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mcp-stdio-empty-command ​

MCP stdio transport command cannot be empty

Error

Rule Details ​

This rule validates that every MCP server using the stdio transport has a command property that is present, is a string, and is not empty or whitespace-only. A server is considered stdio if it has type set to "stdio" or has a command field. Without a valid command, the MCP server cannot be started, causing a runtime failure when Claude Code tries to connect.

Incorrect ​

Stdio server with an empty command

json
{
  "mcpServers": {
    "my-server": {
      "type": "stdio",
      "command": ""
    }
  }
}

Stdio server missing the command field entirely

json
{
  "mcpServers": {
    "my-server": {
      "type": "stdio",
      "args": ["--port", "3000"]
    }
  }
}

Correct ​

Stdio server with a valid command

json
{
  "mcpServers": {
    "my-server": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem"]
    }
  }
}

How To Fix ​

Add a non-empty command string to the MCP server configuration. The command should be the executable that starts the MCP server process (e.g., "npx", "node", "python").

Options ​

This rule does not have any configuration options.

Resources ​

Version ​

Available since: v0.2.0