Agent Sessions Not Cleaned Up When Tasks Are Deleted

[DanielVisca]

Issue: Agent Sessions Not Cleaned Up When Tasks Are Deleted

Problem

Resource Leak: When a user deletes a task, the associated agent session remains active, causing:

• Cloud sessions: Polling continues forever fetching from deleted task's S3 URLs
• Local sessions: tRPC subscriptions stay active, agent processes keep running
• Memory leaks: Session objects accumulate in session store
• Performance degradation over time

Root Cause

Missing cleanup in task deletion flow:

// Current flow in useDeleteTask() - BROKEN
return client.deleteTask(taskId);  // ✅ Deletes task
// ❌ MISSING: Clean up associated sessions

Tasks and sessions have 1-to-many relationship but only 1-way cleanup.

Fix Location

File: apps/twig/src/renderer/features/tasks/hooks/useTasks.ts
Function: useDeleteTask() → mutation.onMutate

Exact Fix

Add session cleanup in the onMutate callback:

export function useDeleteTask() {
  const queryClient = useQueryClient();
  const { view, navigateToTaskInput } = useNavigationStore();
  const unpinTask = usePinnedTasksStore((state) => state.unpin);
  const sessions = useSessions();                    // ✅ Hook at top level
  const sessionActions = useSessionActions();        // ✅ Hook at top level

  const mutation = useAuthenticatedMutation(
    async (client, taskId: string) => {
      // ... existing workspace cleanup ...
      return client.deleteTask(taskId);
    },
    {
      onMutate: async (taskId) => {
        // ✅ NEW: Clean up session resources when task is deleted
        const activeSession = Object.values(sessions).find((s) => s.taskId === taskId);
        if (activeSession) {
          log.info("Cleaning up session during task deletion", { 
            taskRunId: activeSession.taskRunId, 
            taskId 
          });
          
          // ✅ This handles both cloud and local sessions
          await sessionActions.disconnectFromTask(taskId);
        }
        
        // ... existing optimistic update logic ...
      },
    },
  );
}

Why This Fix Works

1. disconnectFromTask() properly handles:

   • Cloud sessions: Stops polling intervals via stopCloudPolling()
   • Local sessions: Cancels agent via agent.cancel.mutate() + unsubscribes

2. Timing: Runs in onMutate before API call, ensuring cleanup even if API fails

3. Scope: Uses taskId to find all sessions for that task (handles 1-to-many)

Validation Steps

Before Fix (Reproduce Issue):

1. Create task + start agent session
2. Add debug log to startCloudPolling(): console.log('🔄 POLLING:', taskRunId)
3. Delete task
4. Observe: Polling continues forever

After Fix (Verify Fix):

1. Repeat same steps
2. Delete task
3. Observe: Polling stops immediately, no more console messages

Impact

• Lines changed: ~10 lines
• Risk: Low (only adds cleanup, no breaking changes)
• Benefit: High (fixes resource leaks, improves performance)

[DanielVisca]

I dont have access to cloud version of this, I had to create a workaround to test. So please validate this issue (infinite polling) is valid