fix: move logging configuration from MCPServer.__init__ to run()#2285
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omar-y-abdi wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
fix: move logging configuration from MCPServer.__init__ to run()#2285omar-y-abdi wants to merge 1 commit intomodelcontextprotocol:mainfrom
omar-y-abdi wants to merge 1 commit intomodelcontextprotocol:mainfrom
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MCPServer.__init__() called configure_logging() which invokes logging.basicConfig(), configuring the root logger with handlers and level on every instantiation. This violates Python's logging best practice for libraries: library code must never configure logging — only application entrypoints should. Move configure_logging() to run(), which is the actual application entrypoint. MCPServer used as a library no longer has logging side effects. Github-Issue: modelcontextprotocol#1656 Reported-by: SimonZehetner
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Problem
MCPServer.__init__()callsconfigure_logging()which invokeslogging.basicConfig()— configuring the root logger with handlers and a level on every instantiation. Per Python's logging documentation:Any application that imports and instantiates
MCPServergets its logging configuration silently overwritten.Fix
Move the single
configure_logging(self.settings.log_level)call from__init__torun(). This is the actual application entrypoint — the method users call when they want to start the server as a standalone process.MCPServer("test")(library usage) — zero logging side effectsmcp.run()(standalone entrypoint) — configures logging before startingChanges
src/mcp/server/mcpserver/server.py— moved 1 call (3 lines removed, 2 added)tests/server/mcpserver/test_server.py— regression test verifying__init__does not callconfigure_loggingFull test suite passes with 100% coverage.
Closes #1656