feat: support multiple worker workdir attachments

crates/client/src/backend_runtime.rs

@@ -943,7 +943,7 @@ mod tests {
             profile: Some("builtin:coder".to_string()),
             ticket_assignment: None,
             initial_submit: Vec::new(),
-            working_directory: None,
+            workdir_attachments: Vec::new(),
             control_operation_id: None,
         };
 
@@ -964,7 +964,7 @@ mod tests {
         assert_eq!(body["display_name"], "Coder one");
         assert_eq!(body["profile"], "builtin:coder");
         assert_eq!(body["initial_submit"], serde_json::json!([]));
-        assert_eq!(body["working_directory"], serde_json::Value::Null);
+        assert_eq!(body["workdir_attachments"], serde_json::json!([]));
     }
 
     #[test]
@@ -1014,29 +1014,35 @@ mod tests {
             "state": "idle",
             "implementation": {"kind": "worker", "display_hint": "Coder"},
             "capabilities": {"can_stop": true, "can_spawn_followup": false},
-            "working_directory": {
-                "working_directory_id": "wd-1",
-                "repository_key": "main",
-                "materializer_kind": "runtime_git_clone",
-                "status": "active",
-                "occupied_by": {
-                    "runtime_id": "arcadia",
-                    "worker_id": "worker-opaque-64",
-                    "display_name": "Coder",
-                    "linked_at": "2026-08-12T00:00:00Z"
+            "workdir_attachments": [{
+                "alias": "checkout",
+                "working_directory": {
+                    "working_directory_id": "wd-1",
+                    "repository_key": "main",
+                    "materializer_kind": "runtime_git_clone",
+                    "status": "active",
+                    "occupied_by": {
+                        "runtime_id": "arcadia",
+                        "worker_id": "worker-opaque-64",
+                        "display_name": "Coder",
+                        "linked_at": "2026-08-12T00:00:00Z"
+                    }
                 }
-            }
+            }]
         });
 
         let worker: BackendWorkerSummary = serde_json::from_value(payload.clone()).unwrap();
-        let workdir = worker.working_directory.unwrap();
+        let attachment = worker.workdir_attachments.into_iter().next().unwrap();
+        assert_eq!(attachment.alias, "checkout");
+        let workdir = attachment.working_directory;
         assert_eq!(workdir.repository_key, "main");
         let occupied_by = workdir.occupied_by.expect("occupied Workdir");
         assert_eq!(occupied_by.runtime_id, "arcadia");
         assert_eq!(occupied_by.worker_id, "worker-opaque-64");
 
         let mut stale = payload;
-        stale["working_directory"]["occupied_by"]["runtime_worker_id"] = serde_json::json!(64);
+        stale["workdir_attachments"][0]["working_directory"]["occupied_by"]["runtime_worker_id"] =
+            serde_json::json!(64);
         assert!(serde_json::from_value::<BackendWorkerSummary>(stale).is_err());
     }
 

crates/client/src/workspace_product.rs

@@ -312,7 +312,7 @@ impl BackendWorkspaceProductClient {
             initial_submit: vec![protocol::Segment::Text {
                 content: format!("Please handle intake for Ticket {ticket_id}."),
             }],
-            working_directory: None,
+            workdir_attachments: Vec::new(),
             control_operation_id: None,
         };
         let response: BrowserCreateWorkerResponse =

crates/protocol/src/subscription.rs

@@ -572,6 +572,41 @@ pub enum SubscriptionWorkerAvailability {
     Unavailable,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+pub struct SubscriptionWorkerWorkdirAttachment {
+    /// Stable Worker-local routing alias.
+    pub alias: String,
+    /// Runtime-internal Repository id. Workspace-facing TypeScript contracts
+    /// omit this field and require `repository_key` from the Server projection.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[cfg_attr(feature = "typescript", ts(skip))]
+    pub repository_id: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub repository_key: Option<String>,
+    pub working_directory_id: SubscriptionWorkdirId,
+}
+
+impl SubscriptionWorkerWorkdirAttachment {
+    pub fn validate(&self) -> Result<(), SubscriptionValidationError> {
+        validate_identifier(
+            "workdir_attachment_alias",
+            &self.alias,
+            MAX_RESOURCE_ID_BYTES,
+        )?;
+        self.working_directory_id.validate()?;
+        match (&self.repository_id, &self.repository_key) {
+            (Some(repository_id), None) => {
+                validate_identifier("repository_id", repository_id, MAX_RESOURCE_ID_BYTES)
+            }
+            (None, Some(repository_key)) => validate_repository_key(repository_key),
+            _ => Err(SubscriptionValidationError::InvalidIdentifier {
+                field: "repository_authority",
+            }),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 pub struct SubscriptionWorker {
@@ -604,15 +639,8 @@ pub struct SubscriptionWorker {
     pub display_name: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub profile: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    #[cfg_attr(feature = "typescript", ts(skip))]
-    pub repository_id: Option<String>,
-    /// Workspace-facing Repository key. Runtime producers leave this unset and
-    /// Workspace Server projections replace `repository_id` with this field.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub repository_key: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory_id: Option<SubscriptionWorkdirId>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<SubscriptionWorkerWorkdirAttachment>,
 }
 
 impl SubscriptionWorker {
@@ -624,19 +652,20 @@ impl SubscriptionWorker {
         if let Some(resource_key) = &self.resource_key {
             validate_identifier("resource_key", resource_key, MAX_RESOURCE_ID_BYTES)?;
         }
-        if let Some(repository_id) = &self.repository_id {
-            validate_identifier("repository_id", repository_id, MAX_RESOURCE_ID_BYTES)?;
-        }
-        if let Some(repository_key) = &self.repository_key {
-            validate_repository_key(repository_key)?;
-        }
-        if self.repository_id.is_some() && self.repository_key.is_some() {
-            return Err(SubscriptionValidationError::InvalidIdentifier {
-                field: "repository_authority",
-            });
-        }
-        if let Some(working_directory_id) = &self.working_directory_id {
-            working_directory_id.validate()?;
+        let mut aliases = HashSet::new();
+        let mut workdir_ids = HashSet::new();
+        for attachment in &self.workdir_attachments {
+            attachment.validate()?;
+            if !aliases.insert(attachment.alias.as_str()) {
+                return Err(SubscriptionValidationError::InvalidIdentifier {
+                    field: "workdir_attachment_alias",
+                });
+            }
+            if !workdir_ids.insert(attachment.working_directory_id.as_str()) {
+                return Err(SubscriptionValidationError::InvalidIdentifier {
+                    field: "working_directory_id",
+                });
+            }
         }
         Ok(())
     }
@@ -654,8 +683,6 @@ pub struct SubscriptionWorkdir {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub repository_key: Option<String>,
     pub state: String,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub primary_worker_id: Option<SubscriptionWorkerId>,
 }
 
 impl SubscriptionWorkdir {
@@ -673,9 +700,6 @@ impl SubscriptionWorkdir {
             }
         }
         validate_identifier("workdir_state", &self.state, MAX_RESOURCE_ID_BYTES)?;
-        if let Some(worker_id) = &self.primary_worker_id {
-            worker_id.validate()?;
-        }
         Ok(())
     }
 }
@@ -688,8 +712,6 @@ pub struct WorkspaceSubscriptionWorkdir {
     pub working_directory_id: SubscriptionWorkdirId,
     pub repository_key: String,
     pub state: String,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub primary_worker_id: Option<SubscriptionWorkerId>,
 }
 
 impl WorkspaceSubscriptionWorkdir {
@@ -697,9 +719,6 @@ impl WorkspaceSubscriptionWorkdir {
         self.working_directory_id.validate()?;
         validate_repository_key(&self.repository_key)?;
         validate_identifier("workdir_state", &self.state, MAX_RESOURCE_ID_BYTES)?;
-        if let Some(worker_id) = &self.primary_worker_id {
-            worker_id.validate()?;
-        }
         Ok(())
     }
 }
@@ -903,36 +922,58 @@ mod tests {
             workspace_id: Some("workspace-1".to_string()),
             display_name: Some(format!("Worker {value}")),
             profile: Some("builtin:coder".to_string()),
-            repository_id: None,
-            repository_key: None,
-            working_directory_id: None,
+            workdir_attachments: Vec::new(),
         }
     }
 
     #[test]
     fn runtime_and_workspace_repository_identity_projections_do_not_alias() {
         let mut runtime_worker = worker("worker-1");
-        runtime_worker.repository_id = Some("01890f47-3c22-7cc0-98c4-dc0c0c07398f".to_string());
+        runtime_worker
+            .workdir_attachments
+            .push(SubscriptionWorkerWorkdirAttachment {
+                alias: "checkout".to_string(),
+                repository_id: Some("01890f47-3c22-7cc0-98c4-dc0c0c07398f".to_string()),
+                repository_key: None,
+                working_directory_id: SubscriptionWorkdirId::new("workdir-1").unwrap(),
+            });
         runtime_worker.validate().unwrap();
         let runtime_json = serde_json::to_value(&runtime_worker).unwrap();
         assert_eq!(
-            runtime_json["repository_id"],
+            runtime_json["workdir_attachments"][0]["repository_id"],
             "01890f47-3c22-7cc0-98c4-dc0c0c07398f"
         );
-        assert!(runtime_json.get("repository_key").is_none());
+        assert!(
+            runtime_json["workdir_attachments"][0]
+                .get("repository_key")
+                .is_none()
+        );
 
         let mut workspace_worker = worker("worker-1");
-        workspace_worker.repository_key = Some("main".to_string());
+        workspace_worker
+            .workdir_attachments
+            .push(SubscriptionWorkerWorkdirAttachment {
+                alias: "checkout".to_string(),
+                repository_id: None,
+                repository_key: Some("main".to_string()),
+                working_directory_id: SubscriptionWorkdirId::new("workdir-1").unwrap(),
+            });
         workspace_worker.validate().unwrap();
         let workspace_json = serde_json::to_value(&workspace_worker).unwrap();
-        assert_eq!(workspace_json["repository_key"], "main");
-        assert!(workspace_json.get("repository_id").is_none());
+        assert_eq!(
+            workspace_json["workdir_attachments"][0]["repository_key"],
+            "main"
+        );
+        assert!(
+            workspace_json["workdir_attachments"][0]
+                .get("repository_id")
+                .is_none()
+        );
 
         let workspace_workdir = WorkspaceSubscriptionWorkdir {
             working_directory_id: SubscriptionWorkdirId::new("workdir-1").unwrap(),
             repository_key: "main".to_string(),
             state: "active".to_string(),
-            primary_worker_id: Some(worker_id("worker-1")),
         };
         workspace_workdir.validate().unwrap();
         let workdir_json = serde_json::to_value(&workspace_workdir).unwrap();

crates/protocol/src/typescript.rs

@@ -22,7 +22,8 @@ use crate::{
         SubscriptionRequestId, SubscriptionResponse, SubscriptionSnapshot,
         SubscriptionTerminationCode, SubscriptionWorkdirId, SubscriptionWorker,
         SubscriptionWorkerAvailability, SubscriptionWorkerId, SubscriptionWorkerIds,
-        SubscriptionWorkerProtocolMethod, SubscriptionWorkerState, WorkspaceSubscriptionWorkdir,
+        SubscriptionWorkerProtocolMethod, SubscriptionWorkerState,
+        SubscriptionWorkerWorkdirAttachment, WorkspaceSubscriptionWorkdir,
     },
 };
 
@@ -114,6 +115,7 @@ pub fn generated_protocol_types() -> String {
     push_decl::<SubscriptionWorkerState>(&cfg, &mut output);
     push_decl::<SubscriptionWorkerAvailability>(&cfg, &mut output);
     push_decl::<EventSubscriptionSelector>(&cfg, &mut output);
+    push_decl::<SubscriptionWorkerWorkdirAttachment>(&cfg, &mut output);
     push_decl::<SubscriptionWorker>(&cfg, &mut output);
     push_decl::<WorkspaceSubscriptionWorkdir>(&cfg, &mut output);
     push_decl::<SubscriptionSnapshot>(&cfg, &mut output);

crates/runtime-api/src/lib.rs

@@ -335,6 +335,8 @@ pub struct RepositoryMaterializationContext {
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct WorkingDirectoryRequest {
     pub repository: WorkingDirectoryRepository,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     #[serde(default)]
     pub materializer: MaterializerKind,
     #[serde(default, skip_serializing_if = "Option::is_none")]
@@ -344,12 +346,31 @@ pub struct WorkingDirectoryRequest {
 }
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
-pub struct WorkingDirectoryClaim {
+pub struct WorkingDirectoryAttachmentClaim {
+    /// Stable Worker-local routing key. This is not a Workdir id or display name.
+    pub alias: workdir::WorkdirAttachmentAlias,
     pub working_directory_id: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub relative_cwd: Option<String>,
 }
 
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct WorkerWorkdirAttachmentsRequest {
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentClaim>,
+}
+
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct WorkingDirectoryAttachmentRequest {
+    pub alias: workdir::WorkdirAttachmentAlias,
+    pub working_directory: WorkingDirectoryRequest,
+}
+
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct WorkingDirectoryAttachmentStatus {
+    pub alias: workdir::WorkdirAttachmentAlias,
+    pub working_directory: WorkingDirectoryStatus,
+}
+
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct WorkingDirectoryStatus {
     pub summary: RuntimeWorkingDirectorySummary,
@@ -387,10 +408,10 @@ pub struct CreateWorkerRequest {
     pub config_bundle: Option<ConfigBundleRef>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub initial_input: Option<WorkerInput>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory_request: Option<WorkingDirectoryRequest>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectoryClaim>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachment_requests: Vec<WorkingDirectoryAttachmentRequest>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentClaim>,
     #[serde(default, skip_serializing_if = "std::ops::Not::not")]
     pub worker_observation_enabled: bool,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
@@ -413,8 +434,8 @@ pub struct WorkerSummary {
     pub worker_state: Option<WorkerStateSnapshot>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub workspace_id: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectoryStatus>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
     pub profile: ProfileSelector,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub display_name: Option<String>,
@@ -726,6 +747,17 @@ pub trait RuntimeApi {
         #[body] request: WorkerWorkspaceApiRequest,
     ) -> Result<WorkerResponse, RuntimeApiError>;
 
+    #[post(
+        "/v1/workers/{worker_id}/workdir-attachments",
+        status = 200,
+        error_status = 400
+    )]
+    async fn replace_worker_workdir_attachments(
+        &self,
+        #[path] worker_id: String,
+        #[body] request: WorkerWorkdirAttachmentsRequest,
+    ) -> Result<WorkerResponse, RuntimeApiError>;
+
     #[post(
         "/v1/workers/{worker_id}/completions",
         status = 200,
@@ -1002,6 +1034,13 @@ mod tests {
         ) -> Result<WorkerResponse, RuntimeApiError> {
             Err(test_error(501))
         }
+        async fn replace_worker_workdir_attachments(
+            &self,
+            _worker_id: String,
+            _request: WorkerWorkdirAttachmentsRequest,
+        ) -> Result<WorkerResponse, RuntimeApiError> {
+            Err(test_error(501))
+        }
         async fn complete_worker_arguments(
             &self,
             _worker_id: String,
@@ -1072,7 +1111,7 @@ mod tests {
     #[test]
     fn contract_inventory_is_complete_and_unique() {
         let operations = RuntimeApiMetadata::OPERATIONS;
-        assert_eq!(operations.len(), 15);
+        assert_eq!(operations.len(), 16);
         let mut routes = operations
             .iter()
             .map(|operation| (format!("{:?}", operation.method), operation.path))

crates/server-api/src/lib.rs

@@ -1583,6 +1583,9 @@ pub struct RuntimeWorkingDirectoryCleanupTarget {
 #[serde(deny_unknown_fields)]
 pub struct RuntimeWorkingDirectorySummary {
     pub working_directory_id: String,
+    /// Optional human-facing label, never a routing key.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_id: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub creation_selector: Option<String>,
@@ -1606,8 +1609,6 @@ pub struct RuntimeWorkingDirectorySummary {
     #[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<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
@@ -1618,6 +1619,9 @@ pub struct RuntimeWorkingDirectorySummary {
 #[serde(deny_unknown_fields)]
 pub struct WorkingDirectorySummary {
     pub working_directory_id: String,
+    /// Optional human-facing label, never a routing key.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_key: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub creation_selector: Option<String>,
@@ -1641,8 +1645,6 @@ 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<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
@@ -1713,6 +1715,7 @@ impl From<workdir::workspace::RuntimeWorkingDirectorySummary> for RuntimeWorking
     fn from(value: workdir::workspace::RuntimeWorkingDirectorySummary) -> Self {
         Self {
             working_directory_id: value.working_directory_id,
+            display_name: value.display_name,
             repository_id: value.repository_id,
             creation_selector: value.creation_selector,
             creation_ref: value.creation_ref,
@@ -1725,7 +1728,6 @@ impl From<workdir::workspace::RuntimeWorkingDirectorySummary> for RuntimeWorking
             cleanup_target: value.cleanup_target.map(Into::into),
             status: value.status.into(),
             cleanliness: value.cleanliness,
-            primary_worker_id: value.primary_worker_id,
             occupied_by: value.occupied_by.map(Into::into),
         }
     }
@@ -1735,6 +1737,7 @@ impl From<workdir::workspace::WorkingDirectorySummary> for WorkingDirectorySumma
     fn from(value: workdir::workspace::WorkingDirectorySummary) -> Self {
         Self {
             working_directory_id: value.working_directory_id,
+            display_name: value.display_name,
             repository_key: value.repository_key,
             creation_selector: value.creation_selector,
             creation_ref: value.creation_ref,
@@ -1747,7 +1750,6 @@ impl From<workdir::workspace::WorkingDirectorySummary> for WorkingDirectorySumma
             cleanup_target: value.cleanup_target.map(Into::into),
             status: value.status.into(),
             cleanliness: value.cleanliness,
-            primary_worker_id: value.primary_worker_id,
             occupied_by: value.occupied_by.map(Into::into),
         }
     }
@@ -1765,6 +1767,9 @@ impl From<workdir::workspace::WorkingDirectorySummary> for WorkingDirectorySumma
 pub struct WorkingDirectoryCreateRequest {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub runtime_id: Option<String>,
+    /// Optional human-facing label, independent of every Worker attachment alias.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_key: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub selector: Option<String>,
@@ -2445,6 +2450,24 @@ pub struct WorkspaceWorkerDiscoveryPage {
     pub next_cursor: Option<String>,
 }
 
+/// One Workspace Worker Workdir attachment. `alias` is the stable Worker-local
+/// routing key; the nested Workdir id and display name are inventory metadata.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct WorkerWorkdirAttachmentSummary {
+    pub alias: String,
+    pub working_directory: WorkingDirectorySummary,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct RuntimeWorkerWorkdirAttachmentSummary {
+    pub alias: String,
+    pub working_directory: RuntimeWorkingDirectorySummary,
+}
+
 /// Workspace-authoritative Worker projection.
 ///
 /// `resource_key` is required here even though Runtime-internal Worker summaries
@@ -2478,8 +2501,8 @@ pub struct WorkerSummary {
     pub retention_state: String,
     pub implementation: WorkerImplementationSummary,
     pub capabilities: WorkerCapabilitySummary,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectorySummary>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkerWorkdirAttachmentSummary>,
     #[serde(default)]
     pub diagnostics: Vec<Diagnostic>,
 }
@@ -2507,9 +2530,8 @@ pub struct WorkerLaunchWorkerSummary {
     pub retention_state: String,
     pub implementation: WorkerImplementationSummary,
     pub capabilities: WorkerCapabilitySummary,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    #[cfg_attr(feature = "typescript", ts(optional = nullable))]
-    pub working_directory: Option<RuntimeWorkingDirectorySummary>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<RuntimeWorkerWorkdirAttachmentSummary>,
     #[serde(default)]
     pub diagnostics: Vec<Diagnostic>,
 }
@@ -2563,6 +2585,8 @@ pub struct WorkingDirectoryRepositoryOption {
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[serde(deny_unknown_fields)]
 pub struct BrowserWorkerWorkingDirectorySelection {
+    /// Stable Worker-local routing alias.
+    pub alias: String,
     pub working_directory_id: String,
     #[serde(default)]
     pub relative_cwd: Option<String>,
@@ -2589,7 +2613,7 @@ pub struct CreateWorkspaceWorkerRequest {
     #[serde(default)]
     pub initial_submit: Vec<protocol::Segment>,
     #[serde(default)]
-    pub working_directory: Option<BrowserWorkerWorkingDirectorySelection>,
+    pub workdir_attachments: Vec<BrowserWorkerWorkingDirectorySelection>,
     /// Backend idempotency key used only for authenticated Worker-owned spawn/control.
     #[serde(default)]
     pub control_operation_id: Option<String>,
@@ -3663,6 +3687,7 @@ pub fn worker_launch_api_typescript() -> String {
         WorkerWorkspaceSummary::decl(&config),
         WorkerImplementationSummary::decl(&config),
         WorkerCapabilitySummary::decl(&config),
+        RuntimeWorkerWorkdirAttachmentSummary::decl(&config),
         WorkerLaunchWorkerSummary::decl(&config),
         WorkerLaunchRuntimeOption::decl(&config),
         WorkerLaunchProfileCandidate::decl(&config),
@@ -4100,7 +4125,7 @@ mod tests {
                 can_stop: true,
                 can_spawn_followup: false,
             },
-            working_directory: None,
+            workdir_attachments: Vec::new(),
             diagnostics: Vec::new(),
         }
     }
@@ -4178,7 +4203,7 @@ mod tests {
             profile: None,
             ticket_assignment: None,
             initial_submit: Vec::new(),
-            working_directory: None,
+            workdir_attachments: Vec::new(),
             control_operation_id: None,
         })
         .unwrap();
@@ -4190,7 +4215,7 @@ mod tests {
                 "profile": null,
                 "ticket_assignment": null,
                 "initial_submit": [],
-                "working_directory": null,
+                "workdir_attachments": [],
                 "control_operation_id": null,
             })
         );
@@ -5097,6 +5122,7 @@ mod tests {
     fn workdir_summary_omits_absent_optional_fields_on_the_wire() {
         let value = serde_json::to_value(WorkingDirectorySummary {
             working_directory_id: "workdir-1".into(),
+            display_name: None,
             repository_key: "main".into(),
             creation_selector: None,
             creation_ref: None,
@@ -5109,7 +5135,6 @@ mod tests {
             cleanup_target: None,
             status: WorkingDirectoryStatusKind::Active,
             cleanliness: None,
-            primary_worker_id: None,
             occupied_by: None,
         })
         .expect("serialize Workdir summary");
@@ -5125,7 +5150,6 @@ mod tests {
             "observed_at_epoch_seconds",
             "cleanup_target",
             "cleanliness",
-            "primary_worker_id",
             "occupied_by",
         ] {
             assert!(

crates/tui/src/backend_spawn.rs

@@ -164,7 +164,7 @@ fn request_from_selection(selection: Selection) -> BackendCreateWorkerRequest {
         display_name: selection.display_name,
         profile: Some(selection.profile),
         initial_submit: Vec::new(),
-        working_directory: None,
+        workdir_attachments: Vec::new(),
         ticket_assignment: None,
         control_operation_id: None,
     }
@@ -477,7 +477,7 @@ mod tests {
         assert_eq!(request.display_name, "Coder one");
         assert_eq!(request.profile.as_deref(), Some("builtin:coder"));
         assert!(request.initial_submit.is_empty());
-        assert!(request.working_directory.is_none());
+        assert!(request.workdir_attachments.is_empty());
         assert!(request.ticket_assignment.is_none());
     }
 }

crates/tui/src/backend_worker_picker.rs

@@ -408,10 +408,22 @@ fn short_worker_id(worker: &BackendWorkerSummary) -> String {
 }
 
 fn working_directory_text(worker: &BackendWorkerSummary) -> String {
-    let Some(wd) = worker.working_directory.as_ref() else {
+    if worker.workdir_attachments.is_empty() {
         return "wd:—".to_string();
-    };
-    format!("wd:{}・{}", wd.repository_key, wd.working_directory_id)
+    }
+    if worker.workdir_attachments.len() > 1 {
+        return format!("wd:{} attachments", worker.workdir_attachments.len());
+    }
+    let attachment = &worker.workdir_attachments[0];
+    let directory = &attachment.working_directory;
+    let label = directory
+        .display_name
+        .as_deref()
+        .unwrap_or(&directory.repository_key);
+    format!(
+        "wd:{}:{}・{}",
+        attachment.alias, label, directory.working_directory_id
+    )
 }
 
 #[cfg(test)]
@@ -456,7 +468,7 @@ mod tests {
                 can_stop: true,
                 can_spawn_followup: false,
             },
-            working_directory: None,
+            workdir_attachments: Vec::new(),
             diagnostics: Vec::new(),
         }
     }
@@ -529,22 +541,26 @@ mod tests {
         worker.label = "Coder · T-585".to_string();
         worker.state = "stopped".to_string();
         worker.worker_state = None;
-        worker.working_directory = Some(
+        worker.workdir_attachments = vec![
             serde_json::from_value(serde_json::json!({
-                "working_directory_id": "001a06a9f0202000000",
-                "repository_key": "main",
-                "materializer_kind": "runtime_git_clone",
-                "status": "active",
-                "cleanliness": "clean"
+                "alias": "checkout",
+                "working_directory": {
+                    "working_directory_id": "001a06a9f0202000000",
+                    "display_name": "Checkout",
+                    "repository_key": "main",
+                    "materializer_kind": "runtime_git_clone",
+                    "status": "active",
+                    "cleanliness": "clean"
+                }
             }))
             .unwrap(),
-        );
+        ];
         let widths = WorkerColumnWidths::from_workers(std::slice::from_ref(&worker));
         let text = row_text(&worker, &widths);
 
         assert_eq!(
             text,
-            "  W-90  Coder · T-585  [stopped]  wd:main・001a06a9f0202000000"
+            "  W-90  Coder · T-585  [stopped]  wd:checkout:Checkout・001a06a9f0202000000"
         );
         assert!(!text.contains("profile:"));
         assert!(!text.contains("active clean"));
@@ -570,15 +586,18 @@ mod tests {
         long.worker_state = None;
 
         for worker in [&mut short, &mut long] {
-            worker.working_directory = Some(
+            worker.workdir_attachments = vec![
                 serde_json::from_value(serde_json::json!({
-                    "working_directory_id": "workdir-1",
-                    "repository_key": "main",
-                    "materializer_kind": "runtime_git_clone",
-                    "status": "active"
+                    "alias": "checkout",
+                    "working_directory": {
+                        "working_directory_id": "workdir-1",
+                        "repository_key": "main",
+                        "materializer_kind": "runtime_git_clone",
+                        "status": "active"
+                    }
                 }))
                 .unwrap(),
-            );
+            ];
         }
 
         let workers = vec![short, long];
@@ -595,8 +614,8 @@ mod tests {
             display_column(&second, "[stopped]")
         );
         assert_eq!(
-            display_column(&first, "wd:main"),
-            display_column(&second, "wd:main")
+            display_column(&first, "wd:checkout:main"),
+            display_column(&second, "wd:checkout:main")
         );
     }
 

crates/workdir/src/lib.rs

@@ -8,6 +8,7 @@
 pub mod http;
 mod local;
 mod operation;
+mod router;
 mod scope;
 pub mod workspace;
 
@@ -27,6 +28,7 @@ pub use local::{
     LocalWorkdirSession, SymlinkInfo, WorkdirSessionResource, direct_symlink, first_symlink,
 };
 pub use operation::*;
+pub use router::{RoutedWorkdirSession, WorkdirAttachmentAlias, WorkdirSessionRouter};
 pub use scope::{
     ReadOnlyWorkdirSession, WorkdirScopeAuthorizationRequest, WorkdirScopeLease,
     WorkdirScopeOverlapRequest, WorkdirToolBroker, WorkdirToolScope, WorkdirToolScopePermission,

crates/workdir/src/router.rs

@@ -0,0 +1,651 @@
+//! Alias-keyed Worker Workdir session routing.
+//!
+//! The router owns live provider sessions without exposing whether a session is
+//! local or transported over HTTP.  Attachment aliases are Worker-local stable
+//! identities; provider Workdir ids and human display names are deliberately not
+//! routing keys.
+
+use std::collections::{BTreeMap, HashSet};
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::sync::{Arc, Mutex, RwLock};
+
+use async_trait::async_trait;
+use serde::{Deserialize, Serialize};
+use tokio::sync::broadcast;
+
+use crate::{
+    CommandEvent, CommandHandle, CommandOutput, CommandOutputRequest, CommandRequest,
+    CommandSnapshot, CommandStatus, EditRequest, EditResult, GlobRequest, GlobResult, GrepRequest,
+    GrepResult, ListRequest, ListResult, ReadRequest, ReadResult, StatRequest, StatResult, Workdir,
+    WorkdirError, WorkdirScopeAuthorizationRequest, WorkdirScopeOverlapRequest, WorkdirSession,
+    WorkdirSessionCapabilities, WorkdirSessionHandle, WriteRequest, WriteResult,
+};
+
+/// Stable Worker-local routing key for one attached Workdir.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize)]
+#[serde(transparent)]
+pub struct WorkdirAttachmentAlias(String);
+
+impl WorkdirAttachmentAlias {
+    pub fn new(value: impl Into<String>) -> Result<Self, WorkdirError> {
+        let value = value.into();
+        let valid = !value.is_empty()
+            && value.len() <= 64
+            && value.bytes().enumerate().all(|(index, byte)| match byte {
+                b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' => true,
+                b'_' | b'-' | b'.' => index > 0,
+                _ => false,
+            });
+        if !valid {
+            return Err(WorkdirError::InvalidArgument(
+                "attachment alias must be 1-64 ASCII letters, digits, '.', '_' or '-', and start with a letter or digit"
+                    .to_string(),
+            ));
+        }
+        Ok(Self(value))
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+
+impl<'de> Deserialize<'de> for WorkdirAttachmentAlias {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let value = String::deserialize(deserializer)?;
+        Self::new(value).map_err(serde::de::Error::custom)
+    }
+}
+
+impl std::fmt::Display for WorkdirAttachmentAlias {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter.write_str(&self.0)
+    }
+}
+
+#[derive(Debug)]
+struct RoutedSessionState {
+    session: WorkdirSessionHandle,
+    detached: AtomicBool,
+    active_operations: AtomicUsize,
+    active_commands: Mutex<HashSet<CommandHandle>>,
+}
+
+impl RoutedSessionState {
+    fn enter(&self) -> Result<ActiveOperation<'_>, WorkdirError> {
+        if self.detached.load(Ordering::Acquire) {
+            return Err(WorkdirError::Unavailable(
+                "Workdir attachment is detached".to_string(),
+            ));
+        }
+        self.active_operations.fetch_add(1, Ordering::AcqRel);
+        if self.detached.load(Ordering::Acquire) {
+            self.active_operations.fetch_sub(1, Ordering::AcqRel);
+            return Err(WorkdirError::Unavailable(
+                "Workdir attachment is detaching".to_string(),
+            ));
+        }
+        Ok(ActiveOperation(self))
+    }
+
+    fn is_busy(&self) -> bool {
+        if self.active_operations.load(Ordering::Acquire) != 0 {
+            return true;
+        }
+        self.reconcile_terminal_commands(&self.session.command_snapshot());
+        !self
+            .active_commands
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .is_empty()
+    }
+
+    async fn is_busy_for_detach(&self) -> bool {
+        if self.active_operations.load(Ordering::Acquire) != 0 {
+            return true;
+        }
+        self.reconcile_terminal_commands(&self.session.command_snapshot());
+        let handles = self
+            .active_commands
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .iter()
+            .cloned()
+            .collect::<Vec<_>>();
+        for handle in handles {
+            match self.session.command_status(handle.clone()).await {
+                Ok(status) => self.mark_terminal(&handle, status),
+                Err(WorkdirError::UnknownCommand(_)) => {
+                    self.active_commands
+                        .lock()
+                        .unwrap_or_else(std::sync::PoisonError::into_inner)
+                        .remove(&handle);
+                }
+                Err(_) => {}
+            }
+        }
+        self.active_operations.load(Ordering::Acquire) != 0
+            || !self
+                .active_commands
+                .lock()
+                .unwrap_or_else(std::sync::PoisonError::into_inner)
+                .is_empty()
+    }
+
+    fn reconcile_terminal_commands(&self, snapshots: &[CommandSnapshot]) {
+        let terminal = snapshots
+            .iter()
+            .filter(|snapshot| snapshot.status != CommandStatus::Running)
+            .map(|snapshot| snapshot.command_id.as_str())
+            .collect::<HashSet<_>>();
+        if terminal.is_empty() {
+            return;
+        }
+        self.active_commands
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .retain(|handle| !terminal.contains(handle.0.as_str()));
+    }
+
+    fn mark_terminal(&self, handle: &CommandHandle, status: CommandStatus) {
+        if status != CommandStatus::Running {
+            self.active_commands
+                .lock()
+                .unwrap_or_else(std::sync::PoisonError::into_inner)
+                .remove(handle);
+        }
+    }
+}
+
+struct ActiveOperation<'a>(&'a RoutedSessionState);
+
+impl Drop for ActiveOperation<'_> {
+    fn drop(&mut self) {
+        self.0.active_operations.fetch_sub(1, Ordering::AcqRel);
+    }
+}
+
+/// A session handle bound to one alias in a [`WorkdirSessionRouter`].
+#[derive(Debug, Clone)]
+pub struct RoutedWorkdirSession {
+    state: Arc<RoutedSessionState>,
+}
+
+#[async_trait]
+impl WorkdirSession for RoutedWorkdirSession {
+    fn workdir(&self) -> &Workdir {
+        self.state.session.workdir()
+    }
+
+    fn capabilities(&self) -> WorkdirSessionCapabilities {
+        self.state.session.capabilities()
+    }
+
+    async fn authorize_scope_path(
+        &self,
+        request: WorkdirScopeAuthorizationRequest,
+    ) -> Result<(), WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.authorize_scope_path(request).await
+    }
+
+    async fn scope_rules_overlap(
+        &self,
+        request: WorkdirScopeOverlapRequest,
+    ) -> Result<bool, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.scope_rules_overlap(request).await
+    }
+
+    async fn stat(&self, request: StatRequest) -> Result<StatResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.stat(request).await
+    }
+
+    async fn read(&self, request: ReadRequest) -> Result<ReadResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.read(request).await
+    }
+
+    async fn write(&self, request: WriteRequest) -> Result<WriteResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.write(request).await
+    }
+
+    async fn edit(&self, request: EditRequest) -> Result<EditResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.edit(request).await
+    }
+
+    async fn list(&self, request: ListRequest) -> Result<ListResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.list(request).await
+    }
+
+    async fn glob(&self, request: GlobRequest) -> Result<GlobResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.glob(request).await
+    }
+
+    async fn grep(&self, request: GrepRequest) -> Result<GrepResult, WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.grep(request).await
+    }
+
+    async fn start_command(&self, request: CommandRequest) -> Result<CommandHandle, WorkdirError> {
+        let _active = self.state.enter()?;
+        let handle = self.state.session.start_command(request).await?;
+        self.state
+            .active_commands
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .insert(handle.clone());
+        Ok(handle)
+    }
+
+    async fn command_status(&self, handle: CommandHandle) -> Result<CommandStatus, WorkdirError> {
+        let _active = self.state.enter()?;
+        let status = self.state.session.command_status(handle.clone()).await?;
+        self.state.mark_terminal(&handle, status);
+        Ok(status)
+    }
+
+    async fn command_output(
+        &self,
+        request: CommandOutputRequest,
+    ) -> Result<CommandOutput, WorkdirError> {
+        let _active = self.state.enter()?;
+        let handle = request.handle.clone();
+        let output = self.state.session.command_output(request).await?;
+        self.state.mark_terminal(&handle, output.status);
+        Ok(output)
+    }
+
+    async fn cancel_command(&self, handle: CommandHandle) -> Result<(), WorkdirError> {
+        let _active = self.state.enter()?;
+        self.state.session.cancel_command(handle.clone()).await?;
+        self.state
+            .active_commands
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .remove(&handle);
+        Ok(())
+    }
+
+    fn subscribe_command_events(&self) -> Option<broadcast::Receiver<CommandEvent>> {
+        self.state.session.subscribe_command_events()
+    }
+
+    fn command_snapshot(&self) -> Vec<CommandSnapshot> {
+        let snapshots = self.state.session.command_snapshot();
+        self.state.reconcile_terminal_commands(&snapshots);
+        snapshots
+    }
+
+    async fn close(&self) -> Result<(), WorkdirError> {
+        if self.state.is_busy() {
+            return Err(WorkdirError::Conflict(
+                "Workdir attachment has active operations or commands".to_string(),
+            ));
+        }
+        self.state.session.close().await
+    }
+}
+
+/// Worker-owned map of stable attachment aliases to provider-neutral sessions.
+#[derive(Debug, Default)]
+pub struct WorkdirSessionRouter {
+    sessions: RwLock<BTreeMap<WorkdirAttachmentAlias, Arc<RoutedSessionState>>>,
+}
+
+impl WorkdirSessionRouter {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn aliases(&self) -> Vec<WorkdirAttachmentAlias> {
+        self.sessions
+            .read()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .keys()
+            .cloned()
+            .collect()
+    }
+
+    pub fn len(&self) -> usize {
+        self.sessions
+            .read()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    pub fn attach(
+        &self,
+        alias: WorkdirAttachmentAlias,
+        session: WorkdirSessionHandle,
+    ) -> Result<WorkdirSessionHandle, WorkdirError> {
+        let mut sessions = self.sessions.write().map_err(|_| {
+            WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+        })?;
+        if sessions.contains_key(&alias) {
+            return Err(WorkdirError::Conflict(format!(
+                "Workdir attachment alias `{alias}` already exists"
+            )));
+        }
+        let state = Arc::new(RoutedSessionState {
+            session,
+            detached: AtomicBool::new(false),
+            active_operations: AtomicUsize::new(0),
+            active_commands: Mutex::new(HashSet::new()),
+        });
+        sessions.insert(alias, state.clone());
+        Ok(Arc::new(RoutedWorkdirSession { state }))
+    }
+
+    pub fn session(&self, alias: &WorkdirAttachmentAlias) -> Option<WorkdirSessionHandle> {
+        self.sessions
+            .read()
+            .ok()?
+            .get(alias)
+            .cloned()
+            .map(|state| Arc::new(RoutedWorkdirSession { state }) as WorkdirSessionHandle)
+    }
+
+    /// Compatibility projection used only while filesystem tool schemas have no
+    /// `target_workdir`: exactly one attachment is unambiguous; zero or multiple
+    /// attachments expose no implicit primary.
+    pub fn only_session(&self) -> Option<WorkdirSessionHandle> {
+        let sessions = self.sessions.read().ok()?;
+        if sessions.len() != 1 {
+            return None;
+        }
+        sessions
+            .values()
+            .next()
+            .cloned()
+            .map(|state| Arc::new(RoutedWorkdirSession { state }) as WorkdirSessionHandle)
+    }
+
+    pub fn can_detach(&self, alias: &WorkdirAttachmentAlias) -> Result<(), WorkdirError> {
+        let state = self
+            .sessions
+            .read()
+            .map_err(|_| {
+                WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+            })?
+            .get(alias)
+            .cloned()
+            .ok_or_else(|| WorkdirError::NotFound(alias.as_str().into()))?;
+        if state.detached.load(Ordering::Acquire) {
+            return Err(WorkdirError::Unavailable(
+                "Workdir attachment is already detaching".to_string(),
+            ));
+        }
+        if state.is_busy() {
+            return Err(WorkdirError::Conflict(format!(
+                "Workdir attachment `{alias}` has active operations or commands"
+            )));
+        }
+        Ok(())
+    }
+
+    /// Atomically fence new operations before an external detach transaction begins.
+    pub async fn begin_detach(&self, alias: &WorkdirAttachmentAlias) -> Result<(), WorkdirError> {
+        let state = self
+            .sessions
+            .read()
+            .map_err(|_| {
+                WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+            })?
+            .get(alias)
+            .cloned()
+            .ok_or_else(|| WorkdirError::NotFound(alias.as_str().into()))?;
+        if state.detached.swap(true, Ordering::AcqRel) {
+            return Err(WorkdirError::Unavailable(
+                "Workdir attachment is already detaching".to_string(),
+            ));
+        }
+        if state.is_busy_for_detach().await {
+            state.detached.store(false, Ordering::Release);
+            return Err(WorkdirError::Conflict(format!(
+                "Workdir attachment `{alias}` has active operations or commands"
+            )));
+        }
+        Ok(())
+    }
+
+    /// Reopen a route after the external detach transaction failed before commit.
+    pub fn cancel_detach(&self, alias: &WorkdirAttachmentAlias) {
+        if let Ok(sessions) = self.sessions.read()
+            && let Some(state) = sessions.get(alias)
+        {
+            state.detached.store(false, Ordering::Release);
+        }
+    }
+
+    pub async fn finish_detach(
+        &self,
+        alias: &WorkdirAttachmentAlias,
+    ) -> Result<WorkdirSessionHandle, WorkdirError> {
+        let state = {
+            let sessions = self.sessions.read().map_err(|_| {
+                WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+            })?;
+            sessions
+                .get(alias)
+                .cloned()
+                .ok_or_else(|| WorkdirError::NotFound(alias.as_str().into()))?
+        };
+        if !state.detached.load(Ordering::Acquire) {
+            return Err(WorkdirError::Conflict(format!(
+                "Workdir attachment `{alias}` was not prepared for detach"
+            )));
+        }
+        if state.is_busy_for_detach().await {
+            state.detached.store(false, Ordering::Release);
+            return Err(WorkdirError::Conflict(format!(
+                "Workdir attachment `{alias}` has active operations or commands"
+            )));
+        }
+        if let Err(error) = state.session.close().await {
+            state.detached.store(false, Ordering::Release);
+            return Err(error);
+        }
+        let mut sessions = self.sessions.write().map_err(|_| {
+            WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+        })?;
+        if sessions
+            .get(alias)
+            .is_some_and(|current| Arc::ptr_eq(current, &state))
+        {
+            sessions.remove(alias);
+        }
+        Ok(state.session.clone())
+    }
+
+    pub async fn detach(
+        &self,
+        alias: &WorkdirAttachmentAlias,
+    ) -> Result<WorkdirSessionHandle, WorkdirError> {
+        self.begin_detach(alias).await?;
+        self.finish_detach(alias).await
+    }
+
+    /// Close every attachment during Worker shutdown or startup rollback.
+    ///
+    /// Unlike [`Self::detach`], lifecycle teardown is authoritative and delegates
+    /// cancellation or draining of active commands to each provider session.
+    pub async fn close_all(&self) -> Result<(), WorkdirError> {
+        let aliases = self.aliases();
+        for alias in aliases {
+            let state = {
+                let sessions = self.sessions.read().map_err(|_| {
+                    WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+                })?;
+                sessions.get(&alias).cloned()
+            };
+            let Some(state) = state else {
+                continue;
+            };
+            state.detached.store(true, Ordering::Release);
+            if let Err(error) = state.session.close().await {
+                state.detached.store(false, Ordering::Release);
+                return Err(error);
+            }
+            let mut sessions = self.sessions.write().map_err(|_| {
+                WorkdirError::Unavailable("Workdir attachment router is poisoned".to_string())
+            })?;
+            if sessions
+                .get(&alias)
+                .is_some_and(|current| Arc::ptr_eq(current, &state))
+            {
+                sessions.remove(&alias);
+            }
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::LocalWorkdirSession;
+    use manifest::Scope;
+    use tempfile::TempDir;
+
+    fn session(id: &str, dir: &TempDir) -> WorkdirSessionHandle {
+        Arc::new(LocalWorkdirSession::materialized_bound(
+            Workdir::new(id),
+            dir.path().to_path_buf(),
+            dir.path().to_path_buf(),
+            manifest::SharedScope::new(Scope::writable(dir.path()).unwrap()),
+            WorkdirSessionCapabilities::ALL,
+        ))
+    }
+
+    #[tokio::test]
+    async fn router_holds_multiple_aliases_without_implicit_primary() {
+        let left = TempDir::new().unwrap();
+        let right = TempDir::new().unwrap();
+        let router = WorkdirSessionRouter::new();
+        router
+            .attach(
+                WorkdirAttachmentAlias::new("left").unwrap(),
+                session("wd-left", &left),
+            )
+            .unwrap();
+        router
+            .attach(
+                WorkdirAttachmentAlias::new("right").unwrap(),
+                session("wd-right", &right),
+            )
+            .unwrap();
+        assert_eq!(
+            router
+                .aliases()
+                .iter()
+                .map(WorkdirAttachmentAlias::as_str)
+                .collect::<Vec<_>>(),
+            ["left", "right"]
+        );
+        assert!(router.only_session().is_none());
+        router.close_all().await.unwrap();
+    }
+
+    #[tokio::test]
+    async fn detach_allows_naturally_completed_command_without_final_poll() {
+        let dir = TempDir::new().unwrap();
+        let router = WorkdirSessionRouter::new();
+        let alias = WorkdirAttachmentAlias::new("checkout").unwrap();
+        let underlying = session("wd", &dir);
+        let routed = router
+            .attach(alias.clone(), Arc::clone(&underlying))
+            .unwrap();
+        let handle = routed
+            .start_command(CommandRequest {
+                command: "printf done".to_string(),
+                timeout_secs: 5,
+                output_limit: 1024,
+                cwd: None,
+                spill_dir: None,
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+        let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(2);
+        loop {
+            let completed = underlying.command_snapshot().iter().any(|snapshot| {
+                snapshot.command_id == handle.0 && snapshot.status != CommandStatus::Running
+            });
+            if completed {
+                break;
+            }
+            assert!(tokio::time::Instant::now() < deadline);
+            tokio::time::sleep(std::time::Duration::from_millis(10)).await;
+        }
+
+        router.detach(&alias).await.unwrap();
+        assert!(router.is_empty());
+    }
+
+    #[tokio::test]
+    async fn lifecycle_close_all_closes_sessions_with_active_commands() {
+        let dir = TempDir::new().unwrap();
+        let router = WorkdirSessionRouter::new();
+        let alias = WorkdirAttachmentAlias::new("checkout").unwrap();
+        let underlying = session("wd", &dir);
+        let routed = router.attach(alias, Arc::clone(&underlying)).unwrap();
+        let handle = routed
+            .start_command(CommandRequest {
+                command: "sleep 30".to_string(),
+                timeout_secs: 60,
+                output_limit: 1024,
+                cwd: None,
+                spill_dir: None,
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+
+        router.close_all().await.unwrap();
+
+        assert!(router.is_empty());
+        assert!(matches!(
+            underlying.command_status(handle).await,
+            Err(WorkdirError::Unavailable(_))
+        ));
+    }
+
+    #[tokio::test]
+    async fn detach_rejects_active_command_until_cancelled() {
+        let dir = TempDir::new().unwrap();
+        let router = WorkdirSessionRouter::new();
+        let alias = WorkdirAttachmentAlias::new("checkout").unwrap();
+        let routed = router.attach(alias.clone(), session("wd", &dir)).unwrap();
+        let handle = routed
+            .start_command(CommandRequest {
+                command: "sleep 30".to_string(),
+                timeout_secs: 60,
+                output_limit: 1024,
+                cwd: None,
+                spill_dir: None,
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+        assert!(matches!(
+            router.detach(&alias).await,
+            Err(WorkdirError::Conflict(_))
+        ));
+        routed.cancel_command(handle).await.unwrap();
+        router.detach(&alias).await.unwrap();
+        assert!(router.is_empty());
+    }
+}

crates/workdir/src/workspace.rs

@@ -70,6 +70,9 @@ pub struct RuntimeWorkingDirectoryCleanupTarget {
 #[serde(deny_unknown_fields)]
 pub struct RuntimeWorkingDirectorySummary {
     pub working_directory_id: String,
+    /// Optional human-facing label. Never used for routing or identity.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_id: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub creation_selector: Option<String>,
@@ -92,8 +95,6 @@ pub struct RuntimeWorkingDirectorySummary {
     #[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<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
@@ -101,6 +102,9 @@ pub struct RuntimeWorkingDirectorySummary {
 #[serde(deny_unknown_fields)]
 pub struct WorkingDirectorySummary {
     pub working_directory_id: String,
+    /// Optional human-facing label. Never used for attachment routing.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_key: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub creation_selector: Option<String>,
@@ -123,8 +127,6 @@ 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<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
@@ -184,8 +186,6 @@ 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<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
@@ -214,6 +214,7 @@ mod tests {
     fn working_directory_summary_preserves_server_projection_wire_shape() {
         let summary = WorkingDirectorySummary {
             working_directory_id: "wd-1".to_string(),
+            display_name: Some("Checkout".to_string()),
             repository_key: "repo-1".to_string(),
             creation_selector: None,
             creation_ref: None,
@@ -226,7 +227,6 @@ mod tests {
             cleanup_target: None,
             status: WorkingDirectoryStatusKind::Active,
             cleanliness: None,
-            primary_worker_id: None,
             occupied_by: None,
         };
         let value = serde_json::to_value(summary).unwrap();

crates/worker-runtime/src/catalog.rs

@@ -161,6 +161,8 @@ pub struct WorkingDirectoryRepositoryAccessRequest {
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct WorkingDirectoryRequest {
     pub repository: WorkingDirectoryRepository,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     #[serde(default)]
     pub materializer: MaterializerKind,
     /// Backend-assigned stable Workdir id. Runtimes use this when present so the
@@ -197,12 +199,25 @@ pub struct RepositoryRefObservation {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub struct WorkingDirectoryClaim {
+pub struct WorkingDirectoryAttachmentClaim {
+    pub alias: workdir::WorkdirAttachmentAlias,
     pub working_directory_id: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub relative_cwd: Option<String>,
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct WorkingDirectoryAttachmentRequest {
+    pub alias: workdir::WorkdirAttachmentAlias,
+    pub working_directory: WorkingDirectoryRequest,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct WorkingDirectoryAttachmentStatus {
+    pub alias: workdir::WorkdirAttachmentAlias,
+    pub working_directory: WorkingDirectoryStatus,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct WorkingDirectoryStatus {
     pub summary: WorkingDirectorySummary,
@@ -247,10 +262,10 @@ pub struct CreateWorkerRequest {
     pub config_bundle: Option<ConfigBundleRef>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub initial_input: Option<WorkerInput>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory_request: Option<WorkingDirectoryRequest>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectoryClaim>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachment_requests: Vec<WorkingDirectoryAttachmentRequest>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentClaim>,
     /// Backend-only feature enablement. Grants still define local Runtime peers;
     /// the Workspace provider reauthorizes its dynamic set per operation.
     #[serde(default, skip_serializing_if = "is_false")]
@@ -308,8 +323,8 @@ pub struct WorkerSummary {
     pub worker_state: Option<protocol::WorkerStateSnapshot>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub workspace_id: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectoryStatus>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
     pub profile: ProfileSelector,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub display_name: Option<String>,
@@ -333,8 +348,8 @@ pub struct WorkerDetail {
     pub worker_state: Option<protocol::WorkerStateSnapshot>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub workspace_id: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectoryStatus>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
     pub profile: ProfileSelector,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub display_name: Option<String>,

crates/worker-runtime/src/execution.rs

@@ -12,6 +12,7 @@ use crate::observation::WorkerObservationEvent;
 use crate::working_directory::{WorkingDirectoryBinding, WorkingDirectoryDiagnostic};
 use protocol::{Method, UploadedFileRef};
 use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
 use std::fmt;
 use std::sync::Arc;
 use workdir::WorkdirSessionHandle;
@@ -246,7 +247,7 @@ pub struct WorkerExecutionSpawnRequest {
     pub request: crate::catalog::CreateWorkerRequest,
     pub workspace_scope: Option<crate::runtime::RuntimeWorkspaceScope>,
     pub context: WorkerExecutionContext,
-    pub working_directory: Option<WorkingDirectoryBinding>,
+    pub workdir_attachments: BTreeMap<workdir::WorkdirAttachmentAlias, WorkingDirectoryBinding>,
     pub config_bundle: Option<ConfigBundle>,
 }
 
@@ -257,8 +258,8 @@ pub struct WorkerExecutionRestoreRequest {
     pub request: crate::catalog::CreateWorkerRequest,
     pub workspace_scope: Option<crate::runtime::RuntimeWorkspaceScope>,
     pub context: WorkerExecutionContext,
-    pub previous_working_directory: Option<WorkingDirectoryStatus>,
-    pub working_directory: Option<WorkingDirectoryBinding>,
+    pub previous_workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
+    pub workdir_attachments: BTreeMap<workdir::WorkdirAttachmentAlias, WorkingDirectoryBinding>,
     pub config_bundle: Option<ConfigBundle>,
 }
 
@@ -284,7 +285,7 @@ pub enum WorkerExecutionSpawnResult {
     Connected {
         handle: WorkerExecutionHandle,
         worker_state: protocol::WorkerStateSnapshot,
-        working_directory: Option<WorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     },
     /// A read-only preflight rejected the operation before live work started.
     Rejected(WorkerExecutionResult),
@@ -297,7 +298,7 @@ pub enum WorkerExecutionSpawnResult {
         result: WorkerExecutionResult,
         handle: Option<WorkerExecutionHandle>,
         worker_state: Option<protocol::WorkerStateSnapshot>,
-        working_directory: Option<WorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     },
     /// Legacy spawn failure. Restore implementations must use `RolledBack` or
     /// `ReconciliationRequired` after crossing their live side-effect boundary.
@@ -308,12 +309,12 @@ impl WorkerExecutionSpawnResult {
     pub fn connected(
         handle: WorkerExecutionHandle,
         worker_state: protocol::WorkerStateSnapshot,
-        working_directory: Option<WorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     ) -> Self {
         Self::Connected {
             handle,
             worker_state,
-            working_directory,
+            workdir_attachments,
         }
     }
 }

crates/worker-runtime/src/fs_store.rs

@@ -1,6 +1,7 @@
 use crate::catalog::{
     ConfigBundleRef, CreateWorkerRequest, ProfileSelector, WorkerRestoreIntent, WorkerStatus,
-    WorkingDirectoryStatus,
+    WorkingDirectoryAttachmentClaim, WorkingDirectoryAttachmentRequest,
+    WorkingDirectoryAttachmentStatus, WorkingDirectoryRequest,
 };
 use crate::config_bundle::ConfigBundle;
 use crate::diagnostics::{DiagnosticSeverity, RuntimeDiagnostic};
@@ -442,7 +443,7 @@ pub(crate) struct PersistedWorkerRecord {
     pub(crate) status: WorkerStatus,
     pub(crate) execution_state: PersistedWorkerExecutionState,
     pub(crate) workspace_id: Option<String>,
-    pub(crate) working_directory: Option<WorkingDirectoryStatus>,
+    pub(crate) workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
 }
 
 fn runtime_io_error(operation: &'static str, path: &Path, source: std::io::Error) -> RuntimeError {
@@ -1685,11 +1686,18 @@ struct WorkerIdentityRecord {
     status: WorkerStatus,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     workspace_id: Option<String>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    working_directory: Option<WorkingDirectoryStatus>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
+    /// Schema-v8 compatibility input. New records serialize only `workdir_attachments`.
+    #[serde(
+        default,
+        rename = "working_directory",
+        skip_serializing_if = "Option::is_none"
+    )]
+    legacy_working_directory: Option<crate::catalog::WorkingDirectoryStatus>,
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug, Serialize)]
 #[serde(deny_unknown_fields)]
 struct WorkerExecutionRecord {
     schema_version: u32,
@@ -1699,6 +1707,72 @@ struct WorkerExecutionRecord {
     restore_intent: WorkerRestoreIntent,
 }
 
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct RawWorkerExecutionRecord {
+    schema_version: u32,
+    request: serde_json::Value,
+    #[serde(default)]
+    binding: Option<PersistedWorkerExecutionBinding>,
+    restore_intent: WorkerRestoreIntent,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct LegacyWorkingDirectoryClaim {
+    working_directory_id: String,
+    #[serde(default)]
+    relative_cwd: Option<String>,
+}
+
+impl<'de> Deserialize<'de> for WorkerExecutionRecord {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let raw = RawWorkerExecutionRecord::deserialize(deserializer)?;
+        let mut request_value = raw.request;
+        let request_object = request_value
+            .as_object_mut()
+            .ok_or_else(|| serde::de::Error::custom("Worker create request must be an object"))?;
+        let legacy_request = request_object.remove("working_directory_request");
+        let legacy_claim = request_object.remove("working_directory");
+        let mut request: CreateWorkerRequest =
+            serde_json::from_value(request_value).map_err(serde::de::Error::custom)?;
+        if request.workdir_attachment_requests.is_empty() && request.workdir_attachments.is_empty()
+        {
+            let alias = workdir::WorkdirAttachmentAlias::new("workdir")
+                .expect("static compatibility alias is valid");
+            if let Some(value) = legacy_request.filter(|value| !value.is_null()) {
+                let working_directory: WorkingDirectoryRequest =
+                    serde_json::from_value(value).map_err(serde::de::Error::custom)?;
+                request
+                    .workdir_attachment_requests
+                    .push(WorkingDirectoryAttachmentRequest {
+                        alias,
+                        working_directory,
+                    });
+            } else if let Some(value) = legacy_claim.filter(|value| !value.is_null()) {
+                let claim: LegacyWorkingDirectoryClaim =
+                    serde_json::from_value(value).map_err(serde::de::Error::custom)?;
+                request
+                    .workdir_attachments
+                    .push(WorkingDirectoryAttachmentClaim {
+                        alias,
+                        working_directory_id: claim.working_directory_id,
+                        relative_cwd: claim.relative_cwd,
+                    });
+            }
+        }
+        Ok(Self {
+            schema_version: raw.schema_version,
+            request,
+            binding: raw.binding,
+            restore_intent: raw.restore_intent,
+        })
+    }
+}
+
 impl WorkerIdentityRecord {
     fn from_persisted(worker: &PersistedWorkerRecord) -> Self {
         Self {
@@ -1712,7 +1786,8 @@ impl WorkerIdentityRecord {
             created_at_ms: worker.created_at_ms,
             status: worker.status,
             workspace_id: worker.workspace_id.clone(),
-            working_directory: worker.working_directory.clone(),
+            workdir_attachments: worker.workdir_attachments.clone(),
+            legacy_working_directory: None,
         }
     }
 
@@ -1760,6 +1835,19 @@ impl WorkerIdentityRecord {
         self,
         execution_state: PersistedWorkerExecutionState,
     ) -> PersistedWorkerRecord {
+        let workdir_attachments = if self.workdir_attachments.is_empty() {
+            self.legacy_working_directory
+                .map(|working_directory| {
+                    vec![WorkingDirectoryAttachmentStatus {
+                        alias: workdir::WorkdirAttachmentAlias::new("workdir")
+                            .expect("static compatibility alias is valid"),
+                        working_directory,
+                    }]
+                })
+                .unwrap_or_default()
+        } else {
+            self.workdir_attachments
+        };
         PersistedWorkerRecord {
             worker_ref: self.worker_ref,
             worker_id: self.worker_id,
@@ -1771,7 +1859,7 @@ impl WorkerIdentityRecord {
             status: self.status,
             execution_state,
             workspace_id: self.workspace_id,
-            working_directory: self.working_directory,
+            workdir_attachments,
         }
     }
 }
@@ -2215,6 +2303,72 @@ mod tests {
         document
     }
 
+    #[test]
+    fn schema_v8_singular_workdir_fields_normalize_to_one_attachment() {
+        let worker_id = WorkerId::now_v7();
+        let workdir_status = serde_json::json!({
+            "summary": {
+                "working_directory_id": "wd-legacy",
+                "repository_id": "repo",
+                "materializer_kind": "runtime_git_clone",
+                "status": "active"
+            }
+        });
+        let identity: WorkerIdentityRecord = serde_json::from_value(serde_json::json!({
+            "schema_version": SCHEMA_VERSION,
+            "worker_ref": { "worker_id": worker_id },
+            "worker_id": worker_id,
+            "profile": { "kind": "builtin", "value": "builtin:coder" },
+            "display_name": null,
+            "profile_source": {
+                "id": "archive-1",
+                "digest": "sha256:archive",
+                "size_bytes": 0,
+                "source_graph": {
+                    "source_count": 0,
+                    "total_source_bytes": 0,
+                    "entrypoints": {},
+                    "import_count": 0
+                }
+            },
+            "config_bundle": null,
+            "status": "stopped",
+            "working_directory": workdir_status
+        }))
+        .unwrap();
+        let persisted = identity.into_persisted(PersistedWorkerExecutionState::Unavailable);
+        assert_eq!(persisted.workdir_attachments.len(), 1);
+        assert_eq!(persisted.workdir_attachments[0].alias.as_str(), "workdir");
+        assert_eq!(
+            persisted.workdir_attachments[0]
+                .working_directory
+                .summary
+                .working_directory_id,
+            "wd-legacy"
+        );
+
+        let mut request = schema_v7_worker_document(worker_id)["request"].clone();
+        request["working_directory"] = serde_json::json!({
+            "working_directory_id": "wd-legacy",
+            "relative_cwd": "crates/yoi"
+        });
+        let execution: WorkerExecutionRecord = serde_json::from_value(serde_json::json!({
+            "schema_version": SCHEMA_VERSION,
+            "request": request,
+            "binding": null,
+            "restore_intent": "explicit"
+        }))
+        .unwrap();
+        assert!(execution.request.workdir_attachment_requests.is_empty());
+        assert_eq!(execution.request.workdir_attachments.len(), 1);
+        let attachment = &execution.request.workdir_attachments[0];
+        assert_eq!(attachment.alias.as_str(), "workdir");
+        assert_eq!(attachment.working_directory_id, "wd-legacy");
+        assert_eq!(attachment.relative_cwd.as_deref(), Some("crates/yoi"));
+        let serialized = serde_json::to_value(execution).unwrap();
+        assert!(serialized["request"].get("working_directory").is_none());
+    }
+
     #[test]
     fn startup_recovers_staging_created_before_source_backup() {
         let temp = tempfile::tempdir().unwrap();

crates/worker-runtime/src/http_server.rs

@@ -2282,7 +2282,11 @@ fn required_runtime_permission(method: &Method, path: &str) -> Option<&'static s
     if path.ends_with("/workspace-api") {
         return Some("workers:create");
     }
-    if path.ends_with("/input") || path.ends_with("/restore") || path.contains("/attachments") {
+    if path.ends_with("/input")
+        || path.ends_with("/restore")
+        || path.contains("/attachments")
+        || path.contains("/workdir-attachments")
+    {
         return Some("workers:input");
     }
     if path.ends_with("/stop") || path.ends_with("/cancel") {
@@ -3072,8 +3076,8 @@ mod tests {
                 digest: bundle.metadata.digest,
             }),
             initial_input: None,
-            working_directory_request: None,
-            working_directory: None,
+            workdir_attachment_requests: Vec::new(),
+            workdir_attachments: Vec::new(),
             worker_observation_enabled: false,
             worker_observation_grants: Vec::new(),
             workspace_api: None,
@@ -3319,10 +3323,16 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(
+                        |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        },
+                    )
+                    .collect(),
             }
         }
 
@@ -3335,7 +3345,7 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request.previous_working_directory,
+                workdir_attachments: request.previous_workdir_attachments,
             }
         }
 
@@ -3907,10 +3917,16 @@ mod ws_tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(
+                        |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        },
+                    )
+                    .collect(),
             }
         }
 
@@ -4020,8 +4036,8 @@ mod ws_tests {
                 digest: bundle.metadata.digest,
             }),
             initial_input: None,
-            working_directory_request: None,
-            working_directory: None,
+            workdir_attachment_requests: Vec::new(),
+            workdir_attachments: Vec::new(),
             worker_observation_enabled: false,
             worker_observation_grants: Vec::new(),
             workspace_api: None,

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

@@ -423,6 +423,31 @@ impl runtime_api::RuntimeApi for RuntimeManagementApi {
         Ok(runtime_api::WorkerResponse { worker })
     }
 
+    async fn replace_worker_workdir_attachments(
+        &self,
+        worker_id: String,
+        value: runtime_api::WorkerWorkdirAttachmentsRequest,
+    ) -> Result<runtime_api::WorkerResponse, runtime_api::RuntimeApiError> {
+        let attachments = request(value.workdir_attachments)?;
+        let worker_ref = worker_ref_for(&self.state.runtime, worker_id).map_err(api_error)?;
+        let worker = match auth_workspace_scope(&self.state, auth_extension().as_ref())
+            .map_err(api_error)?
+        {
+            Some(scope) => self
+                .state
+                .runtime
+                .replace_worker_workdir_attachments_scoped(&scope, &worker_ref, attachments),
+            None => self
+                .state
+                .runtime
+                .replace_worker_workdir_attachments(&worker_ref, attachments),
+        }
+        .map_err(RuntimeHttpRestError::runtime)
+        .map_err(api_error)?;
+        let worker = response(worker)?;
+        Ok(runtime_api::WorkerResponse { worker })
+    }
+
     async fn complete_worker_arguments(
         &self,
         worker_id: String,

crates/worker-runtime/src/runtime.rs

@@ -1,7 +1,8 @@
 use crate::catalog::{
     ConfigBundleRef, CreateWorkerRequest, ProfileSelector, ProfileSourceArchiveSource,
     RepositoryRefObservation, RepositoryRefObservationRequest, WorkerDetail, WorkerLifecycleAck,
-    WorkerRestoreIntent, WorkerStatus, WorkerSummary, WorkingDirectoryRepositoryAccessRequest,
+    WorkerRestoreIntent, WorkerStatus, WorkerSummary, WorkingDirectoryAttachmentClaim,
+    WorkingDirectoryAttachmentStatus, WorkingDirectoryRepositoryAccessRequest,
     WorkingDirectoryRequest, WorkingDirectoryStatus as CatalogWorkingDirectoryStatus,
     WorkspaceApiRef,
 };
@@ -43,7 +44,7 @@ use crate::retention::{
 use protocol::subscription::{
     EventSubscriptionSelector, SubscriptionEventPayload, SubscriptionSnapshot,
     SubscriptionValidationError, SubscriptionWorkdirId, SubscriptionWorker, SubscriptionWorkerId,
-    SubscriptionWorkerState,
+    SubscriptionWorkerState, SubscriptionWorkerWorkdirAttachment,
 };
 use protocol::{Event, Method};
 use server_api::WorkerRestoreState;
@@ -729,8 +730,9 @@ impl Runtime {
                     .get(&worker_ref.worker_id)
                     .is_some_and(|worker| {
                         worker.belongs_to_workspace(&scope.workspace_id)
-                            && worker.working_directory.as_ref().is_some_and(|status| {
-                                status.summary.working_directory_id == working_directory_id
+                            && worker.workdir_attachments.iter().any(|attachment| {
+                                attachment.working_directory.summary.working_directory_id
+                                    == working_directory_id
                             })
                     });
                 if !owns_workdir {
@@ -764,7 +766,7 @@ impl Runtime {
         let backend = {
             let state = self.lock()?;
             state.ensure_running()?;
-            if let Some(worker_id) = state.primary_worker_id_for_workdir(working_directory_id) {
+            if let Some(worker_id) = state.worker_id_for_workdir(working_directory_id) {
                 return Err(RuntimeError::InvalidRequest(format!(
                     "working directory {working_directory_id} is assigned to worker {worker_id}"
                 )));
@@ -792,12 +794,8 @@ impl Runtime {
 
     fn annotate_working_directory_status(
         &self,
-        mut status: CatalogWorkingDirectoryStatus,
+        status: CatalogWorkingDirectoryStatus,
     ) -> Result<CatalogWorkingDirectoryStatus, RuntimeError> {
-        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.to_string());
         Ok(status)
     }
 
@@ -1023,10 +1021,8 @@ impl Runtime {
                 return Ok(existing.detail());
             }
             state.validate_worker_config_boundary(&request)?;
-            if let Some(working_directory_id) = requested_primary_workdir_id(&request) {
-                if let Some(owner_worker_id) =
-                    state.primary_worker_id_for_workdir(working_directory_id)
-                {
+            for working_directory_id in requested_workdir_ids(&request) {
+                if let Some(owner_worker_id) = state.worker_id_for_workdir(working_directory_id) {
                     return Err(RuntimeError::InvalidRequest(format!(
                         "working directory {working_directory_id} is already assigned to worker {owner_worker_id}"
                     )));
@@ -1064,7 +1060,7 @@ impl Runtime {
                 execution_metadata_available: true,
                 execution_bound: true,
                 restore_intent: WorkerRestoreIntent::Explicit,
-                working_directory: None,
+                workdir_attachments: Vec::new(),
                 execution_handle: None,
                 internal_workers: InternalWorkerActivityProjection::default(),
             };
@@ -1076,19 +1072,19 @@ impl Runtime {
                 request,
                 workspace_scope: scope.cloned(),
                 context: self.execution_context(worker_ref.clone()),
-                working_directory: None,
+                workdir_attachments: BTreeMap::new(),
                 config_bundle,
             };
             (backend, worker_ref, spawn_request)
         };
 
         let spawn_result = backend.spawn_worker(spawn_request);
-        let (handle, initial_worker_state, working_directory) = match spawn_result {
+        let (handle, initial_worker_state, workdir_attachments) = match spawn_result {
             WorkerExecutionSpawnResult::Connected {
                 handle,
                 worker_state,
-                working_directory,
-            } => (handle, worker_state, working_directory),
+                workdir_attachments,
+            } => (handle, worker_state, workdir_attachments),
             WorkerExecutionSpawnResult::Rejected(result)
             | WorkerExecutionSpawnResult::RolledBack(result)
             | WorkerExecutionSpawnResult::Errored(result) => {
@@ -1101,8 +1097,30 @@ impl Runtime {
                     result,
                 });
             }
-            WorkerExecutionSpawnResult::ReconciliationRequired { result, .. } => {
-                self.rollback_failed_create(&worker_ref)?;
+            WorkerExecutionSpawnResult::ReconciliationRequired {
+                result,
+                handle,
+                worker_state,
+                workdir_attachments,
+            } => {
+                let retain_result =
+                    if let (Some(handle), Some(worker_state)) = (handle, worker_state) {
+                        self.retain_restore_execution_evidence(
+                            &worker_ref,
+                            handle,
+                            worker_state,
+                            workdir_attachments,
+                        )
+                    } else {
+                        self.retain_create_reconciliation_pending(&worker_ref, workdir_attachments)
+                    };
+                if let Err(error) = retain_result {
+                    tracing::error!(
+                        worker_id = %worker_ref.worker_id,
+                        %error,
+                        "failed to persist Worker create reconciliation evidence"
+                    );
+                }
                 return Err(RuntimeError::WorkerExecutionRejected {
                     worker_id: worker_ref.worker_id.clone(),
                     operation: result.operation,
@@ -1160,7 +1178,7 @@ impl Runtime {
                 &worker_ref,
                 handle.clone(),
                 initial_worker_state.clone(),
-                working_directory,
+                workdir_attachments,
                 dispatch_result,
             ) {
                 Ok(detail) => detail,
@@ -1179,7 +1197,7 @@ impl Runtime {
                 &worker_ref,
                 handle.clone(),
                 initial_worker_state,
-                working_directory,
+                workdir_attachments,
                 WorkerExecutionResult::accepted(WorkerExecutionOperation::Spawn),
             ) {
                 Ok(detail) => Ok(detail),
@@ -1425,6 +1443,119 @@ impl Runtime {
         Ok(state.worker(worker_ref)?.detail())
     }
 
+    pub fn replace_worker_workdir_attachments_scoped(
+        &self,
+        scope: &RuntimeWorkspaceScope,
+        worker_ref: &WorkerRef,
+        attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> Result<WorkerDetail, RuntimeError> {
+        self.ensure_worker_in_workspace(scope, worker_ref)?;
+        self.replace_worker_workdir_attachments(worker_ref, attachments)
+    }
+
+    /// Persist the exact current attachment set used by live mutation and future restore.
+    pub fn replace_worker_workdir_attachments(
+        &self,
+        worker_ref: &WorkerRef,
+        mut attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> Result<WorkerDetail, RuntimeError> {
+        let operation_lock = self.worker_operation_lock(worker_ref.worker_id)?;
+        let _operation_guard = operation_lock
+            .lock()
+            .map_err(|_| RuntimeError::StatePoisoned)?;
+
+        let backend = {
+            let state = self.lock()?;
+            let worker = state.worker(worker_ref)?;
+            if worker.execution_handle.is_none() || !worker.status.is_active() {
+                return Err(RuntimeError::WorkerExecutionUnavailable {
+                    worker_id: worker.worker_id,
+                    message: "Workdir attachments can only be changed for a live Worker"
+                        .to_string(),
+                });
+            }
+            let request = worker.request.as_ref().ok_or_else(|| {
+                RuntimeError::WorkerExecutionUnavailable {
+                    worker_id: worker.worker_id,
+                    message: "persisted Worker restore request is unavailable".to_string(),
+                }
+            })?;
+            for attachment in &mut attachments {
+                if attachment.relative_cwd.is_none()
+                    && let Some(previous) = request.workdir_attachments.iter().find(|previous| {
+                        previous.alias == attachment.alias
+                            && previous.working_directory_id == attachment.working_directory_id
+                    })
+                {
+                    attachment.relative_cwd = previous.relative_cwd.clone();
+                }
+            }
+            let mut candidate = request.clone();
+            candidate.workdir_attachment_requests.clear();
+            candidate.workdir_attachments = attachments.clone();
+            validate_create_worker_request(&candidate)?;
+            state.execution_backend.clone().ok_or_else(|| {
+                RuntimeError::ExecutionBackendUnavailable {
+                    message: "Workdir attachment mutation requires an execution backend"
+                        .to_string(),
+                }
+            })?
+        };
+
+        let statuses = attachments
+            .iter()
+            .map(|attachment| {
+                backend
+                    .working_directory(&attachment.working_directory_id)
+                    .map(|working_directory| WorkingDirectoryAttachmentStatus {
+                        alias: attachment.alias.clone(),
+                        working_directory,
+                    })
+                    .map_err(RuntimeError::from)
+            })
+            .collect::<Result<Vec<_>, RuntimeError>>()?;
+        if let Some(inactive) = statuses.iter().find(|attachment| {
+            attachment.working_directory.summary.status
+                != workdir::workspace::WorkingDirectoryStatusKind::Active
+        }) {
+            return Err(RuntimeError::InvalidRequest(format!(
+                "working directory {} is not active ({})",
+                inactive.working_directory.summary.working_directory_id,
+                inactive.working_directory.summary.status
+            )));
+        }
+
+        let mut state = self.lock()?;
+        for attachment in &attachments {
+            if let Some(owner_worker_id) =
+                state.worker_id_for_workdir(&attachment.working_directory_id)
+                && owner_worker_id != worker_ref.worker_id
+            {
+                return Err(RuntimeError::InvalidRequest(format!(
+                    "working directory {} is already assigned to worker {owner_worker_id}",
+                    attachment.working_directory_id
+                )));
+            }
+        }
+        let previous = state.worker(worker_ref)?.clone();
+        {
+            let worker = state.worker_mut(worker_ref)?;
+            let request = worker
+                .request
+                .as_mut()
+                .expect("restore request checked above");
+            request.workdir_attachment_requests.clear();
+            request.workdir_attachments = attachments;
+            worker.workdir_attachments = statuses;
+        }
+        if let Err(error) = state.persist_worker(&worker_ref.worker_id) {
+            state.workers.insert(worker_ref.worker_id, previous);
+            return Err(error);
+        }
+        state.publish_worker_upsert(worker_ref.worker_id)?;
+        Ok(state.worker(worker_ref)?.detail())
+    }
+
     /// Observe a Worker's live protocol availability or its retained Session.
     /// The same lifecycle lock used by stop/restore fences the decision and read.
     pub fn worker_session_scoped(
@@ -1570,8 +1701,8 @@ impl Runtime {
                 request: worker_request,
                 workspace_scope,
                 context: self.execution_context(worker_ref.clone()),
-                previous_working_directory: worker.working_directory.clone(),
-                working_directory: None,
+                previous_workdir_attachments: worker.workdir_attachments.clone(),
+                workdir_attachments: BTreeMap::new(),
                 config_bundle: None,
             };
             (backend, request)
@@ -1589,14 +1720,14 @@ impl Runtime {
             WorkerExecutionSpawnResult::Connected {
                 handle,
                 worker_state,
-                working_directory,
+                workdir_attachments,
             } => {
                 let commit = self.commit_restored_worker_execution(
                     worker_ref,
                     handle.clone(),
                     worker_state.clone(),
                     WorkerStatus::Idle,
-                    working_directory.clone(),
+                    workdir_attachments.clone(),
                 );
                 match commit {
                     Ok(worker) => Ok(RuntimeWorkerRestoreResult::accepted(worker)),
@@ -1625,7 +1756,7 @@ impl Runtime {
                                     worker_ref,
                                     handle,
                                     worker_state,
-                                    working_directory,
+                                    workdir_attachments,
                                 ) {
                                     tracing::error!(
                                         worker_id = %worker_ref.worker_id,
@@ -1663,14 +1794,14 @@ impl Runtime {
                 result: _result,
                 handle,
                 worker_state,
-                working_directory,
+                workdir_attachments,
             } => {
                 if let (Some(handle), Some(worker_state)) = (handle, worker_state) {
                     if let Err(retain_error) = self.retain_restore_execution_evidence(
                         worker_ref,
                         handle,
                         worker_state,
-                        working_directory,
+                        workdir_attachments,
                     ) {
                         tracing::error!(
                             worker_id = %worker_ref.worker_id,
@@ -2079,7 +2210,7 @@ impl Runtime {
         worker_ref: &WorkerRef,
         handle: WorkerExecutionHandle,
         initial_worker_state: protocol::WorkerStateSnapshot,
-        working_directory: Option<CatalogWorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
         result: WorkerExecutionResult,
     ) -> Result<WorkerDetail, RuntimeError> {
         let mut state = self.lock()?;
@@ -2094,7 +2225,7 @@ impl Runtime {
                 let _ = worker.apply_worker_state(snapshot);
             }
             worker.restore_intent = restore_intent_for_status(worker.status);
-            worker.working_directory = working_directory;
+            worker.workdir_attachments = workdir_attachments;
             worker.detail()
         };
         state.publish_worker_upsert(worker_ref.worker_id)?;
@@ -2367,9 +2498,13 @@ impl Runtime {
             state.ensure_running()?;
             state.ensure_worker_ref(worker_ref)?;
             let worker = state.worker(worker_ref)?;
-            if worker.execution_handle.is_some() && worker.status.is_active() {
+            if worker.status.is_active()
+                && (worker.execution_handle.is_some()
+                    || (!worker.execution_metadata_available
+                        && !worker.workdir_attachments.is_empty()))
+            {
                 return Err(RuntimeError::InvalidRequest(format!(
-                    "worker {} is running and must be stopped before deletion",
+                    "worker {} is active or requires reconciliation and must be stopped before deletion",
                     worker_ref.worker_id
                 )));
             }
@@ -2398,9 +2533,12 @@ impl Runtime {
         state.ensure_running()?;
         state.ensure_worker_ref(worker_ref)?;
         let worker = state.worker(worker_ref)?;
-        if worker.execution_handle.is_some() && worker.status.is_active() {
+        if worker.status.is_active()
+            && (worker.execution_handle.is_some()
+                || (!worker.execution_metadata_available && !worker.workdir_attachments.is_empty()))
+        {
             return Err(RuntimeError::InvalidRequest(format!(
-                "worker {} became active before deletion",
+                "worker {} became active or reconciliation-required before deletion",
                 worker_ref.worker_id
             )));
         }
@@ -2662,7 +2800,7 @@ impl Runtime {
         handle: WorkerExecutionHandle,
         worker_state: protocol::WorkerStateSnapshot,
         status: WorkerStatus,
-        working_directory: Option<CatalogWorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     ) -> Result<WorkerDetail, RuntimeError> {
         let mut state = self.lock()?;
         state.ensure_worker_ref(worker_ref)?;
@@ -2679,7 +2817,7 @@ impl Runtime {
         candidate.status = status;
         let _ = candidate.apply_worker_state(&worker_state);
         candidate.restore_intent = restore_intent_for_status(candidate.status);
-        candidate.working_directory = working_directory;
+        candidate.workdir_attachments = workdir_attachments;
 
         // Validate the exact subscription projection before persistence. The
         // subsequent publish uses the same pure projection while the Worker
@@ -2708,7 +2846,7 @@ impl Runtime {
         worker_ref: &WorkerRef,
         handle: WorkerExecutionHandle,
         worker_state: protocol::WorkerStateSnapshot,
-        working_directory: Option<CatalogWorkingDirectoryStatus>,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     ) -> Result<(), RuntimeError> {
         let mut state = self.lock()?;
         let mut candidate = state.worker(worker_ref)?.clone();
@@ -2718,7 +2856,26 @@ impl Runtime {
         candidate.status = WorkerStatus::Idle;
         let _ = candidate.apply_worker_state(&worker_state);
         candidate.restore_intent = WorkerRestoreIntent::Automatic;
-        candidate.working_directory = working_directory;
+        candidate.workdir_attachments = workdir_attachments;
+        state.workers.insert(worker_ref.worker_id, candidate);
+        state.publish_worker_upsert(worker_ref.worker_id)?;
+        state.persist_worker(&worker_ref.worker_id)?;
+        Ok(())
+    }
+
+    fn retain_create_reconciliation_pending(
+        &self,
+        worker_ref: &WorkerRef,
+        workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
+    ) -> Result<(), RuntimeError> {
+        let mut state = self.lock()?;
+        let mut candidate = state.worker(worker_ref)?.clone();
+        candidate.execution_handle = None;
+        candidate.execution_metadata_available = false;
+        candidate.execution_bound = true;
+        candidate.status = WorkerStatus::Idle;
+        candidate.restore_intent = WorkerRestoreIntent::Explicit;
+        candidate.workdir_attachments = workdir_attachments;
         state.workers.insert(worker_ref.worker_id, candidate);
         state.publish_worker_upsert(worker_ref.worker_id)?;
         state.persist_worker(&worker_ref.worker_id)?;
@@ -3078,7 +3235,7 @@ impl RuntimeState {
                     execution_metadata_available,
                     execution_bound,
                     restore_intent,
-                    working_directory: worker.working_directory,
+                    workdir_attachments: worker.workdir_attachments,
                     execution_handle: None,
                     internal_workers: InternalWorkerActivityProjection::default(),
                 },
@@ -3394,18 +3551,25 @@ impl RuntimeState {
     ) -> Result<SubscriptionWorker, RuntimeError> {
         let worker_id = SubscriptionWorkerId::new(worker.worker_id.to_string())
             .map_err(subscription_validation_error)?;
-        let repository_id = worker
-            .working_directory
-            .as_ref()
-            .map(|working_directory| working_directory.summary.repository_id.clone());
-        let working_directory_id = worker
-            .working_directory
-            .as_ref()
-            .map(|working_directory| {
-                SubscriptionWorkdirId::new(working_directory.summary.working_directory_id.clone())
-                    .map_err(subscription_validation_error)
+        let workdir_attachments = worker
+            .workdir_attachments
+            .iter()
+            .map(|attachment| {
+                Ok(SubscriptionWorkerWorkdirAttachment {
+                    alias: attachment.alias.to_string(),
+                    repository_id: Some(attachment.working_directory.summary.repository_id.clone()),
+                    repository_key: None,
+                    working_directory_id: SubscriptionWorkdirId::new(
+                        attachment
+                            .working_directory
+                            .summary
+                            .working_directory_id
+                            .clone(),
+                    )
+                    .map_err(subscription_validation_error)?,
+                })
             })
-            .transpose()?;
+            .collect::<Result<Vec<_>, RuntimeError>>()?;
         let profile = match &worker.profile {
             ProfileSelector::Builtin(name) | ProfileSelector::Named(name) => Some(name.clone()),
         };
@@ -3425,9 +3589,7 @@ impl RuntimeState {
             workspace_id: worker.workspace_id.clone(),
             display_name: worker.display_name.clone(),
             profile,
-            repository_id,
-            repository_key: None,
-            working_directory_id,
+            workdir_attachments,
         })
     }
 
@@ -3525,22 +3687,15 @@ impl RuntimeState {
         }
     }
 
-    fn primary_worker_id_for_workdir(&self, working_directory_id: &str) -> Option<WorkerId> {
+    fn worker_id_for_workdir(&self, working_directory_id: &str) -> Option<WorkerId> {
         self.workers.values().find_map(|worker| {
-            if worker
-                .working_directory
-                .as_ref()
-                .is_some_and(|binding| binding.summary.working_directory_id == working_directory_id)
-                || worker
-                    .request
-                    .as_ref()
-                    .and_then(requested_primary_workdir_id)
-                    == Some(working_directory_id)
-            {
-                Some(worker.worker_id)
-            } else {
-                None
-            }
+            let has_status = worker.workdir_attachments.iter().any(|attachment| {
+                attachment.working_directory.summary.working_directory_id == working_directory_id
+            });
+            let has_request = worker.request.as_ref().is_some_and(|request| {
+                requested_workdir_ids(request).contains(&working_directory_id)
+            });
+            (has_status || has_request).then_some(worker.worker_id)
         })
     }
 
@@ -3976,7 +4131,7 @@ struct WorkerRecord {
     execution_metadata_available: bool,
     execution_bound: bool,
     restore_intent: WorkerRestoreIntent,
-    working_directory: Option<CatalogWorkingDirectoryStatus>,
+    workdir_attachments: Vec<crate::catalog::WorkingDirectoryAttachmentStatus>,
     execution_handle: Option<WorkerExecutionHandle>,
     internal_workers: InternalWorkerActivityProjection,
 }
@@ -3999,7 +4154,7 @@ impl WorkerRecord {
             execution_metadata_available: self.execution_metadata_available,
             worker_state: self.worker_state.clone(),
             workspace_id: self.workspace_id.clone(),
-            working_directory: self.working_directory.clone(),
+            workdir_attachments: self.workdir_attachments.clone(),
             profile: self.profile.clone(),
             display_name: self.display_name.clone(),
             profile_source: self.profile_source.clone(),
@@ -4016,7 +4171,7 @@ impl WorkerRecord {
             execution_metadata_available: self.execution_metadata_available,
             worker_state: self.worker_state.clone(),
             workspace_id: self.workspace_id.clone(),
-            working_directory: self.working_directory.clone(),
+            workdir_attachments: self.workdir_attachments.clone(),
             profile: self.profile.clone(),
             display_name: self.display_name.clone(),
             profile_source: self.profile_source.clone(),
@@ -4049,7 +4204,7 @@ impl WorkerRecord {
             status: self.status,
             execution_state,
             workspace_id: self.workspace_id.clone(),
-            working_directory: self.working_directory.clone(),
+            workdir_attachments: self.workdir_attachments.clone(),
         }
     }
 }
@@ -4100,25 +4255,28 @@ fn repository_resource_error(error: BackendResourceError) -> RuntimeError {
 
 fn durable_create_worker_request(request: &CreateWorkerRequest) -> CreateWorkerRequest {
     let mut durable = request.clone();
-    if let Some(working_directory) = durable.working_directory_request.as_mut()
-        && let Some(materialization) = working_directory.materialization.as_mut()
-    {
-        materialization.ssh = None;
+    for attachment in &mut durable.workdir_attachment_requests {
+        if let Some(materialization) = attachment.working_directory.materialization.as_mut() {
+            materialization.ssh = None;
+        }
     }
     durable
 }
 
-fn requested_primary_workdir_id(request: &CreateWorkerRequest) -> Option<&str> {
+fn requested_workdir_ids(request: &CreateWorkerRequest) -> Vec<&str> {
     request
-        .working_directory
-        .as_ref()
+        .workdir_attachments
+        .iter()
         .map(|claim| claim.working_directory_id.as_str())
-        .or_else(|| {
+        .chain(
             request
-                .working_directory_request
-                .as_ref()
-                .and_then(|request| request.backend_workdir_id.as_deref())
-        })
+                .workdir_attachment_requests
+                .iter()
+                .filter_map(|attachment| {
+                    attachment.working_directory.backend_workdir_id.as_deref()
+                }),
+        )
+        .collect()
 }
 
 fn validate_create_worker_request(request: &CreateWorkerRequest) -> Result<(), RuntimeError> {
@@ -4127,6 +4285,42 @@ fn validate_create_worker_request(request: &CreateWorkerRequest) -> Result<(), R
             "create_fingerprint must not be empty".to_string(),
         ));
     }
+    let mut aliases = std::collections::BTreeSet::new();
+    let mut workdir_ids = std::collections::BTreeSet::new();
+    for (alias, workdir_id) in request
+        .workdir_attachments
+        .iter()
+        .map(|attachment| {
+            (
+                &attachment.alias,
+                Some(attachment.working_directory_id.as_str()),
+            )
+        })
+        .chain(
+            request
+                .workdir_attachment_requests
+                .iter()
+                .map(|attachment| {
+                    (
+                        &attachment.alias,
+                        attachment.working_directory.backend_workdir_id.as_deref(),
+                    )
+                }),
+        )
+    {
+        if !aliases.insert(alias.as_str()) {
+            return Err(RuntimeError::InvalidRequest(format!(
+                "duplicate Workdir attachment alias `{alias}`"
+            )));
+        }
+        if let Some(workdir_id) = workdir_id
+            && !workdir_ids.insert(workdir_id)
+        {
+            return Err(RuntimeError::InvalidRequest(format!(
+                "working directory `{workdir_id}` cannot be attached more than once"
+            )));
+        }
+    }
     match &request.profile_source {
         crate::catalog::ProfileSourceArchiveSource::Embedded { archive } => {
             archive.verify().map_err(|err| {
@@ -4420,8 +4614,8 @@ mod tests {
     use crate::catalog::{
         ConfigBundleRef, MaterializerKind, ProfileSelector, RepositoryMaterializationContext,
         RepositorySshCredentialCandidate, RepositorySshMaterializationAccess, SensitiveString,
-        WorkingDirectoryClaim, WorkingDirectoryRepository, WorkingDirectoryRequest,
-        WorkspaceApiRef,
+        WorkingDirectoryAttachmentClaim, WorkingDirectoryAttachmentRequest,
+        WorkingDirectoryRepository, WorkingDirectoryRequest, WorkspaceApiRef,
     };
     use crate::config_bundle::{
         ConfigBundle, ConfigBundleMetadata, ConfigBundleProvenance, ConfigDeclaration,
@@ -4913,8 +5107,8 @@ mod tests {
                 digest: bundle.metadata.digest,
             }),
             initial_input: None,
-            working_directory_request: None,
-            working_directory: None,
+            workdir_attachment_requests: Vec::new(),
+            workdir_attachments: Vec::new(),
             worker_observation_enabled: false,
             worker_observation_grants: Vec::new(),
             workspace_api: None,
@@ -4929,60 +5123,64 @@ mod tests {
     #[test]
     fn durable_worker_request_omits_repository_credentials() {
         let mut request = task_request("worker-secret-redaction");
-        request.working_directory_request = Some(WorkingDirectoryRequest {
-            repository: WorkingDirectoryRepository {
-                id: "repository-1".to_string(),
-                provider: "git".to_string(),
-                source: server_api::RepositorySource {
-                    kind: server_api::RepositorySourceKind::Ssh,
-                    uri: "ssh://git@example.test/repo.git".to_string(),
+        request.workdir_attachment_requests = vec![WorkingDirectoryAttachmentRequest {
+            alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+            working_directory: WorkingDirectoryRequest {
+                repository: WorkingDirectoryRepository {
+                    id: "repository-1".to_string(),
+                    provider: "git".to_string(),
+                    source: server_api::RepositorySource {
+                        kind: server_api::RepositorySourceKind::Ssh,
+                        uri: "ssh://git@example.test/repo.git".to_string(),
+                    },
+                    source_revision: 1,
+                    source_fingerprint: "sha256:source".to_string(),
+                    selector: None,
                 },
-                source_revision: 1,
-                source_fingerprint: "sha256:source".to_string(),
-                selector: None,
-            },
-            materializer: MaterializerKind::RuntimeGitClone,
-            backend_workdir_id: Some("working-directory-1".to_string()),
-            materialization: Some(RepositoryMaterializationContext {
-                workspace_id: "workspace-1".to_string(),
-                runtime_id: "runtime-1".to_string(),
-                operation_id: "operation-1".to_string(),
-                config_revision: 1,
-                config_projection_digest: "sha256:projection".to_string(),
-                ssh: Some(RepositorySshMaterializationAccess {
-                    credential_candidates: vec![RepositorySshCredentialCandidate {
-                        credential_id: "credential-1".to_string(),
-                        credential_revision: 1,
-                        private_key: SensitiveString::new("private-key-bytes"),
-                    }],
-                    host_trust_id: "host-trust-1".to_string(),
-                    host_trust_revision: 1,
-                    access: server_api::RepositoryAccessMode::ReadOnly,
-                    expires_at_epoch_seconds: u64::MAX,
-                    repository_id: "repository-1".to_string(),
-                    repository_source_fingerprint: "sha256:source".to_string(),
-                    repository_uri: "ssh://git@example.test/repo.git".to_string(),
-                    secret_resource: repository_resource_handle(),
-                    known_hosts_entry: SensitiveString::new("known-hosts-entry"),
+                display_name: None,
+                materializer: MaterializerKind::RuntimeGitClone,
+                backend_workdir_id: Some("working-directory-1".to_string()),
+                materialization: Some(RepositoryMaterializationContext {
+                    workspace_id: "workspace-1".to_string(),
+                    runtime_id: "runtime-1".to_string(),
+                    operation_id: "operation-1".to_string(),
+                    config_revision: 1,
+                    config_projection_digest: "sha256:projection".to_string(),
+                    ssh: Some(RepositorySshMaterializationAccess {
+                        credential_candidates: vec![RepositorySshCredentialCandidate {
+                            credential_id: "credential-1".to_string(),
+                            credential_revision: 1,
+                            private_key: SensitiveString::new("private-key-bytes"),
+                        }],
+                        host_trust_id: "host-trust-1".to_string(),
+                        host_trust_revision: 1,
+                        access: server_api::RepositoryAccessMode::ReadOnly,
+                        expires_at_epoch_seconds: u64::MAX,
+                        repository_id: "repository-1".to_string(),
+                        repository_source_fingerprint: "sha256:source".to_string(),
+                        repository_uri: "ssh://git@example.test/repo.git".to_string(),
+                        secret_resource: repository_resource_handle(),
+                        known_hosts_entry: SensitiveString::new("known-hosts-entry"),
+                    }),
                 }),
-            }),
-        });
+            },
+        }];
 
         let durable = durable_create_worker_request(&request);
 
         assert!(
             request
-                .working_directory_request
-                .as_ref()
-                .and_then(|working_directory| working_directory.materialization.as_ref())
+                .workdir_attachment_requests
+                .first()
+                .and_then(|attachment| attachment.working_directory.materialization.as_ref())
                 .and_then(|materialization| materialization.ssh.as_ref())
                 .is_some()
         );
         assert!(
             durable
-                .working_directory_request
-                .as_ref()
-                .and_then(|working_directory| working_directory.materialization.as_ref())
+                .workdir_attachment_requests
+                .first()
+                .and_then(|attachment| attachment.working_directory.materialization.as_ref())
                 .and_then(|materialization| materialization.ssh.as_ref())
                 .is_none()
         );
@@ -5172,6 +5370,7 @@ mod tests {
                 source_fingerprint: "sha256:source".to_string(),
                 selector: None,
             },
+            display_name: None,
             materializer: MaterializerKind::RuntimeGitClone,
             backend_workdir_id: Some("working-directory-1".to_string()),
             materialization: Some(RepositoryMaterializationContext {
@@ -5342,6 +5541,7 @@ mod tests {
 
     #[derive(Default)]
     struct TestExecutionBackend {
+        spawn_result: Mutex<Option<WorkerExecutionSpawnResult>>,
         dispatch_result: Mutex<Option<WorkerExecutionResult>>,
         stop_result: Mutex<Option<WorkerExecutionResult>>,
         stop_gate: Mutex<Option<Arc<RestoreGate>>>,
@@ -5447,6 +5647,9 @@ mod tests {
         }
 
         fn spawn_worker(&self, request: WorkerExecutionSpawnRequest) -> WorkerExecutionSpawnResult {
+            if let Some(result) = self.spawn_result.lock().unwrap().take() {
+                return result;
+            }
             self.config_bundles
                 .lock()
                 .unwrap()
@@ -5460,10 +5663,16 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(
+                        |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        },
+                    )
+                    .collect(),
             }
         }
 
@@ -5502,10 +5711,16 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(
+                        |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        },
+                    )
+                    .collect(),
             }
         }
 
@@ -6263,10 +6478,11 @@ mod tests {
         let runtime = runtime_with_backend();
         let mut request = task_request("idempotent");
         request.create_fingerprint = "sha256:input-1".to_string();
-        request.working_directory = Some(WorkingDirectoryClaim {
+        request.workdir_attachments = vec![WorkingDirectoryAttachmentClaim {
+            alias: workdir::WorkdirAttachmentAlias::new("workdir").unwrap(),
             working_directory_id: "workdir-idempotent".to_string(),
             relative_cwd: None,
-        });
+        }];
 
         let first = runtime.create_worker(request.clone()).unwrap();
         let workdir_count_after_first = runtime.list_working_directories().unwrap().len();
@@ -6631,6 +6847,49 @@ mod tests {
         assert!(runtime.list_workers().unwrap().is_empty());
     }
 
+    #[test]
+    fn reconciliation_required_create_retains_durable_worker_evidence() {
+        let (runtime, backend) = runtime_and_backend();
+        runtime.store_config_bundle(test_bundle()).unwrap();
+        *backend.spawn_result.lock().unwrap() =
+            Some(WorkerExecutionSpawnResult::ReconciliationRequired {
+                result: WorkerExecutionResult::errored(
+                    WorkerExecutionOperation::Spawn,
+                    "Workdir cleanup could not be proven",
+                ),
+                handle: None,
+                worker_state: None,
+                workdir_attachments: vec![WorkingDirectoryAttachmentStatus {
+                    alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+                    working_directory: serde_json::from_value(serde_json::json!({
+                        "summary": {
+                            "working_directory_id": "wd-uncertain",
+                            "repository_id": "repo",
+                            "materializer_kind": "runtime_git_clone",
+                            "status": "active"
+                        }
+                    }))
+                    .unwrap(),
+                }],
+            });
+        let request = task_request("uncertain create cleanup");
+        let worker_ref = WorkerRef::new(request.worker_id);
+
+        let error = runtime.create_worker(request).unwrap_err();
+
+        assert!(matches!(
+            error,
+            RuntimeError::WorkerExecutionRejected { .. }
+        ));
+        let retained = runtime.worker_detail(&worker_ref).unwrap();
+        assert_eq!(retained.status, WorkerStatus::Idle);
+        assert!(!retained.execution_metadata_available);
+        assert!(matches!(
+            runtime.delete_worker(&worker_ref),
+            Err(RuntimeError::InvalidRequest(_))
+        ));
+    }
+
     #[test]
     fn create_worker_without_execution_backend_is_rejected_and_not_persisted() {
         let runtime = Runtime::new_memory();
@@ -6804,10 +7063,16 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(
+                        |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        },
+                    )
+                    .collect(),
             }
         }
 
@@ -7667,7 +7932,7 @@ mod tests {
                 ),
                 handle: None,
                 worker_state: None,
-                working_directory: None,
+                workdir_attachments: Vec::new(),
             },
         );
 

crates/worker-runtime/src/worker_backend.rs

@@ -7,7 +7,7 @@
 //! socket paths, session paths, manifests, credentials, or handles leave this
 //! module.
 
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::future::Future;
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
@@ -17,8 +17,9 @@ use std::time::Duration;
 use crate::auth::{BACKEND_RESOURCE_FETCH_PERMISSION, RuntimeIdentityMaterial};
 use crate::catalog::{
     CreateWorkerRequest, ProfileSourceArchiveSource, RepositoryRefObservation,
-    RepositoryRefObservationRequest, WorkingDirectoryRepositoryAccessRequest,
-    WorkingDirectoryRequest, WorkingDirectoryStatus, WorkingDirectoryStatusKind,
+    RepositoryRefObservationRequest, WorkingDirectoryAttachmentStatus,
+    WorkingDirectoryRepositoryAccessRequest, WorkingDirectoryRequest, WorkingDirectoryStatus,
+    WorkingDirectoryStatusKind,
 };
 use crate::config_bundle::{ConfigBundle, workspace_config_etag};
 use crate::execution::{
@@ -44,6 +45,45 @@ use protocol::{Event, Method, Segment, WorkerCommandEnvelope};
 
 static NEXT_INTERNAL_COMMAND_ID: AtomicU64 = AtomicU64::new(1);
 
+fn rollback_materialized_spawn_workdirs(
+    materializer: &dyn WorkingDirectoryMaterializer,
+    bindings: &BTreeMap<WorkdirAttachmentAlias, WorkingDirectoryBinding>,
+    workdir_ids: &[String],
+    failure_context: &str,
+) -> Result<(), WorkerExecutionSpawnResult> {
+    let mut cleanup_failures = Vec::new();
+    let mut uncertain_attachments = Vec::new();
+    for workdir_id in workdir_ids.iter().rev() {
+        if let Err(error) = materializer.cleanup_working_directory(workdir_id) {
+            cleanup_failures.push(format!("{workdir_id}: {error}"));
+            if let Some((alias, binding)) = bindings
+                .iter()
+                .find(|(_, binding)| binding.working_directory.id == *workdir_id)
+            {
+                uncertain_attachments.push(WorkingDirectoryAttachmentStatus {
+                    alias: alias.clone(),
+                    working_directory: binding.status(),
+                });
+            }
+        }
+    }
+    if cleanup_failures.is_empty() {
+        return Ok(());
+    }
+    Err(WorkerExecutionSpawnResult::ReconciliationRequired {
+        result: WorkerExecutionResult::errored(
+            WorkerExecutionOperation::Spawn,
+            format!(
+                "{failure_context}; Workdir cleanup could not be proven: {}",
+                cleanup_failures.join("; ")
+            ),
+        ),
+        handle: None,
+        worker_state: None,
+        workdir_attachments: uncertain_attachments,
+    })
+}
+
 fn next_internal_command(
     state: &RwLock<protocol::WorkerStateSnapshot>,
 ) -> Result<WorkerCommandEnvelope, String> {
@@ -68,7 +108,10 @@ use session_store::{FsStore, FsWorkerStore};
 use tokio::runtime::Runtime;
 #[cfg(feature = "ws-server")]
 use tokio::sync::broadcast;
-use workdir::{LocalWorkdirSession, Workdir, WorkdirSessionCapabilities, WorkdirSessionHandle};
+use workdir::{
+    LocalWorkdirSession, Workdir, WorkdirAttachmentAlias, WorkdirSessionCapabilities,
+    WorkdirSessionHandle, WorkdirSessionRouter,
+};
 
 #[cfg(test)]
 use worker::WorkerController;
@@ -730,6 +773,29 @@ fn runtime_local_workdir_session(
     ))
 }
 
+fn runtime_local_workdir_router(
+    attachments: &BTreeMap<WorkdirAttachmentAlias, WorkingDirectoryBinding>,
+    scope: manifest::SharedScope,
+) -> Result<Arc<WorkdirSessionRouter>, String> {
+    let router = Arc::new(WorkdirSessionRouter::new());
+    for (alias, binding) in attachments {
+        router
+            .attach(
+                alias.clone(),
+                runtime_local_workdir_session(
+                    &binding.working_directory.id,
+                    binding.root(),
+                    binding.cwd(),
+                    scope.clone(),
+                    binding.command_environment(),
+                    binding.session_resources(),
+                ),
+            )
+            .map_err(|error| format!("bind Workdir attachment `{alias}`: {error}"))?;
+    }
+    Ok(router)
+}
+
 fn bind_workspace_memory_settings(
     manifest: &mut manifest::WorkerManifest,
     request: &CreateWorkerRequest,
@@ -845,15 +911,14 @@ impl RuntimeWorkerFactory for ProfileRuntimeWorkerFactory {
     ) -> Result<RuntimeWorkerController, String> {
         let worker_name = Self::runtime_worker_name(&request);
         let profile = Self::runtime_profile(&request);
-        let has_local_filesystem = request.working_directory.is_some();
-        let worker_root = request
-            .working_directory
-            .as_ref()
+        let has_local_filesystem = request.workdir_attachments.len() == 1;
+        let only_binding = (request.workdir_attachments.len() == 1)
+            .then(|| request.workdir_attachments.values().next())
+            .flatten();
+        let worker_root = only_binding
             .map(|binding| binding.root().to_path_buf())
             .unwrap_or_else(|| self.profile_base_dir.clone());
-        let filesystem_authority = request
-            .working_directory
-            .as_ref()
+        let filesystem_authority = only_binding
             .map(|binding| {
                 WorkerFilesystemAuthority::local(
                     binding.root().to_path_buf(),
@@ -965,18 +1030,10 @@ impl RuntimeWorkerFactory for ProfileRuntimeWorkerFactory {
         })?;
         let worker = prepared.worker_mut();
         validate_worker_memory_settings(worker.manifest(), &request.request)?;
-        if let Some(binding) = request.working_directory.as_ref() {
-            worker.bind_workdir_session(Some(runtime_local_workdir_session(
-                &binding.working_directory.id,
-                binding.root(),
-                binding.cwd(),
-                worker.scope().clone(),
-                binding.command_environment(),
-                binding.session_resources(),
-            )));
-        } else {
-            worker.bind_workdir_session(None);
-        }
+        worker.bind_workdir_sessions(runtime_local_workdir_router(
+            &request.workdir_attachments,
+            worker.scope().clone(),
+        )?);
         if let (Some(runtime_id), Some(workspace_id)) =
             (observation_runtime_id, observation_workspace_id.clone())
             && observation_enabled
@@ -1095,9 +1152,10 @@ impl RuntimeWorkerFactory for ProfileRuntimeWorkerFactory {
         request: WorkerExecutionRestoreRequest,
     ) -> Result<RuntimeWorkerController, String> {
         let worker_name = Self::runtime_worker_name_for_ref(&request.worker_ref);
-        let filesystem_authority = request
-            .working_directory
-            .as_ref()
+        let only_binding = (request.workdir_attachments.len() == 1)
+            .then(|| request.workdir_attachments.values().next())
+            .flatten();
+        let filesystem_authority = only_binding
             .map(|binding| {
                 WorkerFilesystemAuthority::local(
                     binding.root().to_path_buf(),
@@ -1201,18 +1259,10 @@ impl RuntimeWorkerFactory for ProfileRuntimeWorkerFactory {
         };
         validate_worker_memory_settings(worker.manifest(), &request.request)?;
         let flow_transition_enabled = worker.manifest().feature.flow.enabled;
-        if let Some(binding) = request.working_directory.as_ref() {
-            worker.bind_workdir_session(Some(runtime_local_workdir_session(
-                &binding.working_directory.id,
-                binding.root(),
-                binding.cwd(),
-                worker.scope().clone(),
-                binding.command_environment(),
-                binding.session_resources(),
-            )));
-        } else {
-            worker.bind_workdir_session(None);
-        }
+        worker.bind_workdir_sessions(runtime_local_workdir_router(
+            &request.workdir_attachments,
+            worker.scope().clone(),
+        )?);
         if let (Some(runtime_id), Some(workspace_id)) =
             (observation_runtime_id, observation_workspace_id.clone())
             && observation_enabled
@@ -1738,7 +1788,7 @@ where
         handle: WorkerHandle,
         shutdown: Arc<tokio::sync::Mutex<Option<worker::ShutdownReceiver>>>,
         controller_task: tokio::task::JoinHandle<()>,
-        working_directory: Option<WorkingDirectoryBinding>,
+        workdir_attachments: BTreeMap<WorkdirAttachmentAlias, WorkingDirectoryBinding>,
         workspace_client: Option<Arc<dyn WorkspaceClient>>,
     ) -> WorkerExecutionSpawnResult {
         #[cfg(feature = "ws-server")]
@@ -1818,8 +1868,13 @@ where
                             Err(_) => {
                                 let retained_state =
                                     worker_state.read().ok().map(|state| state.clone());
-                                let retained_working_directory =
-                                    working_directory.as_ref().map(|binding| binding.status());
+                                let retained_workdir_attachments = workdir_attachments
+                                    .iter()
+                                    .map(|(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                                        alias: alias.clone(),
+                                        working_directory: binding.status(),
+                                    })
+                                    .collect();
                                 let retained_handle = self
                                     .retain_uncertain_unconnected_controller(
                                         &worker_ref,
@@ -1834,7 +1889,7 @@ where
                                     result,
                                     handle: retained_handle,
                                     worker_state: retained_state,
-                                    working_directory: retained_working_directory,
+                                    workdir_attachments: retained_workdir_attachments,
                                 }
                             }
                         }
@@ -1878,7 +1933,7 @@ where
                         result,
                         handle: Some(existing_handle),
                         worker_state: existing_worker_state,
-                        working_directory: None,
+                        workdir_attachments: Vec::new(),
                     },
                 }
             } else {
@@ -1904,7 +1959,15 @@ where
         WorkerExecutionSpawnResult::Connected {
             handle: WorkerExecutionHandle::new(worker_ref, self.backend_id()),
             worker_state: connected_worker_state,
-            working_directory: working_directory.map(|binding| binding.status()),
+            workdir_attachments: workdir_attachments
+                .into_iter()
+                .map(
+                    |(alias, binding)| crate::catalog::WorkingDirectoryAttachmentStatus {
+                        alias,
+                        working_directory: binding.status(),
+                    },
+                )
+                .collect(),
         }
     }
 }
@@ -2118,67 +2181,134 @@ where
         }
 
         let mut request = request;
-        let mut rollback_working_directory = None;
-        let working_directory = match (
-            request.request.working_directory_request.as_ref(),
-            request.request.working_directory.as_ref(),
-        ) {
-            (Some(_), Some(_)) => {
+        let Some(materializer) = self.working_directory_materializer.as_ref().or_else(|| {
+            (request.request.workdir_attachment_requests.is_empty()
+                && request.request.workdir_attachments.is_empty())
+            .then_some(())
+            .and(None)
+        }) else {
+            if request.request.workdir_attachment_requests.is_empty()
+                && request.request.workdir_attachments.is_empty()
+            {
+                // No provider is needed for a Workdir-less Worker.
+                let factory = self.factory.clone();
+                let bridge_context = request.context.clone();
+                let worker_ref = request.worker_ref.clone();
+                let spawn_result = self
+                    .run_cancellable_on_adapter_runtime(self.spawn_restore_timeout, async move {
+                        factory.spawn_controller(request).await
+                    });
+                let controller = match spawn_result {
+                    Ok(controller) => controller,
+                    Err(message) => {
+                        return WorkerExecutionSpawnResult::Errored(
+                            WorkerExecutionResult::errored(
+                                WorkerExecutionOperation::Spawn,
+                                message,
+                            ),
+                        );
+                    }
+                };
+                return self.connect_handle(
+                    WorkerExecutionOperation::Spawn,
+                    worker_ref,
+                    bridge_context,
+                    controller.handle,
+                    controller.shutdown,
+                    controller.controller_task,
+                    BTreeMap::new(),
+                    Some(controller.workspace_client),
+                );
+            }
+            return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                WorkerExecutionOperation::Spawn,
+                "Workdir attachments were requested, but no materializer is configured for this Runtime backend",
+            ));
+        };
+        let mut rollback_workdirs: Vec<String> = Vec::new();
+        for attachment in request.request.workdir_attachment_requests.clone() {
+            if request.workdir_attachments.contains_key(&attachment.alias) {
+                let message = format!("duplicate Workdir attachment alias `{}`", attachment.alias);
+                if let Err(result) = rollback_materialized_spawn_workdirs(
+                    materializer.as_ref(),
+                    &request.workdir_attachments,
+                    &rollback_workdirs,
+                    &message,
+                ) {
+                    return result;
+                }
                 return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
                     WorkerExecutionOperation::Spawn,
-                    "worker spawn cannot specify both working_directory_request and working_directory",
+                    message,
                 ));
             }
-            (Some(working_directory_request), None) => {
-                let Some(materializer) = self.working_directory_materializer.as_ref() else {
+            match materializer.materialize(&request.worker_ref, &attachment.working_directory) {
+                Ok(binding) => {
+                    rollback_workdirs.push(binding.working_directory.id.clone());
+                    request
+                        .workdir_attachments
+                        .insert(attachment.alias, binding);
+                }
+                Err(error) => {
+                    let message = error.to_string();
+                    if let Err(result) = rollback_materialized_spawn_workdirs(
+                        materializer.as_ref(),
+                        &request.workdir_attachments,
+                        &rollback_workdirs,
+                        &message,
+                    ) {
+                        return result;
+                    }
                     return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
                         WorkerExecutionOperation::Spawn,
-                        "working directory materialization requested, but no materializer is configured for this runtime backend",
+                        message,
                     ));
-                };
-                match materializer.materialize(&request.worker_ref, working_directory_request) {
-                    Ok(binding) => {
-                        request.working_directory = Some(binding.clone());
-                        rollback_working_directory = Some(binding.clone());
-                        Some(binding)
-                    }
-                    Err(error) => {
-                        return WorkerExecutionSpawnResult::Rejected(
-                            WorkerExecutionResult::rejected(
-                                WorkerExecutionOperation::Spawn,
-                                error.to_string(),
-                            ),
-                        );
-                    }
                 }
             }
-            (None, Some(working_directory)) => {
-                let Some(materializer) = self.working_directory_materializer.as_ref() else {
-                    return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
-                        WorkerExecutionOperation::Spawn,
-                        "working directory working_directory requested, but no materializer is configured for this runtime backend",
-                    ));
-                };
-                match materializer.bind_working_directory(
-                    &working_directory.working_directory_id,
-                    working_directory.relative_cwd.as_deref(),
+        }
+        for attachment in request.request.workdir_attachments.clone() {
+            if request.workdir_attachments.contains_key(&attachment.alias) {
+                let message = format!("duplicate Workdir attachment alias `{}`", attachment.alias);
+                if let Err(result) = rollback_materialized_spawn_workdirs(
+                    materializer.as_ref(),
+                    &request.workdir_attachments,
+                    &rollback_workdirs,
+                    &message,
                 ) {
-                    Ok(binding) => {
-                        request.working_directory = Some(binding.clone());
-                        Some(binding)
-                    }
-                    Err(error) => {
-                        return WorkerExecutionSpawnResult::Rejected(
-                            WorkerExecutionResult::rejected(
-                                WorkerExecutionOperation::Spawn,
-                                error.to_string(),
-                            ),
-                        );
+                    return result;
+                }
+                return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                    WorkerExecutionOperation::Spawn,
+                    message,
+                ));
+            }
+            match materializer.bind_working_directory(
+                &attachment.working_directory_id,
+                attachment.relative_cwd.as_deref(),
+            ) {
+                Ok(binding) => {
+                    request
+                        .workdir_attachments
+                        .insert(attachment.alias, binding);
+                }
+                Err(error) => {
+                    let message = error.to_string();
+                    if let Err(result) = rollback_materialized_spawn_workdirs(
+                        materializer.as_ref(),
+                        &request.workdir_attachments,
+                        &rollback_workdirs,
+                        &message,
+                    ) {
+                        return result;
                     }
+                    return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                        WorkerExecutionOperation::Spawn,
+                        message,
+                    ));
                 }
             }
-            (None, None) => None,
-        };
+        }
+        let workdir_attachments = request.workdir_attachments.clone();
 
         let factory = self.factory.clone();
         let bridge_context = request.context.clone();
@@ -2191,11 +2321,13 @@ where
         let controller = match spawn_result {
             Ok(controller) => controller,
             Err(message) => {
-                if let (Some(materializer), Some(binding)) = (
-                    self.working_directory_materializer.as_ref(),
-                    rollback_working_directory.as_ref(),
+                if let Err(result) = rollback_materialized_spawn_workdirs(
+                    materializer.as_ref(),
+                    &workdir_attachments,
+                    &rollback_workdirs,
+                    &message,
                 ) {
-                    let _ = materializer.cleanup_working_directory(&binding.working_directory.id);
+                    return result;
                 }
                 return WorkerExecutionSpawnResult::Errored(WorkerExecutionResult::errored(
                     WorkerExecutionOperation::Spawn,
@@ -2211,7 +2343,7 @@ where
             controller.handle,
             controller.shutdown,
             controller.controller_task,
-            working_directory,
+            workdir_attachments,
             Some(controller.workspace_client),
         )
     }
@@ -2232,46 +2364,56 @@ where
         }
         drop(workers);
 
-        if let Some(previous) = request.previous_working_directory.as_ref() {
+        if !request.previous_workdir_attachments.is_empty() {
             let materializer = self
                 .working_directory_materializer
                 .as_ref()
                 .ok_or_else(|| {
                     WorkerExecutionResult::rejected(
                         WorkerExecutionOperation::Restore,
-                        "Persisted Worker Workdir binding cannot be restored by this Runtime",
+                        "Persisted Worker Workdir attachments cannot be restored by this Runtime",
                     )
                 })?;
-            let current = materializer
-                .working_directory_status(&previous.summary.working_directory_id)
-                .map_err(|message| {
-                    WorkerExecutionResult::rejected(
+            for previous in &request.previous_workdir_attachments {
+                let current = materializer
+                    .working_directory_status(
+                        &previous.working_directory.summary.working_directory_id,
+                    )
+                    .map_err(|message| {
+                        WorkerExecutionResult::rejected(
+                            WorkerExecutionOperation::Restore,
+                            format!(
+                                "Persisted Worker Workdir attachment `{}` is unavailable: {message}",
+                                previous.alias
+                            ),
+                        )
+                    })?;
+                if current.summary.status != WorkingDirectoryStatusKind::Active {
+                    return Err(WorkerExecutionResult::rejected(
                         WorkerExecutionOperation::Restore,
-                        format!("Persisted Worker Workdir is unavailable: {message}"),
-                    )
-                })?;
-            if current.summary.status != WorkingDirectoryStatusKind::Active {
-                return Err(WorkerExecutionResult::rejected(
-                    WorkerExecutionOperation::Restore,
-                    "Persisted Worker Workdir is not active",
-                ));
+                        format!(
+                            "Persisted Worker Workdir attachment `{}` is not active",
+                            previous.alias
+                        ),
+                    ));
+                }
             }
         }
-        if request.previous_working_directory.is_none()
-            && request.request.working_directory_request.is_some()
+        if request.previous_workdir_attachments.is_empty()
+            && !request.request.workdir_attachment_requests.is_empty()
         {
             return Err(WorkerExecutionResult::rejected(
                 WorkerExecutionOperation::Restore,
-                "Persisted Worker Workdir allocation is unavailable",
+                "Persisted Worker Workdir allocations are unavailable",
             ));
         }
-        if request.previous_working_directory.is_none()
-            && request.request.working_directory.is_some()
+        if request.previous_workdir_attachments.is_empty()
+            && !request.request.workdir_attachments.is_empty()
             && self.working_directory_materializer.is_none()
         {
             return Err(WorkerExecutionResult::rejected(
                 WorkerExecutionOperation::Restore,
-                "Persisted Worker Workdir claim cannot be restored by this Runtime",
+                "Persisted Worker Workdir claims cannot be restored by this Runtime",
             ));
         }
         if let Some(workspace_api) = request.request.workspace_api.as_ref() {
@@ -2321,58 +2463,40 @@ where
         }
         drop(workers);
 
-        let working_directory = match request.previous_working_directory.clone() {
-            Some(status) => {
-                let Some(materializer) = self.working_directory_materializer.as_ref() else {
-                    return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
-                        WorkerExecutionOperation::Restore,
-                        "persisted worker has a working directory binding, but no materializer is configured for this runtime backend",
-                    ));
-                };
-                let relative_cwd = request
-                    .request
-                    .working_directory
-                    .as_ref()
-                    .and_then(|working_directory| working_directory.relative_cwd.as_deref());
-                match materializer
-                    .bind_working_directory(&status.summary.working_directory_id, relative_cwd)
-                {
-                    Ok(binding) => {
-                        request.working_directory = Some(binding.clone());
-                        Some(binding)
-                    }
-                    Err(error) => {
-                        return WorkerExecutionSpawnResult::Rejected(
-                            WorkerExecutionResult::rejected(
-                                WorkerExecutionOperation::Restore,
-                                error.to_string(),
-                            ),
-                        );
-                    }
-                }
-            }
-            None if request.request.working_directory_request.is_some() => {
+        let mut workdir_attachments = BTreeMap::new();
+        if !request.previous_workdir_attachments.is_empty() {
+            let Some(materializer) = self.working_directory_materializer.as_ref() else {
                 return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
                     WorkerExecutionOperation::Restore,
-                    "persisted worker requested a working directory, but no persisted working directory binding is available to restore",
+                    "persisted Worker has Workdir attachments, but no materializer is configured for this Runtime backend",
                 ));
-            }
-            None if request.request.working_directory.is_some() => {
-                let Some(materializer) = self.working_directory_materializer.as_ref() else {
-                    return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
-                        WorkerExecutionOperation::Restore,
-                        "persisted worker has a working directory claim, but no materializer is configured for this runtime backend",
-                    ));
-                };
-                let working_directory =
-                    request.request.working_directory.as_ref().expect("checked");
+            };
+            for status in request.previous_workdir_attachments.clone() {
+                let relative_cwd = request
+                    .request
+                    .workdir_attachments
+                    .iter()
+                    .find(|claim| claim.alias == status.alias)
+                    .and_then(|claim| claim.relative_cwd.as_deref());
                 match materializer.bind_working_directory(
-                    &working_directory.working_directory_id,
-                    working_directory.relative_cwd.as_deref(),
+                    &status.working_directory.summary.working_directory_id,
+                    relative_cwd,
                 ) {
                     Ok(binding) => {
-                        request.working_directory = Some(binding.clone());
-                        Some(binding)
+                        if workdir_attachments
+                            .insert(status.alias.clone(), binding)
+                            .is_some()
+                        {
+                            return WorkerExecutionSpawnResult::Rejected(
+                                WorkerExecutionResult::rejected(
+                                    WorkerExecutionOperation::Restore,
+                                    format!(
+                                        "duplicate persisted Workdir attachment alias `{}`",
+                                        status.alias
+                                    ),
+                                ),
+                            );
+                        }
                     }
                     Err(error) => {
                         return WorkerExecutionSpawnResult::Rejected(
@@ -2384,8 +2508,43 @@ where
                     }
                 }
             }
-            None => None,
-        };
+        } else if !request.request.workdir_attachments.is_empty() {
+            let Some(materializer) = self.working_directory_materializer.as_ref() else {
+                return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                    WorkerExecutionOperation::Restore,
+                    "persisted Worker has Workdir claims, but no materializer is configured for this Runtime backend",
+                ));
+            };
+            for claim in request.request.workdir_attachments.clone() {
+                match materializer.bind_working_directory(
+                    &claim.working_directory_id,
+                    claim.relative_cwd.as_deref(),
+                ) {
+                    Ok(binding) => {
+                        if workdir_attachments
+                            .insert(claim.alias.clone(), binding)
+                            .is_some()
+                        {
+                            return WorkerExecutionSpawnResult::Rejected(
+                                WorkerExecutionResult::rejected(
+                                    WorkerExecutionOperation::Restore,
+                                    format!("duplicate Workdir attachment alias `{}`", claim.alias),
+                                ),
+                            );
+                        }
+                    }
+                    Err(error) => {
+                        return WorkerExecutionSpawnResult::Rejected(
+                            WorkerExecutionResult::rejected(
+                                WorkerExecutionOperation::Restore,
+                                error.to_string(),
+                            ),
+                        );
+                    }
+                }
+            }
+        }
+        request.workdir_attachments = workdir_attachments.clone();
 
         let factory = self.factory.clone();
         let bridge_context = request.context.clone();
@@ -2405,7 +2564,7 @@ where
                     ),
                     handle: None,
                     worker_state: None,
-                    working_directory: None,
+                    workdir_attachments: Vec::new(),
                 };
             }
         };
@@ -2417,7 +2576,7 @@ where
             controller.handle,
             controller.shutdown,
             controller.controller_task,
-            working_directory,
+            workdir_attachments,
             Some(controller.workspace_client),
         )
     }
@@ -2739,8 +2898,8 @@ mod tests {
     use crate::Runtime as EmbeddedRuntime;
     use crate::catalog::{
         ConfigBundleRef, CreateWorkerRequest, MaterializerKind, ProfileSelector,
-        RepositorySelector, WorkingDirectoryClaim, WorkingDirectoryRepository,
-        WorkingDirectoryRequest, WorkspaceApiRef,
+        RepositorySelector, WorkingDirectoryAttachmentClaim, WorkingDirectoryAttachmentRequest,
+        WorkingDirectoryRepository, WorkingDirectoryRequest, WorkspaceApiRef,
     };
     use crate::execution::WorkerExecutionContext;
     use crate::identity::WorkerId;
@@ -3279,18 +3438,17 @@ mod tests {
                 FsStore::new(&self.store_dir).map_err(|err| err.to_string())?,
                 FsWorkerStore::new(&self.worker_metadata_dir).map_err(|err| err.to_string())?,
             );
-            let filesystem_authority = request
-                .working_directory
-                .as_ref()
+            let only_workdir = (request.workdir_attachments.len() == 1)
+                .then(|| request.workdir_attachments.values().next())
+                .flatten();
+            let filesystem_authority = only_workdir
                 .map(|binding| {
                     let cwd = binding.cwd().to_path_buf();
                     self.observed_cwds.lock().unwrap().push(cwd.clone());
                     WorkerFilesystemAuthority::local(binding.root().to_path_buf(), cwd)
                 })
                 .unwrap_or(WorkerFilesystemAuthority::None);
-            let scope_root = request
-                .working_directory
-                .as_ref()
+            let scope_root = only_workdir
                 .map(|binding| binding.root().to_path_buf())
                 .unwrap_or_else(|| self.cwd.clone());
             let workspace_backend_ref = RuntimeWorkspaceBackendRef::from_worker_request(
@@ -3348,7 +3506,7 @@ mod tests {
                 request: request.request,
                 workspace_scope: request.workspace_scope,
                 context: request.context,
-                working_directory: request.working_directory,
+                workdir_attachments: request.workdir_attachments,
                 config_bundle: request.config_bundle,
             };
             self.spawn_controller(request).await
@@ -3513,8 +3671,8 @@ mod tests {
                 digest: bundle.metadata.digest,
             }),
             initial_input: None,
-            working_directory_request: None,
-            working_directory: None,
+            workdir_attachment_requests: Vec::new(),
+            workdir_attachments: Vec::new(),
             worker_observation_enabled: false,
             worker_observation_grants: Vec::new(),
             workspace_api: None,
@@ -3595,6 +3753,7 @@ mod tests {
                 source_fingerprint: "sha256:test".to_string(),
                 selector: Some(RepositorySelector::from("HEAD")),
             },
+            display_name: None,
             materializer: MaterializerKind::RuntimeGitClone,
             backend_workdir_id: None,
             materialization: None,
@@ -3698,7 +3857,7 @@ mod tests {
             request: create_request("1"),
             workspace_scope: None,
             context: test_execution_context(worker_ref),
-            working_directory: None,
+            workdir_attachments: BTreeMap::new(),
             config_bundle: None,
         };
 
@@ -3830,8 +3989,8 @@ mod tests {
                     "server-main",
                 )),
                 context: test_execution_context(worker_ref),
-                previous_working_directory: None,
-                working_directory: None,
+                previous_workdir_attachments: Vec::new(),
+                workdir_attachments: BTreeMap::new(),
                 config_bundle: None,
             })
             .await
@@ -3920,8 +4079,8 @@ mod tests {
                 request: create_request("embedded restore"),
                 workspace_scope: None,
                 context: test_execution_context(worker_ref),
-                previous_working_directory: None,
-                working_directory: None,
+                previous_workdir_attachments: Vec::new(),
+                workdir_attachments: BTreeMap::new(),
                 config_bundle: None,
             })
             .await
@@ -3988,7 +4147,7 @@ mod tests {
             &[
                 "WorkerBootstrap::new(",
                 ".prepare()",
-                "worker.bind_workdir_session(",
+                "worker.bind_workdir_sessions(",
                 "worker.bind_worker_observation_provider(",
                 "install_runtime_flow_transition_feature()",
                 "prepared.start()",
@@ -3998,7 +4157,7 @@ mod tests {
             restore,
             &[
                 "Worker::restore_from_worker_metadata_with_context(",
-                "worker.bind_workdir_session(",
+                "worker.bind_workdir_sessions(",
                 "worker.bind_worker_observation_provider(",
                 "install_runtime_flow_transition_feature()",
                 "PreparedWorker::new(",
@@ -4354,7 +4513,10 @@ mod tests {
                 .unwrap();
         runtime.store_config_bundle(test_bundle()).unwrap();
         let mut request = create_request("chat");
-        request.working_directory_request = Some(working_directory_request(repo.path()));
+        request.workdir_attachment_requests = vec![WorkingDirectoryAttachmentRequest {
+            alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+            working_directory: working_directory_request(repo.path()),
+        }];
 
         let detail = runtime.create_worker(request).unwrap();
         runtime
@@ -4376,7 +4538,7 @@ mod tests {
             );
         }
 
-        assert!(detail.working_directory.is_some());
+        assert_eq!(detail.workdir_attachments.len(), 1);
         let cwds = observed_cwds.lock().unwrap();
         assert_eq!(cwds.len(), 1);
         let cwd = &cwds[0];
@@ -4387,6 +4549,71 @@ mod tests {
             observed_workspace_clients.lock().unwrap().as_slice(),
             &[("unavailable".to_string(), None, false)]
         );
+
+        let workdir_id = detail.workdir_attachments[0]
+            .working_directory
+            .summary
+            .working_directory_id
+            .clone();
+        let second = runtime.create_worker(create_request("second")).unwrap();
+        let conflict = runtime
+            .replace_worker_workdir_attachments(
+                &second.worker_ref,
+                vec![WorkingDirectoryAttachmentClaim {
+                    alias: workdir::WorkdirAttachmentAlias::new("conflict").unwrap(),
+                    working_directory_id: workdir_id.clone(),
+                    relative_cwd: None,
+                }],
+            )
+            .unwrap_err();
+        assert!(matches!(
+            conflict,
+            crate::error::RuntimeError::InvalidRequest(_)
+        ));
+        let inactive = runtime
+            .create_working_directory(working_directory_request(repo.path()))
+            .unwrap();
+        let inactive_id = inactive.summary.working_directory_id;
+        runtime.cleanup_working_directory(&inactive_id).unwrap();
+        let inactive_error = runtime
+            .replace_worker_workdir_attachments(
+                &second.worker_ref,
+                vec![WorkingDirectoryAttachmentClaim {
+                    alias: workdir::WorkdirAttachmentAlias::new("inactive").unwrap(),
+                    working_directory_id: inactive_id,
+                    relative_cwd: None,
+                }],
+            )
+            .unwrap_err();
+        assert!(matches!(
+            inactive_error,
+            crate::error::RuntimeError::InvalidRequest(_)
+                | crate::error::RuntimeError::WorkingDirectory(_)
+        ));
+
+        let detached = runtime
+            .replace_worker_workdir_attachments(&detail.worker_ref, Vec::new())
+            .unwrap();
+        assert!(detached.workdir_attachments.is_empty());
+        runtime.stop_worker(&detail.worker_ref, None).unwrap();
+        let restored_without_workdir = runtime.restore_worker(&detail.worker_ref).unwrap();
+        assert!(restored_without_workdir.workdir_attachments.is_empty());
+
+        let alias = workdir::WorkdirAttachmentAlias::new("restored").unwrap();
+        runtime
+            .replace_worker_workdir_attachments(
+                &detail.worker_ref,
+                vec![WorkingDirectoryAttachmentClaim {
+                    alias: alias.clone(),
+                    working_directory_id: workdir_id,
+                    relative_cwd: None,
+                }],
+            )
+            .unwrap();
+        runtime.stop_worker(&detail.worker_ref, None).unwrap();
+        let stopped = runtime.worker_detail(&detail.worker_ref).unwrap();
+        assert_eq!(stopped.workdir_attachments.len(), 1);
+        assert_eq!(stopped.workdir_attachments[0].alias, alias);
     }
 
     #[test]
@@ -4620,12 +4847,13 @@ mod tests {
                 .unwrap();
         runtime.store_config_bundle(test_bundle()).unwrap();
         let mut request = create_request("chat");
-        request.working_directory_request = Some(working_directory_request(repo.path()));
+        request.workdir_attachment_requests = vec![WorkingDirectoryAttachmentRequest {
+            alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+            working_directory: working_directory_request(repo.path()),
+        }];
         let detail = runtime.create_worker(request).unwrap();
-        let workdir_id = detail
+        let workdir_id = detail.workdir_attachments[0]
             .working_directory
-            .as_ref()
-            .unwrap()
             .summary
             .working_directory_id
             .clone();
@@ -4642,7 +4870,6 @@ mod tests {
             crate::catalog::WorkingDirectoryStatusKind::Active
         );
         assert_eq!(status.summary.cleanliness.as_deref(), Some("clean"));
-        assert_eq!(status.summary.primary_worker_id, None);
     }
 
     #[test]
@@ -4663,10 +4890,11 @@ mod tests {
         let clone_root = materialized_clone_root(runtime_base.path(), &workdir_id);
         assert!(clone_root.join("README.md").exists());
         let mut request = create_request("chat");
-        request.working_directory = Some(WorkingDirectoryClaim {
+        request.workdir_attachments = vec![WorkingDirectoryAttachmentClaim {
+            alias: workdir::WorkdirAttachmentAlias::new("workdir").unwrap(),
             working_directory_id: workdir_id.clone(),
             relative_cwd: None,
-        });
+        }];
 
         let error = runtime.create_worker(request).unwrap_err();
 
@@ -4691,7 +4919,17 @@ mod tests {
                 .unwrap();
         runtime.store_config_bundle(test_bundle()).unwrap();
         let mut request = create_request("chat");
-        request.working_directory_request = Some(working_directory_request(repo.path()));
+        let second_repo = create_clean_repo();
+        request.workdir_attachment_requests = vec![
+            WorkingDirectoryAttachmentRequest {
+                alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+                working_directory: working_directory_request(repo.path()),
+            },
+            WorkingDirectoryAttachmentRequest {
+                alias: workdir::WorkdirAttachmentAlias::new("docs").unwrap(),
+                working_directory: working_directory_request(second_repo.path()),
+            },
+        ];
 
         let error = runtime.create_worker(request).unwrap_err();
 
@@ -4708,4 +4946,41 @@ mod tests {
         assert_eq!(remaining_workdirs, 0);
         assert!(!working_directories_root.join(".repository-cache").exists());
     }
+
+    #[test]
+    fn second_materialization_failure_rolls_back_first_attachment() {
+        let runtime_base = tempfile::tempdir().unwrap();
+        let repo = create_clean_repo();
+        let missing_repo = runtime_base.path().join("missing-repository");
+        let backend = WorkerRuntimeExecutionBackend::new(FailingFactory)
+            .unwrap()
+            .with_working_directory_materializer(RuntimeGitMaterializer::new(runtime_base.path()));
+        let runtime =
+            EmbeddedRuntime::with_execution_backend(RuntimeOptions::default(), Arc::new(backend))
+                .unwrap();
+        runtime.store_config_bundle(test_bundle()).unwrap();
+        let mut request = create_request("chat");
+        request.workdir_attachment_requests = vec![
+            WorkingDirectoryAttachmentRequest {
+                alias: workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+                working_directory: working_directory_request(repo.path()),
+            },
+            WorkingDirectoryAttachmentRequest {
+                alias: workdir::WorkdirAttachmentAlias::new("docs").unwrap(),
+                working_directory: working_directory_request(&missing_repo),
+            },
+        ];
+
+        let error = runtime.create_worker(request).unwrap_err();
+        assert!(format!("{error:?}").contains("repository"));
+        let remaining_workdirs = fs::read_dir(runtime_base.path())
+            .map(|entries| {
+                entries
+                    .flatten()
+                    .filter(|entry| !entry.file_name().to_string_lossy().starts_with('.'))
+                    .count()
+            })
+            .unwrap_or(0);
+        assert_eq!(remaining_workdirs, 0);
+    }
 }

crates/worker-runtime/src/working_directory.rs

@@ -57,6 +57,8 @@ pub struct WorkingDirectoryEvidence {
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct WorkingDirectory {
     pub id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub display_name: Option<String>,
     pub repository_id: String,
     pub materializer_kind: MaterializerKind,
     pub evidence: WorkingDirectoryEvidence,
@@ -68,6 +70,7 @@ impl WorkingDirectory {
     pub fn status_summary(&self) -> WorkingDirectorySummary {
         WorkingDirectorySummary {
             working_directory_id: self.id.clone(),
+            display_name: self.display_name.clone(),
             repository_id: self.repository_id.clone(),
             creation_selector: self.evidence.requested_selector.clone(),
             creation_ref: Some(self.evidence.resolved_commit.clone()),
@@ -80,7 +83,6 @@ impl WorkingDirectory {
             cleanup_target: Some(self.cleanup_target.clone()),
             status: self.status.clone(),
             cleanliness: None,
-            primary_worker_id: None,
             occupied_by: None,
         }
     }
@@ -717,6 +719,7 @@ impl RuntimeGitMaterializer {
         WorkingDirectoryStatus {
             summary: WorkingDirectorySummary {
                 working_directory_id: working_directory_id.to_string(),
+                display_name: None,
                 repository_id: "unknown".to_string(),
                 creation_selector: None,
                 creation_ref: None,
@@ -733,7 +736,6 @@ impl RuntimeGitMaterializer {
                 }),
                 status: WorkingDirectoryStatusKind::Corrupted,
                 cleanliness: Some("unknown".to_string()),
-                primary_worker_id: None,
                 occupied_by: None,
             },
         }
@@ -1072,6 +1074,7 @@ impl RuntimeGitMaterializer {
         let context = request.materialization.as_ref();
         let working_directory = WorkingDirectory {
             id: working_directory_id.clone(),
+            display_name: request.display_name.clone(),
             repository_id: request.repository.id.clone(),
             materializer_kind: MaterializerKind::RuntimeGitClone,
             evidence: WorkingDirectoryEvidence {
@@ -1211,6 +1214,7 @@ impl WorkingDirectoryMaterializer for RuntimeGitMaterializer {
 
         let working_request = WorkingDirectoryRequest {
             repository: request.repository.clone(),
+            display_name: None,
             materializer: MaterializerKind::RuntimeGitClone,
             backend_workdir_id: None,
             materialization: request.materialization.clone(),
@@ -3316,6 +3320,7 @@ mod tests {
                 source_fingerprint: "sha256:test".to_string(),
                 selector: Some(RepositorySelector::from("HEAD")),
             },
+            display_name: None,
             materializer: MaterializerKind::RuntimeGitClone,
             backend_workdir_id: None,
             materialization: None,

crates/worker/src/bootstrap.rs

@@ -145,7 +145,7 @@ where
         .map_err(WorkerBootstrapError::Worker)?;
 
         if let Some(workdir_session) = self.workdir_session {
-            worker.bind_workdir_session(Some(workdir_session));
+            worker.bind_single_workdir_session(Some(workdir_session));
         }
         Ok(PreparedWorker::new(worker, self.layout, self.transport))
     }
@@ -168,7 +168,7 @@ where
             .map_err(WorkerBootstrapError::Worker)?;
 
         if let Some(workdir_session) = self.workdir_session {
-            worker.bind_workdir_session(Some(workdir_session));
+            worker.bind_single_workdir_session(Some(workdir_session));
         }
         Ok(PreparedWorker::new(worker, self.layout, self.transport))
     }
@@ -222,7 +222,7 @@ where
     C: LlmClient + Clone + 'static,
     St: Store + WorkerMetadataStore + Clone + Send + Sync + 'static,
 {
-    let cleanup_session = worker.workdir_session().cloned();
+    let cleanup_sessions = worker.workdir_sessions();
     let controller = match layout {
         WorkerBootstrapLayout::Direct {
             runtime_base,
@@ -257,10 +257,7 @@ where
             controller_task,
         }),
         Err(source) => {
-            let cleanup_failed = match cleanup_session {
-                Some(session) => session.close().await.is_err(),
-                None => false,
-            };
+            let cleanup_failed = cleanup_sessions.close_all().await.is_err();
             Err(WorkerBootstrapError::Controller {
                 source,
                 cleanup_failed,

crates/worker/src/controller.rs

@@ -617,7 +617,7 @@ impl WorkerController {
         C: LlmClient + Clone + 'static,
         St: Store + WorkerMetadataStore + Clone + Send + Sync + 'static,
     {
-        let session = worker.workdir_session().cloned();
+        let sessions = worker.workdir_sessions();
         let result = Self::spawn_initialized(
             worker,
             runtime_base,
@@ -628,10 +628,9 @@ impl WorkerController {
         )
         .await;
         if result.is_err()
-            && let Some(session) = session
-            && let Err(error) = session.close().await
+            && let Err(error) = sessions.close_all().await
         {
-            tracing::warn!(%error, "Workdir session close after controller startup failure failed");
+            tracing::warn!(%error, "Workdir sessions close after controller startup failure failed");
         }
         result
     }
@@ -1154,20 +1153,17 @@ where
     // below so the worker borrow doesn't conflict with reads on `worker`.
     let feature_config = worker.manifest().feature.clone();
     let mut workdir_tool_broker = inherited_workdir_tool_broker;
-    if feature_config.manage_workdir.enabled && worker.workdir_session().is_none() {
+    if feature_config.manage_workdir.enabled {
         let workspace_client = worker.workspace_client_handle();
-        let broker = workdir::WorkdirToolBroker::new(
+        workdir_tool_broker = Some(workdir::WorkdirToolBroker::new(
             crate::feature::builtin::manage_workdir::WorkspaceAttachedWorkdirSession::handle(
                 workspace_client,
             ),
-        );
-        worker.bind_workdir_session(Some(broker.tool_session()));
-        workdir_tool_broker = Some(broker);
+        ));
     } else if workdir_tool_broker.is_none()
-        && let Some(existing) = worker.workdir_session().cloned()
+        && let Some(existing) = worker.workdir_session()
     {
         let broker = workdir::WorkdirToolBroker::new(existing);
-        worker.bind_workdir_session(Some(broker.tool_session()));
         workdir_tool_broker = Some(broker);
     }
     let worker_workdir = workdir_tool_broker
@@ -1344,6 +1340,7 @@ where
         feature_registry.add_module(
             crate::feature::builtin::manage_workdir::ManageWorkdirFeature::with_child_lifecycle(
                 workspace_client,
+                worker.workdir_sessions(),
                 Arc::new(move || {
                     let child_registry = shutdown_registry.clone();
                     Box::pin(async move { child_registry.shutdown_internal().await })
@@ -2610,14 +2607,13 @@ async fn controller_loop<C, St>(
         }
     }
 
-    if let Some(session) = worker.workdir_session() {
-        loop {
-            match session.close().await {
-                Ok(()) => break,
-                Err(error) => {
-                    tracing::warn!(%error, "Workdir session close failed; retrying");
-                    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
-                }
+    let sessions = worker.workdir_sessions();
+    while !sessions.is_empty() {
+        match sessions.close_all().await {
+            Ok(()) => break,
+            Err(error) => {
+                tracing::warn!(%error, "Workdir session set close failed; retrying");
+                tokio::time::sleep(std::time::Duration::from_millis(100)).await;
             }
         }
     }

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

@@ -52,9 +52,9 @@ const DETACH_TOOL: &str = "WorkdirDetach";
 const DELETE_TOOL: &str = "WorkdirDelete";
 
 const LIST_DESCRIPTION: &str = "List persistent Workdirs in the current Workspace through Backend Workspace API authority. The result contains safe summaries and diagnostics, never host paths or Runtime connection details.";
-const CREATE_DESCRIPTION: &str = "Materialize a persistent Workdir on a selected Runtime from a Workspace repository and optional selector. This does not change this Worker's attachment; use WorkdirAttach explicitly after creation.";
-const ATTACH_DESCRIPTION: &str = "Attach this Worker to one existing Workdir. The Backend enforces one active Workdir per Worker and one active Worker per Workdir, then opens an ephemeral operation session.";
-const DETACH_DESCRIPTION: &str = "Detach this Worker from its active Workdir and release Workdir occupancy. Any ephemeral operation session is closed.";
+const CREATE_DESCRIPTION: &str = "Materialize a persistent Workdir with an optional human-facing display name on a selected Runtime from a Workspace repository and optional selector. The display name is independent of attachment aliases. This does not change this Worker's attachment; use WorkdirAttach explicitly after creation.";
+const ATTACH_DESCRIPTION: &str = "Attach one existing Workdir to this Worker under a stable Worker-local alias. The Backend preserves one active Worker per Workdir while allowing this Worker to own multiple aliases.";
+const DETACH_DESCRIPTION: &str = "Detach one Workdir attachment by its Worker-local alias. Active operations, commands, or Internal SubWorkers cause safe rejection rather than implicit authority loss.";
 pub(crate) type BeforeWorkdirRelease =
     Arc<dyn Fn() -> Pin<Box<dyn Future<Output = std::io::Result<()>> + Send>> + Send + Sync>;
 pub(crate) type AfterWorkdirAttach = Arc<dyn Fn() + Send + Sync>;
@@ -64,6 +64,7 @@ const DELETE_DESCRIPTION: &str = "Request removal of one persistent Workdir by i
 #[derive(Clone)]
 pub struct ManageWorkdirFeature {
     client: Arc<dyn WorkspaceClient>,
+    session_router: Arc<workdir::WorkdirSessionRouter>,
     before_workdir_release: Option<BeforeWorkdirRelease>,
     after_workdir_attach: Option<AfterWorkdirAttach>,
 }
@@ -82,6 +83,7 @@ impl ManageWorkdirFeature {
     pub fn new(client: Arc<dyn WorkspaceClient>) -> Self {
         Self {
             client,
+            session_router: Arc::new(workdir::WorkdirSessionRouter::new()),
             before_workdir_release: None,
             after_workdir_attach: None,
         }
@@ -89,11 +91,13 @@ impl ManageWorkdirFeature {
 
     pub(crate) fn with_child_lifecycle(
         client: Arc<dyn WorkspaceClient>,
+        session_router: Arc<workdir::WorkdirSessionRouter>,
         before_workdir_release: BeforeWorkdirRelease,
         after_workdir_attach: AfterWorkdirAttach,
     ) -> Self {
         Self {
             client,
+            session_router,
             before_workdir_release: Some(before_workdir_release),
             after_workdir_attach: Some(after_workdir_attach),
         }
@@ -116,10 +120,12 @@ impl FeatureModule for ManageWorkdirFeature {
     }
 
     fn install(&self, context: &mut FeatureInstallContext<'_>) -> Result<(), FeatureInstallError> {
-        let backend = WorkspaceHttpWorkdirBackend::new(self.client.clone()).with_child_lifecycle(
-            self.before_workdir_release.clone(),
-            self.after_workdir_attach.clone(),
-        );
+        let backend = WorkspaceHttpWorkdirBackend::new(self.client.clone())
+            .with_session_router(self.session_router.clone())
+            .with_child_lifecycle(
+                self.before_workdir_release.clone(),
+                self.after_workdir_attach.clone(),
+            );
         for (name, definition) in [
             (
                 LIST_TOOL,
@@ -183,6 +189,8 @@ impl FeatureModule for ManageWorkdirFeature {
 #[derive(Clone)]
 struct WorkspaceHttpWorkdirBackend {
     client: Arc<dyn WorkspaceClient>,
+    session_router: Arc<workdir::WorkdirSessionRouter>,
+    attachment_mutation_lock: Arc<tokio::sync::Mutex<()>>,
     before_workdir_release: Option<BeforeWorkdirRelease>,
     after_workdir_attach: Option<AfterWorkdirAttach>,
 }
@@ -399,11 +407,18 @@ impl WorkspaceHttpWorkdirBackend {
     fn new(client: Arc<dyn WorkspaceClient>) -> Self {
         Self {
             client,
+            session_router: Arc::new(workdir::WorkdirSessionRouter::new()),
+            attachment_mutation_lock: Arc::new(tokio::sync::Mutex::new(())),
             before_workdir_release: None,
             after_workdir_attach: None,
         }
     }
 
+    fn with_session_router(mut self, session_router: Arc<workdir::WorkdirSessionRouter>) -> Self {
+        self.session_router = session_router;
+        self
+    }
+
     fn with_child_lifecycle(
         mut self,
         before_workdir_release: Option<BeforeWorkdirRelease>,
@@ -449,10 +464,12 @@ impl WorkspaceHttpWorkdirBackend {
             .transpose()?;
         let repository_key =
             validate_identity(&input.repository_key, CREATE_TOOL, "repository_key")?;
+        let display_name = validate_optional_display_name(input.display_name)?;
         let selector = validate_optional_selector(input.selector)?;
         let workspace_id = encode_path_segment(self.workspace_id()?);
         let request = WorkdirCreateRequest {
             runtime_id: runtime_id.map(str::to_string),
+            display_name,
             repository_key: repository_key.to_string(),
             selector,
             operation_id: Some(operation_id),
@@ -472,32 +489,67 @@ impl WorkspaceHttpWorkdirBackend {
     }
 
     fn attach(&self, input: WorkdirAttachInput) -> Result<ToolOutput, ToolError> {
-        let workdir_id = validate_identity(&input.workdir_id, ATTACH_TOOL, "workdir_id")?;
-        let response = self.attach_response(workdir_id)?;
-        workdir_output(format!("Attached to Workdir {workdir_id}"), &response)
+        let alias = validate_identity(&input.alias, ATTACH_TOOL, "alias")?;
+        workdir::WorkdirAttachmentAlias::new(alias)
+            .map_err(|error| ToolError::InvalidArgument(error.to_string()))?;
+        let working_directory_id = validate_identity(
+            &input.working_directory_id,
+            ATTACH_TOOL,
+            "working_directory_id",
+        )?;
+        let alias_key = workdir::WorkdirAttachmentAlias::new(alias)
+            .map_err(|error| ToolError::InvalidArgument(error.to_string()))?;
+        if self.session_router.session(&alias_key).is_some() {
+            return Err(ToolError::InvalidArgument(format!(
+                "attachment alias `{alias}` already exists"
+            )));
+        }
+        let response = self.attach_response(alias, working_directory_id)?;
+        if let Err(error) = self.session_router.attach(
+            alias_key.clone(),
+            WorkspaceAttachedWorkdirSession::handle(self.client.clone()),
+        ) {
+            let _ = self.detach(alias);
+            return Err(ToolError::ExecutionFailed(format!(
+                "attach Workdir session route: {error}"
+            )));
+        }
+        workdir_output(
+            format!("Attached Workdir {working_directory_id} as {alias}"),
+            &response,
+        )
     }
 
-    fn attach_response(&self, workdir_id: &str) -> Result<WorkdirAttachmentResponse, ToolError> {
+    fn attach_response(
+        &self,
+        alias: &str,
+        working_directory_id: &str,
+    ) -> Result<WorkdirAttachmentResponse, ToolError> {
         let workspace_id = encode_path_segment(self.workspace_id()?);
         self.execute_json::<WorkdirAttachmentResponse>(WorkspaceRequest::json(
             WorkspaceRequestMethod::Post,
-            format!("/api/w/{workspace_id}/workers/self/workdir-attachment"),
+            format!("/api/w/{workspace_id}/workers/self/workdir-attachments"),
             serde_json::to_string(&WorkdirAttachRequest {
-                workdir_id: workdir_id.to_string(),
+                alias: alias.to_string(),
+                working_directory_id: working_directory_id.to_string(),
             })
             .map_err(decode_error)?,
         ))
     }
 
-    fn detach(&self) -> Result<ToolOutput, ToolError> {
+    fn detach(&self, alias: &str) -> Result<ToolOutput, ToolError> {
         let workspace_id = encode_path_segment(self.workspace_id()?);
+        let alias_path = encode_path_segment(alias);
         let response = self.execute_json::<WorkdirAttachmentResponse>(WorkspaceRequest {
             method: WorkspaceRequestMethod::Delete,
-            path: format!("/api/w/{workspace_id}/workers/self/workdir-attachment"),
+            path: format!("/api/w/{workspace_id}/workers/self/workdir-attachments/{alias_path}"),
             body: None,
         })?;
         workdir_output(
-            format!("Detached from Workdir {}", response.workdir_id),
+            format!(
+                "Detached Workdir {} ({})",
+                response.working_directory_id, response.alias
+            ),
             &response,
         )
     }
@@ -590,6 +642,7 @@ impl Tool for WorkspaceHttpWorkdirTool {
                 ctx.call_id.to_string(),
             ),
             WorkdirOperation::Attach => {
+                let _mutation_guard = self.backend.attachment_mutation_lock.lock().await;
                 let result = self
                     .backend
                     .attach(parse_input::<WorkdirAttachInput>(input_json)?);
@@ -601,15 +654,41 @@ impl Tool for WorkspaceHttpWorkdirTool {
                 result
             }
             WorkdirOperation::Detach => {
-                let _input = parse_input::<WorkdirDetachInput>(input_json)?;
-                if let Some(before_release) = &self.backend.before_workdir_release {
-                    before_release().await.map_err(|error| {
+                let _mutation_guard = self.backend.attachment_mutation_lock.lock().await;
+                let input = parse_input::<WorkdirDetachInput>(input_json)?;
+                let alias = validate_identity(&input.alias, DETACH_TOOL, "alias")?;
+                let alias_key = workdir::WorkdirAttachmentAlias::new(alias)
+                    .map_err(|error| ToolError::InvalidArgument(error.to_string()))?;
+                self.backend
+                    .session_router
+                    .begin_detach(&alias_key)
+                    .await
+                    .map_err(|error| ToolError::ExecutionFailed(error.to_string()))?;
+                if let Some(before_release) = &self.backend.before_workdir_release
+                    && let Err(error) = before_release().await
+                {
+                    self.backend.session_router.cancel_detach(&alias_key);
+                    return Err(ToolError::ExecutionFailed(format!(
+                        "stop Internal SubWorkers before Workdir detach: {error}"
+                    )));
+                }
+                let result = match self.backend.detach(alias) {
+                    Ok(result) => result,
+                    Err(error) => {
+                        self.backend.session_router.cancel_detach(&alias_key);
+                        return Err(error);
+                    }
+                };
+                self.backend
+                    .session_router
+                    .finish_detach(&alias_key)
+                    .await
+                    .map_err(|error| {
                         ToolError::ExecutionFailed(format!(
-                            "stop Internal SubWorkers before Workdir detach: {error}"
+                            "detach Workdir session route after Backend release: {error}"
                         ))
                     })?;
-                }
-                self.backend.detach()
+                Ok(result)
             }
             WorkdirOperation::Delete => self
                 .backend
@@ -672,6 +751,25 @@ fn validate_delete_reason(reason: &str) -> Result<&str, ToolError> {
     Ok(reason)
 }
 
+fn validate_optional_display_name(
+    display_name: Option<String>,
+) -> Result<Option<String>, ToolError> {
+    let Some(display_name) = display_name else {
+        return Ok(None);
+    };
+    let display_name = display_name.trim();
+    if display_name.is_empty()
+        || display_name.len() > 80
+        || display_name.chars().any(char::is_control)
+    {
+        return Err(ToolError::InvalidArgument(
+            "WorkdirCreate display_name must be non-empty, contain no control characters, and be at most 80 bytes"
+                .to_string(),
+        ));
+    }
+    Ok(Some(display_name.to_string()))
+}
+
 fn validate_optional_selector(selector: Option<String>) -> Result<Option<String>, ToolError> {
     let Some(selector) = selector else {
         return Ok(None);
@@ -725,6 +823,7 @@ fn create_schema() -> serde_json::Value {
         "required": ["repository_key"],
         "properties": {
             "runtime_id": {"type": ["string", "null"], "minLength": 1},
+            "display_name": {"type": ["string", "null"], "minLength": 1, "maxLength": 80},
             "repository_key": {"type": "string", "minLength": 1},
             "selector": {"type": ["string", "null"], "minLength": 1}
         }
@@ -735,15 +834,23 @@ fn attach_schema() -> serde_json::Value {
     json!({
         "type": "object",
         "additionalProperties": false,
-        "required": ["workdir_id"],
+        "required": ["alias", "working_directory_id"],
         "properties": {
-            "workdir_id": {"type": "string", "minLength": 1}
+            "alias": {"type": "string", "minLength": 1, "maxLength": 64},
+            "working_directory_id": {"type": "string", "minLength": 1}
         }
     })
 }
 
 fn detach_schema() -> serde_json::Value {
-    list_schema()
+    json!({
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["alias"],
+        "properties": {
+            "alias": {"type": "string", "minLength": 1, "maxLength": 64}
+        }
+    })
 }
 
 fn delete_schema() -> serde_json::Value {
@@ -767,6 +874,8 @@ struct WorkdirListInput {}
 struct WorkdirCreateInput {
     #[serde(default)]
     runtime_id: Option<String>,
+    #[serde(default)]
+    display_name: Option<String>,
     repository_key: String,
     #[serde(default)]
     selector: Option<String>,
@@ -775,22 +884,27 @@ struct WorkdirCreateInput {
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
 struct WorkdirAttachInput {
-    workdir_id: String,
+    alias: String,
+    working_directory_id: String,
 }
 
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
-struct WorkdirDetachInput {}
+struct WorkdirDetachInput {
+    alias: String,
+}
 
 #[derive(Debug, Serialize)]
 struct WorkdirAttachRequest {
-    workdir_id: String,
+    alias: String,
+    working_directory_id: String,
 }
 
 #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
 struct WorkdirAttachmentResponse {
     workspace_id: String,
-    workdir_id: String,
+    alias: String,
+    working_directory_id: String,
     attached: bool,
 }
 
@@ -1021,7 +1135,10 @@ mod tests {
         );
         assert!(create["properties"].get("path").is_none());
         assert!(create["properties"].get("session_id").is_none());
-        assert_eq!(attach_schema()["required"], json!(["workdir_id"]));
+        assert_eq!(
+            attach_schema()["required"],
+            json!(["alias", "working_directory_id"])
+        );
         assert!(attach_schema()["properties"].get("session_id").is_none());
         assert_eq!(
             delete_schema()["required"],
@@ -1057,12 +1174,14 @@ mod tests {
             })),
             response(json!({
                 "workspace_id": "workspace/test",
-                "workdir_id": "wd-created",
+                "alias": "checkout",
+                "working_directory_id": "wd-created",
                 "attached": true
             })),
             response(json!({
                 "workspace_id": "workspace/test",
-                "workdir_id": "wd-created",
+                "alias": "checkout",
+                "working_directory_id": "wd-created",
                 "attached": false
             })),
             response(json!({
@@ -1089,6 +1208,7 @@ mod tests {
             .create(
                 WorkdirCreateInput {
                     runtime_id: Some("runtime/one".to_string()),
+                    display_name: Some("Review checkout".to_string()),
                     repository_key: "main".to_string(),
                     selector: Some("refs/heads/topic".to_string()),
                 },
@@ -1106,10 +1226,11 @@ mod tests {
         assert_eq!(client.requests().len(), 2);
         backend
             .attach(WorkdirAttachInput {
-                workdir_id: "wd-created".to_string(),
+                alias: "checkout".to_string(),
+                working_directory_id: "wd-created".to_string(),
             })
             .unwrap();
-        backend.detach().unwrap();
+        backend.detach("checkout").unwrap();
         backend
             .delete(WorkdirDeleteInput {
                 working_directory_id: "wd-created".to_string(),
@@ -1132,16 +1253,17 @@ mod tests {
             serde_json::from_str(requests[1].body.as_deref().unwrap()).unwrap();
         assert_eq!(body["repository_key"], "main");
         assert_eq!(body["runtime_id"], "runtime/one");
+        assert_eq!(body["display_name"], "Review checkout");
         assert_eq!(body["operation_id"], "call-create-1");
         assert_eq!(body["selector"], "refs/heads/topic");
         assert_eq!(
             requests[2].path,
-            "/api/w/workspace%2Ftest/workers/self/workdir-attachment"
+            "/api/w/workspace%2Ftest/workers/self/workdir-attachments"
         );
         assert_eq!(requests[2].method, WorkspaceRequestMethod::Post);
         assert_eq!(
             requests[3].path,
-            "/api/w/workspace%2Ftest/workers/self/workdir-attachment"
+            "/api/w/workspace%2Ftest/workers/self/workdir-attachments/checkout"
         );
         assert_eq!(requests[3].method, WorkspaceRequestMethod::Delete);
         assert_eq!(
@@ -1323,6 +1445,7 @@ mod tests {
             .create(
                 WorkdirCreateInput {
                     runtime_id: None,
+                    display_name: None,
                     repository_key: "main".to_string(),
                     selector: None,
                 },
@@ -1348,6 +1471,7 @@ mod tests {
             .create(
                 WorkdirCreateInput {
                     runtime_id: Some(" ".to_string()),
+                    display_name: None,
                     repository_key: "main".to_string(),
                     selector: None,
                 },
@@ -1363,9 +1487,17 @@ mod tests {
     async fn detach_stops_internal_subworkers_before_backend_release() {
         let client = Arc::new(RecordingWorkspaceClient::new(vec![response(json!({
             "workspace_id": "workspace/test",
-            "workdir_id": "wd-attached",
+            "alias": "checkout",
+            "working_directory_id": "wd-attached",
             "attached": false
         }))]));
+        let router = Arc::new(workdir::WorkdirSessionRouter::new());
+        router
+            .attach(
+                workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+                WorkspaceAttachedWorkdirSession::handle(client.clone()),
+            )
+            .unwrap();
         let cleanup_calls = Arc::new(AtomicUsize::new(0));
         let cleanup_calls_for_guard = cleanup_calls.clone();
         let before_release: BeforeWorkdirRelease = Arc::new(move || {
@@ -1377,11 +1509,12 @@ mod tests {
         });
         let tool = WorkspaceHttpWorkdirTool {
             backend: WorkspaceHttpWorkdirBackend::new(client.clone())
+                .with_session_router(router)
                 .with_child_lifecycle(Some(before_release), None),
             operation: WorkdirOperation::Detach,
         };
 
-        tool.execute("{}", ToolExecutionContext::default())
+        tool.execute(r#"{"alias":"checkout"}"#, ToolExecutionContext::default())
             .await
             .unwrap();
 
@@ -1389,23 +1522,31 @@ mod tests {
         assert_eq!(client.requests().len(), 1);
         assert_eq!(
             client.requests()[0].path,
-            "/api/w/workspace%2Ftest/workers/self/workdir-attachment"
+            "/api/w/workspace%2Ftest/workers/self/workdir-attachments/checkout"
         );
     }
 
     #[tokio::test]
     async fn detach_does_not_release_backend_when_child_cleanup_fails() {
         let client = Arc::new(RecordingWorkspaceClient::new(Vec::new()));
+        let router = Arc::new(workdir::WorkdirSessionRouter::new());
+        router
+            .attach(
+                workdir::WorkdirAttachmentAlias::new("checkout").unwrap(),
+                WorkspaceAttachedWorkdirSession::handle(client.clone()),
+            )
+            .unwrap();
         let before_release: BeforeWorkdirRelease =
             Arc::new(|| Box::pin(async { Err(std::io::Error::other("child cleanup failed")) }));
         let tool = WorkspaceHttpWorkdirTool {
             backend: WorkspaceHttpWorkdirBackend::new(client.clone())
+                .with_session_router(router)
                 .with_child_lifecycle(Some(before_release), None),
             operation: WorkdirOperation::Detach,
         };
 
         let error = tool
-            .execute("{}", ToolExecutionContext::default())
+            .execute(r#"{"alias":"checkout"}"#, ToolExecutionContext::default())
             .await
             .unwrap_err();
 
@@ -1413,11 +1554,77 @@ mod tests {
         assert!(client.requests().is_empty());
     }
 
+    #[tokio::test]
+    async fn detach_reconciles_naturally_completed_workspace_command() {
+        let client = Arc::new(RecordingWorkspaceClient::new(vec![
+            response(json!({
+                "workspace_id": "workspace/test",
+                "alias": "checkout",
+                "working_directory_id": "wd-attached",
+                "attached": true
+            })),
+            response(json!({
+                "operation": "command_start",
+                "result": "command-1"
+            })),
+            response(json!({
+                "operation": "command_status",
+                "result": "completed"
+            })),
+            response(json!({
+                "workspace_id": "workspace/test",
+                "alias": "checkout",
+                "working_directory_id": "wd-attached",
+                "attached": false
+            })),
+        ]));
+        let backend = WorkspaceHttpWorkdirBackend::new(client.clone());
+        backend
+            .attach(WorkdirAttachInput {
+                alias: "checkout".to_string(),
+                working_directory_id: "wd-attached".to_string(),
+            })
+            .unwrap();
+        let alias = workdir::WorkdirAttachmentAlias::new("checkout").unwrap();
+        backend
+            .session_router
+            .session(&alias)
+            .unwrap()
+            .start_command(CommandRequest {
+                command: "printf done".to_string(),
+                timeout_secs: 5,
+                output_limit: 1024,
+                cwd: None,
+                spill_dir: None,
+                tool_call_id: None,
+            })
+            .await
+            .unwrap();
+        let tool = WorkspaceHttpWorkdirTool {
+            backend,
+            operation: WorkdirOperation::Detach,
+        };
+
+        tool.execute(r#"{"alias":"checkout"}"#, ToolExecutionContext::default())
+            .await
+            .unwrap();
+
+        let requests = client.requests();
+        assert_eq!(requests.len(), 4);
+        assert!(
+            requests[2]
+                .body
+                .as_deref()
+                .is_some_and(|body| body.contains("command_status"))
+        );
+    }
+
     #[tokio::test]
     async fn successful_attach_reopens_internal_subworker_admission() {
         let client = Arc::new(RecordingWorkspaceClient::new(vec![response(json!({
             "workspace_id": "workspace/test",
-            "workdir_id": "wd-attached",
+            "alias": "checkout",
+            "working_directory_id": "wd-attached",
             "attached": true
         }))]));
         let reopen_calls = Arc::new(AtomicUsize::new(0));
@@ -1432,7 +1639,7 @@ mod tests {
         };
 
         tool.execute(
-            r#"{"workdir_id":"wd-attached"}"#,
+            r#"{"alias":"checkout","working_directory_id":"wd-attached"}"#,
             ToolExecutionContext::default(),
         )
         .await

crates/worker/src/internal_worker.rs

@@ -165,7 +165,7 @@ where
     })?;
     worker.disable_manifest_lifecycle_features();
     if let Some(session) = inherited_workdir_session {
-        worker.bind_workdir_session(Some(session));
+        worker.bind_single_workdir_session(Some(session));
     }
 
     let install_report = worker.install_features(features);
@@ -608,7 +608,7 @@ pub(crate) async fn spawn_internal_worker_session(
     })?;
     worker.disable_manifest_lifecycle_features();
     if let Some(session) = inherited_workdir_session {
-        worker.bind_workdir_session(Some(session));
+        worker.bind_single_workdir_session(Some(session));
     }
     let install_report = worker.install_features(features);
     let installed_tools = install_report.installed_tool_names();
@@ -701,7 +701,7 @@ pub(crate) fn prepare_internal_worker_from_spec(
         })?;
         worker.disable_manifest_lifecycle_features();
         if let Some(session) = inherited_workdir_session {
-            worker.bind_workdir_session(Some(session));
+            worker.bind_single_workdir_session(Some(session));
         }
         let install_report = worker.install_features(features);
         let installed_tools = install_report.installed_tool_names();
@@ -782,7 +782,7 @@ pub(crate) async fn prepare_internal_worker_session(
     if let Some(broker) = command_event_broker.as_ref() {
         wire_workdir_command_events(&broker.tool_session(), &in_flight);
     } else if let Some(session) = worker.workdir_session() {
-        wire_workdir_command_events(session, &in_flight);
+        wire_workdir_command_events(&session, &in_flight);
     }
     let actor_in_flight = in_flight.clone();
     worker.attach_alerter(alerter.clone());

crates/worker/src/worker.rs

@@ -374,7 +374,8 @@ use protocol::{
 use tokio::net::UnixStream;
 use tokio::sync::broadcast;
 use workdir::{
-    LocalWorkdirSession, ReadOnlyWorkdirSession, WorkdirSessionCapabilities, WorkdirSessionHandle,
+    LocalWorkdirSession, ReadOnlyWorkdirSession, WorkdirAttachmentAlias,
+    WorkdirSessionCapabilities, WorkdirSessionHandle, WorkdirSessionRouter,
 };
 
 const RESTORE_RECONCILIATION_REACHABILITY_TIMEOUT: Duration = Duration::from_millis(500);
@@ -2128,9 +2129,9 @@ pub struct Worker<C: LlmClient, St: Store> {
     /// Explicit local filesystem authority, or `None` for Workers with no
     /// local cwd and no filesystem/Bash tool surface.
     filesystem_authority: WorkerFilesystemAuthority,
-    /// Live WorkdirSession provider derived once from the Worker–Workdir binding.
-    /// Local tools, file views, and compaction workers clone this handle.
-    workdir_session: Option<WorkdirSessionHandle>,
+    /// Alias-keyed live Workdir sessions. Provider transport remains hidden
+    /// behind each handle and no attachment is designated primary.
+    workdir_sessions: Arc<WorkdirSessionRouter>,
     /// Path-free workspace identity/client context injected by Runtime/host.
     /// This never grants local filesystem authority.
     workspace_context: WorkerWorkspaceContext,
@@ -2464,7 +2465,7 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
         let prompts = Arc::new(ArcSwap::from(PromptCatalog::builtins_only()?));
         DelegationScope::from_config(&manifest.delegation_scope).map_err(WorkerError::Scope)?;
         let scope = SharedScope::new(scope);
-        let workdir_session = workdir_session_from_authority(&filesystem_authority, &scope);
+        let workdir_sessions = workdir_sessions_from_authority(&filesystem_authority, &scope);
         let mut worker = Self {
             manifest,
             engine: Some(worker),
@@ -2475,7 +2476,7 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
             worker_metadata_segment_cas: None,
             segment_state: SegmentState::new(session_id, segment_id, 0),
             filesystem_authority,
-            workdir_session,
+            workdir_sessions,
             workspace_context,
             flow_runtime_state: Arc::new(Mutex::new(None)),
             flow_feature_enabled: false,
@@ -2652,15 +2653,36 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
         self.filesystem_authority.as_local()
     }
 
-    pub fn workdir_session(&self) -> Option<&WorkdirSessionHandle> {
-        self.workdir_session.as_ref()
+    /// Compatibility projection for tool schemas that do not yet carry a
+    /// target alias. It is available only when the attachment set has exactly
+    /// one member, so multiple attachments never acquire an implicit primary.
+    pub fn workdir_session(&self) -> Option<WorkdirSessionHandle> {
+        self.workdir_sessions.only_session()
     }
 
-    /// Replace the constructor fallback with the provider binding resolved by
-    /// the owning Runtime. Runtime calls this before the Worker controller is
-    /// spawned, so tools only ever observe the Runtime-bound handle.
-    pub fn bind_workdir_session(&mut self, workdir_session: Option<WorkdirSessionHandle>) {
-        self.workdir_session = workdir_session;
+    pub fn workdir_sessions(&self) -> Arc<WorkdirSessionRouter> {
+        self.workdir_sessions.clone()
+    }
+
+    /// Replace the constructor fallback with the complete alias-keyed provider
+    /// set resolved by the owning Runtime before controller startup.
+    pub fn bind_workdir_sessions(&mut self, workdir_sessions: Arc<WorkdirSessionRouter>) {
+        self.workdir_sessions = workdir_sessions;
+    }
+
+    /// Bind one session for direct/Internal Worker construction. Runtime Worker
+    /// creation uses [`Self::bind_workdir_sessions`] with the complete set.
+    pub fn bind_single_workdir_session(&mut self, workdir_session: Option<WorkdirSessionHandle>) {
+        let router = Arc::new(WorkdirSessionRouter::new());
+        if let Some(session) = workdir_session {
+            router
+                .attach(
+                    WorkdirAttachmentAlias::new("workdir").expect("static alias is valid"),
+                    session,
+                )
+                .expect("fresh Workdir router accepts its only attachment");
+        }
+        self.workdir_sessions = router;
     }
 
     /// Path-free workspace identity, if Runtime/host associated this Worker
@@ -2929,8 +2951,7 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
             location.segment_id,
         );
         let read_only_tools = self
-            .workdir_session
-            .clone()
+            .workdir_session()
             .map(|source| Arc::new(ReadOnlyWorkdirSession::new(source)) as WorkdirSessionHandle)
             .map(tools::read_only_builtin_tools)
             .unwrap_or_default();
@@ -4061,7 +4082,7 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
     /// unresolved placeholder stays in the flattened user message so the LLM
     /// still sees the intent.
     async fn resolve_file_refs(&self, segments: &[Segment]) -> Vec<SystemItem> {
-        let Some(workdir) = self.workdir_session.clone() else {
+        let Some(workdir) = self.workdir_session() else {
             for seg in segments {
                 if let Segment::FileRef { path } = seg {
                     self.alert(
@@ -5428,7 +5449,7 @@ impl<C: LlmClient + 'static, St: Store> Worker<C, St> {
 
         // Build a normal parent-owned Internal Worker over a pinned immutable
         // capture. Only SessionExplore and compaction output tools are installed.
-        let workdir = self.workdir_session.clone();
+        let workdir = self.workdir_session();
         let read_only_workdir = workdir.clone().map(|session| {
             Arc::new(ReadOnlyWorkdirSession::new(session)) as workdir::WorkdirSessionHandle
         });
@@ -6139,7 +6160,8 @@ where
         let worker_metadata_writer = Some(worker_metadata_writer_for_store(&store));
         let worker_metadata_segment_cas = Some(worker_metadata_segment_cas_for_store(&store));
         let scope = SharedScope::new(common.scope);
-        let workdir_session = workdir_session_from_authority(&common.filesystem_authority, &scope);
+        let workdir_sessions =
+            workdir_sessions_from_authority(&common.filesystem_authority, &scope);
 
         let mut worker = Self {
             manifest,
@@ -6151,7 +6173,7 @@ where
             worker_metadata_segment_cas,
             segment_state: SegmentState::new(session_id, segment_id, 0),
             filesystem_authority: common.filesystem_authority,
-            workdir_session,
+            workdir_sessions,
             workspace_context: common.workspace_context,
             flow_runtime_state: Arc::new(Mutex::new(None)),
             flow_feature_enabled: false,
@@ -6228,7 +6250,8 @@ where
         apply_worker_manifest(&mut engine, &manifest.engine);
         engine.set_cache_key(Some(segment_id.to_string()));
         let scope = SharedScope::new(common.scope);
-        let workdir_session = workdir_session_from_authority(&common.filesystem_authority, &scope);
+        let workdir_sessions =
+            workdir_sessions_from_authority(&common.filesystem_authority, &scope);
         let mut worker = Self {
             manifest,
             engine: Some(engine),
@@ -6239,7 +6262,7 @@ where
             worker_metadata_segment_cas: None,
             segment_state: SegmentState::new(session_id, segment_id, 0),
             filesystem_authority: common.filesystem_authority,
-            workdir_session,
+            workdir_sessions,
             workspace_context: common.workspace_context,
             flow_runtime_state: Arc::new(Mutex::new(None)),
             flow_feature_enabled: false,
@@ -6350,7 +6373,8 @@ where
         let worker_metadata_writer = Some(worker_metadata_writer_for_store(&store));
         let worker_metadata_segment_cas = Some(worker_metadata_segment_cas_for_store(&store));
         let scope = SharedScope::new(common.scope);
-        let workdir_session = workdir_session_from_authority(&common.filesystem_authority, &scope);
+        let workdir_sessions =
+            workdir_sessions_from_authority(&common.filesystem_authority, &scope);
 
         let mut worker = Self {
             manifest,
@@ -6362,7 +6386,7 @@ where
             worker_metadata_segment_cas,
             segment_state: SegmentState::new(session_id, segment_id, 0),
             filesystem_authority: common.filesystem_authority,
-            workdir_session,
+            workdir_sessions,
             workspace_context: common.workspace_context,
             flow_runtime_state: Arc::new(Mutex::new(None)),
             flow_feature_enabled: false,
@@ -6726,7 +6750,8 @@ where
         let worker_metadata_writer = Some(worker_metadata_writer_for_store(&store));
         let worker_metadata_segment_cas = Some(worker_metadata_segment_cas_for_store(&store));
         let scope = SharedScope::new(common.scope);
-        let workdir_session = workdir_session_from_authority(&common.filesystem_authority, &scope);
+        let workdir_sessions =
+            workdir_sessions_from_authority(&common.filesystem_authority, &scope);
 
         let mut worker = Self {
             manifest,
@@ -6738,7 +6763,7 @@ where
             worker_metadata_segment_cas,
             segment_state: SegmentState::new(session_id, segment_id, state.entries_count),
             filesystem_authority: common.filesystem_authority,
-            workdir_session,
+            workdir_sessions,
             workspace_context: common.workspace_context,
             flow_runtime_state: Arc::new(Mutex::new(restored_flow_runtime_state(
                 &state.extensions,
@@ -7580,18 +7605,26 @@ pub enum WorkerError {
     },
 }
 
-fn workdir_session_from_authority(
+fn workdir_sessions_from_authority(
     authority: &WorkerFilesystemAuthority,
     scope: &SharedScope,
-) -> Option<WorkdirSessionHandle> {
-    authority.as_local().map(|local| {
-        Arc::new(LocalWorkdirSession::materialized(
+) -> Arc<WorkdirSessionRouter> {
+    let router = Arc::new(WorkdirSessionRouter::new());
+    if let Some(local) = authority.as_local() {
+        let session = Arc::new(LocalWorkdirSession::materialized(
             local.root.clone(),
             local.cwd.clone(),
             scope.clone(),
             WorkdirSessionCapabilities::ALL,
-        )) as WorkdirSessionHandle
-    })
+        )) as WorkdirSessionHandle;
+        router
+            .attach(
+                WorkdirAttachmentAlias::new("workdir").expect("static alias is valid"),
+                session,
+            )
+            .expect("fresh Workdir router accepts its only attachment");
+    }
+    router
 }
 
 /// Bundle of resources that every high-level Worker constructor needs:

crates/worker/tests/controller_test.rs

@@ -349,7 +349,7 @@ async fn shutdown_closes_bound_workdir_session() {
         })
         .await
         .unwrap();
-    worker.bind_workdir_session(Some(Arc::clone(&session)));
+    worker.bind_single_workdir_session(Some(Arc::clone(&session)));
 
     let runtime_base = tempfile::tempdir().unwrap();
     let bash_output_dir = runtime_base.path().join("bash-output");
@@ -384,7 +384,7 @@ async fn controller_projects_workdir_command_events_and_snapshot_state() {
         worker.scope().clone(),
         WorkdirSessionCapabilities::ALL,
     ));
-    worker.bind_workdir_session(Some(Arc::clone(&session)));
+    worker.bind_single_workdir_session(Some(Arc::clone(&session)));
     let handle = spawn_controller(worker).await;
     let mut events = handle.subscribe();
 
@@ -495,7 +495,7 @@ async fn controller_refreshes_command_snapshot_after_high_output_provider_lag()
         worker.scope().clone(),
         WorkdirSessionCapabilities::ALL,
     ));
-    worker.bind_workdir_session(Some(Arc::clone(&session)));
+    worker.bind_single_workdir_session(Some(Arc::clone(&session)));
     let handle = spawn_controller(worker).await;
 
     // Local command telemetry uses 8 KiB chunks and a 256-event channel. One
@@ -572,7 +572,7 @@ async fn controller_startup_failure_closes_bound_workdir_session() {
         worker.scope().clone(),
         WorkdirSessionCapabilities::ALL,
     ));
-    worker.bind_workdir_session(Some(Arc::clone(&session)));
+    worker.bind_single_workdir_session(Some(Arc::clone(&session)));
     let runtime_base = tempfile::tempdir().unwrap();
     let invalid_runtime_base = runtime_base.path().join("not-a-directory");
     std::fs::write(&invalid_runtime_base, "file").unwrap();

crates/workspace-server/src/hosts.rs

@@ -32,8 +32,9 @@ use worker_runtime::catalog::{
     ConfigBundleRef, CreateWorkerRequest, ProfileSelector, ProfileSourceArchiveSource,
     RepositoryRefObservation, RepositoryRefObservationRequest,
     WorkerDetail as EmbeddedWorkerDetail, WorkerStatus as EmbeddedWorkerStatus,
-    WorkingDirectoryClaim, WorkingDirectoryRepositoryAccessRequest, WorkingDirectoryRequest,
-    WorkingDirectoryStatus, WorkingDirectorySummary, WorkspaceApiRef,
+    WorkingDirectoryAttachmentClaim, WorkingDirectoryAttachmentRequest,
+    WorkingDirectoryAttachmentStatus, WorkingDirectoryRepositoryAccessRequest,
+    WorkingDirectoryRequest, WorkingDirectoryStatus, WorkspaceApiRef,
 };
 use worker_runtime::config_bundle::{ConfigBundle, ConfigBundleAvailability, ConfigBundleSummary};
 #[cfg(test)]
@@ -270,8 +271,8 @@ pub struct WorkerSummary {
     pub retention_state: String,
     pub implementation: WorkerImplementationSummary,
     pub capabilities: WorkerCapabilitySummary,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory: Option<WorkingDirectorySummary>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachments: Vec<WorkingDirectoryAttachmentStatus>,
     pub diagnostics: Vec<RuntimeDiagnostic>,
 }
 
@@ -336,7 +337,7 @@ impl From<RuntimeSummary> for server_api::RuntimeSummary {
 pub(crate) fn workspace_worker_summary(
     summary: WorkerSummary,
     resource_key: String,
-    working_directory: Option<server_api::WorkingDirectorySummary>,
+    workdir_attachments: Vec<server_api::WorkerWorkdirAttachmentSummary>,
 ) -> server_api::WorkerSummary {
     server_api::WorkerSummary {
         runtime_id: summary.worker.runtime_id,
@@ -366,7 +367,7 @@ pub(crate) fn workspace_worker_summary(
             can_stop: summary.capabilities.can_stop,
             can_spawn_followup: summary.capabilities.can_spawn_followup,
         },
-        working_directory,
+        workdir_attachments,
         diagnostics: summary.diagnostics.into_iter().map(Into::into).collect(),
     }
 }
@@ -483,6 +484,13 @@ pub struct WorkerCreateBinding {
     pub create_fingerprint: String,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(deny_unknown_fields)]
+pub struct WorkerSpawnWorkingDirectoryAttachmentRequest {
+    pub alias: workdir::WorkdirAttachmentAlias,
+    pub working_directory: WorkerSpawnWorkingDirectoryRequest,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(deny_unknown_fields)]
 pub struct WorkerSpawnRequest {
@@ -495,15 +503,13 @@ pub struct WorkerSpawnRequest {
     pub ticket_assignment: Option<WorkerTicketAssignmentRequest>,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub initial_submit: Vec<Segment>,
-    /// Optional safe working-directory creation request. The Workspace server resolves
-    /// this into a runtime-internal `WorkingDirectoryRequest` from configured
-    /// repositories before calling a host.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub working_directory_request: Option<WorkerSpawnWorkingDirectoryRequest>,
+    /// Safe working-directory materialization requests, keyed by stable Worker-local aliases.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub workdir_attachment_requests: Vec<WorkerSpawnWorkingDirectoryAttachmentRequest>,
     #[serde(skip, default)]
-    pub resolved_working_directory_request: Option<WorkingDirectoryRequest>,
+    pub resolved_workdir_attachment_requests: Vec<WorkingDirectoryAttachmentRequest>,
     #[serde(skip, default)]
-    pub resolved_working_directory: Option<WorkingDirectoryClaim>,
+    pub resolved_workdir_attachments: Vec<WorkingDirectoryAttachmentClaim>,
     #[serde(skip, default)]
     pub resolved_config_bundle: Option<ConfigBundle>,
     #[serde(skip, default)]
@@ -905,6 +911,24 @@ pub trait WorkspaceWorkerRuntime: Send + Sync {
         }
     }
 
+    fn replace_worker_workdir_attachments(
+        &self,
+        worker_id: &str,
+        _attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> WorkerWorkspaceApiResult {
+        WorkerWorkspaceApiResult {
+            state: WorkerOperationState::Unsupported,
+            worker: None,
+            diagnostics: vec![diagnostic(
+                "worker_workdir_attachments_replace_unsupported",
+                DiagnosticSeverity::Info,
+                format!(
+                    "runtime does not support replacing Workdir attachments for worker `{worker_id}`"
+                ),
+            )],
+        }
+    }
+
     fn create_working_directory(
         &self,
         _request: WorkingDirectoryRequest,
@@ -1489,6 +1513,19 @@ impl RuntimeRegistry {
         Ok(runtime.replace_worker_workspace_api(worker_id, workspace_api))
     }
 
+    pub fn replace_worker_workdir_attachments(
+        &self,
+        worker: &RuntimeWorkerRef,
+        attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> Result<WorkerWorkspaceApiResult, RuntimeRegistryError> {
+        let runtime_id = worker.runtime_id.as_str();
+        let worker_id = worker.worker_id.as_str();
+        validate_backend_identifier("runtime_id", runtime_id)?;
+        validate_backend_identifier("worker_id", worker_id)?;
+        let runtime = self.runtime(runtime_id)?;
+        Ok(runtime.replace_worker_workdir_attachments(worker_id, attachments))
+    }
+
     pub fn observe_workspace_prompt_projection(
         &self,
         projection: worker::WorkspacePromptProjection,
@@ -2176,7 +2213,7 @@ impl EmbeddedWorkerRuntime {
                     && self.can_stop_embedded_worker(summary.status),
                 can_spawn_followup: false,
             },
-            working_directory: summary.working_directory.map(|status| status.summary),
+            workdir_attachments: summary.workdir_attachments,
             diagnostics: embedded_worker_projection_diagnostics(
                 summary.execution_metadata_available,
             ),
@@ -2220,7 +2257,7 @@ impl EmbeddedWorkerRuntime {
                     && self.can_stop_embedded_worker(detail.status),
                 can_spawn_followup: false,
             },
-            working_directory: detail.working_directory.map(|status| status.summary),
+            workdir_attachments: detail.workdir_attachments,
             diagnostics: embedded_worker_projection_diagnostics(
                 detail.execution_metadata_available,
             ),
@@ -2429,6 +2466,39 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
         }
     }
 
+    fn replace_worker_workdir_attachments(
+        &self,
+        worker_id: &str,
+        attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> WorkerWorkspaceApiResult {
+        let Some(worker_ref) = self.worker_ref(worker_id) else {
+            return WorkerWorkspaceApiResult {
+                state: WorkerOperationState::Rejected,
+                worker: None,
+                diagnostics: vec![diagnostic(
+                    "embedded_worker_id_invalid",
+                    DiagnosticSeverity::Warning,
+                    "Worker id was empty and cannot change Workdir attachments".to_string(),
+                )],
+            };
+        };
+        match self
+            .runtime
+            .replace_worker_workdir_attachments(&worker_ref, attachments)
+        {
+            Ok(detail) => WorkerWorkspaceApiResult {
+                state: WorkerOperationState::Accepted,
+                worker: Some(self.map_worker_detail(detail)),
+                diagnostics: Vec::new(),
+            },
+            Err(err) => WorkerWorkspaceApiResult {
+                state: WorkerOperationState::Rejected,
+                worker: None,
+                diagnostics: vec![embedded_runtime_diagnostic(&err)],
+            },
+        }
+    }
+
     fn create_working_directory(
         &self,
         _request: WorkingDirectoryRequest,
@@ -2491,8 +2561,8 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
         request: WorkerSpawnRequest,
     ) -> WorkerSpawnResult {
         let mut diagnostics = Vec::new();
-        if request.resolved_working_directory_request.is_some()
-            || request.resolved_working_directory.is_some()
+        if !request.resolved_workdir_attachment_requests.is_empty()
+            || !request.resolved_workdir_attachments.is_empty()
         {
             diagnostics.push(embedded_workdir_unsupported_diagnostic());
             return WorkerSpawnResult {
@@ -2573,8 +2643,8 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
             config_bundle,
             profile_source,
             initial_input: initial_worker_input(&request.initial_submit),
-            working_directory_request: request.resolved_working_directory_request.clone(),
-            working_directory: request.resolved_working_directory.clone(),
+            workdir_attachment_requests: request.resolved_workdir_attachment_requests.clone(),
+            workdir_attachments: request.resolved_workdir_attachments.clone(),
             worker_observation_enabled: request.resolved_worker_observation_enabled,
             worker_observation_grants: request.resolved_worker_observation_grants.clone(),
             workspace_api: Some(workspace_api),
@@ -3982,7 +4052,7 @@ impl RemoteWorkerRuntime {
                     && runtime_worker_can_stop(true, summary.status),
                 can_spawn_followup: false,
             },
-            working_directory: summary.working_directory.map(|status| status.summary),
+            workdir_attachments: summary.workdir_attachments,
             diagnostics: remote_worker_projection_diagnostics(summary.execution_metadata_available),
         }
     }
@@ -4024,7 +4094,7 @@ impl RemoteWorkerRuntime {
                     && runtime_worker_can_stop(true, detail.status),
                 can_spawn_followup: false,
             },
-            working_directory: detail.working_directory.map(|status| status.summary),
+            workdir_attachments: detail.workdir_attachments,
             diagnostics: remote_worker_projection_diagnostics(detail.execution_metadata_available),
         }
     }
@@ -4388,6 +4458,51 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
         }
     }
 
+    fn replace_worker_workdir_attachments(
+        &self,
+        worker_id: &str,
+        attachments: Vec<WorkingDirectoryAttachmentClaim>,
+    ) -> WorkerWorkspaceApiResult {
+        let workdir_attachments = match runtime_contract_convert(attachments) {
+            Ok(attachments) => attachments,
+            Err(diagnostic) => {
+                return WorkerWorkspaceApiResult {
+                    state: WorkerOperationState::Rejected,
+                    worker: None,
+                    diagnostics: vec![diagnostic],
+                };
+            }
+        };
+        let request = runtime_api::WorkerWorkdirAttachmentsRequest {
+            workdir_attachments,
+        };
+        let worker_id = worker_id.to_string();
+        match self
+            .run_runtime_api(
+                self.request_timeout,
+                MAX_REMOTE_RUNTIME_RESPONSE_BYTES,
+                move |client| async move {
+                    client
+                        .replace_worker_workdir_attachments(worker_id, request)
+                        .await
+                },
+            )
+            .and_then(|value| {
+                runtime_contract_convert::<_, worker_runtime::catalog::WorkerDetail>(value.worker)
+            }) {
+            Ok(response) => WorkerWorkspaceApiResult {
+                state: WorkerOperationState::Accepted,
+                worker: Some(self.map_worker_detail(response)),
+                diagnostics: Vec::new(),
+            },
+            Err(diagnostic) => WorkerWorkspaceApiResult {
+                state: WorkerOperationState::Rejected,
+                worker: None,
+                diagnostics: vec![diagnostic],
+            },
+        }
+    }
+
     fn create_working_directory(
         &self,
         request: WorkingDirectoryRequest,
@@ -4567,8 +4682,8 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
             config_bundle,
             profile_source,
             initial_input: initial_worker_input(&request.initial_submit),
-            working_directory_request: request.resolved_working_directory_request.clone(),
-            working_directory: request.resolved_working_directory.clone(),
+            workdir_attachment_requests: request.resolved_workdir_attachment_requests.clone(),
+            workdir_attachments: request.resolved_workdir_attachments.clone(),
             worker_observation_enabled: request.resolved_worker_observation_enabled,
             worker_observation_grants: request.resolved_worker_observation_grants.clone(),
             workspace_api: Some(workspace_api),
@@ -5724,7 +5839,7 @@ pub fn placeholder_worker(host_id: impl Into<String>) -> WorkerSummary {
             can_stop: false,
             can_spawn_followup: false,
         },
-        working_directory: None,
+        workdir_attachments: Vec::new(),
         diagnostics: vec![diagnostic(
             "runtime_capability_unsupported",
             DiagnosticSeverity::Info,
@@ -6265,10 +6380,16 @@ mod tests {
                 worker_state: protocol::WorkerStateSnapshot {
                     ..protocol::WorkerStatus::Idle.into()
                 },
-                working_directory: request
-                    .working_directory
-                    .as_ref()
-                    .map(|binding| binding.status()),
+                workdir_attachments: request
+                    .workdir_attachments
+                    .iter()
+                    .map(|(alias, binding)| {
+                        worker_runtime::catalog::WorkingDirectoryAttachmentStatus {
+                            alias: alias.clone(),
+                            working_directory: binding.status(),
+                        }
+                    })
+                    .collect(),
             }
         }
 
@@ -6360,7 +6481,7 @@ mod tests {
                         can_stop: false,
                         can_spawn_followup: false,
                     },
-                    working_directory: None,
+                    workdir_attachments: Vec::new(),
                     diagnostics: Vec::new(),
                 }],
                 observed_prompt_revisions: Arc::new(Mutex::new(Vec::new())),
@@ -6650,9 +6771,9 @@ mod tests {
             profile: ProfileSelector::Builtin("builtin:coder".to_string()),
             ticket_assignment: None,
             initial_submit: Vec::new(),
-            working_directory_request: None,
-            resolved_working_directory_request: None,
-            resolved_working_directory: None,
+            workdir_attachment_requests: Vec::new(),
+            resolved_workdir_attachment_requests: Vec::new(),
+            resolved_workdir_attachments: Vec::new(),
             resolved_config_bundle: None,
             resolved_worker_observation_enabled: false,
             resolved_worker_observation_grants: Vec::new(),
@@ -6890,9 +7011,9 @@ mod tests {
                     profile: ProfileSelector::Builtin("builtin:coder".to_string()),
                     ticket_assignment: None,
                     initial_submit: Vec::new(),
-                    working_directory_request: None,
-                    resolved_working_directory_request: None,
-                    resolved_working_directory: None,
+                    workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachments: Vec::new(),
                     resolved_config_bundle: None,
                     resolved_worker_observation_enabled: false,
                     resolved_worker_observation_grants: Vec::new(),
@@ -6990,9 +7111,9 @@ mod tests {
                     profile: ProfileSelector::Builtin("builtin:coder".to_string()),
                     ticket_assignment: None,
                     initial_submit: Vec::new(),
-                    working_directory_request: None,
-                    resolved_working_directory_request: None,
-                    resolved_working_directory: None,
+                    workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachments: Vec::new(),
                     resolved_config_bundle: None,
                     resolved_worker_observation_enabled: false,
                     resolved_worker_observation_grants: Vec::new(),
@@ -7029,9 +7150,9 @@ mod tests {
                     profile: ProfileSelector::Builtin("builtin:companion".to_string()),
                     ticket_assignment: None,
                     initial_submit: Vec::new(),
-                    working_directory_request: None,
-                    resolved_working_directory_request: None,
-                    resolved_working_directory: None,
+                    workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachment_requests: Vec::new(),
+                    resolved_workdir_attachments: Vec::new(),
                     resolved_config_bundle: None,
                     resolved_worker_observation_enabled: false,
                     resolved_worker_observation_grants: Vec::new(),

crates/workspace-server/src/latest_schema.sql

@@ -667,6 +667,7 @@ CREATE TABLE workdir_create_credential_revision_retentions (
 CREATE TABLE "workdir_registry" (
     workspace_id TEXT NOT NULL,
     workdir_id TEXT NOT NULL,
+    display_name TEXT,
     runtime_id TEXT NOT NULL,
     repository_id TEXT NOT NULL,
     creation_selector TEXT,
@@ -859,10 +860,10 @@ CREATE TABLE "worker_workdir_links" (
             runtime_id TEXT NOT NULL,
             worker_id TEXT NOT NULL,
             workdir_id TEXT NOT NULL,
-            role TEXT NOT NULL,
+            alias TEXT NOT NULL,
             linked_at TEXT NOT NULL,
             unlinked_at TEXT,
-            PRIMARY KEY (workspace_id, worker_id, workdir_id, role),
+            PRIMARY KEY (workspace_id, worker_id, workdir_id, alias),
             FOREIGN KEY (workspace_id, worker_id)
                 REFERENCES "worker_registry"(workspace_id, worker_id) ON DELETE CASCADE,
             FOREIGN KEY (workspace_id, workdir_id)
@@ -1093,8 +1094,8 @@ CREATE INDEX worker_removal_operations_worker_idx ON worker_removal_operations(w
 CREATE UNIQUE INDEX worker_workdir_links_active_workdir_unique
             ON worker_workdir_links(workspace_id, workdir_id)
             WHERE unlinked_at IS NULL;
-CREATE UNIQUE INDEX worker_workdir_links_active_worker_unique
-            ON worker_workdir_links(workspace_id, worker_id)
+CREATE UNIQUE INDEX worker_workdir_links_active_alias_unique
+            ON worker_workdir_links(workspace_id, worker_id, alias)
             WHERE unlinked_at IS NULL;
 CREATE INDEX worker_workdir_links_workdir
             ON worker_workdir_links(workspace_id, workdir_id);

crates/workspace-server/src/runtime_subscription_tests.rs

@@ -22,7 +22,7 @@ impl WorkerExecutionBackend for TestExecutionBackend {
             protocol::WorkerStateSnapshot {
                 ..protocol::WorkerStatus::Idle.into()
             },
-            None,
+            Vec::new(),
         )
     }
 
@@ -64,8 +64,8 @@ fn create_request(name: &str) -> CreateWorkerRequest {
             .unwrap(),
         },
         initial_input: None,
-        working_directory_request: None,
-        working_directory: None,
+        workdir_attachment_requests: Vec::new(),
+        workdir_attachments: Vec::new(),
         worker_observation_enabled: false,
         worker_observation_grants: Vec::new(),
         workspace_api: None,

crates/workspace-server/src/store.rs

@@ -21,7 +21,7 @@ use crate::workspace_deletion::WorkspaceDeletionStore;
 use crate::{Error, Result};
 
 const OLDEST_SCHEMA_VERSION: i64 = 50;
-const LATEST_SCHEMA_VERSION: i64 = 62;
+const LATEST_SCHEMA_VERSION: i64 = 63;
 const SCHEMA_BASELINE_NAME: &str = "workspace schema baseline";
 const WORKSPACE_RUNTIME_BINDINGS_MIGRATION_NAME: &str = "workspace runtime bindings";
 const RUNTIME_BINDING_AUDIT_MIGRATION_NAME: &str = "workspace Runtime binding revision and audit";
@@ -41,6 +41,8 @@ const RUNTIME_REMOVAL_OPERATION_MIGRATION_NAME: &str = "guarded Runtime removal
 const REMOVE_WORKER_RUN_GENERATION_MIGRATION_NAME: &str = "remove obsolete Worker run generation";
 const WORKER_REGISTRY_PROJECTION_MIGRATION_NAME: &str =
     "durable Runtime-backed Worker registry projection";
+const MULTI_WORKDIR_ATTACHMENTS_MIGRATION_NAME: &str =
+    "multiple Worker Workdir attachments and Workdir display names";
 const WORKER_REGISTRY_PROJECTION_SCHEMA: &str = r#"
 CREATE TABLE IF NOT EXISTS worker_registry_observations (
     workspace_id TEXT NOT NULL,
@@ -146,6 +148,11 @@ const MIGRATIONS: &[Migration] = &[
         name: WORKER_REGISTRY_PROJECTION_MIGRATION_NAME,
         apply: migrate_worker_registry_projection_v61_to_v62,
     },
+    Migration {
+        version: 63,
+        name: MULTI_WORKDIR_ATTACHMENTS_MIGRATION_NAME,
+        apply: migrate_multi_workdir_attachments_v62_to_v63,
+    },
 ];
 
 #[derive(Clone, Copy)]
@@ -764,6 +771,7 @@ pub struct WorkdirCreateOperationRecord {
 pub struct WorkdirRegistryRecord {
     pub workspace_id: String,
     pub workdir_id: String,
+    pub display_name: Option<String>,
     pub runtime_id: String,
     pub repository_id: String,
     pub creation_selector: Option<String>,
@@ -784,7 +792,7 @@ pub struct WorkerWorkdirLinkRecord {
     pub workspace_id: String,
     pub worker: RuntimeWorkerRef,
     pub workdir_id: String,
-    pub role: String,
+    pub alias: String,
     pub linked_at: String,
     pub unlinked_at: Option<String>,
 }
@@ -7275,12 +7283,13 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
         self.with_conn(|conn| {
             conn.execute(
                 r#"INSERT INTO workdir_registry (
-                    workspace_id, workdir_id, runtime_id, repository_id,
+                    workspace_id, workdir_id, display_name, runtime_id, repository_id,
                     creation_selector, creation_ref, creation_tree,
                     current_selector, current_ref, current_tree, observed_at_epoch_seconds,
                     materialization_status, cleanliness, created_at, updated_at
-                ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15)
+                ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15, ?16)
                 ON CONFLICT(workspace_id, workdir_id) DO UPDATE SET
+                    display_name = excluded.display_name,
                     runtime_id = excluded.runtime_id,
                     repository_id = excluded.repository_id,
                     creation_selector = excluded.creation_selector,
@@ -7296,6 +7305,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                 params![
                     record.workspace_id,
                     record.workdir_id,
+                    record.display_name,
                     record.runtime_id,
                     record.repository_id,
                     record.creation_selector,
@@ -7474,10 +7484,15 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
         record: &WorkerWorkdirLinkRecord,
         reservation_id: &str,
     ) -> Result<WorkerWorkdirLinkRecord> {
-        if record.role != "attachment" || record.unlinked_at.is_some() {
+        workdir::WorkdirAttachmentAlias::new(record.alias.clone()).map_err(|error| {
+            Error::WorkdirAttachmentConflict(format!(
+                "invalid Workdir attachment alias `{}`: {error}",
+                record.alias
+            ))
+        })?;
+        if record.unlinked_at.is_some() {
             return Err(Error::WorkdirAttachmentConflict(
-                "reserved attachment finalization requires an active canonical attachment"
-                    .to_string(),
+                "reserved attachment finalization requires an active attachment".to_string(),
             ));
         }
         self.with_conn(|conn| {
@@ -7501,9 +7516,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             tx.execute(
                 r#"INSERT INTO worker_workdir_links (
-                    workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                    workspace_id, runtime_id, worker_id, workdir_id, alias, linked_at, unlinked_at
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, NULL)
-                ON CONFLICT(workspace_id, worker_id, workdir_id, role) DO UPDATE SET
+                ON CONFLICT(workspace_id, worker_id, workdir_id, alias) DO UPDATE SET
                     linked_at = excluded.linked_at,
                     unlinked_at = NULL"#,
                 params![
@@ -7511,7 +7526,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                     record.worker.runtime_id,
                     record.worker.worker_id,
                     record.workdir_id,
-                    record.role,
+                    record.alias,
                     record.linked_at,
                 ],
             )
@@ -7539,12 +7554,12 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
         &self,
         record: &WorkerWorkdirLinkRecord,
     ) -> Result<WorkerWorkdirLinkRecord> {
-        if record.role != "attachment" {
-            return Err(Error::WorkdirAttachmentConflict(format!(
-                "unsupported Workdir attachment role `{}`",
-                record.role
-            )));
-        }
+        workdir::WorkdirAttachmentAlias::new(record.alias.clone()).map_err(|error| {
+            Error::WorkdirAttachmentConflict(format!(
+                "invalid Workdir attachment alias `{}`: {error}",
+                record.alias
+            ))
+        })?;
         if record.unlinked_at.is_some() {
             return Err(Error::WorkdirAttachmentConflict(
                 "a new attachment cannot already be unlinked".to_string(),
@@ -7583,32 +7598,34 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                     record.workdir_id
                 )));
             }
-            let active_for_worker = tx
+            let active_for_alias = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, alias, linked_at, unlinked_at
                        FROM worker_workdir_links
-                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL"#,
+                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3
+                         AND alias = ?4 AND unlinked_at IS NULL"#,
                     params![
                         record.workspace_id,
                         record.worker.runtime_id,
                         record.worker.worker_id,
+                        record.alias,
                     ],
                     read_worker_workdir_link_record,
                 )
                 .optional()?;
-            if let Some(active) = active_for_worker {
+            if let Some(active) = active_for_alias {
                 if active.workdir_id == record.workdir_id {
                     tx.commit()?;
                     return Ok(active);
                 }
                 return Err(Error::WorkdirAttachmentConflict(format!(
-                    "Worker {}:{} is already attached to Workdir {}",
-                    record.worker.runtime_id, record.worker.worker_id, active.workdir_id
+                    "Worker {}:{} attachment alias `{}` is already bound to Workdir {}",
+                    record.worker.runtime_id, record.worker.worker_id, record.alias, active.workdir_id
                 )));
             }
             let active_for_workdir = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, alias, 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],
@@ -7623,9 +7640,9 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             }
             let write = tx.execute(
                 r#"INSERT INTO worker_workdir_links (
-                    workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                    workspace_id, runtime_id, worker_id, workdir_id, alias, linked_at, unlinked_at
                 ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, NULL)
-                ON CONFLICT(workspace_id, worker_id, workdir_id, role) DO UPDATE SET
+                ON CONFLICT(workspace_id, worker_id, workdir_id, alias) DO UPDATE SET
                     linked_at = excluded.linked_at,
                     unlinked_at = NULL"#,
                 params![
@@ -7633,7 +7650,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
                     record.worker.runtime_id,
                     record.worker.worker_id,
                     record.workdir_id,
-                    record.role,
+                    record.alias,
                     record.linked_at,
                 ],
             );
@@ -7665,32 +7682,32 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
             )?;
             let active = tx
                 .query_row(
-                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                    r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, alias, linked_at, unlinked_at
                        FROM worker_workdir_links
-                       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],
+                       WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3
+                         AND (?4 IS NULL OR workdir_id = ?4) AND unlinked_at IS NULL"#,
+                    params![workspace_id, worker.runtime_id, worker.worker_id, expected_workdir_id],
                     read_worker_workdir_link_record,
                 )
                 .optional()?;
             let Some(active) = active else {
+                if let Some(expected_workdir_id) = expected_workdir_id {
+                    return Err(Error::WorkdirAttachmentConflict(format!(
+                        "Worker {}:{} is not attached to Workdir {expected_workdir_id}",
+                        worker.runtime_id, worker.worker_id
+                    )));
+                }
                 tx.commit()?;
                 return Ok(None);
             };
-            if let Some(expected_workdir_id) = expected_workdir_id {
-                if active.workdir_id != expected_workdir_id {
-                    return Err(Error::WorkdirAttachmentConflict(format!(
-                        "Worker {}:{} is attached to Workdir {}, not {expected_workdir_id}",
-                        worker.runtime_id, worker.worker_id, active.workdir_id
-                    )));
-                }
-            }
             let changed = tx.execute(
                 r#"UPDATE worker_workdir_links
                    SET unlinked_at = ?4
-                   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],
+                   WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3
+                     AND (?5 IS NULL OR workdir_id = ?5) AND unlinked_at IS NULL"#,
+                params![workspace_id, worker.runtime_id, worker.worker_id, unlinked_at, expected_workdir_id],
             )?;
-            if changed != 1 {
+            if changed == 0 || (expected_workdir_id.is_some() && changed != 1) {
                 return Err(Error::WorkdirAttachmentConflict(format!(
                     "Worker {}:{} attachment changed during detach",
                     worker.runtime_id, worker.worker_id
@@ -7729,7 +7746,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
     ) -> Result<Vec<WorkerWorkdirLinkRecord>> {
         self.with_conn(|conn| {
             let mut stmt = conn.prepare(
-                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, alias, linked_at, unlinked_at
                    FROM worker_workdir_links
                    WHERE workspace_id = ?1 AND runtime_id = ?2 AND worker_id = ?3 AND unlinked_at IS NULL
                    ORDER BY linked_at DESC"#,
@@ -7750,7 +7767,7 @@ impl ControlPlaneStore for SqliteWorkspaceStore {
     ) -> Result<Vec<WorkerWorkdirLinkRecord>> {
         self.with_conn(|conn| {
             let mut stmt = conn.prepare(
-                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, role, linked_at, unlinked_at
+                r#"SELECT workspace_id, runtime_id, worker_id, workdir_id, alias, 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"#,
@@ -8445,7 +8462,7 @@ fn read_worker_workdir_link_record(
         workspace_id: row.get(0)?,
         worker: RuntimeWorkerRef::new(row.get::<_, String>(1)?, row.get::<_, String>(2)?),
         workdir_id: row.get(3)?,
-        role: row.get(4)?,
+        alias: row.get(4)?,
         linked_at: row.get(5)?,
         unlinked_at: row.get(6)?,
     })
@@ -8621,9 +8638,7 @@ fn read_worker_registry_projection(
                         workspace_id: Some(workspace_id.to_string()),
                         display_name: Some(registry.display_name.clone()),
                         profile: registry.profile.clone(),
-                        repository_id: None,
-                        repository_key: None,
-                        working_directory_id: None,
+                        workdir_attachments: Vec::new(),
                     }
                 };
                 observed_worker.availability = availability;
@@ -9236,7 +9251,7 @@ fn require_expected_ticket_assignment(
 
 fn workdir_registry_select_sql(where_clause: &str) -> String {
     format!(
-        "SELECT workspace_id, workdir_id, runtime_id, repository_id, \
+        "SELECT workspace_id, workdir_id, display_name, runtime_id, repository_id, \
          creation_selector, creation_ref, creation_tree, \
          current_selector, current_ref, current_tree, observed_at_epoch_seconds, \
          materialization_status, cleanliness, created_at, updated_at \
@@ -9250,19 +9265,20 @@ fn read_workdir_registry_record(
     Ok(WorkdirRegistryRecord {
         workspace_id: row.get(0)?,
         workdir_id: row.get(1)?,
-        runtime_id: row.get(2)?,
-        repository_id: row.get(3)?,
-        creation_selector: row.get(4)?,
-        creation_ref: row.get(5)?,
-        creation_tree: row.get(6)?,
-        current_selector: row.get(7)?,
-        current_ref: row.get(8)?,
-        current_tree: row.get(9)?,
-        observed_at_epoch_seconds: row.get::<_, Option<i64>>(10)?.map(|value| value as u64),
-        materialization_status: row.get(11)?,
-        cleanliness: row.get(12)?,
-        created_at: row.get(13)?,
-        updated_at: row.get(14)?,
+        display_name: row.get(2)?,
+        runtime_id: row.get(3)?,
+        repository_id: row.get(4)?,
+        creation_selector: row.get(5)?,
+        creation_ref: row.get(6)?,
+        creation_tree: row.get(7)?,
+        current_selector: row.get(8)?,
+        current_ref: row.get(9)?,
+        current_tree: row.get(10)?,
+        observed_at_epoch_seconds: row.get::<_, Option<i64>>(11)?.map(|value| value as u64),
+        materialization_status: row.get(12)?,
+        cleanliness: row.get(13)?,
+        created_at: row.get(14)?,
+        updated_at: row.get(15)?,
     })
 }
 
@@ -10500,10 +10516,31 @@ fn migrate_worker_registry_projection_v61_to_v62(conn: &Connection) -> Result<()
     tx.execute_batch(WORKER_REGISTRY_PROJECTION_SCHEMA)?;
     tx.execute(
         "INSERT INTO __yoi_schema_migrations (version, name) VALUES (?1, ?2)",
-        params![
-            LATEST_SCHEMA_VERSION,
-            WORKER_REGISTRY_PROJECTION_MIGRATION_NAME
-        ],
+        params![62, WORKER_REGISTRY_PROJECTION_MIGRATION_NAME],
+    )?;
+    tx.commit()?;
+    Ok(())
+}
+
+fn migrate_multi_workdir_attachments_v62_to_v63(conn: &Connection) -> Result<()> {
+    let tx = rusqlite::Transaction::new_unchecked(conn, TransactionBehavior::Exclusive)?;
+    if !column_exists(&tx, "workdir_registry", "display_name")? {
+        tx.execute_batch("ALTER TABLE workdir_registry ADD COLUMN display_name TEXT;")?;
+    }
+    if column_exists(&tx, "worker_workdir_links", "role")?
+        && !column_exists(&tx, "worker_workdir_links", "alias")?
+    {
+        tx.execute_batch("ALTER TABLE worker_workdir_links RENAME COLUMN role TO alias;")?;
+    }
+    tx.execute_batch(
+        "DROP INDEX IF EXISTS worker_workdir_links_active_worker_unique;
+         CREATE UNIQUE INDEX IF NOT EXISTS worker_workdir_links_active_alias_unique
+             ON worker_workdir_links(workspace_id, worker_id, alias)
+             WHERE unlinked_at IS NULL;",
+    )?;
+    tx.execute(
+        "INSERT INTO __yoi_schema_migrations (version, name) VALUES (?1, ?2)",
+        params![63, MULTI_WORKDIR_ATTACHMENTS_MIGRATION_NAME],
     )?;
     tx.commit()?;
     Ok(())
@@ -11884,6 +11921,10 @@ mod tests {
                     version: 62,
                     name: WORKER_REGISTRY_PROJECTION_MIGRATION_NAME.to_string(),
                 },
+                WorkspaceSchemaMigrationStep {
+                    version: 63,
+                    name: MULTI_WORKDIR_ATTACHMENTS_MIGRATION_NAME.to_string(),
+                },
             ]
         );
 
@@ -11935,6 +11976,7 @@ mod tests {
                             REMOVE_WORKER_RUN_GENERATION_MIGRATION_NAME.to_string(),
                         ),
                         (62, WORKER_REGISTRY_PROJECTION_MIGRATION_NAME.to_string()),
+                        (63, MULTI_WORKDIR_ATTACHMENTS_MIGRATION_NAME.to_string()),
                     ]
                 );
                 assert!(!table_exists(conn, "trusted_runtime_records")?);
@@ -12005,7 +12047,7 @@ mod tests {
                 .iter()
                 .map(|migration| migration.version)
                 .collect::<Vec<_>>(),
-            vec![52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62]
+            vec![52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63]
         );
         SqliteWorkspaceStore::migrate_database(&path).unwrap();
         let conn = Connection::open(&path).unwrap();
@@ -12013,7 +12055,9 @@ mod tests {
             current_schema_version(&conn).unwrap(),
             LATEST_SCHEMA_VERSION
         );
-        assert_eq!(workspace_schema_migration_history(&conn).unwrap().len(), 13);
+        assert_eq!(workspace_schema_migration_history(&conn).unwrap().len(), 14);
+        assert!(column_exists(&conn, "worker_workdir_links", "alias").unwrap());
+        assert!(!column_exists(&conn, "worker_workdir_links", "role").unwrap());
     }
 
     #[test]
@@ -14722,6 +14766,7 @@ INSERT INTO worker_registry (
         let workdir = WorkdirRegistryRecord {
             workspace_id: "local-dev".to_string(),
             workdir_id: "0000019a00000000001".to_string(),
+            display_name: Some("Checkout".to_string()),
             runtime_id: "embedded".to_string(),
             repository_id: "repo".to_string(),
             creation_selector: Some("develop".to_string()),
@@ -14740,6 +14785,7 @@ INSERT INTO worker_registry (
         let unmanaged_workdir = WorkdirRegistryRecord {
             workspace_id: "local-dev".to_string(),
             workdir_id: "runtime-direct".to_string(),
+            display_name: None,
             runtime_id: "embedded".to_string(),
             repository_id: "repo".to_string(),
             creation_selector: Some("feature".to_string()),
@@ -14760,7 +14806,7 @@ INSERT INTO worker_registry (
             workspace_id: "local-dev".to_string(),
             worker: worker.worker.clone(),
             workdir_id: workdir.workdir_id.clone(),
-            role: "attachment".to_string(),
+            alias: "checkout".to_string(),
             linked_at: "4".to_string(),
             unlinked_at: None,
         };
@@ -14825,6 +14871,30 @@ INSERT INTO worker_registry (
             Err(Error::WorkdirAttachmentConflict(_))
         ));
 
+        let invalid_alias = WorkerWorkdirLinkRecord {
+            alias: "invalid/alias".to_string(),
+            ..worker_conflict.clone()
+        };
+        assert!(matches!(
+            store.attach_worker_workdir(&invalid_alias),
+            Err(Error::WorkdirAttachmentConflict(_))
+        ));
+        let second_attachment = WorkerWorkdirLinkRecord {
+            alias: "docs".to_string(),
+            ..worker_conflict
+        };
+        assert_eq!(
+            store.attach_worker_workdir(&second_attachment).unwrap(),
+            second_attachment
+        );
+        assert_eq!(
+            store
+                .list_worker_workdir_links("local-dev", &worker.worker)
+                .unwrap()
+                .len(),
+            2
+        );
+
         let second_worker = WorkerRegistryRecord {
             worker: RuntimeWorkerRef::new("embedded", "2"),
             display_name: "Browser 2".to_string(),
@@ -14919,9 +14989,7 @@ INSERT INTO worker_registry (
             workspace_id: Some("local-dev".to_string()),
             display_name: Some("Known Worker".to_string()),
             profile: None,
-            repository_id: None,
-            repository_key: None,
-            working_directory_id: None,
+            workdir_attachments: Vec::new(),
         };
         let orphan = SubscriptionWorker {
             worker_id: SubscriptionWorkerId::new("orphan").unwrap(),
@@ -15063,9 +15131,7 @@ INSERT INTO worker_registry (
             workspace_id: Some("local-dev".to_string()),
             display_name: None,
             profile: None,
-            repository_id: None,
-            repository_key: None,
-            working_directory_id: None,
+            workdir_attachments: Vec::new(),
         };
         let commit = store
             .apply_worker_registry_observation("local-dev", "embedded", 2, &event, "2")

crates/workspace-server/src/workdir_create_operations.rs

@@ -25,6 +25,7 @@ pub fn request_fingerprint(
     repository_id: &str,
     selector: Option<&str>,
     requested_runtime_id: Option<&str>,
+    display_name: Option<&str>,
     repository_source_fingerprint: &str,
     repository_source_revision: u64,
 ) -> String {
@@ -33,6 +34,7 @@ pub fn request_fingerprint(
         Some(repository_id),
         selector,
         requested_runtime_id,
+        display_name,
         Some(repository_source_fingerprint),
     ] {
         match value {
@@ -569,6 +571,7 @@ mod tests {
                 "main",
                 Some("develop"),
                 None,
+                None,
                 "sha256:test",
                 1,
             ),
@@ -718,7 +721,7 @@ mod tests {
         );
         let mut changed_input = record.clone();
         changed_input.request_fingerprint =
-            request_fingerprint("main", Some("main"), None, "sha256:test", 1);
+            request_fingerprint("main", Some("main"), None, None, "sha256:test", 1);
         assert!(
             store
                 .reserve_workdir_create_operation(&changed_input)

crates/workspace-server/src/workdir_removal.rs

@@ -716,7 +716,7 @@ fn load_workdir_record(
     workdir_id: &str,
 ) -> Result<Option<WorkdirRegistryRecord>> {
     conn.query_row(
-        r#"SELECT workspace_id, workdir_id, runtime_id, repository_id,
+        r#"SELECT workspace_id, workdir_id, display_name, runtime_id, repository_id,
                   creation_selector, creation_ref, creation_tree,
                   current_selector, current_ref, current_tree, observed_at_epoch_seconds,
                   materialization_status, cleanliness, created_at, updated_at
@@ -726,19 +726,20 @@ fn load_workdir_record(
             Ok(WorkdirRegistryRecord {
                 workspace_id: row.get(0)?,
                 workdir_id: row.get(1)?,
-                runtime_id: row.get(2)?,
-                repository_id: row.get(3)?,
-                creation_selector: row.get(4)?,
-                creation_ref: row.get(5)?,
-                creation_tree: row.get(6)?,
-                current_selector: row.get(7)?,
-                current_ref: row.get(8)?,
-                current_tree: row.get(9)?,
-                observed_at_epoch_seconds: row.get::<_, Option<i64>>(10)?.map(|value| value as u64),
-                materialization_status: row.get(11)?,
-                cleanliness: row.get(12)?,
-                created_at: row.get(13)?,
-                updated_at: row.get(14)?,
+                display_name: row.get(2)?,
+                runtime_id: row.get(3)?,
+                repository_id: row.get(4)?,
+                creation_selector: row.get(5)?,
+                creation_ref: row.get(6)?,
+                creation_tree: row.get(7)?,
+                current_selector: row.get(8)?,
+                current_ref: row.get(9)?,
+                current_tree: row.get(10)?,
+                observed_at_epoch_seconds: row.get::<_, Option<i64>>(11)?.map(|value| value as u64),
+                materialization_status: row.get(12)?,
+                cleanliness: row.get(13)?,
+                created_at: row.get(14)?,
+                updated_at: row.get(15)?,
             })
         },
     )
@@ -934,6 +935,7 @@ mod tests {
         let workdir = WorkdirRegistryRecord {
             workspace_id: "workspace-a".to_string(),
             workdir_id: "workdir-a".to_string(),
+            display_name: None,
             runtime_id: "runtime-a".to_string(),
             repository_id: "repository-a".to_string(),
             creation_selector: Some("refs/heads/develop".to_string()),

crates/workspace-server/src/workspace_subscription.rs

@@ -413,9 +413,7 @@ fn project_registry_worker(
             workspace_id: Some(record.registry.workspace_id.clone()),
             display_name: Some(record.registry.display_name.clone()),
             profile: record.registry.profile.clone(),
-            repository_id: None,
-            repository_key: None,
-            working_directory_id: None,
+            workdir_attachments: Vec::new(),
         }
     };
     worker.runtime_id = Some(runtime_id);
@@ -440,23 +438,33 @@ fn project_working_directory(
     else {
         return false;
     };
-    if let Some(link) = links.first() {
-        let Ok(Some(workdir)) = api
-            .store
-            .get_workdir_registry(&api.config.workspace_id, &link.workdir_id)
-        else {
-            return false;
-        };
-        if workdir.runtime_id != worker_ref.runtime_id {
-            return false;
+    if !links.is_empty() {
+        let mut attachments = Vec::with_capacity(links.len());
+        for link in links {
+            let Ok(Some(workdir)) = api
+                .store
+                .get_workdir_registry(&api.config.workspace_id, &link.workdir_id)
+            else {
+                return false;
+            };
+            if workdir.runtime_id != worker_ref.runtime_id {
+                return false;
+            }
+            let Ok(working_directory_id) =
+                protocol::subscription::SubscriptionWorkdirId::new(workdir.workdir_id)
+            else {
+                return false;
+            };
+            attachments.push(
+                protocol::subscription::SubscriptionWorkerWorkdirAttachment {
+                    alias: link.alias,
+                    repository_id: Some(workdir.repository_id),
+                    repository_key: None,
+                    working_directory_id,
+                },
+            );
         }
-        let Ok(working_directory_id) =
-            protocol::subscription::SubscriptionWorkdirId::new(workdir.workdir_id)
-        else {
-            return false;
-        };
-        worker.repository_id = Some(workdir.repository_id);
-        worker.working_directory_id = Some(working_directory_id);
+        worker.workdir_attachments = attachments;
     } else {
         let Ok(has_link_history) = api
             .store
@@ -465,26 +473,28 @@ fn project_working_directory(
             return false;
         };
         if has_link_history {
-            worker.repository_id = None;
-            worker.repository_key = None;
-            worker.working_directory_id = None;
+            worker.workdir_attachments.clear();
         }
     }
-    project_repository_key(api, worker)
+    project_repository_keys(api, worker)
 }
 
-fn project_repository_key(api: &WorkspaceApi, worker: &mut SubscriptionWorker) -> bool {
-    let Some(repository_id) = worker.repository_id.take() else {
-        worker.repository_key = None;
-        return true;
-    };
-    let Ok(Some(repository)) = api
-        .store
-        .get_repository(&api.config.workspace_id, &repository_id)
-    else {
-        return false;
-    };
-    worker.repository_key = Some(repository.repository_key);
+fn project_repository_keys(api: &WorkspaceApi, worker: &mut SubscriptionWorker) -> bool {
+    for attachment in &mut worker.workdir_attachments {
+        let Some(repository_id) = attachment.repository_id.take() else {
+            if attachment.repository_key.is_none() {
+                return false;
+            }
+            continue;
+        };
+        let Ok(Some(repository)) = api
+            .store
+            .get_repository(&api.config.workspace_id, &repository_id)
+        else {
+            return false;
+        };
+        attachment.repository_key = Some(repository.repository_key);
+    }
     true
 }
 

web/workspace/src/lib/generated/protocol.ts

@@ -236,6 +236,12 @@ export type SubscriptionWorkerAvailability = "observed" | "unavailable";
 
 export type EventSubscriptionSelector = { "topic": "runtime_workers" } | { "topic": "worker_lifecycle", worker_ids: SubscriptionWorkerIds, } | { "topic": "worker_protocol", worker_id: SubscriptionWorkerId, runtime_id?: string | null, } | { "topic": "workspace_workers" } | { "topic": "workspace_workdirs" };
 
+export type SubscriptionWorkerWorkdirAttachment = {
+/**
+ * Stable Worker-local routing alias.
+ */
+alias: string, repository_key?: string | null, working_directory_id: SubscriptionWorkdirId, };
+
 export type SubscriptionWorker = { worker_id: SubscriptionWorkerId,
 /**
  * Set by the Workspace Server when projecting a Runtime-owned Worker to clients.
@@ -264,14 +270,9 @@ worker_state?: WorkerStateSnapshot | null,
 /**
  * Runtime catalog lifecycle compatibility projection; not foreground-state authority.
  */
-state: SubscriptionWorkerState, has_running_internal_workers: boolean, workspace_id?: string | null, display_name?: string | null, profile?: string | null,
-/**
- * Workspace-facing Repository key. Runtime producers leave this unset and
- * Workspace Server projections replace `repository_id` with this field.
- */
-repository_key?: string | null, working_directory_id?: SubscriptionWorkdirId | null, };
+state: SubscriptionWorkerState, has_running_internal_workers: boolean, workspace_id?: string | null, display_name?: string | null, profile?: string | null, workdir_attachments?: Array<SubscriptionWorkerWorkdirAttachment>, };
 
-export type WorkspaceSubscriptionWorkdir = { working_directory_id: SubscriptionWorkdirId, repository_key: string, state: string, primary_worker_id?: SubscriptionWorkerId | null, };
+export type WorkspaceSubscriptionWorkdir = { working_directory_id: SubscriptionWorkdirId, repository_key: string, state: string, };
 
 export type SubscriptionSnapshot = { "topic": "workers", "data": { workers: Array<SubscriptionWorker>, } } | { "topic": "worker_protocol", "data": { worker_id: SubscriptionWorkerId, events: Array<Event>, } } | { "topic": "workspace_workdirs", "data": { workdirs: Array<WorkspaceSubscriptionWorkdir>, } };
 

web/workspace/src/lib/generated/workdir-api.ts

@@ -13,9 +13,17 @@ export type WorkingDirectoryCleanupTarget = { kind: string, working_directory_id
 
 export type WorkingDirectoryOccupancy = { runtime_id: string, worker_id: string, display_name: string, linked_at: string, };
 
-export type WorkingDirectorySummary = { working_directory_id: string, repository_key: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: WorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, primary_worker_id?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
+export type WorkingDirectorySummary = { working_directory_id: string,
+/**
+ * Optional human-facing label, never a routing key.
+ */
+display_name?: string | null, repository_key: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: WorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
 
-export type WorkingDirectoryCreateRequest = { runtime_id?: string | null, repository_key: string, selector?: string | null, operation_id?: string | null, };
+export type WorkingDirectoryCreateRequest = { runtime_id?: string | null,
+/**
+ * Optional human-facing label, independent of every Worker attachment alias.
+ */
+display_name?: string | null, repository_key: string, selector?: string | null, operation_id?: string | null, };
 
 export type WorkingDirectoryListResponse = { workspace_id: string, items: Array<WorkingDirectorySummary>, diagnostics: Array<Diagnostic>, };
 

web/workspace/src/lib/generated/worker-launch-api.ts

@@ -15,11 +15,19 @@ export type WorkingDirectoryCleanupTarget = { kind: string, working_directory_id
 
 export type RuntimeWorkingDirectoryCleanupTarget = { kind: string, working_directory_id: string, repository_id: string, };
 
-export type RuntimeWorkingDirectorySummary = { working_directory_id: string, repository_id: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: RuntimeWorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, primary_worker_id?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
+export type RuntimeWorkingDirectorySummary = { working_directory_id: string,
+/**
+ * Optional human-facing label, never a routing key.
+ */
+display_name?: string | null, repository_id: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: RuntimeWorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
 
 export type WorkingDirectoryOccupancy = { runtime_id: string, worker_id: string, display_name: string, linked_at: string, };
 
-export type WorkingDirectorySummary = { working_directory_id: string, repository_key: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: WorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, primary_worker_id?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
+export type WorkingDirectorySummary = { working_directory_id: string,
+/**
+ * Optional human-facing label, never a routing key.
+ */
+display_name?: string | null, repository_key: string, creation_selector?: string | null, creation_ref?: string | null, creation_tree?: string | null, current_selector?: string | null, current_ref?: string | null, current_tree?: string | null, observed_at_epoch_seconds?: number | null, materializer_kind: WorkingDirectoryMaterializerKind, cleanup_target?: WorkingDirectoryCleanupTarget | null, status: WorkingDirectoryStatusKind, cleanliness?: string | null, occupied_by?: WorkingDirectoryOccupancy | null, };
 
 export type WorkerWorkspaceSummary = { visibility: string, identity: string, workspace_id?: string | null, };
 
@@ -27,7 +35,9 @@ export type WorkerImplementationSummary = { kind: string, display_hint: string,
 
 export type WorkerCapabilitySummary = { can_stop: boolean, can_spawn_followup: boolean, };
 
-export type WorkerLaunchWorkerSummary = { runtime_id: string, worker_id: string, host_id: string, display_name: string, label: string, profile: string | null, singleton_key: string | null, tags: Array<string>, workspace: WorkerWorkspaceSummary, state: string, last_seen_at: string | null, pinned: boolean, retention_state: string, implementation: WorkerImplementationSummary, capabilities: WorkerCapabilitySummary, working_directory?: RuntimeWorkingDirectorySummary | null, diagnostics: Array<Diagnostic>, };
+export type RuntimeWorkerWorkdirAttachmentSummary = { alias: string, working_directory: RuntimeWorkingDirectorySummary, };
+
+export type WorkerLaunchWorkerSummary = { runtime_id: string, worker_id: string, host_id: string, display_name: string, label: string, profile: string | null, singleton_key: string | null, tags: Array<string>, workspace: WorkerWorkspaceSummary, state: string, last_seen_at: string | null, pinned: boolean, retention_state: string, implementation: WorkerImplementationSummary, capabilities: WorkerCapabilitySummary, workdir_attachments?: Array<RuntimeWorkerWorkdirAttachmentSummary>, diagnostics: Array<Diagnostic>, };
 
 export type WorkerLaunchRuntimeOption = { runtime_id: string, display_name: string, built_in: boolean, worker_creation_available: boolean, working_directory_required: boolean, status: string, diagnostics: Array<Diagnostic>, };
 
@@ -37,11 +47,15 @@ export type WorkingDirectoryRepositoryOption = { repository_key: string, default
 
 export type WorkerLaunchOptionsResponse = { workspace_id: string, runtimes: Array<WorkerLaunchRuntimeOption>, default_profile: string | null, profiles: Array<WorkerLaunchProfileCandidate>, repositories: Array<WorkingDirectoryRepositoryOption>, working_directories: Array<WorkingDirectorySummary>, diagnostics: Array<Diagnostic>, };
 
-export type BrowserWorkerWorkingDirectorySelection = { working_directory_id: string, relative_cwd: string | null, };
+export type BrowserWorkerWorkingDirectorySelection = {
+/**
+ * Stable Worker-local routing alias.
+ */
+alias: string, working_directory_id: string, relative_cwd: string | null, };
 
 export type CreateWorkspaceWorkerTicketAssignmentRequest = { ticket_id: string, operation_id: string, };
 
-export type CreateWorkspaceWorkerRequest = { runtime_id: string, display_name: string, profile: string | null, ticket_assignment: CreateWorkspaceWorkerTicketAssignmentRequest | null, initial_submit: Array<Segment>, working_directory: BrowserWorkerWorkingDirectorySelection | null,
+export type CreateWorkspaceWorkerRequest = { runtime_id: string, display_name: string, profile: string | null, ticket_assignment: CreateWorkspaceWorkerTicketAssignmentRequest | null, initial_submit: Array<Segment>, workdir_attachments: Array<BrowserWorkerWorkingDirectorySelection>,
 /**
  * Backend idempotency key used only for authenticated Worker-owned spawn/control.
  */

web/workspace/src/lib/workspace/api/workdirs.ts

@@ -11,6 +11,7 @@ import type {
 
 const SUMMARY_KEYS = new Set([
   "working_directory_id",
+  "display_name",
   "repository_key",
   "creation_selector",
   "creation_ref",
@@ -23,11 +24,11 @@ const SUMMARY_KEYS = new Set([
   "cleanup_target",
   "status",
   "cleanliness",
-  "primary_worker_id",
   "occupied_by",
 ]);
 const CREATE_REQUEST_KEYS = new Set([
   "runtime_id",
+  "display_name",
   "repository_key",
   "selector",
   "operation_id",
@@ -84,6 +85,7 @@ export function validateWorkingDirectoryCreateRequest(
     repository_key: stringField(record, "repository_key"),
   };
   assignOptionalString(request, record, "runtime_id");
+  assignOptionalString(request, record, "display_name");
   assignOptionalString(request, record, "selector");
   assignOptionalString(request, record, "operation_id");
   return request;
@@ -124,6 +126,7 @@ export function parseWorkingDirectorySummary(
       "unknown",
     ]),
   };
+  assignOptionalString(summary, record, "display_name");
   assignOptionalString(summary, record, "creation_selector");
   assignOptionalString(summary, record, "creation_ref");
   assignOptionalString(summary, record, "creation_tree");
@@ -131,7 +134,6 @@ export function parseWorkingDirectorySummary(
   assignOptionalString(summary, record, "current_ref");
   assignOptionalString(summary, record, "current_tree");
   assignOptionalString(summary, record, "cleanliness");
-  assignOptionalString(summary, record, "primary_worker_id");
   if (record.observed_at_epoch_seconds !== undefined) {
     const observedAt = record.observed_at_epoch_seconds;
     if (observedAt === null) {

web/workspace/src/lib/workspace/api/workers.test.ts

@@ -139,10 +139,11 @@ Deno.test("Worker create request parser requires the complete shared request", (
       { kind: "text", content: "Implement T-565." },
       { kind: "flow", selector: "builtin:coder-review" },
     ],
-    working_directory: {
+    workdir_attachments: [{
+      alias: "source",
       working_directory_id: "workdir-a",
       relative_cwd: null,
-    },
+    }],
     control_operation_id: null,
   };
 

web/workspace/src/lib/workspace/api/workers.ts

@@ -8,6 +8,7 @@ import type {
   DiagnosticSeverity,
   RuntimeWorkingDirectoryCleanupTarget,
   RuntimeWorkingDirectorySummary,
+  RuntimeWorkerWorkdirAttachmentSummary,
   WorkerCapabilitySummary,
   WorkerImplementationSummary,
   WorkerLaunchOptionsResponse,
@@ -261,6 +262,7 @@ function runtimeWorkingDirectory(
     item,
     [
       "working_directory_id",
+      "display_name",
       "repository_id",
       "creation_selector",
       "creation_ref",
@@ -273,7 +275,6 @@ function runtimeWorkingDirectory(
       "cleanup_target",
       "status",
       "cleanliness",
-      "primary_worker_id",
       "occupied_by",
     ],
     label,
@@ -318,6 +319,11 @@ function runtimeWorkingDirectory(
       item.working_directory_id,
       `${label}.working_directory_id`,
     ),
+    display_name: optional(
+      item.display_name,
+      `${label}.display_name`,
+      string,
+    ),
     repository_id: string(item.repository_id, `${label}.repository_id`),
     creation_selector: optional(
       item.creation_selector,
@@ -350,15 +356,25 @@ function runtimeWorkingDirectory(
     ),
     status: status as RuntimeWorkingDirectorySummary["status"],
     cleanliness: optional(item.cleanliness, `${label}.cleanliness`, string),
-    primary_worker_id: optional(
-      item.primary_worker_id,
-      `${label}.primary_worker_id`,
-      string,
-    ),
     occupied_by: occupied,
   };
 }
 
+function runtimeWorkdirAttachment(
+  value: unknown,
+  label: string,
+): RuntimeWorkerWorkdirAttachmentSummary {
+  const item = record(value, label);
+  exact(item, ["alias", "working_directory"], label);
+  return {
+    alias: string(item.alias, `${label}.alias`),
+    working_directory: runtimeWorkingDirectory(
+      item.working_directory,
+      `${label}.working_directory`,
+    ),
+  };
+}
+
 function workerSummary(
   value: unknown,
   label: string,
@@ -382,7 +398,7 @@ function workerSummary(
       "retention_state",
       "implementation",
       "capabilities",
-      "working_directory",
+      "workdir_attachments",
       "diagnostics",
     ],
     label,
@@ -406,11 +422,13 @@ function workerSummary(
       `${label}.implementation`,
     ),
     capabilities: capabilitySummary(item.capabilities, `${label}.capabilities`),
-    working_directory: optional(
-      item.working_directory,
-      `${label}.working_directory`,
-      runtimeWorkingDirectory,
-    ),
+    workdir_attachments: item.workdir_attachments === undefined
+      ? undefined
+      : array(
+        item.workdir_attachments,
+        `${label}.workdir_attachments`,
+        runtimeWorkdirAttachment,
+      ),
     diagnostics: array(item.diagnostics, `${label}.diagnostics`, diagnostic),
   };
 }
@@ -464,8 +482,9 @@ function workingDirectorySelection(
   label: string,
 ): BrowserWorkerWorkingDirectorySelection {
   const item = record(value, label);
-  exact(item, ["working_directory_id", "relative_cwd"], label);
+  exact(item, ["alias", "working_directory_id", "relative_cwd"], label);
   return {
+    alias: string(item.alias, `${label}.alias`),
     working_directory_id: string(
       item.working_directory_id,
       `${label}.working_directory_id`,
@@ -638,7 +657,7 @@ export function parseCreateWorkspaceWorkerRequest(
       "profile",
       "ticket_assignment",
       "initial_submit",
-      "working_directory",
+      "workdir_attachments",
       "control_operation_id",
     ],
     "Worker create request",
@@ -651,9 +670,11 @@ export function parseCreateWorkspaceWorkerRequest(
       ? null
       : ticketAssignment(item.ticket_assignment, "ticket_assignment"),
     initial_submit: array(item.initial_submit, "initial_submit", segment),
-    working_directory: item.working_directory === null
-      ? null
-      : workingDirectorySelection(item.working_directory, "working_directory"),
+    workdir_attachments: array(
+      item.workdir_attachments,
+      "workdir_attachments",
+      workingDirectorySelection,
+    ),
     control_operation_id: nullableString(
       item.control_operation_id,
       "control_operation_id",

web/workspace/src/lib/workspace/sidebar/WorkersNavSection.svelte

@@ -37,6 +37,14 @@
     Math.max(0, workers.length - COLLAPSED_WORKER_COUNT),
   );
 
+  function workdirMeta(worker: SidebarWorker): string {
+    const attachments = worker.workdir_attachments;
+    if (attachments.length === 0) return '—';
+    return attachments
+      .map((attachment) => `${attachment.alias}: ${attachment.repository_key ?? '—'}・${attachment.working_directory_id}`)
+      .join(', ');
+  }
+
   function workerKey(worker: SidebarWorker): string {
     return `${worker.runtime_id}:${worker.worker_id}`;
   }
@@ -190,7 +198,7 @@
             </span>
             <span class="worker-nav-label">{label}</span>
             <small class="worker-nav-meta">
-              {worker.repository_key ?? '—'}・{worker.working_directory_id ?? '—'}
+              {workdirMeta(worker)}
             </small>
           </a>
           <button

web/workspace/src/lib/workspace/sidebar/types.ts

@@ -89,6 +89,11 @@ export type WorkerCapabilities = {
   can_spawn_followup: boolean;
 };
 
+export type WorkerWorkdirAttachment = {
+  alias: string;
+  working_directory: WorkingDirectorySummary;
+};
+
 export type Worker = {
   runtime_id: string;
   worker_id: string;
@@ -107,7 +112,7 @@ export type Worker = {
   last_seen_at?: string | null;
   implementation: { kind: string; display_hint: string };
   capabilities: WorkerCapabilities;
-  working_directory?: WorkingDirectorySummary | null;
+  workdir_attachments?: WorkerWorkdirAttachment[];
   diagnostics: Diagnostic[];
 };
 

web/workspace/src/lib/workspace/sidebar/worker-actions.ts

@@ -7,13 +7,14 @@ import type {
 } from "./types";
 
 type FetchFn = typeof fetch;
+type WorkerActionTarget = Pick<Worker, "runtime_id" | "worker_id" | "state">;
 
 type WorkerLifecycleResponse = {
   state: string;
   diagnostics?: Diagnostic[];
 };
 
-function workerPath(workspaceId: string, worker: Worker): string {
+function workerPath(workspaceId: string, worker: WorkerActionTarget): string {
   return workspaceApiPath(
     workspaceId,
     `/runtimes/${encodeURIComponent(worker.runtime_id)}/workers/${
@@ -45,13 +46,13 @@ function diagnosticMessage(
     fallback;
 }
 
-export function canDeleteSidebarWorker(worker: Worker): boolean {
+export function canDeleteSidebarWorker(worker: WorkerActionTarget): boolean {
   return worker.state === "stopped";
 }
 
 export async function stopSidebarWorker(
   workspaceId: string,
-  worker: Worker,
+  worker: WorkerActionTarget,
   fetchFn: FetchFn = fetch,
 ): Promise<void> {
   const response = await fetchFn(`${workerPath(workspaceId, worker)}/stop`, {
@@ -71,7 +72,7 @@ export async function stopSidebarWorker(
 
 export async function deleteSidebarWorker(
   workspaceId: string,
-  worker: Worker,
+  worker: WorkerActionTarget,
   fetchFn: FetchFn = fetch,
 ): Promise<void> {
   const runtimePath = `/runtimes/${encodeURIComponent(worker.runtime_id)}`;

web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts

@@ -57,7 +57,6 @@ const options: WorkerLaunchOptionsResponse = {
       materializer_kind: "runtime_git_clone",
       status: "active",
       cleanliness: "clean",
-      primary_worker_id: null,
       cleanup_target: {
         kind: "runtime_git_clone",
         working_directory_id: "wd-1-repo",
@@ -180,7 +179,7 @@ Deno.test("defaultWorkerLaunchForm preserves a Ticket repository target", () =>
   assertEquals(form.working_directory_selector, "work/ticket");
 });
 
-Deno.test("buildCreateWorkspaceWorkerRequest sends working_directory id and relative cwd only", () => {
+Deno.test("buildCreateWorkspaceWorkerRequest sends one aliased attachment", () => {
   const request = buildCreateWorkspaceWorkerRequest({
     runtime_id: "embedded",
     display_name: "Worker",
@@ -198,10 +197,11 @@ Deno.test("buildCreateWorkspaceWorkerRequest sends working_directory id and rela
     profile: "builtin:coder",
     ticket_assignment: null,
     initial_submit: [{ kind: "text", content: "go" }],
-    working_directory: {
+    workdir_attachments: [{
+      alias: "workdir",
       working_directory_id: "wd-1-repo",
       relative_cwd: "crates/yoi",
-    },
+    }],
     control_operation_id: null,
   });
 });
@@ -221,7 +221,7 @@ Deno.test("buildCreateWorkspaceWorkerRequest sends no initial segments for an em
   assertEquals(request.initial_submit, []);
 });
 
-Deno.test("buildCreateWorkspaceWorkerRequest emits null for embedded no-workdir launches", () => {
+Deno.test("buildCreateWorkspaceWorkerRequest emits an empty attachment list for workdirless launches", () => {
   const request = buildCreateWorkspaceWorkerRequest({
     runtime_id: "embedded",
     display_name: "Worker",
@@ -239,7 +239,7 @@ Deno.test("buildCreateWorkspaceWorkerRequest emits null for embedded no-workdir
     profile: "builtin:companion",
     ticket_assignment: null,
     initial_submit: [{ kind: "text", content: "chat" }],
-    working_directory: null,
+    workdir_attachments: [],
     control_operation_id: null,
   });
 });

web/workspace/src/lib/workspace/sidebar/worker-launch.ts

@@ -31,7 +31,6 @@ export function defaultWorkerLaunchForm(
     options?.working_directories.filter((directory) =>
       directory.status === "active" &&
       directory.cleanliness === "clean" &&
-      directory.primary_worker_id == null &&
       directory.occupied_by == null
     ) ?? [];
   const selectedRuntime = current.runtime_id
@@ -97,12 +96,13 @@ export function buildCreateWorkspaceWorkerRequest(
     initial_submit: initialMessage
       ? [{ kind: "text", content: form.initial_text }]
       : [],
-    working_directory: form.working_directory_id
-      ? {
+    workdir_attachments: form.working_directory_id
+      ? [{
+        alias: "workdir",
         working_directory_id: form.working_directory_id,
         relative_cwd: form.relative_cwd.trim() || null,
-      }
-      : null,
+      }]
+      : [],
     control_operation_id: null,
   });
 }

web/workspace/src/lib/workspace/sidebar/worker-subscription.test.ts

@@ -32,7 +32,7 @@ function worker(
     workspace_id: 'workspace-test',
     display_name: null,
     profile: null,
-    working_directory_id: null,
+    workdir_attachments: [],
   };
 }
 

web/workspace/src/lib/workspace/sidebar/worker-subscription.ts

@@ -1,5 +1,8 @@
 import { readable, type Readable } from 'svelte/store';
-import type { SubscriptionWorker } from '$lib/generated/protocol';
+import type {
+  SubscriptionWorker,
+  SubscriptionWorkerWorkdirAttachment,
+} from '$lib/generated/protocol';
 import { workspaceMultiplexer } from '$lib/workspace/multiplexer';
 import {
   applyWorkspaceWorkersFrame,
@@ -9,9 +12,8 @@ import { liveWorkerState } from './worker-state';
 import { compareWorkersForSidebar } from './workers';
 import type { Worker } from './types';
 
-export type SidebarWorker = Worker & {
-  repository_key: string | null;
-  working_directory_id: string | null;
+export type SidebarWorker = Omit<Worker, 'workdir_attachments'> & {
+  workdir_attachments: SubscriptionWorkerWorkdirAttachment[];
   has_running_internal_workers: boolean;
 };
 
@@ -103,10 +105,8 @@ function projectWorker(worker: SubscriptionWorker): SidebarWorker {
       can_stop: worker.availability !== 'unavailable' && worker.state !== 'stopped',
       can_spawn_followup: false,
     },
-    repository_key: worker.repository_key ?? null,
-    working_directory_id: worker.working_directory_id ?? null,
+    workdir_attachments: worker.workdir_attachments ?? [],
     has_running_internal_workers: worker.has_running_internal_workers,
-    working_directory: null,
     diagnostics: [],
   };
 }

web/workspace/src/lib/workspace/sidebar/workers.test.ts

@@ -40,7 +40,7 @@ function worker(overrides: Partial<Worker>): Worker {
       can_stop: true,
       can_spawn_followup: false,
     },
-    working_directory: null,
+    workdir_attachments: [],
     diagnostics: [],
     ...overrides,
   };

web/workspace/src/lib/workspace/sidebar/workers.ts

@@ -19,11 +19,15 @@ export function sidebarWorkerActivity(
   return 'none';
 }
 
-export function canShowWorkerInSidebar(worker: Worker): boolean {
+export function canShowWorkerInSidebar(
+  worker: Pick<Worker, 'implementation'>,
+): boolean {
   return worker.implementation.kind !== 'backend_worker_registry';
 }
 
-export function canOpenWorkerConsole(worker: Worker): boolean {
+export function canOpenWorkerConsole(
+  worker: Pick<Worker, 'implementation'>,
+): boolean {
   return canShowWorkerInSidebar(worker);
 }
 

web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte

@@ -138,7 +138,10 @@
           {#each workdirs as workdir}
             {@const cleanup = cleanupCandidate(workdir)}
             <tr>
-              <td><code>{workdir.working_directory_id}</code></td>
+              <td>
+                <span>{workdir.display_name ?? '—'}</span>
+                <small><code>{workdir.working_directory_id}</code></small>
+              </td>
               <td>{workdir.repository_key}</td>
               <td><code>{currentRevision(workdir)}</code></td>
               <td>{workdir.status}</td>

web/workspace/src/routes/w/[workspaceId]/workers/+page.svelte

@@ -145,11 +145,14 @@
   }
 
   function workerDirectory(worker: Worker): string {
-    const directory = worker.working_directory;
-    if (!directory) return '—';
-    const provider = data.repositories?.items.find((repository) => repository.repository_key === directory.repository_key)
-      ?.provider;
-    return `${directory.repository_key} · ${formatCurrentWorkdirRevision(directory, provider)}`;
+    const attachments = worker.workdir_attachments ?? [];
+    if (attachments.length === 0) return '—';
+    return attachments.map(({ alias, working_directory: directory }) => {
+      const provider = data.repositories?.items.find((repository) => repository.repository_key === directory.repository_key)
+        ?.provider;
+      const label = directory.display_name ?? directory.repository_key;
+      return `${alias}: ${label} · ${formatCurrentWorkdirRevision(directory, provider)}`;
+    }).join(', ');
   }
 </script>
 

web/workspace/src/routes/w/[workspaceId]/workers/new/+page.svelte

@@ -33,7 +33,8 @@
   function workdirOptionLabel(directory: WorkingDirectorySummary): string {
     const provider = data.repositories?.items.find((repository) => repository.repository_key === directory.repository_key)
       ?.provider;
-    return `${directory.repository_key} · ${formatCurrentWorkdirRevision(directory, provider)}`;
+    const label = directory.display_name ?? directory.repository_key;
+    return `${label} · ${formatCurrentWorkdirRevision(directory, provider)}`;
   }
 
   let { data }: PageProps = $props();
@@ -62,6 +63,7 @@
   );
   let initialText = $state(ticketContext?.initialInput ?? '');
   let workingDirectoryId = $state('');
+  let workingDirectoryDisplayName = $state('');
   let workingDirectoryRepositoryKey = $state(ticketContext?.repositoryKey ?? '');
   let workingDirectorySelector = $state(ticketContext?.refSelector ?? 'HEAD');
   let relativeCwd = $state('');
@@ -78,7 +80,6 @@
       : (options?.working_directories ?? []).filter((directory) =>
         directory.status === 'active' &&
         directory.cleanliness === 'clean' &&
-        directory.primary_worker_id == null &&
         directory.occupied_by == null
       ),
   );
@@ -168,6 +169,7 @@
     try {
       const request = validateWorkingDirectoryCreateRequest({
         runtime_id: runtimeId,
+        ...(workingDirectoryDisplayName.trim() ? { display_name: workingDirectoryDisplayName.trim() } : {}),
         repository_key: workingDirectoryRepositoryKey,
         ...(workingDirectorySelector ? { selector: workingDirectorySelector } : {}),
       });
@@ -340,6 +342,10 @@
           <div class="new-working-directory-panel">
             <h3>New workdir</h3>
             <div class="new-working-directory-fields">
+              <label>
+                <span>Display name</span>
+                <input bind:value={workingDirectoryDisplayName} autocomplete="off" placeholder="Optional label" maxlength="80" />
+              </label>
               <label>
                 <span>Repository</span>
                 <select bind:value={workingDirectoryRepositoryKey}>

web/workspace/tests/workdir-api.test.ts

@@ -10,6 +10,7 @@ import {
 
 const summary = {
   working_directory_id: "workdir-1",
+  display_name: "Checkout",
   repository_key: "main",
   materializer_kind: "runtime_git_clone",
   status: "active",
@@ -27,6 +28,9 @@ Deno.test("Workdir REST validation accepts the generated list and create contrac
     items: [summary],
     diagnostics: [],
   });
+  if (list.items[0]?.display_name !== "Checkout") {
+    throw new Error("display name was not preserved");
+  }
   if (list.items[0]?.occupied_by?.runtime_id !== "arcadia") {
     throw new Error("occupancy subject was not preserved");
   }
@@ -60,6 +64,7 @@ Deno.test("Workdir REST validation rejects stale response JSON", () => {
 Deno.test("Workdir REST validation enforces create operation fields", () => {
   const request = validateWorkingDirectoryCreateRequest({
     runtime_id: "arcadia",
+    display_name: "Review checkout",
     repository_key: "main",
     selector: "develop",
     operation_id: "operation-1",
@@ -67,6 +72,9 @@ Deno.test("Workdir REST validation enforces create operation fields", () => {
   if (request.operation_id !== "operation-1") {
     throw new Error("operation id was not preserved");
   }
+  if (request.display_name !== "Review checkout") {
+    throw new Error("display name was not preserved");
+  }
 
   for (
     const invalid of [