python-sdk

Summary When shutting down a (e.g. CTRL+C) while clients have active streaming connections, Uvicorn logs: The error occurs because the shutdown path cancels the task group without first gracefully terminating active SSE/streaming connections. Fix Before cancelling the task group in 's block, iterate through all active and call on each transport. This gives each transport a chance to close its SSE connections properly, so clients receive a proper HTTP response instead of an abrupt disconnect. Tests Added — injects a mock transport and verifies is called during shutdown. Fixes #2150

Summary Fixes #2107 ClientSession currently silently drops , , and from the server because only handles and . This makes it impossible for clients to react when a server's tool, prompt, or resource lists change dynamically. Changes 3 callback protocol types: , , — zero-argument async callables (matching the existing / pattern). Default no-op: — silently accepts the notification (backward compatible). 3 keyword-only params in — , , . 3 match cases in — dispatch to the user callback, wrapped in so a misbehaving callback never crashes the session. 3 optional fields on the dataclass — , , . Passthrough to in . 3 optional fields on . Passthrough in . (new) 5 tests: 1. — fires on 2. — fires on 3. — fires on 4. — no callback = silent (no crash) 5. — bad callback logs exception but session survives Updated mock assertion to include the 3 new keyword args. Naming All names use singular** form to match the existing codebase conventions: → → → Backward Compatibility Fully backward compatible — the new parameters are keyword-only with defaults, falling back to a no-op. Test Results

Summary Fixes #1656 calls which previously called , configuring the root logger with handlers and level. This violates Python logging best practices: It is strongly advised that you do not add any handlers other than NullHandler to your library's loggers. This is because the configuration of handlers is the prerogative of the application developer.* — Python Logging HOWTO Problem Any application using the MCP SDK that calls gets its logging configuration silently overridden: Custom log formats are replaced Log levels are changed Handlers (e.g., file handlers, structured JSON logging) are affected Unit test log capture can break Fix Replace with targeted configuration of the namespace logger only: is configured with handlers and level The root logger is left untouched Duplicate handler guards prevent stacking on repeated calls MCP SDK logs still work out of the box for quickstart scripts Test Results 475 server tests pass (2 consecutive clean runs).