MCP Client

What is MCP Client?

MCP Client is a TypeScript implementation of a client for the Model Context Protocol (MCP) that enables language models such as OpenAI’s GPT and Anthropic’s Claude to connect to and use external MCP server tools and services. It is designed for developers who need a standardized way to give LLMs access to external tools.

How to use MCP Client?

After cloning the repository and installing dependencies (npm install), create a .env file with your API keys and LLM provider selection (OPENAI or ANTHROPIC). Configure MCP servers in mcp_config.json by specifying the command, arguments, and optional environment variables. Build the project with npm run build and run it with node build/index.js.

Key features of MCP Client

• Connects to multiple MCP servers simultaneously
• Supports both OpenAI and Anthropic language models
• Cross‑platform compatibility (Windows, macOS, Linux)
• Automatic handling of platform‑specific commands (e.g., npx.cmd)
• Configurable environment variables and server settings

Use cases of MCP Client

• Giving an LLM access to a PostgreSQL database via an MCP server
• Integrating a sequential‑thinking reasoning tool with a language model
• Running multiple external tools (filesystem, web search, etc.) for a single LLM session

FAQ from MCP Client

What prerequisites are needed to run MCP Client?

Node.js (v16+), npm or yarn, and TypeScript are required.

How do I configure which LLM to use and which MCP servers to connect to?

Set the LLM environment variable to OPENAI or ANTHROPIC and provide the corresponding API key. Define your MCP servers in a mcp_config.json file, with each server specifying a command, arguments, and optional environment variables.

Which language model providers are supported?

OpenAI (e.g., gpt-4o) and Anthropic (e.g., claude-3-5-sonnet-20241022).

Does MCP Client handle platform‑specific differences?

Yes. On Windows, npx commands are automatically adjusted to npx.cmd, and Python commands use python on Windows vs. python3 on Unix‑like systems.

Where is the MCP configuration file located by default?

It defaults to ./mcp_config.json in the project root. You can override the path with the MCP_CONFIG_PATH environment variable.