You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.271,
ImprovementsSection of the release
What
claude mcp serve now advertises a listChanged tools capability and sends a tools/list_changed notification whenever the visible set of tools changes (for example after a policy-verdict refresh), using a new debounced watcher.
Tool call handling now reads the progress token (_meta/sendNotification) from the incoming request and opens a progress-tracking resource for the duration of the call.
While a long-running tool call executes, the server sends periodic notifications/progress messages ("Running for Ns") on an interval, using that progress token.
Why
MCP clients connected to Claude Code's built-in server can now stay in sync when the available tools change, and can show live progress instead of appearing stuck during slow tool calls.
