fix(delegate-task): pause timeouts for active sessions

src/features/background-agent/manager.polling.test.ts

@@ -364,6 +364,29 @@ describe("BackgroundManager pollRunningTasks", () => {
       //#then
       expect(task.status).toBe("running")
     })
+
+    test("#when progress is older than prune TTL #then active status still keeps the task running", async () => {
+      //#given
+      const manager = createManagerWithClient({
+        status: async () => ({ data: { "ses-busy-stale": { type: "busy" } } }),
+      })
+      const task = createRunningTask("ses-busy-stale")
+      task.startedAt = new Date(Date.now() - 60 * 60 * 1000)
+      task.progress = {
+        toolCalls: 4,
+        lastUpdate: new Date(Date.now() - 35 * 60 * 1000),
+      }
+      injectTask(manager, task)
+
+      //#when
+      const poll = manager["pollRunningTasks"]
+      await poll.call(manager)
+      manager.shutdown()
+
+      //#then
+      expect(task.status).toBe("running")
+      expect(task.error).toBeUndefined()
+    })
   })
 
   describe("#given a running task whose session has terminal non-idle status", () => {

src/features/background-agent/manager.ts

@@ -2285,11 +2285,12 @@ The task was re-queued on a fallback model after a retryable failure.
     }
   }
 
-  private pruneStaleTasksAndNotifications(): void {
+  private pruneStaleTasksAndNotifications(allStatuses?: SessionStatusMap): void {
     pruneStaleTasksAndNotifications({
       tasks: this.tasks,
       notifications: this.notifications,
       taskTtlMs: this.config?.taskTtlMs,
+      sessionStatuses: allStatuses,
       onTaskPruned: (taskId, task, errorMessage) => {
         const wasPending = task.status === "pending"
         log("[background-agent] Pruning stale task:", { taskId, status: task.status, age: Math.round(((wasPending ? task.queuedAt?.getTime() : task.startedAt?.getTime()) ? (Date.now() - (wasPending ? task.queuedAt!.getTime() : task.startedAt!.getTime())) : 0) / 1000) + "s" })
@@ -2412,8 +2413,6 @@ The task was re-queued on a fallback model after a retryable failure.
     if (this.pollingInFlight) return
     this.pollingInFlight = true
     try {
-      this.pruneStaleTasksAndNotifications()
-
       let allStatuses: SessionStatusMap | undefined
       const sessionStatusMethod = this.client?.session?.status
       if (typeof sessionStatusMethod !== "function") {
@@ -2435,6 +2434,8 @@ The task was re-queued on a fallback model after a retryable failure.
         }
       }
 
+      this.pruneStaleTasksAndNotifications(allStatuses)
+
       await this.checkAndInterruptStaleTasks(allStatuses)
 
       for (const task of this.tasks.values()) {

src/features/background-agent/task-poller.test.ts

@@ -903,6 +903,42 @@ describe("pruneStaleTasksAndNotifications", () => {
     expect(pruned).toContain("stale-task")
   })
 
+  it("#given running task with stale progress and active session #when lastUpdate exceeds TTL #then should NOT prune", () => {
+    //#given
+    const tasks = new Map<string, BackgroundTask>()
+    const activeTask: BackgroundTask = {
+      id: "active-status-task",
+      sessionId: "ses-active-status",
+      parentSessionId: "parent",
+      parentMessageId: "msg",
+      description: "active status",
+      prompt: "active status",
+      agent: "oracle",
+      status: "running",
+      startedAt: new Date(Date.now() - 60 * 60 * 1000),
+      progress: {
+        toolCalls: 10,
+        lastUpdate: new Date(Date.now() - 35 * 60 * 1000),
+      },
+    }
+    tasks.set("active-status-task", activeTask)
+
+    const pruned: string[] = []
+    const notifications = new Map<string, BackgroundTask[]>()
+
+    //#when
+    pruneStaleTasksAndNotifications({
+      tasks,
+      notifications,
+      sessionStatuses: { "ses-active-status": { type: "busy" } },
+      onTaskPruned: (taskId) => pruned.push(taskId),
+    })
+
+    //#then
+    expect(pruned).toEqual([])
+    expect(tasks.has("active-status-task")).toBe(true)
+  })
+
   it("#given custom taskTtlMs #when task exceeds custom TTL #then should prune", () => {
     //#given
     const tasks = new Map<string, BackgroundTask>()

src/features/background-agent/task-poller.ts

@@ -31,6 +31,7 @@ export function pruneStaleTasksAndNotifications(args: {
   notifications: Map<string, BackgroundTask[]>
   onTaskPruned: (taskId: string, task: BackgroundTask, errorMessage: string) => void
   taskTtlMs?: number
+  sessionStatuses?: SessionStatusMap
 }): void {
   const { tasks, notifications, onTaskPruned } = args
   const effectiveTtl = args.taskTtlMs ?? TASK_TTL_MS
@@ -62,6 +63,11 @@ export function pruneStaleTasksAndNotifications(args: {
       continue
     }
 
+    const sessionStatus = task.sessionId ? args.sessionStatuses?.[task.sessionId]?.type : undefined
+    if (task.status === "running" && sessionStatus !== undefined && isActiveSessionStatus(sessionStatus)) {
+      continue
+    }
+
     const lastActivity = task.status === "running" && task.progress?.lastUpdate
       ? task.progress.lastUpdate.getTime()
       : undefined