| # LangChain Docs MCP | |
| This repo uses LangChain, LangGraph, DeepAgents, and related LangChain ecosystem packages. Use current docs when changing those integration points. | |
| ## MCP server | |
| Project-local MCP configuration lives in `.mcp.json`: | |
| ```json | |
| { | |
| "mcpServers": { | |
| "langchain-docs": { | |
| "type": "http", | |
| "url": "https://docs.langchain.com/mcp" | |
| } | |
| } | |
| } | |
| ``` | |
| ## Documentation index | |
| Before exploring individual pages, fetch the complete documentation index: | |
| ```text | |
| https://docs.langchain.com/llms.txt | |
| ``` | |
| Use that index to discover the relevant LangChain, LangGraph, LangSmith, or DeepAgents page before reading deeper. | |
| ## Codex CLI fallback | |
| If the project-local `.mcp.json` is not picked up by your client, register the server manually: | |
| ```bash | |
| codex mcp add langchain-docs --url https://docs.langchain.com/mcp | |
| ``` | |
| If that command fails with `Failed to create OAuth session`, continue using the checked-in `.mcp.json` and retry the CLI registration after refreshing Codex authentication. | |