You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
Tool CallsArea: what it touches
ImprovementsKind: in v2.1.323,
ImprovementsSection of the release
What
When Claude uses a tool, it sends the tool its input as JSON, a structured text format. When that input cannot be read, the error message now lists common causes:
Unescaped backslashes in file paths
Control characters in the text
Output that was cut off before it finished
Why
The more specific message gives the model a better chance to spot what went wrong and send a corrected tool call.
