How to integrate Openrouter MCP with LangChain

This guide walks you through connecting Openrouter to LangChain using the Composio tool router. By the end, you'll have a working Openrouter agent that can generate python code from this prompt, summarize this article using claude-3, list all available llama-3 model endpoints through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Openrouter account through Composio's Openrouter MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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OpenRouter is a unified API platform for accessing language models from various providers. It lets you easily integrate and switch between multiple LLMs with a single API.

13 Tools

Introduction

This guide walks you through connecting Openrouter to LangChain using the Composio tool router. By the end, you'll have a working Openrouter agent that can generate python code from this prompt, summarize this article using claude-3, list all available llama-3 model endpoints through natural language commands.

This guide will help you understand how to give your LangChain agent real control over a Openrouter account through Composio's Openrouter MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Openrouter with

ChatGPTOpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenCodeCursorVS CodeOpenClawHermesCLIGoogle ADKVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Connect your Openrouter project to Composio
  • Create a Tool Router MCP session for Openrouter
  • Initialize an MCP client and retrieve Openrouter tools
  • Build a LangChain agent that can interact with Openrouter
  • Set up an interactive chat interface for testing

What is LangChain?

LangChain is a framework for developing applications powered by language models. It provides tools and abstractions for building agents that can reason, use tools, and maintain conversation context.

Key features include:

  • Agent Framework: Build agents that can use tools and make decisions
  • MCP Integration: Connect to external services through Model Context Protocol adapters
  • Memory Management: Maintain conversation history across interactions
  • Multi-Provider Support: Works with OpenAI, Anthropic, and other LLM providers

What is the Openrouter MCP server, and what's possible with it?

The Openrouter MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Openrouter account. It provides structured and secure access to a wide range of large language models, so your agent can generate completions, manage model access, check credits, and retrieve generation details seamlessly on your behalf.

  • Unified model completions: Let your agent generate chat-based or text completions using any model available through Openrouter, perfect for conversation or content creation tasks.
  • Model catalog and provider discovery: Ask your agent to list all available AI models and providers, helping you compare capabilities, endpoints, and pricing in real time.
  • Credit monitoring and usage tracking: Have your agent fetch your current API credit balance, so you always know your usage limits before starting new tasks.
  • Generation result retrieval: Direct your agent to pull detailed metadata for any previous generation, including token counts, costs, and latency for analysis or auditing.
  • Endpoint and configuration info: Empower your agent to fetch the latest model endpoints and supported parameters, making it easy to fine-tune routing and optimize performance.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step10 STEPS
1

Prerequisites

Before starting this tutorial, make sure you have:
  • Python 3.10 or higher installed on your system
  • A Composio account with an API key
  • An OpenAI API key
  • Basic familiarity with Python and async programming
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.
3

Install dependencies

npm install @composio/langchain @langchain/core @langchain/openai @langchain/mcp-adapters dotenv

Install the required packages for LangChain with MCP support.

What's happening:

  • @composio/langchain provides Composio integration for LangChain
  • @langchain/mcp-adapters enables MCP client connections
  • @langchain/core is the core agent framework
  • dotenv/config loads environment variables
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_composio_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio's API
  • COMPOSIO_USER_ID identifies the user for session management
  • OPENAI_API_KEY enables access to OpenAI's language models
5

Import dependencies

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

dotenv.config();
What's happening:
  • We're importing LangChain's MCP adapter and Composio SDK
  • The dotenv/config import loads environment variables from your .env file
  • This setup prepares the foundation for connecting LangChain with Openrouter functionality through MCP
6

Initialize Composio client

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });
What's happening:
  • We're loading the COMPOSIO_API_KEY from environment variables and validating it exists
  • Creating a Composio instance that will manage our connection to Openrouter tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding
7

Create a Tool Router session

const session = await composio.create(
    userId as string,
    {
        toolkits: ['openrouter']
    }
);

const url = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to Openrouter tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
  • This approach allows the agent to dynamically load and use Openrouter tools as needed
8

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "openrouter-agent": {
        transport: "http",
        url: url,
        headers: {
            "x-api-key": process.env.COMPOSIO_API_KEY
        }
    }
});

const tools = await client.getTools();

const agent = createAgent({ model: "gpt-5", tools });
What's happening:
  • We're creating a MultiServerMCPClient that connects to our Openrouter MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • getTools() retrieves all available Openrouter tools that the agent can use
  • We're creating a LangChain agent using the GPT-5 model
9

Set up interactive chat interface

let conversationHistory: any[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log("Ask any Openrouter related question or task to the agent.\n");

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
});

rl.prompt();

rl.on('line', async (userInput: string) => {
    const trimmedInput = userInput.trim();

    if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
        console.log("\nGoodbye!");
        rl.close();
        process.exit(0);
    }

    if (!trimmedInput) {
        rl.prompt();
        return;
    }

    conversationHistory.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    const response = await agent.invoke({ messages: conversationHistory });
    conversationHistory = response.messages;

    const finalResponse = response.messages[response.messages.length - 1]?.content;
    console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\n👋 Session ended.');
        process.exit(0);
    });
What's happening:
  • We initialize an empty conversationHistory list to maintain context across interactions
  • A readline interface is used to continuously accept user input from the command line
  • When a user types a message, it's added to the conversation history and sent to the agent
  • The agent processes the request using the invoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully
10

Run the application

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});
What's happening:
  • We call the main() function to start the application

Complete Code

Here's the complete code to get you started with Openrouter and LangChain:

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";  
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

    const session = await composio.create(
        userId as string,
        {
            toolkits: ['openrouter']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "openrouter-agent": {
            transport: "http",
            url: url,
            headers: {
                "x-api-key": process.env.COMPOSIO_API_KEY
            }
        }
    });
    
    const tools = await client.getTools();
  
    const agent = createAgent({ model: "gpt-5", tools });
    
    let conversationHistory: any[] = [];
    
    console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
    console.log("Ask any Openrouter related question or task to the agent.\n");
    
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
        prompt: 'You: '
    });

    rl.prompt();

    rl.on('line', async (userInput: string) => {
        const trimmedInput = userInput.trim();
        
        if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
            console.log("\nGoodbye!");
            rl.close();
            process.exit(0);
        }
        
        if (!trimmedInput) {
            rl.prompt();
            return;
        }
        
        conversationHistory.push({ role: "user", content: trimmedInput });
        console.log("\nAgent is thinking...\n");
        
        const response = await agent.invoke({ messages: conversationHistory });
        conversationHistory = response.messages;
        
        const finalResponse = response.messages[response.messages.length - 1]?.content;
        console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\nSession ended.');
        process.exit(0);
    });
}

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});

Conclusion

You've successfully built a LangChain agent that can interact with Openrouter through Composio's Tool Router.

Key features of this implementation:

  • Dynamic tool loading through Composio's Tool Router
  • Conversation history maintenance for context-aware responses
  • Async Python provides clean, efficient execution of agent workflows
You can extend this further by adding error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.
TOOLS

Supported Tools

Every Openrouter action and event your agent gets out of the box.

Create Chat Completion

Tool to generate a chat-style completion.

Create Coinbase Charge

Tool to create a Coinbase charge for crypto payment to add credits to your OpenRouter account.

Create Message (Anthropic Format)

Tool to create a message using Anthropic Messages API format via OpenRouter.

Get Credits

Tool to get the current API credit balance for the authenticated user.

Get Current Key

Tool to get information about the currently authenticated API key.

Get Generation

Tool to retrieve a generation result by its unique ID.

Get Models Count

Tool to get the total count of available models on OpenRouter.

List Available Models

Tool to list available models via OpenRouter API.

List Embedding Models

Tool to list all available embeddings models via OpenRouter API.

OpenRouter List Model Endpoints

Tool to list endpoints for a specific model.

OpenRouter List Providers

Tool to list all AI model providers available through the OpenRouter API.

List User Models

Tool to list models filtered by user provider preferences, privacy settings, and guardrails.

OpenRouter List ZDR Endpoints

Tool to preview the impact of Zero Data Retention (ZDR) on the available endpoints.

FRAMEWORKS

How to build Openrouter MCP Agent with another framework

ChatGPT logo

ChatGPT

Use Openrouter MCP with ChatGPT

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Openrouter MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Openrouter MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Openrouter MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Openrouter MCP with Claude Cowork

Codex logo

Codex

Use Openrouter MCP with Codex

Cursor logo

Cursor

Use Openrouter MCP with Cursor

OpenClaw logo

OpenClaw

Use Openrouter MCP with OpenClaw

Hermes logo

Hermes

Use Openrouter MCP with Hermes

CLI logo

CLI

Use Openrouter MCP with CLI

Google ADK logo

Google ADK

Use Openrouter MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Openrouter MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Openrouter MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Openrouter MCP with LlamaIndex

CrewAI logo

CrewAI

Use Openrouter MCP with CrewAI

OpenCode logo

OpenCode

Use Openrouter MCP with OpenCode

VS Code logo

VS Code

Use Openrouter MCP with VS Code

FAQ

Frequently asked questions

With a standalone Openrouter MCP server, the agents and LLMs can only access a fixed set of Openrouter tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Openrouter and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. LangChain fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Openrouter tools.

Yes, absolutely. You can configure which Openrouter scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Openrouter data and credentials are handled as safely as possible.

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