Missing task_send_sent_event prevents queue wait time visibility

Without task_send_sent_event=True in configuration, Celery does not emit events when tasks are sent to the queue. This prevents measuring queue wait time—the duration between task submission and worker pickup—which is the best early indicator of capacity problems and worker saturation.

Enable task_send_sent_event=True in Celery configuration alongside worker_send_task_events=True and task_track_started=True. Monitor celery_task_queue_time_seconds metric in Prometheus. Set alerts for increasing queue wait times to detect capacity problems before they cause outages.