Exact LangChain signatures, so your agent stops guessing parameters.

Classes, methods, parameters and signatures for every LangChain package are its whole job. LangChain recommends pairing it with its docs server, which explains the concepts and how-tos behind them.

What it is

A remote MCP server LangChain offers at reference.langchain.com/mcp. It searches LangChain's public API reference and does not reach your own LangSmith data. It needs no sign-in and no key.

What you get

The API reference searched for classes, functions and other symbols
Full documentation for one symbol: its signature, parameters and examples

Requirements

An MCP client that can reach a remote address. LangChain gives setup steps for Claude Code, Claude Desktop, Codex CLI, Cursor, VS Code, Antigravity and Deep Agents Code.

Setup effort

Paste a URL — add the endpoint to your client