prepare(
+            "SELECT workspace_id, runtime_id, runtime_worker_id FROM worker_registry \
+             ORDER BY workspace_id, runtime_id, runtime_worker_id",
+        )?;
+        statement
+            .query_map([], |row| {
+                Ok((
+                    row.get::<_, String>(0)?,
+                    row.get::<_, String>(1)?,
+                    row.get::<_, i64>(2)?,
+                ))
+            })?
+            .collect::<std::result::Result<Vec<_>, _>>()?
+    };
+    for (workspace_id, runtime_id, runtime_worker_id) in legacy_workers {
+        conn.execute(
+            "INSERT INTO worker_identity_v37(\
+                workspace_id, runtime_id, runtime_worker_id, worker_id\
+             ) VALUES (?1, ?2, ?3, ?4)",
+            params![
+                workspace_id,
+                runtime_id,
+                runtime_worker_id,
+                WorkerId::from_legacy_binding(
+                    &workspace_id,
+                    &runtime_id,
+                    u64::try_from(runtime_worker_id).map_err(|_| {
+                        Error::InvalidInput(format!(
+                            "legacy Runtime Worker id {runtime_worker_id} is negative"
+                        ))
+                    })?,
+                )
+                .to_string()
+            ],
+        )?;
+    }
+
+    conn.execute_batch(
+        r#"
+        CREATE TABLE worker_registry_v37 (
+            workspace_id TEXT NOT NULL,
+            worker_id TEXT NOT NULL,
+            runtime_id TEXT NOT NULL,
+            display_name TEXT NOT NULL,
+            profile TEXT,
+            retention_state TEXT NOT NULL CHECK (retention_state IN ('normal', 'pinned')),
+            transcript_ref TEXT,
+            session_ref TEXT,
+            summary_ref TEXT,
+            diagnostics_ref TEXT,
+            created_at TEXT NOT NULL,
+            updated_at TEXT NOT NULL,
+            PRIMARY KEY (workspace_id, worker_id),
+            FOREIGN KEY (workspace_id) REFERENCES workspaces(workspace_id) ON DELETE CASCADE
+        );
+        INSERT INTO worker_registry_v37(
+            workspace_id, worker_id, runtime_id, display_name, profile,
+            retention_state, transcript_ref, session_ref, summary_ref,
+            diagnostics_ref, created_at, updated_at
+        )
+        SELECT r.workspace_id, m.worker_id, r.runtime_id, r.display_name, r.profile,
+               r.retention_state, r.transcript_ref, r.session_ref, r.summary_ref,
+               r.diagnostics_ref, r.created_at, r.updated_at
+        FROM worker_registry r
+        JOIN worker_identity_v37 m
+          ON m.workspace_id = r.workspace_id
+         AND m.runtime_id = r.runtime_id
+         AND m.runtime_worker_id = r.runtime_worker_id;
+
+        CREATE TABLE worker_workdir_links_v37 (
+            workspace_id TEXT NOT NULL,
+            runtime_id TEXT NOT NULL,
+            worker_id TEXT NOT NULL,
+            workdir_id TEXT NOT NULL,
+            role TEXT NOT NULL,
+            linked_at TEXT NOT NULL,
+            unlinked_at TEXT,
+            PRIMARY KEY (workspace_id, worker_id, workdir_id, role),
+            FOREIGN KEY (workspace_id, worker_id)
+                REFERENCES worker_registry_v37(workspace_id, worker_id) ON DELETE CASCADE,
+            FOREIGN KEY (workspace_id, workdir_id)
+                REFERENCES workdir_registry(workspace_id, workdir_id) ON DELETE CASCADE
+        );
+        INSERT INTO worker_workdir_links_v37(
+            workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+        )
+        SELECT l.workspace_id, l.runtime_id, m.worker_id, l.workdir_id, l.role, l.linked_at, l.unlinked_at
+        FROM worker_workdir_links l
+        JOIN worker_identity_v37 m
+          ON m.workspace_id = l.workspace_id
+         AND m.runtime_id = l.runtime_id
+         AND m.runtime_worker_id = l.runtime_worker_id;
+
+        CREATE TABLE worker_control_grants_v37 (
+            grant_id TEXT NOT NULL,
+            workspace_id TEXT NOT NULL,
+            controller_runtime_id TEXT NOT NULL,
+            controller_worker_id TEXT NOT NULL,
+            subject_runtime_id TEXT NOT NULL,
+            subject_worker_id TEXT NOT NULL,
+            relation TEXT NOT NULL,
+            origin TEXT NOT NULL,
+            permissions_json TEXT NOT NULL,
+            operation_id TEXT NOT NULL,
+            created_at TEXT NOT NULL,
+            revoked_at TEXT,
+            PRIMARY KEY (workspace_id, grant_id),
+            UNIQUE (workspace_id, controller_worker_id, operation_id),
+            FOREIGN KEY (workspace_id, controller_worker_id)
+                REFERENCES worker_registry_v37(workspace_id, worker_id) ON DELETE CASCADE,
+            FOREIGN KEY (workspace_id, subject_worker_id)
+                REFERENCES worker_registry_v37(workspace_id, worker_id) ON DELETE CASCADE
+        );
+        INSERT INTO worker_control_grants_v37(
+            grant_id, workspace_id,
+            controller_runtime_id, controller_worker_id,
+            subject_runtime_id, subject_worker_id,
+            relation, origin, permissions_json, operation_id,
+            created_at, revoked_at
+        )
+        SELECT g.grant_id, g.workspace_id,
+               g.controller_runtime_id, controller.worker_id,
+               g.subject_runtime_id, subject.worker_id,
+               g.relation, g.origin, g.permissions_json, g.operation_id,
+               g.created_at, g.revoked_at
+        FROM worker_control_grants g
+        JOIN worker_identity_v37 controller
+          ON controller.workspace_id = g.workspace_id
+         AND controller.runtime_id = g.controller_runtime_id
+         AND controller.runtime_worker_id = g.controller_worker_id
+        JOIN worker_identity_v37 subject
+          ON subject.workspace_id = g.workspace_id
+         AND subject.runtime_id = g.subject_runtime_id
+         AND subject.runtime_worker_id = g.subject_worker_id;
+
+        DROP TABLE worker_control_grants;
+        DROP TABLE worker_workdir_links;
+        DROP TABLE worker_registry;
+        ALTER TABLE worker_registry_v37 RENAME TO worker_registry;
+        ALTER TABLE worker_workdir_links_v37 RENAME TO worker_workdir_links;
+        ALTER TABLE worker_control_grants_v37 RENAME TO worker_control_grants;
+        CREATE INDEX worker_registry_runtime
+            ON worker_registry(workspace_id, runtime_id, worker_id);
+        CREATE INDEX worker_workdir_links_workdir
+            ON worker_workdir_links(workspace_id, workdir_id);
+        CREATE UNIQUE INDEX worker_workdir_links_active_worker_unique
+            ON worker_workdir_links(workspace_id, worker_id)
+            WHERE unlinked_at IS NULL;
+        CREATE UNIQUE INDEX worker_workdir_links_active_workdir_unique
+            ON worker_workdir_links(workspace_id, workdir_id)
+            WHERE unlinked_at IS NULL;
+        CREATE INDEX worker_control_grants_controller
+            ON worker_control_grants(
+                workspace_id, controller_worker_id, revoked_at
+            );
+        CREATE INDEX worker_control_grants_subject
+            ON worker_control_grants(
+                workspace_id, subject_worker_id, revoked_at
+            );
+        CREATE TABLE worker_create_reservations (
+            workspace_id TEXT NOT NULL,
+            allocation_key TEXT NOT NULL,
+            worker_id TEXT NOT NULL,
+            runtime_id TEXT NOT NULL,
+            create_fingerprint TEXT NOT NULL,
+            state TEXT NOT NULL CHECK (state IN ('reserved', 'created')),
+            created_at TEXT NOT NULL,
+            updated_at TEXT NOT NULL,
+            PRIMARY KEY (workspace_id, allocation_key),
+            UNIQUE (workspace_id, worker_id),
+            FOREIGN KEY (workspace_id) REFERENCES workspaces(workspace_id) ON DELETE CASCADE
+        );
+        CREATE INDEX worker_create_reservations_worker
+            ON worker_create_reservations(workspace_id, worker_id);
+        DROP TABLE worker_identity_v37;
+        "#,
+    )?;
+    Ok(())
+}
+
 fn remove_worker_control_delegation_authority(conn: &Connection) -> Result<()> {
     let mut statement =
         conn.prepare("SELECT workspace_id, grant_id, permissions_json FROM worker_control_grants")?;
@@ -5822,8 +6108,53 @@ INSERT INTO worker_control_grants (
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 36);
+        assert_eq!(current_schema_version(&conn).unwrap(), 37);
         assert!(!table_exists(&conn, "worker_control_delegation_operations").unwrap());
+        let controller_worker_id: String = conn
+            .query_row(
+                "SELECT worker_id FROM worker_registry WHERE display_name = 'Controller'",
+                [],
+                |row| row.get(0),
+            )
+            .unwrap();
+        assert_eq!(
+            controller_worker_id,
+            WorkerId::from_legacy_binding("workspace-a", "runtime-a", 1).to_string()
+        );
+        let (grant_controller, grant_subject): (String, String) = conn
+            .query_row(
+                "SELECT controller_worker_id, subject_worker_id \
+                 FROM worker_control_grants WHERE grant_id = 'spawned'",
+                [],
+                |row| Ok((row.get(0)?, row.get(1)?)),
+            )
+            .unwrap();
+        assert_eq!(grant_controller, controller_worker_id);
+        assert_eq!(
+            grant_subject,
+            WorkerId::from_legacy_binding("workspace-a", "runtime-a", 2).to_string()
+        );
+        let worker_registry_pk = {
+            let mut statement = conn.prepare("PRAGMA table_info(worker_registry)").unwrap();
+            statement
+                .query_map([], |row| {
+                    Ok((row.get::<_, String>(1)?, row.get::<_, i64>(5)?))
+                })
+                .unwrap()
+                .filter_map(|row| {
+                    let (name, position) = row.unwrap();
+                    (position > 0).then_some((position, name))
+                })
+                .collect::<Vec<_>>()
+        };
+        assert_eq!(
+            worker_registry_pk,
+            vec![
+                (1, "workspace_id".to_string()),
+                (2, "worker_id".to_string())
+            ]
+        );
+
         let (permissions_json, revoked_at): (String, Option<String>) = conn
             .query_row(
                 "SELECT permissions_json, revoked_at FROM worker_control_grants WHERE grant_id = 'spawned'",
@@ -5870,7 +6201,7 @@ INSERT INTO worker_control_grants (
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 36);
+        assert_eq!(current_schema_version(&conn).unwrap(), 37);
         assert!(table_exists(&conn, "worker_workdir_attachment_reservations").unwrap());
     }
 
@@ -5903,7 +6234,7 @@ CREATE TABLE flow_events (event_id TEXT PRIMARY KEY);
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 36);
+        assert_eq!(current_schema_version(&conn).unwrap(), 37);
         assert!(table_exists(&conn, "flow_sources").unwrap());
         assert!(table_exists(&conn, "flow_source_revisions").unwrap());
         assert!(!table_exists(&conn, "flow_instances").unwrap());
@@ -5970,7 +6301,7 @@ INSERT INTO worker_workdir_attachment_reservations (
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 36);
+        assert_eq!(current_schema_version(&conn).unwrap(), 37);
         let repositories_sql: String = conn
             .query_row(
                 "SELECT sql FROM sqlite_master WHERE type = 'table' AND name = 'repositories'",
@@ -6150,7 +6481,7 @@ INSERT INTO workdir_registry (
         let db = dir.path().join("control-plane.sqlite");
         let store = SqliteWorkspaceStore::open(&db).unwrap();
 
-        assert_eq!(store.schema_version().await.unwrap(), 36);
+        assert_eq!(store.schema_version().await.unwrap(), 37);
         assert!(
             !store
                 .with_conn(|conn| table_exists(conn, "worker_workspace_credentials"))
@@ -6167,13 +6498,64 @@ INSERT INTO workdir_registry (
         store.upsert_workspace(&record).await.unwrap();
 
         let reopened = SqliteWorkspaceStore::open(&db).unwrap();
-        assert_eq!(reopened.schema_version().await.unwrap(), 36);
+        assert_eq!(reopened.schema_version().await.unwrap(), 37);
         assert_eq!(
             reopened.get_workspace("local-dev").await.unwrap(),
             Some(record)
         );
     }
 
+    #[tokio::test]
+    async fn worker_create_reservation_allocates_uuid_before_runtime_and_replays_exact_input() {
+        let dir = tempfile::tempdir().unwrap();
+        let store = SqliteWorkspaceStore::open(dir.path().join("server.db")).unwrap();
+        store
+            .upsert_workspace(&WorkspaceRecord {
+                workspace_id: "workspace-a".to_string(),
+                owner_account_id: None,
+                display_name: "Workspace A".to_string(),
+                state: "active".to_string(),
+                created_at: "2026-08-06T00:00:00Z".to_string(),
+                updated_at: "2026-08-06T00:00:00Z".to_string(),
+            })
+            .await
+            .unwrap();
+
+        let reserved = store
+            .reserve_worker_create("workspace-a", "arcadia", "operation-1", "sha256:one")
+            .unwrap();
+        assert_eq!(
+            reserved.as_uuid().get_version(),
+            Some(uuid::Version::SortRand)
+        );
+        assert_eq!(
+            store
+                .reserve_worker_create("workspace-a", "arcadia", "operation-1", "sha256:one")
+                .unwrap(),
+            reserved
+        );
+        assert!(
+            store
+                .reserve_worker_create("workspace-a", "arcadia", "operation-1", "sha256:different")
+                .is_err()
+        );
+        store
+            .complete_worker_create_reservation("workspace-a", reserved)
+            .unwrap();
+        let state: String = store
+            .with_conn(|conn| {
+                conn.query_row(
+                    "SELECT state FROM worker_create_reservations \
+                     WHERE workspace_id = 'workspace-a' AND worker_id = ?1",
+                    [reserved.to_string()],
+                    |row| row.get(0),
+                )
+                .map_err(Error::from)
+            })
+            .unwrap();
+        assert_eq!(state, "created");
+    }
+
     #[tokio::test]
     async fn workspace_flow_sources_keep_revisions_and_builtins_stay_resources() {
         let dir = tempfile::tempdir().unwrap();
@@ -6528,6 +6910,7 @@ INSERT INTO workdir_registry (
             "artifacts",
             "audit_events",
             "worker_registry",
+            "worker_create_reservations",
             "ticket_worker_assignments",
             "ticket_current_worker_assignments",
             "ticket_worker_assignment_events",
@@ -6607,8 +6990,8 @@ INSERT INTO workdir_registry (
             "worker_registry",
             [
                 "workspace_id",
+                "worker_id",
                 "runtime_id",
-                "runtime_worker_id",
                 "display_name",
                 "profile",
                 "retention_state",
@@ -6714,7 +7097,7 @@ INSERT INTO workdir_registry (
         .unwrap();
 
         let store = SqliteWorkspaceStore::from_connection(conn).unwrap();
-        assert_eq!(store.schema_version().await.unwrap(), 36);
+        assert_eq!(store.schema_version().await.unwrap(), 37);
 
         store
             .with_conn(|conn| {
@@ -6903,7 +7286,7 @@ CREATE TABLE ticket_assignment_operations (
     #[tokio::test]
     async fn repository_records_round_trip() {
         let store = SqliteWorkspaceStore::in_memory().unwrap();
-        assert_eq!(store.schema_version().await.unwrap(), 36);
+        assert_eq!(store.schema_version().await.unwrap(), 37);
         let workspace = WorkspaceRecord {
             workspace_id: "local-dev".to_string(),
             owner_account_id: None,
@@ -6969,7 +7352,7 @@ CREATE TABLE ticket_assignment_operations (
     #[tokio::test]
     async fn memory_authority_records_round_trip_and_close_staging() {
         let store = SqliteWorkspaceStore::in_memory().unwrap();
-        assert_eq!(store.schema_version().await.unwrap(), 36);
+        assert_eq!(store.schema_version().await.unwrap(), 37);
         let workspace = WorkspaceRecord {
             workspace_id: "local-dev".to_string(),
             owner_account_id: None,
@@ -7360,7 +7743,7 @@ CREATE TABLE ticket_assignment_operations (
     #[tokio::test]
     async fn account_and_login_records_round_trip() {
         let store = SqliteWorkspaceStore::in_memory().unwrap();
-        assert_eq!(store.schema_version().await.unwrap(), 36);
+        assert_eq!(store.schema_version().await.unwrap(), 37);
         let now = "2026-07-22T00:00:00Z".to_string();
         let account = AccountRecord {
             account_id: "acct-user-alice".to_string(),