langchain-mcp-connect 2.0.1

Model context protocol connector for LangChain

Langchain Model Context Protocol Connector

Introduction

This project introduces tools to easily integrate Anthropic Model Context Protocol(MCP) with langchain. It provides a simple way to connect to MCP servers and access tools that can be made available to LangChain.

MCP integrations with langchain expands the capabilities of LLM by providing access to an ecosystem of community build servers and additional resources. This means that we do not need to create custom tools for each LLM, but rather use the same tools across different LLMs.

What is the Model Context Protocol (MCP)?

The Model Context Protocol (MCP) is an open-source standard released by Anthropic. The Model Context Protocol highlights the importance of tooling standardisation through open protocols. Specifically, it standardises how applications interact and provide context to LLMs. Just like how HTTP standardises how we communicate across the internet, MCP provides a standard protocol for LLM to interact with external tools. You can find out more about the MCP at https://github.com/modelcontextprotocol and https://modelcontextprotocol.io/introduction.

Example usage

The langchain_mcp_connect contain key methods to determine available tools and resources in the model context protocol. The schemas of input arguments for tools and resources are injected into the system prompt and form part of the initial prompt. Before starting, please ensure you meet the pre-requisites.

For a detail example on how langchain_mcp_connect can be used, see this demo project.

Pre requisites

1. Install uv

Defining a tool

Define your tool within claude_mcp_config.json file in the root directory. For a list of available tools and how to confiure tools see here.

{
  "mcpServers": {
    "git": {
      "command": "uvx",
      "args": ["mcp-server-git", "--repository", "./"]
    },
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "./"
      ]
    },
    "github": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-github"
      ],
      "env": {
        "GITHUB_PERSONAL_ACCESS_TOKEN": "ENV_GITHUB_PERSONAL_ACCESS_TOKEN"
      }
    }
  }
}

Environment Variables

Managing secrets is a key aspect of any project. The langchain_mcp_connect tool is able to inject secrets from the current environment. To do so, prefix the name of your environment variable with ENV_ in claude_mcp_config.json to inject envrionment variables into the current context. In the example above, ensure you have defined GITHUB_PERSONAL_ACCESS_TOKEN in your current environment with:

export GITHUB_PERSONAL_ACCESS_TOKEN="<YOUR_TOKEN_HERE>"
export OPENAI_API_KEY="<YOUR_KEY_HERE>"

Running the example

uv run src/example/agent.py