Tool execution failures now provide more specific error messages distinguishing between different failure types:
tool input error:for input validation failurestool validation error:for custom validation failurestool permission deniedfor rejected tool callstool error (Nms):for runtime errors with execution timing
Evidence
Tool error messages (search for "tool input error" and "tool validation error")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.