refactor: migrate delegate_task to task tool with metadata fixes

- Rename delegate_task tool to task across codebase (100 files)
- Update model references: claude-opus-4-6 → 4-5, gpt-5.3-codex → 5.2-codex
- Add tool-metadata-store to restore metadata overwritten by fromPlugin()
- Add session ID polling for BackgroundManager task sessions
- Await async ctx.metadata() calls in tool executors
- Add ses_ prefix guard to getMessageDir for performance
- Harden BackgroundManager with idle deferral and error handling
- Fix duplicate task key in sisyphus-junior test object literals
- Fix unawaited showOutputToUser in ast_grep_replace
- Fix background=true → run_in_background=true in ultrawork prompt
- Fix duplicate task/task references in docs and comments

src/features/background-agent/manager.ts

@@ -88,6 +88,7 @@ export class BackgroundManager {
   private queuesByKey: Map<string, QueueItem[]> = new Map()
   private processingKeys: Set<string> = new Set()
   private completionTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
+  private idleDeferralTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
 
   constructor(
     ctx: PluginInput,
@@ -328,7 +329,6 @@ export class BackgroundManager {
         tools: {
           ...getAgentToolRestrictions(input.agent),
           task: false,
-          delegate_task: false,
           call_omo_agent: true,
           question: false,
         },
@@ -357,6 +357,7 @@ export class BackgroundManager {
         }).catch(() => {})
 
         this.markForNotification(existingTask)
+        this.cleanupPendingByParent(existingTask)
         this.notifyParentSession(existingTask).catch(err => {
           log("[background-agent] Failed to notify on error:", err)
         })
@@ -410,7 +411,7 @@ export class BackgroundManager {
   }
 
   /**
-   * Track a task created elsewhere (e.g., from delegate_task) for notification tracking.
+   * Track a task created elsewhere (e.g., from task) for notification tracking.
    * This allows tasks created by other tools to receive the same toast/prompt notifications.
    */
   async trackTask(input: {
@@ -458,7 +459,7 @@ export class BackgroundManager {
       return existingTask
     }
 
-    const concurrencyGroup = input.concurrencyKey ?? input.agent ?? "delegate_task"
+    const concurrencyGroup = input.concurrencyKey ?? input.agent ?? "task"
 
     // Acquire concurrency slot if a key is provided
     if (input.concurrencyKey) {
@@ -472,7 +473,7 @@ export class BackgroundManager {
       parentMessageID: "",
       description: input.description,
       prompt: "",
-      agent: input.agent || "delegate_task",
+      agent: input.agent || "task",
       status: "running",
       startedAt: new Date(),
       progress: {
@@ -587,7 +588,6 @@ export class BackgroundManager {
         tools: {
           ...getAgentToolRestrictions(existingTask.agent),
           task: false,
-          delegate_task: false,
           call_omo_agent: true,
           question: false,
         },
@@ -614,6 +614,7 @@ export class BackgroundManager {
       }
 
       this.markForNotification(existingTask)
+      this.cleanupPendingByParent(existingTask)
       this.notifyParentSession(existingTask).catch(err => {
         log("[background-agent] Failed to notify on resume error:", err)
       })
@@ -651,6 +652,13 @@ export class BackgroundManager {
       const task = this.findBySession(sessionID)
       if (!task) return
 
+      // Clear any pending idle deferral timer since the task is still active
+      const existingTimer = this.idleDeferralTimers.get(task.id)
+      if (existingTimer) {
+        clearTimeout(existingTimer)
+        this.idleDeferralTimers.delete(task.id)
+      }
+
       if (partInfo?.type === "tool" || partInfo?.tool) {
         if (!task.progress) {
           task.progress = {
@@ -677,7 +685,17 @@ export class BackgroundManager {
       // Edge guard: Require minimum elapsed time (5 seconds) before accepting idle
       const elapsedMs = Date.now() - startedAt.getTime()
       if (elapsedMs < MIN_IDLE_TIME_MS) {
-        log("[background-agent] Ignoring early session.idle, elapsed:", { elapsedMs, taskId: task.id })
+        const remainingMs = MIN_IDLE_TIME_MS - elapsedMs
+        if (!this.idleDeferralTimers.has(task.id)) {
+          log("[background-agent] Deferring early session.idle:", { elapsedMs, remainingMs, taskId: task.id })
+          const timer = setTimeout(() => {
+            this.idleDeferralTimers.delete(task.id)
+            this.handleEvent({ type: "session.idle", properties: { sessionID } })
+          }, remainingMs)
+          this.idleDeferralTimers.set(task.id, timer)
+        } else {
+          log("[background-agent] session.idle already deferred:", { elapsedMs, taskId: task.id })
+        }
         return
       }
 
@@ -736,6 +754,12 @@ export class BackgroundManager {
         clearTimeout(existingTimer)
         this.completionTimers.delete(task.id)
       }
+
+      const idleTimer = this.idleDeferralTimers.get(task.id)
+      if (idleTimer) {
+        clearTimeout(idleTimer)
+        this.idleDeferralTimers.delete(task.id)
+      }
       this.cleanupPendingByParent(task)
       this.tasks.delete(task.id)
       this.clearNotificationsForTask(task.id)
@@ -890,6 +914,12 @@ export class BackgroundManager {
       this.completionTimers.delete(task.id)
     }
 
+    const idleTimer = this.idleDeferralTimers.get(task.id)
+    if (idleTimer) {
+      clearTimeout(idleTimer)
+      this.idleDeferralTimers.delete(task.id)
+    }
+
     this.cleanupPendingByParent(task)
 
     if (abortSession && task.sessionID) {
@@ -1025,6 +1055,15 @@ export class BackgroundManager {
 
     this.markForNotification(task)
 
+    // Ensure pending tracking is cleaned up even if notification fails
+    this.cleanupPendingByParent(task)
+
+    const idleTimer = this.idleDeferralTimers.get(task.id)
+    if (idleTimer) {
+      clearTimeout(idleTimer)
+      this.idleDeferralTimers.delete(task.id)
+    }
+
     if (task.sessionID) {
       this.client.session.abort({
         path: { id: task.sessionID },
@@ -1511,6 +1550,11 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
     }
     this.completionTimers.clear()
 
+    for (const timer of this.idleDeferralTimers.values()) {
+      clearTimeout(timer)
+    }
+    this.idleDeferralTimers.clear()
+
     this.concurrencyManager.clear()
     this.tasks.clear()
     this.notifications.clear()