> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-docsja-1783484944-f86c4f0.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Reference

Comprehensive API reference documentation for the LangChain and LangGraph Python and TypeScript libraries.

## Reference sites

<CardGroup cols={2}>
  <Card title="LangChain" icon="https://mintcdn.com/langchain-5e9cc07a-preview-docsja-1783484944-f86c4f0/nnKgmAH8bHPkB-un/images/brand/langchain-icon.png?fit=max&auto=format&n=nnKgmAH8bHPkB-un&q=85&s=a94a54e5f03f350f4fc41c8b5b4bda74" href="https://reference.langchain.com/javascript/langchain" width="195" height="195" data-path="images/brand/langchain-icon.png">
    Complete API reference for LangChain JavaScript/TypeScript, including chat models, tools, agents, and more.
  </Card>

  <Card title="LangGraph" icon="https://mintcdn.com/langchain-5e9cc07a-preview-docsja-1783484944-f86c4f0/nnKgmAH8bHPkB-un/images/brand/langgraph-icon.png?fit=max&auto=format&n=nnKgmAH8bHPkB-un&q=85&s=8f107a7d6da5c34146d5733de512f6b1" href="https://reference.langchain.com/javascript/langchain-langgraph" width="195" height="195" data-path="images/brand/langgraph-icon.png">
    Complete API reference for LangGraph JavaScript/TypeScript, including graph APIs, state management, checkpointing, and more.
  </Card>

  <Card title="Deep Agents" icon="https://mintcdn.com/langchain-5e9cc07a-preview-docsja-1783484944-f86c4f0/nnKgmAH8bHPkB-un/images/brand/deep-agents-icon.png?fit=max&auto=format&n=nnKgmAH8bHPkB-un&q=85&s=738db7eff8faac0cec81c7b2a0da33cb" href="https://reference.langchain.com/javascript/deepagents" width="195" height="195" data-path="images/brand/deep-agents-icon.png">
    Build agents that can plan, use subagents, and leverage file systems for complex tasks
  </Card>

  <Card title="MCP Adapter" icon="plug" href="https://reference.langchain.com/javascript/langchain-mcp-adapters">
    Use Model Context Protocol (MCP) tools within LangChain and LangGraph applications.
  </Card>

  <Card title="Deep Agents" icon="https://mintcdn.com/langchain-5e9cc07a-preview-docsja-1783484944-f86c4f0/nnKgmAH8bHPkB-un/images/brand/deep-agents-icon.png?fit=max&auto=format&n=nnKgmAH8bHPkB-un&q=85&s=738db7eff8faac0cec81c7b2a0da33cb" href="https://reference.langchain.com/javascript/deepagents" width="195" height="195" data-path="images/brand/deep-agents-icon.png">
    Build agents that can plan, use subagents, and leverage file systems for complex tasks.
  </Card>
</CardGroup>

***

<div className="source-links">
  <Callout icon="terminal-2">
    [Connect these docs](/use-these-docs) to Claude, VSCode, and more via MCP for real-time answers.
  </Callout>

  <Callout icon="edit">
    [Edit this page on GitHub](https://github.com/langchain-ai/docs/edit/main/src/oss/reference/overview.mdx) or [file an issue](https://github.com/langchain-ai/docs/issues/new/choose).
  </Callout>
</div>