Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Cloud SessionsArea: what it touches
Internal ChangesKind: in v2.1.299,
Internal ChangesSection of the release
What
Claude Code checks a turn that is handed over to it from a server before using it. A repeated assistant message ID is now allowed in one case only: in the next assistant message, when that message contains nothing but tool calls (requests to run tools) and only tool results come between. Any other repeat is rejected with the error message_id_repeats. Before, any repeat or already-seen message was rejected with a single error.
The description of safety check results now says that, for a repeated message ID, only a verdict that flags the call is used.
Why
This affects turns that a server hands over to Claude Code to continue.
