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  • AgentArmor teamTeam3d agoNeeds helpSolved

    Supabase MCP server disconnects with "You must supply a command" error in Claude Desktop

    The Supabase MCP server disconnects immediately in Claude Desktop (0.9.2) on macOS 15 after configuring claude_desktop_config.json. The log shows npx printing its help text with "You must supply a command" and then "Server disconnected". I use nvm, and the npx in the log appears to come from Node v12. How do I fix this?

    Originally asked on GitHub: https://github.com/supabase/mcp/issues/49

    6 answers

    • Best answerAgentArmor teamTeam3d ago

      The thread is still open with no upstream code fix; the cause is environmental, and the workaround that succeeded is pinning the MCP server to an nvm-managed Node 22 binary in claude_desktop_config.json. The log shows Claude Desktop launching npx from an old nvm install (Node v12), and that npx exits immediately printing You must supply a command, which closes the MCP transport. A maintainer suggested checking for Node.js versions installed outside nvm (e.g. from the website) and removing nvm versions older than 22, then restarting the computer.

      On macOS, a commenter confirmed this config works (replace the paths with your nvm Node 22 path):

      json
      {
  "mcpServers": {
    "supabase": {
      "command": "/Users/<you>/.nvm/versions/node/v22.15.0/bin/npx",
      "args": [
        "-y",
        "@supabase/mcp-server-supabase@latest",
        "--access-token",
        "sbp_..."
      ],
      "env": {
        "PATH": "/Users/<you>/.nvm/versions/node/v22.15.0/bin:/usr/local/bin:/usr/bin:/bin",
        "NODE_PATH": "/Users/<you>/.nvm/versions/node/v22.15.0/lib/node_modules"
      }
    }
  }
}

      On Windows, another commenter ran it with cmd /c npx -y @supabase/mcp-server-supabase@latest, supplying the token via the SUPABASE_ACCESS_TOKEN env variable instead of the --access-token flag. A later commenter with nvm confirmed that setting the same PATH/NODE_PATH env block and switching to Node v22 did the trick.

      Did this work for you?
    • AgentArmor teamTeam3d ago

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

      Configured the Supabase server in claude_desktop_config.json to run npx with -y @supabase/mcp-server-supabase@latest and --access-token, then restarted Claude Desktop. npx failed immediately with 'You must supply a command' and the server disconnected.

      Source: https://github.com/supabase/mcp/issues/49 (opens external site)

      Did this work for you?
    • AgentArmor teamTeam3d ago

      What @nabossha tried on GitHub (Worked)

      On macOS, pointed the command at the nvm Node v22.15.0 npx binary and set PATH and NODE_PATH in the server's env block to the same Node 22 directories.

      Source: https://github.com/supabase/mcp/issues/49#issuecomment-2848134068 (opens external site)

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    • AgentArmor teamTeam3d ago

      What @Basilakis tried on GitHub (Worked)

      On Windows, ran the server via cmd /c npx -y @supabase/mcp-server-supabase@latest with SUPABASE_ACCESS_TOKEN set in the env block instead of passing --access-token.

      Source: https://github.com/supabase/mcp/issues/49#issuecomment-3094675480 (opens external site)

      Did this work for you?
    • AgentArmor teamTeam3d ago

      What @diogeneshamilton tried on GitHub (Worked)

      Used nvm, applied the same PATH/NODE_PATH env block from the earlier workaround, and switched to Node v22; this resolved the disconnect.

      Source: https://github.com/supabase/mcp/issues/49#issuecomment-3211416296 (opens external site)

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    • AgentArmor teamTeam3d ago

      What @gregnr tried on GitHub (Outcome unclear)

      A maintainer suggested verifying no Node.js was installed outside nvm (e.g. manually from the website) and removing nvm versions older than 22, then restarting the computer. The thread does not record whether the reporter tried this.

      Source: https://github.com/supabase/mcp/issues/49#issuecomment-2802223742 (opens external site)

      Did this work for you?

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