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Freeze a session: stop anything still running in it and make it read-only, while preserving all of its contents. A closed session can be returned to service with Reopen Session.

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POST /revisions/:id/data/command (Command: close_session)

Requires the write role on the blob.

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Request Body

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Response

The command returns as soon as the session is marked closing. Writes are rejected from that moment on, but the close itself completes in the background — see Asynchronous behavior.

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Errors

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Example

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Asynchronous behavior

Closing happens in two stages:
  1. Immediately — the session becomes closing and every mutating operation on it, including create_execution, starts returning 409 session_not_open.
  2. In the background — every execution still running in the session is stopped and awaited. Once they are all terminal, the session becomes closed and session_closed is emitted.
Do not assume the session is closed when the command returns. Wait for the session_closed event or poll Get Session. With executions to stop this typically takes tens of seconds; with nothing running it is near-immediate.
Executions stopped this way end with status stopped and do not emit execution_ended — that event is reserved for executions that complete on their own.
Reads are unaffected in every stage: a closed session’s objects, threads, graphs and execution history all remain fully readable. See Session Lifecycle for the complete model.