langchaingo-mcp-adapters

LangchainGo MCP Adapters

This library provides a lightweight wrapper that makes Model Context Protocol (MCP) tools compatible with LangchainGo.

Features

• 🛠️ Convert MCP tools into LangchainGo tools that can be used with LangchainGo agents.
• 📦 A client implementation (MultiServerMCPClient) that allows you to connect to multiple MCP servers (via stdio or SSE) and load tools from them.

References: The MCP adapters of Python implementation and TypeScript implementation.

Installation

go get github.com/akihiro-fukuchi/langchaingo-mcp-adapters

You will also need to install the underlying MCP Go SDK and LangchainGo:

go get github.com/mark3labs/mcp-go
go get github.com/tmc/langchaingo

Quickstart

Here is a simple example of using MCP tools with a LangchainGo agent.

Server

First, let's build an example MCP server that can add and multiply numbers.

Build the server: go build -o math-server examples/math-server/main.go

Client

Now, use the MultiServerMCPClient to connect to the server and use its tools with a LangchainGo agent.

Run the client: go run examples/agent/main.go

Note: OPENAI_API_KEY is required to run the agent. It is expect to be set as an environment variable.

Multiple MCP Servers

The MultiServerMCPClient is designed to handle connections to multiple servers simultaneously. Simply add more entries to the connections map during initialization, specifying either StdioConnection or SSEConnection for each server.

	// Example with Math (stdio) and Weather (sse) servers
	connections := map[string]mcpclient.ConnectionConfig{
		"math": mcpclient.StdioConnection{
			Transport: "stdio",
			Command:   "/path/to/your/go/math-server", // Absolute path
			Args:      []string{},
		},
		"weather": mcpclient.SSEConnection{
			Transport: "sse",
			URL:       "http://localhost:8081/sse", // URL of your Go weather server SSE endpoint
		},
	}

	client := mcpclient.NewMultiServerMCPClient(connections, mcp.Implementation{}, mcp.ClientCapabilities{})
	// ... start client, get tools, run agent ...

The client.GetTools() method will return a combined list of tools from all successfully connected and initialized servers.