Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
MCPArea: what it touches
Internal ChangesKind: in v2.1.311,
Internal ChangesSection of the release
What
MCP servers are outside tools Claude Code connects to, and each describes the tools it offers. Claude Code used to run a check on every tool's description. It now first looks for x-mcp-header, an extension, anywhere in the server's tool list. If it is not there, the check is skipped.
Why
Most MCP servers don't use that extension, so they no longer go through work that was not needed.
