How to integrate Fly MCP with LangChain

This guide walks you through connecting Fly to LangChain using the Composio tool router. By the end, you'll have a working Fly agent that can deploy latest image to fly in tokyo, list all running fly apps by region, scale up your fly app to 3 instances through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Fly account through Composio's Fly MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Introduction

This guide walks you through connecting Fly to LangChain using the Composio tool router. By the end, you'll have a working Fly agent that can deploy latest image to fly in tokyo, list all running fly apps by region, scale up your fly app to 3 instances through natural language commands.

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

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

Also integrate Fly with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Connect your Fly project to Composio
  • Create a Tool Router MCP session for Fly
  • Initialize an MCP client and retrieve Fly tools
  • Build a LangChain agent that can interact with Fly
  • 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 Fly MCP server, and what's possible with it?

The Fly MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Fly account. It provides structured and secure access so your agent can perform Fly operations on your behalf.

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 Fly 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 Fly 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: ['fly']
    }
);

const url = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to Fly 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 Fly tools as needed
8

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "fly-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 Fly MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • getTools() retrieves all available Fly 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 Fly 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 Fly 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: ['fly']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "fly-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 Fly 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 Fly 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 Fly action and event your agent gets out of the box.

Add WireGuard Peer

Tool to add a WireGuard peer connection to a Fly.

Check App Name Availability

Tool to validate an app name for Fly.

Check Jobs

Execute GraphQL queries against the Fly.

Check User Only Token

Check whether the authentication token only allows user access.

Create Health Check Job

Tool to create a health check job for monitoring application endpoints in Fly.

Create Check Job Run

Triggers a run of an existing health check job on Fly.

Create Delegated WireGuard Token

Tool to create a delegated WireGuard token for peer management in a Fly.

Create Third-Party Configuration

Tool to create a third-party service configuration for discharging macaroon caveats.

Delete Delegated WireGuard Token

Tool to delete a delegated WireGuard token from a Fly.

Delete Organization

Tool to delete a Fly.

Delete Remote Builder

Tool to delete a remote builder configuration for a Fly.

Delete Third Party Configuration

Tool to delete a third-party service configuration from Fly.

Detach Postgres Cluster

Tool to detach a Postgres cluster from a Fly.

Establish SSH Key

Tool to establish an SSH key for a Fly.

Fetch Nodes by IDs

Fetches a list of node objects from Fly.

Get Add-On

Tool to find a Fly.

Get Add-On Provider

Tool to query information about a specific Fly.

Get app details

Tool to retrieve detailed information about a specific Fly.

Get Certificate

Tool to retrieve a certificate by its ID from Fly.

Get Current Token Info

Tool to get information about the current authentication token.

Get Latest Image Details

Tool to retrieve the latest available tag details for a given image repository from Fly.

Get Latest Image Tag

Tool to retrieve the latest available image tag for a Fly.

Get Machine

Tool to get a single machine by ID from Fly.

Get Nearest Region

Tool to retrieve the nearest Fly.

Get Node by ID

Tool to fetch an object by its globally unique ID using Fly.

Get Organization

Tool to find a Fly.

Get Personal Organization

Tool to retrieve the user's personal organization details from Fly.

Get Placements

Tool to get placement recommendations for Machines in Fly.

Get Platform Information

Tool to retrieve Fly.

Get Products and Pricing

Tool to retrieve Fly.

Get Regions

Tool to get the list of available Fly.

Get Viewer Info

Tool to retrieve the authenticated user's account information from Fly.

Issue Certificate

Tool to issue an SSH certificate for accessing Fly.

List Add-On Plans

Tool to list available add-on service plans from Fly.

List Add-Ons

Tool to list add-ons associated with an organization in Fly.

List Apps

Tool to list all Fly Apps in an organization.

List Apps via GraphQL

List all Fly.

Check Locations

Retrieve all available Fly.

List Machines

Tool to list Fly.

List Organization Machines

Tool to list all Machines across all apps in a Fly organization.

Remove WireGuard Peer

Tool to remove a WireGuard peer connection from a Fly.

Set Apps V2 Default

Tool to configure whether new apps in an organization use Apps V2 by default on Fly.

Update Third-Party Configuration

Tool to update an existing third-party service configuration for discharging macaroon caveats.

Validate Config

Tool to validate a Fly.

Validate WireGuard Peers

Tool to validate WireGuard peer IP addresses in a Fly.

FRAMEWORKS

How to build Fly MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Fly MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Fly MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Fly MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Fly MCP with Claude Cowork

Codex logo

Codex

Use Fly MCP with Codex

OpenClaw logo

OpenClaw

Use Fly MCP with OpenClaw

Hermes logo

Hermes

Use Fly MCP with Hermes

CLI logo

CLI

Use Fly MCP with CLI

Google ADK logo

Google ADK

Use Fly MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Fly MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Fly MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Fly MCP with LlamaIndex

CrewAI logo

CrewAI

Use Fly MCP with CrewAI

FAQ

Frequently asked questions

With a standalone Fly MCP server, the agents and LLMs can only access a fixed set of Fly tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Fly 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 Fly tools.

Yes, absolutely. You can configure which Fly 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 Fly data and credentials are handled as safely as possible.

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A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

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As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

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Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

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With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

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