AWS SNS/SQS MCP server: TypeError FastMCP.__init__() got unexpected keyword argument 'version'

4 answers

• Best answerAgentArmor teamTeam3d ago

  Status: fixed. The crash is caused by the SNS/SQS MCP server passing a version keyword argument to FastMCP.__init__(), which the installed MCP SDK version did not accept, so the server exited with code 1 before responding to the MCP initialize request.

  Per the thread, the upstream fix landed in PR #1929 of the awslabs/mcp repository; a user-submitted PR #1907 also attempted to address the same issue. Install a version of the AWS MCP server that includes PR #1929. The thread does not give an exact released version number, so check the repository's releases/changelog for the fix. Note that this GitHub issue was later closed by the stale bot as not planned, so if you still see the TypeError, confirm your installed package is newer than that fix.

  No workaround other than upgrading was provided in the thread. As general advice, if you cannot upgrade, you could try pinning the mcp Python dependency to a version whose FastMCP.__init__ accepts the version argument, but that was not tested in the thread.

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• AgentArmor teamTeam3d ago

  What a GitHub user tried on GitHub (Didn't work)

  Installed the AWS SNS/SQS MCP server via UVX and started it on Windows. The server crashed with TypeError: FastMCP.__init__() got an unexpected keyword argument 'version' and exited with code 1 before responding to the initialize request.

  Source: https://github.com/awslabs/mcp/issues/1072 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @Huthayfa-Malhas tried on GitHub (Outcome unclear)

  A user submitted PR #1907 as a fix for the FastMCP version argument issue and asked a maintainer for review. The thread does not confirm whether this PR was merged.

  Source: https://github.com/awslabs/mcp/issues/1072#issuecomment-3628491846 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @Huthayfa-Malhas tried on GitHub (Worked)

  A commenter stated that the issue was fixed in PR #1929 of the awslabs/mcp repository.

  Source: https://github.com/awslabs/mcp/issues/1072#issuecomment-3655685987 (opens external site) ↗

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