LangChain - MCP Toolkit

The LangChainAdapter converts MCP tools into LangChain’s DynamicStructuredTool format.

Installation

npm install @mcp-ts/sdk @langchain/core zod

Usage

import { MultiSessionClient } from '@mcp-ts/sdk/server';
import { LangChainAdapter } from '@mcp-ts/sdk/adapters/langchain';

const client = new MultiSessionClient('user_123');
await client.connect();

const adapter = new LangChainAdapter(client);
const tools = await adapter.getTools();

// Use with LangChain agent
const agent = createReactAgent({
  llm,
  tools,
  // ...
});

Configuration

The LangChainAdapter supports simplified error messages, which can be useful for LLMs to better understand failures:

const adapter = new LangChainAdapter(client, {
  simplifyErrors: true  // Returns error.message instead of full error object
});

API Reference

See the LangChainAdapter API Reference for more details.