README.md

🔌 MCP Client Configuration

This document details the configuration for the built-in MCP client. For a broader overview of the src directory and the client-server architecture, please see the Source Code Overview.

The client's behavior is managed via the mcp-config.json file located in this directory.

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mcp-config.json

The primary configuration file for the MCP client is src/mcp-client/client-config/mcp-config.json. If this file is missing, the application will throw a startup error. An example configuration can be found in mcp-config.json.example.

This file defines the external MCP servers that the client can connect to and interact with. The client implementation strictly adheres to the MCP 2025-03-26 specification.

Example mcp-config.json:

For the complete example and all available options, please refer to src/mcp-client/client-config/mcp-config.json.example. A snippet is shown below:

{
  "mcpServers": {
    "my-stdio-server": {
      "command": "node",
      "args": ["/path/to/my-server/index.js"],
      "env": {
        "LOG_LEVEL": "debug"
      },
      "transportType": "stdio"
    },
    "my-http-server": {
      "command": "http://localhost:8080",
      "args": [],
      "env": {},
      "transportType": "http"
    }
  }
}

Key Configuration Fields:

• command:
  • For stdio transport: The executable or command to run the server (e.g., node, python).
  • For http transport: The base URL of the MCP server (e.g., http://localhost:8080).
• args:
  • An array of string arguments to pass to the command when using stdio transport. This is required for stdio.
  • Not used for http transport.
• env:
  • An optional object defining environment variables to set for the server process.
  • Primarily used with stdio transport.
• transportType:
  • Specifies the communication protocol.
  • "stdio" (default if omitted): For servers communicating over standard input/output.
  • "http": For servers communicating over HTTP/HTTPS.

Schema and Validation:

The structure and validation rules for mcp-config.json are defined using Zod in src/mcp-client/client-config/configLoader.ts. This ensures that the configuration is correctly formatted and contains all necessary information before the client attempts to establish connections.

For a comprehensive example demonstrating all features and a detailed structure, please consult the src/mcp-client/client-config/mcp-config.json.example file.