Cancel a journey run
Accepts a durable Stop request and returns immediately. cleanupPending indicates that attempts are being settled in the background; status remains the current stored run status. IDEMPOTENT: cancelling an already-cancelled run answers 200 with alreadyCanceled: true and finalized: 0, not a 409.
Addressed entirely by the path runId — there is no body.
Deliberately NOT behind the beta gate: cancelling REDUCES exposure and spend, so an organization that loses the flag can still stop a run that is under way.
Authorizations
MCPJam API key (sk_…). Create one at Settings → API keys. Guest sessions cannot use the API, and API keys cannot manage other API keys.
Path Parameters
ID of the hosted project that contains the server.
Eval run ID, as returned by POST /eval-runs.
Response
Stop accepted (or already requested); cleanup may still be pending.
Current run status; may still be running while cleanup is pending.
true True when the run was already cancelled and this call did nothing.
Attempts this call moved to terminal. Zero on an idempotent replay.
Stop accepted; background cleanup is pending. Absent means false on older servers.

