> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mcp-assistant.in/llms.txt
> Use this file to discover all available pages before exploring further.

# LangChain

> Use LangChainAdapter to convert MCP tools into DynamicStructuredTool instances for LangChain agents, with optional simplified error messages for LLMs.

The `LangChainAdapter` converts MCP tools into LangChain's `DynamicStructuredTool` format.

## Installation

```bash theme={null}
npm install @mcp-ts/sdk @langchain/core zod
```

## Usage

```typescript theme={null}
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:

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

## API Reference

See the [LangChainAdapter API Reference](/reference/server#adapters) for more details.