Swarm runs
Cancel a journey run
Stops a run and settles its in-flight attempts. 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.
post/projects/{projectId}/journey-runs/{runId}/cancel
Response
The run was cancelled (or already was).