Skip to content

langchain-mcp

Directory actions

More options

Directory actions

More options

Latest commit

 

History

History

langchain-mcp

Folders and files

NameName
Last commit message
Last commit date

parent directory

..
README.md
README.md
 
 
example.py
example.py
 
 
requirements.txt
requirements.txt
 
 

README.md

LangChain + AgentCred MCP Integration

Use AgentCred's MCP server as tools in LangChain agents — zero Python SDK needed. Your agent gets cryptographic signing capabilities via the Model Context Protocol.

Prerequisites

  • Node.js 18+ (for the AgentCred MCP server)
  • Python 3.10+
  • GitHub token (ghp_...) with no special scopes required
  • GitHub username (for signing in the MCP server)

Installation

pip install langchain-mcp-adapters langchain-openai langgraph

Quick Start

import os

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain_mcp_adapters.tools import load_mcp_tools
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent

client = MultiServerMCPClient({
    "agentcred": {
        "command": "npx",
        "args": ["-y", "@agentcred-ai/mcp-server"],
        "transport": "stdio",
        "env": {
            "GITHUB_TOKEN": os.environ["GITHUB_TOKEN"],
            "GITHUB_USERNAME": os.environ["GITHUB_USERNAME"],
        },
    }
})
async with client.session("agentcred") as session:
    tools = await load_mcp_tools(session, server_name="agentcred")
    agent = create_react_agent(ChatOpenAI(model="gpt-4o"), tools)
    result = await agent.ainvoke({
        "messages": [{"role": "user", "content": "Sign this: Hello from LangChain!"}]
    })

Available AgentCred Tools

Tool Description Parameters
agentcred_init Initialize identity (links GitHub to Ed25519 keypair) github_token (optional)
agentcred_sign Sign content and return verifiable envelope content (required), agent (optional)
agentcred_verify Verify an AgentCred envelope envelope (required, JSON string)
agentcred_whoami Check current identity (none)

How It Works

  1. MultiServerMCPClient spawns the AgentCred MCP server as a subprocess
  2. await client.get_tools() loads all 4 AgentCred tools via MCP
  3. The agent can call agentcred_sign to sign any content
  4. Recipients verify signatures with agentcred_verify

Full Example

See example.py for a complete runnable example.

Troubleshooting

Issue Solution
npx: command not found Install Node.js 18+ from https://nodejs.org
GITHUB_TOKEN not set export GITHUB_TOKEN=ghp_your_token
No identity configured The agent needs to call agentcred_init first
MCP connection timeout Ensure npx can download packages (check proxy/firewall)

Learn More