You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
ToolsArea: what it touches
Bug FixesKind: in v2.1.281,
Bug FixesSection of the release
What
The repair of malformed responses now also covers tool names that are too long. When a request to use a tool (a tool_use block) names a tool with more than 200 characters, the name is cut to its first 200 characters. That shortened name is used to find the tool and is kept in the returned block. A warning is logged, and tengu_content_block_healed is reported with the action name_truncated.
The same limit is applied when saved conversation history is cleaned up:
dropApiInvalidAssistantBlocks shortens overlong names in the transcript to the API's limit and reports a tool_name_truncated outcome.
History cleanup counts shortened names in a new truncated tally, and a helper reports overlongToolNames alongside foreignBlocks.
Why
The Anthropic API rejects tool names over 200 characters in requests, so one overlong name in the history could otherwise stop the conversation from being sent again.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeImproved screen-reader output in /mcp: a disabled server is read as "off" instead of "pending"
