Originating integration platform. Do not set this for known integrations (e.g. slack, pumble) — those must trigger runs via their platform webhook, not this endpoint directly.
Returns 400 with "Deliverables are disabled for this agent" if the agent’s config doesn’t enable deliverables. Returns 400 with "Integration mentions must use the platform webhook" if metadata.source is a recognized integration.
For long-running tasks, poll GET .../runs/{runId} every few seconds until status is completed or failed, then read artifacts. To cancel a run in progress, see Cancel Run.