LangGraph Docs MCP Server provides transparent, user-controlled access to llms.txt documentation indexes for LangGraph, LangChain, and other supported libraries. Instead of relying on opaque built-in tools within IDEs, developers can audit every tool call and the exact context retrieved. Key capabilities: - Fetch_docs tool reads URLs from user-defined llms.txt files - Pre-configured support for LangGraph (Python and JS) and LangChain (Python and JS) documentation - Security controls with strict domain access restrictions based on configured llms.txt sources - Full auditability of documentation retrieval for Cursor, Windsurf, Claude Code/Desktop, and other MCP hosts

MCP LLMS-TXT Documentation Server

Overview

llms.txt is a website index for LLMs, providing background information, guidance, and links to detailed markdown files. IDEs like Cursor and Windsurf or apps like Claude Code/Desktop can use llms.txt to retrieve context for tasks. However, these apps use different built-in tools to read and process files like llms.txt. The retrieval process can be opaque, and there is not always a way to audit the tool calls or the context returned.

MCP offers a way for developers to have *full control* over tools used by these applications. Here, we create an open source MCP server to provide MCP host applications (e.g., Cursor, Windsurf, Claude Code/Desktop) with (1) a user-defined list of llms.txt files and (2) a simple fetch_docs tool read URLs within any of the provided llms.txt files. This allows the user to audit each tool call as well as the context returned.

llms-txt

You can find llms.txt files for langgraph and langchain here:

| Library | llms.txt | |------------------|------------------------------------------------------------------------------------------------------------| | LangGraph Python | https://langchain-ai.github.io/langgraph/llms.txt | | LangGraph JS | https://langchain-ai.github.io/langgraphjs/llms.txt | | LangChain Python | https://python.langchain.com/llms.txt | | LangChain JS | https://js.langchain.com/llms.txt |

Quickstart

#### Install uv

curl -LsSf https://astral.sh/uv/install.sh | sh

#### Choose an llms.txt file to use.

> Note: Security and Domain Access Control > > For security reasons, mcpdoc implements strict domain access controls: > > 1. Remote llms.txt files: When you specify a remote llms.txt URL (e.g., https://langchain-ai.github.io/langgraph/llms.txt), mcpdoc automatically adds only that specific domain (langchain-ai.github.io) to the allowed domains list. This means the tool can only fetch documentation from URLs on that domain. > > 2. Local llms.txt files: When using a local file, NO domains are automatically added to the allowed list. You MUST explicitly specify which domains to allow using the --allowed-domains parameter. > > 3. Adding additional domains: To allow fetching from domains beyond those automatically included: > - Use --allowed-domains domain1.com domain2.com to add specific domains > - Use --allowed-domains '*' to allow all domains (use with caution) > > This security measure prevents unauthorized access to domains not explicitly approved by the user, ensuring that documentation can only be retrieved from trusted sources.

#### (Optional) Test the MCP server locally with your llms.txt file(s) of choice:

uvx --from mcpdoc mcpdoc \
    --urls "LangGraph:https://langchain-ai.github.io/langgraph/llms.txt" "LangChain:https://python.langchain.com/llms.txt" \
    --transport sse \
    --port 8082 \
    --host localhost

npx @modelcontextprotocol/inspector

#### Connect to Cursor

{
  "mcpServers": {
    "langgraph-docs-mcp": {
      "command": "uvx",
      "args": [
        "--from",
        "mcpdoc",
        "mcpdoc",
        "--urls",
        "LangGraph:https://langchain-ai.github.io/langgraph/llms.txt LangChain:https://python.langchain.com/llms.txt",
        "--transport",
        "stdio"
      ]
    }
  }
}