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Guide2 min read

Connect LangGraph to an MCP server (2026 guide)

LangGraph 1.0 is the production standard for agent orchestration, and MCP is the fastest way to give its graphs real tools. How to wire servers in with langchain-mcp-adapters — for one agent or a whole swarm.

LangGraph shipped 1.0 as the production standard for agent orchestration, and the fastest way to give its graphs real tools is Model Context Protocol. Instead of hand-wiring every integration into your Python code, you point a LangGraph node at an MCP server and its tools appear as native LangChain tools. Here's the clean path — vetted, minimal, and the same shape whether you run one agent or a swarm.

The bridge: langchain-mcp-adapters

The official glue is the langchain-mcp-adapters package. It converts each MCP tool's JSON schema into a langchain_core BaseTool that any LangGraph node can call, so servers behave exactly like tools you wrote by hand. You need Python 3.11 or newer — the adapters won't load on older runtimes.

pip install langgraph langchain-mcp-adapters

Wire up a client

MultiServerMCPClient connects to one or many servers and returns their tools in a single list. Point it at a local stdio server or a remote Streamable HTTP endpoint, then hand the tools to a prebuilt ReAct agent:

from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent

client = MultiServerMCPClient({
    "github": {"transport": "streamable_http", "url": "https://api.githubcopilot.com/mcp/"},
})
tools = await client.get_tools()
agent = create_react_agent("anthropic:claude-opus-4-8", tools)

Multi-agent graphs

The real payoff is at scale. LangGraph gives you checkpointing, human-in-the-loop pauses and durable state; MCP gives every node in the graph a live, versioned, network-accessible toolbox. A supervisor can route work to specialist agents that each own a different server — one on GitHub, one on a database, one on search — without any of them sharing code. That separation is what keeps a large graph auditable and lets you swap a tool without touching agent logic.

Which servers to start with

Give a coding graph the GitHub server and the filesystem server; give a research graph Exa or Firecrawl. Because the adapter speaks standard MCP, anything in our directory drops in unchanged — curated, categorised and vetted so you're not wiring a random GitHub repo into a production graph.

Going further

Deciding stdio vs HTTP? See transports compared. Building the servers yourself starts with the Python MCP tutorial. For orchestration theory, read multi-agent orchestration patterns, and browse the ML engineer loadout. Keep third-party servers vetted with MCP security best practices.

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