Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Tool ValidationArea: what it touches
Internal ChangesKind: in v2.1.277,
Internal ChangesSection of the release
What
Tool result handling now checks for a detached flag; when set, it shows a distinct message and stops early, sometimes reporting 'Execution stopped by hook' if a hook triggered it. Separately, when a PostToolUse hook's updatedToolOutput (a hook's replacement for a tool's result) fails validation or mapping, the error message now includes a machine-readable reason code — schema_invalid issues=..., mapper_undefined, or mapper_throw — alongside the existing human-readable message.
Why
The reason codes make it easier to diagnose exactly why a hook's tool-output rewrite was rejected, rather than only seeing a generic failure message. The detached path gives tool execution a distinct, clearly-labeled way to stop when a hook halts it.
