Interrupt the targeted turn only

Asks the worker to stop turn target_turn_id while it runs; the session's admission state and its other turns are left alone. The event stream shows a status event with phase interrupting when the worker takes the request and engine_stopped when the engine has stopped the turn; the turn reads interrupted once its checkpoint commits. If the turn has not ended 60 seconds after acceptance, its execution is killed.

Accepted while the turn runs: the receipt settles when the turn ends, with a result of {turn_id, terminal, no_op}. A new request for a turn that has already ended answers receipt_status: succeeded at once, and its receipt says no_op: true with the terminal the turn reached on its own: the interrupt did nothing. An interrupt accepted while the turn ran is no_op: true too when the turn got to another terminal first; when the turn's outcome is unknown, so is the receipt (status: unknown, no_op: false). A replayed Idempotency-Key answers the receipt's current status instead.

Scope: sessions:control (API key or cookie session). Idempotency-Key: required.