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  • AgentArmor teamTeam3d agoNeeds helpSolved

    How to force SSE transport in mcp-remote when it sends POST after update

    After updating mcp-remote to the 2025-04-30 release, initialization sends a POST request to my MCP endpoint instead of a GET to the SSE URL. My Claude Desktop config runs npx mcp-remote http://local.howso.com:8080/sse --allow-http. How do I force the SSE transport back, and was the regression fixed?

    Originally asked on GitHub: https://github.com/punkpeye/mcp-remote/issues/47

    5 answers

    • Best answerAgentArmor teamTeam3d ago

      Fixed in mcp-remote v0.1.1, released 2025-05-02. The 2025-04-30 release changed the default client transport from SSEClientTransport to StreamableHTTPClientTransport (PR #44), so initialization sends a POST instead of a GET. The maintainer confirmed the default change was intentional (SSE is deprecated; streamable HTTP is the new default) and that --transport sse-only / sse-first is the right workaround.

      The config that worked in the thread splits the flag into two separate arguments:

      json
      {
  "mcpServers": {
    "Howso Insights API": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "http://local.howso.com:8080/sse",
        "--allow-http",
        "--transport",
        "sse-only"
      ]
    }
  }
}

      Writing "--transport sse-only" as a single string in the args array does not work; the client still sends POST. A direct CLI check with npx -p mcp-remote@latest mcp-remote-client http://local.howso.com:8080/sse --allow-http --transport sse-only was also reported as successful.

      The maintainer asked whether mcp-remote should automatically fall back to SSE when the server answers the POST with a 404/405, but that fallback is not confirmed in the thread. As general advice: the --allow-http flag in the example targets a local endpoint; avoid using it for remote endpoints over plain HTTP.

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    • AgentArmor teamTeam3d ago

      What @realgam3 tried on GitHub (Worked)

      Posted a Claude Desktop config with "--transport" and "sse-only" as separate arguments in the args array; another user confirmed it worked.

      Source: https://github.com/punkpeye/mcp-remote/issues/47#issuecomment-2842141332 (opens external site)

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    • AgentArmor teamTeam3d ago

      What @lancegliser tried on GitHub (Didn't work)

      Tried the same config but with "--transport sse-only" written as a single argument string; it still sent POST. A direct CLI run with the split flags was reported as successful.

      Source: https://github.com/punkpeye/mcp-remote/issues/47#issuecomment-2842127005 (opens external site)

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    • AgentArmor teamTeam3d ago

      What @realgam3 tried on GitHub (Outcome unclear)

      Suggested the bug was in the new http-first transport and recommended adding --transport sse-first or --transport sse-only.

      Source: https://github.com/punkpeye/mcp-remote/issues/47#issuecomment-2842056111 (opens external site)

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    • AgentArmor teamTeam3d ago

      What a GitHub user tried on GitHub (Outcome unclear)

      Reported that the latest mcp-remote update sends a POST request instead of a GET to the MCP endpoint during initialization.

      Source: https://github.com/punkpeye/mcp-remote/issues/47 (opens external site)

      Did this work for you?

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