Add a user message

POST 
/api/v1/sessions/:session_id/messages

Saves a user message to the session. When autoGenerate is enabled on the session and no generation is currently in progress, generation is triggered automatically and the response mirrors GenerateSessionResponse. Otherwise returns the saved user message.

Request

Responses

200

Duplicate request — original message returned (idempotency_key matched)

201

User message saved

401

Authentication required

403

Insufficient permissions

404

Not found

429

QUOTA_EXCEEDED: the session auto-generates and an enforce-mode generation quota is exhausted. error.meta carries quota_id, metric, limit, window and resets_at, with a Retry-After header. The message is saved. A session with message_delay_seconds answers 201 before the quota is read.