The operation and receipt now commit before the queue send. A Postgres 23505 on operations_agent_id_seq_no_key is answered with 400 PREV_HASH_MISMATCH carrying the stored chain hash so hook retries can resync. A failed enqueue after the commit is logged as operation.enqueue_failed and the receipt is still returned. Every producer now names its message: MessageQueue.send takes the durable message id, and the BullMQ adapter passes it as the job id, so the receipt's queue_message_id is the real queue identifier. Claude-Session: https://claude.ai/code/session_01QoUjdc7HGKTsgj5GhG8HvF