How to integrate Campayn MCP with LangChain

This guide walks you through connecting Campayn to LangChain using the Composio tool router. By the end, you'll have a working Campayn agent that can add new subscriber to weekly newsletter list, list all active contact lists in account, fetch details for your last sent campaign through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Campayn account through Composio's Campayn MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Campayn is an email marketing platform for creating, sending, and managing campaigns. It helps businesses engage contacts and grow audiences with easy-to-use tools.

14 Tools

Introduction

This guide walks you through connecting Campayn to LangChain using the Composio tool router. By the end, you'll have a working Campayn agent that can add new subscriber to weekly newsletter list, list all active contact lists in account, fetch details for your last sent campaign through natural language commands.

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

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

Also integrate Campayn 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 Campayn project to Composio
  • Create a Tool Router MCP session for Campayn
  • Initialize an MCP client and retrieve Campayn tools
  • Build a LangChain agent that can interact with Campayn
  • 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 Campayn MCP server, and what's possible with it?

The Campayn MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Campayn account. It provides structured and secure access to your contact lists, email campaigns, and subscriber management, so your agent can handle tasks like creating contacts, managing lists, fetching messages, and maintaining your email marketing automation—all on your behalf.

  • Effortless contact management: Easily add new contacts, update existing ones, or permanently delete subscribers from your Campayn lists through your agent.
  • Automated list organization: Ask your agent to create, retrieve, or clean up contact lists, making it simple to segment and manage your audience.
  • Campaign and message insights: Have your agent fetch the details of individual messages or retrieve all campaign messages to keep you up to date with your email marketing efforts.
  • Streamlined webform management: Direct your agent to delete outdated or unnecessary webforms, keeping your lead capture workflow tidy and current.
  • Bulk data retrieval: Let your agent pull all contacts in a specific list or fetch all available lists with a single command, saving you time and effort when working with large datasets.

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 Campayn 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 Campayn 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: ['campayn']
    }
);

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

Configure the agent with the MCP URL

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

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

Create Contact

Tool to create a new contact in a specific list.

Delete Contact

Tool to delete a specific contact.

Delete List

Tool to delete a specific contact list.

Delete webform

Delete a specific webform from a contact list.

Get Contact

Tool to retrieve a specific contact by ID.

Get Contacts

Retrieves all contacts from a specific contact list in Campayn.

Get Lists

Tool to retrieve all contact lists.

Get Message Statistics

Tool to retrieve engagement statistics for a specific email message by ID.

Get Messages

Tool to retrieve all email messages.

Get Reports

Tool to retrieve report URLs and metadata for sent and scheduled emails.

Get Webform

Tool to retrieve details of a specific webform by ID.

Get Webforms

Tool to retrieve all webforms for a specific contact list.

Unsubscribe Contact

Tool to unsubscribe contacts from a list by contact id or email address.

Update List

Tool to update a contact list.

FRAMEWORKS

How to build Campayn MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Campayn MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Campayn MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Campayn MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Campayn MCP with Claude Cowork

Codex logo

Codex

Use Campayn MCP with Codex

OpenClaw logo

OpenClaw

Use Campayn MCP with OpenClaw

Hermes logo

Hermes

Use Campayn MCP with Hermes

CLI logo

CLI

Use Campayn MCP with CLI

Google ADK logo

Google ADK

Use Campayn MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Campayn MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Campayn MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Campayn MCP with LlamaIndex

CrewAI logo

CrewAI

Use Campayn MCP with CrewAI

FAQ

Frequently asked questions

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

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

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