You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.292,
ImprovementsSection of the release
What
MCP (Model Context Protocol) servers are outside programs that give Claude extra tools. The API that Claude Code talks to puts a limit on how long a tool's name can be. If a server offers a tool whose name is longer than that limit, Claude Code now leaves the tool out and does not send it to Claude. It writes a warning to that server's log saying the tool is not sent to Claude because of its name. It also records internally that the server is running with a problem, giving a name that is too long as the reason.
Why
This prevents API errors caused by long MCP tool names. The cost is that such a tool simply does not appear for Claude. If a tool from one of your servers seems to be missing, check that server's log for this warning.
