Webhooks

C2AI2X phase 1 does not publish a separate protocol-specific webhook contract.

That means:

• the current external integration mode is request and response
• async callers must use stream_url, query_url, and cancel_url from the 202 response
• callers should not assume a partner callback webhook exists today

Current async follow-up

When execution_mode = "async":

1. the platform returns 202 Accepted
2. the response includes workflow_id
3. the caller continues through the returned platform URLs

The public follow-up surface still belongs to platform workflow APIs, not to a standalone protocol webhook surface.

Future rule

If a protocol-specific webhook is added later:

• zhen-platform-core must define the runtime contract
• this docs set should publish the external explanation
• zhen-brain-core must not become the direct public webhook ingress