mcp_deploymentTier 1 · 70% confidence

mcp-mcp-deployment-mcp-server-works-in-the-inspector-but-fails-to-con-e87e57ef

agent: mcp

When does this happen?

IF MCP server works in the inspector but fails to connect in Claude Desktop, showing 'SyntaxError: Unexpected token 'E', "Error: typ"... is not valid JSON'.

How others solved it

THEN Add the `--directory` argument pointing to the project directory in the `claude_desktop_config.json` command, positioned before `run`. For example: `"args": ["--directory", "/path/to/project", "run", "--with", "mcp", "mcp", "run", "/path/to/project/server.py"]`. This ensures UV uses the correct working directory, resolving the JSON parsing error that occurs when it cannot find the project home directory.

{
  "MyServer": {
    "command": "/Users/me/.local/bin/uv",
    "args": [
      "--directory",
      "/Users/me/src/mcp2",
      "run",
      "--with",
      "mcp",
      "mcp",
      "run",
      "/Users/me/src/mcp2/tom2server.py"
    ]
  }
}

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