You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
Tool SearchArea: what it touches
ImprovementsKind: in v2.1.323,
ImprovementsSection of the release
What
Some tools are deferred: Claude Code lists them, but the model does not get their full description of required inputs until it looks them up. Claude Code now checks a call to such a tool for missing required arguments before it asks you for permission. If any are missing, the tool does not run. The model gets an InputValidationError with the text "Missing required arguments", telling it to call the tool again with all of them.
Why
It saves a wasted step when the model calls a tool whose details it never loaded, and you are not asked to approve a call that would fail anyway.
