Always true: validation passed and the turn was enqueued.
Your handle on this submission. It comes back as the stored message's
MessageResource.clientRef (NOT its id, which we assign) — match
on it to reconcile an optimistically rendered message. It is also the
idempotency key: retrying a timed-out POST with the same body will not
enqueue the turn twice.
202response ofPOST /v1/agent/messages. The turn is enqueued, not yet answered — pollGET /v1/agent/messagesfor the agent's reply (typically a few seconds; longer when the patient sent a file to read).