You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
AgentsArea: what it touches
ImprovementsKind: in v2.1.307,
ImprovementsSection of the release
What
Programs that control Claude Code, such as apps built with the Agent SDK, can ask it to switch to a different model. The reply to that request used to say only that it succeeded. It now also includes the model that is in use. When the request fails, the error also includes the model.
The error shown when an earlier switch is still in progress has new wording. It now says that an earlier model change, a check with the API or a PreModelSwitch hook has not finished. A PreModelSwitch hook is a command you configure to run before a model switch is applied.
Why
A program can now see which model Claude Code actually ended up using, instead of assuming its request was applied as asked.
