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Title: Fixes to stdio_client to support Windows more robustly by saqadri · Pull Request #372 · modelcontextprotocol/python-sdk · GitHub

Open Graph Title: Fixes to stdio_client to support Windows more robustly by saqadri · Pull Request #372 · modelcontextprotocol/python-sdk

X Title: Fixes to stdio_client to support Windows more robustly by saqadri · Pull Request #372 · modelcontextprotocol/python-sdk

Description: This change should fix most cases of #359, with issues spawning stdio MCP servers on Windows. Motivation and Context There is a somewhat longstanding issue with stdio_cleint that it doesn't work on Windows. Example: Servers running with "npx" have problems because of the way "npx" command is handled in Windows (it is typically stored as a ps1 script): mcp: servers: todoist: command: "npx" args: [ "@abhiz123/todoist-mcp-server", "-y"] brave-search: command: "npx" args: ["@modelcontextprotocol/server-brave-search", "-y"] fetch: command: "uvx" args: ["mcp-server-fetch"] Replacing "npx" with "npx.cmd" usually mitigates this, but that makes the command platform-specific. This change adds some of that handling in the stdio_client itself, and adds helpers for processing the command and spawning a process in platform-specific ways. How Has This Been Tested? Tested on Windows VM in Azure using all mcp-agent examples. All of them use stdio_client, and all of them now work. Note: for using with streamlit, I had to add an additional change which I didn't add to this PR, since it may not belong to the SDK: asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy()) In addition: All tests pass some pyright failures in repo, but unrelated to this change Breaking Changes None Types of changes Bug fix (non-breaking change which fixes an issue) New feature (non-breaking change which adds functionality) Breaking change (fix or feature that would cause existing functionality to change) Documentation update Checklist I have read the MCP Documentation My code follows the repository's style guidelines New and existing tests pass locally I have added appropriate error handling I have added or updated documentation as needed Additional context Open to feedback on how to make this more elegant.

Open Graph Description: This change should fix most cases of #359, with issues spawning stdio MCP servers on Windows. Motivation and Context There is a somewhat longstanding issue with stdio_cleint that it doesn't wor...

X Description: This change should fix most cases of #359, with issues spawning stdio MCP servers on Windows. Motivation and Context There is a somewhat longstanding issue with stdio_cleint that it doesn't...

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a78d7fc Fixes to stdio_client to support Windows more robustly saqadri Mar 26, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/a78d7fce4f7b1fbc2baf1e896cfbd7756c190709
3b974aa subprocess.PIPE -> sys.stderr for errlog saqadri Mar 26, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/3b974aa09282ae0143bd183a26fa6083caf1057f
c289efa Minor update to docstring saqadri Mar 26, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/c289efaba8b9d5d2c5746d767a844dac8fa481eb
725dc61 PR fixes saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/725dc61f5087e6608797c5f04d7eb0267a5cd58d
627704a Address PR comments saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/627704ab85b8d0d6285945a807d4d47796ba05cb
8918b67 Merge branch 'modelcontextprotocol:main' into main saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/8918b67925b66ff0ab4288fde72bd8372e6fb2c6
c712f04 Undo uv.lock update saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/c712f04bbfd066e1342fc5d4fe4b6859dd823423
03b5266 Move process termination to win32.py as well saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/03b526616549241684e5e1d6ae90d3aad0677278
9720d99 Add missing await saqadri Mar 27, 2025 https://github.com/modelcontextprotocol/python-sdk/pull/372/commits/9720d992eec8934787ee27cc672e73c666c4410d
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