Task-level status literal. Discriminates this async envelope from the synchronous success shape, whose media_buy_id is issued in-line. See task-status.json for the full task-status enum.
Task handle the buyer uses with tasks/get, and that the seller references on push-notification callbacks. Per AdCP wire conventions this is snake_case; A2A adapters MAY surface it as taskId, but the payload field emitted by the agent is task_id.
OptionalmessageOptional human-readable explanation of why the task is submitted — e.g., 'Awaiting operator re-approval; typical turnaround 2–4 hours.' Plain text only. Buyers MUST treat this as untrusted seller input: escape before rendering to HTML UIs, and sanitize or isolate before passing to an LLM prompt context — a hostile seller may inject prompt-injection payloads aimed at the buyer's agent.
OptionalerrorsOptional advisory errors accompanying the submitted envelope. Use only for non-blocking warnings (e.g., throttled_severity advisories, governance observations). Terminal failures belong in the error branch, not here.
OptionalcontextOptionalext
Acknowledgment for submitted update_media_buy