> ## Documentation Index
> Fetch the complete documentation index at: https://docs.langchain.com/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="Deep Agents" icon="https://mintcdn.com/langchain-5e9cc07a/nQm-sjd_MByLhgeW/images/brand/deep-agents-icon.png?fit=max&auto=format&n=nQm-sjd_MByLhgeW&q=85&s=1cc68f66a9e7550331cc0875f1ba53af" href="https://reference.langchain.com/python/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="LangChain" icon="https://mintcdn.com/langchain-5e9cc07a/nQm-sjd_MByLhgeW/images/brand/langchain-icon.png?fit=max&auto=format&n=nQm-sjd_MByLhgeW&q=85&s=663b30f85baf99ad708b97e05da2a5a4" href="https://reference.langchain.com/python/langchain" width="195" height="195" data-path="images/brand/langchain-icon.png">
    Complete API reference for LangChain Python, including chat models, tools, agents, and more.
  </Card>

  <Card title="LangGraph" icon="https://mintcdn.com/langchain-5e9cc07a/nQm-sjd_MByLhgeW/images/brand/langgraph-icon.png?fit=max&auto=format&n=nQm-sjd_MByLhgeW&q=85&s=b997e1a7487d507a36556eedbfd99f81" href="https://reference.langchain.com/python/langgraph" width="195" height="195" data-path="images/brand/langgraph-icon.png">
    Complete API reference for LangGraph Python, including graph APIs, state management, checkpointing, and more.
  </Card>

  <Card title="LangChain Integrations" icon="plug" href="https://reference.langchain.com/python/integrations/overview">
    LangChain packages to connect with popular LLM providers, vector stores, tools, and other services.
  </Card>

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