You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.323,
ImprovementsSection of the release
What
MCP servers are outside programs that give Claude Code extra tools. What a server offers can change from one message to the next. Claude Code now has a notice telling the model which tools their server is not offering at the moment.
Those tools stay in the model's list of tools, but calling them will fail. The notice tells the model not to call them until it is told they are available again.
Why
The model should stop calling tools that would only fail, which saves wasted attempts and confusing errors.
