How to integrate Instantly MCP with LangChain

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Introduction

This guide walks you through connecting Instantly to LangChain using the Composio tool router. By the end, you'll have a working Instantly agent that can create a new cold email campaign, add a new lead to my campaign, check unread emails in my inbox, run an inbox placement test for gmail through natural language commands.

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

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

TL;DR

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

The Instantly MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Instantly account. It provides structured and secure access to your campaigns, leads, and outreach tools, so your agent can perform actions like launching new campaigns, managing leads, tracking inbox statistics, and handling API credentials on your behalf.

  • Automated campaign creation and management: Ask your agent to launch new cold email campaigns or update existing ones, streamlining your outreach workflow without manual setup.
  • Lead and lead list management: Let your agent add new leads, organize them into lists, or enrich them with AI-driven insights to maximize your campaign effectiveness.
  • Email verification and deliverability tracking: Direct your agent to check the verification status of email addresses or run inbox placement tests to monitor and improve deliverability across providers.
  • Inbox activity monitoring: Fetch unread email counts or campaign engagement metrics, helping you stay on top of your outreach performance in real time.
  • API key and webhook automation: Have your agent create or delete API keys for secure integrations, or set up webhooks to receive instant notifications about important Instantly events.

Supported Tools & Triggers

Tools
Check Email Verification StatusTool to check status of an email verification job.
Count Unread EmailsTool to retrieve the count of unread emails.
Create AI EnrichmentTool to create an AI enrichment job for a campaign or lead list.
Create API KeyTool to create a new API key.
Create CampaignTool to create a new campaign.
Create Inbox Placement TestTool to create an inbox placement test.
Create LeadTool to create a new lead.
Create Lead ListTool to create a new lead list.
Create WebhookTool to create a new webhook endpoint.
Delete API KeyTool to delete an API key.
Delete CampaignTool to delete a campaign.
Delete LeadTool to delete a lead by its ID.
Delete Lead ListTool to delete a lead list by ID.
Delete WebhookTool to delete a webhook.
Disable Account WarmupTool to disable the warm-up process for email accounts.
Enable Account WarmupTool to enable the warm-up process for email accounts.
Get CampaignTool to retrieve campaign details.
Get Campaign AnalyticsTool to retrieve analytics for campaigns.
Get Daily Campaign AnalyticsTool to retrieve daily analytics for a campaign.
Get Email Service Provider OptionsTool to retrieve email service provider options for inbox placement tests.
Get Inbox Placement TestTool to retrieve inbox placement test results.
Get LeadTool to retrieve details of a specific lead by its ID.
Get Lead ListTool to retrieve details of a specific lead list by its ID.
Get Lead List Verification StatsTool to retrieve verification statistics for a lead list.
Get WebhookTool to retrieve details of a specific webhook subscription.
Get Webhook EventTool to retrieve details of a specific webhook event.
List Email AccountsTool to list all email accounts for the authenticated user.
List API KeysTool to list all API keys.
List CampaignsTool to list all campaigns.
List Custom TagsTool to list custom tags.
List DFY Email Account OrdersTool to list DFY email account orders.
List EmailsTool to list emails.
List Inbox Placement Blacklist & SpamAssassin ReportsTool to list inbox placement blacklist & SpamAssassin reports.
List Inbox Placement TestsTool to list inbox placement tests.
List Lead ListsTool to list all lead lists.
List LeadsTool to list leads.
List Email ThreadsTool to list email threads.
List Webhook EventsTool to list webhook events.
List WebhooksTool to list configured webhooks.
Mark Thread As ReadTool to mark all emails in a specific thread as read.
Merge LeadsTool to merge multiple leads into a single lead.
Search Campaigns by Lead EmailTool to search campaigns by a lead's email address.
Update CampaignTool to update details of a campaign.
Update LeadTool to update a lead's details.
Update Lead Interest StatusTool to update a lead's interest status.
Update Lead ListTool to update details of a specific lead list by its ID.
Verify EmailTool to initiate email verification.

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

What is Tool Router?

Composio's Tool Router 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 Tool Router

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

How the Tool Router works

The Tool Router 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

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

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.

Install dependencies

pip install composio-langchain langchain-mcp-adapters langchain python-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 is the core agent framework
  • python-dotenv loads environment variables

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

Import dependencies

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

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

Initialize Composio client

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))

    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
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 Instantly tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

# Create Tool Router session for Instantly
session = composio.create(
    user_id=os.getenv("COMPOSIO_USER_ID"),
    toolkits=['instantly']
)

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

Configure the agent with the MCP URL

client = MultiServerMCPClient({
    "instantly-agent": {
        "transport": "streamable_http",
        "url": session.mcp.url,
        "headers": {
            "x-api-key": os.getenv("COMPOSIO_API_KEY")
        }
    }
})

tools = await client.get_tools()

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

Set up interactive chat interface

conversation_history = []

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

while True:
    user_input = input("You: ").strip()

    if user_input.lower() in ['exit', 'quit', 'bye']:
        print("\nGoodbye!")
        break

    if not user_input:
        continue

    conversation_history.append({"role": "user", "content": user_input})
    print("\nAgent is thinking...\n")

    response = await agent.ainvoke({"messages": conversation_history})
    conversation_history = response['messages']
    final_response = response['messages'][-1].content
    print(f"Agent: {final_response}\n")
What's happening:
  • We initialize an empty conversation_history list to maintain context across interactions
  • A while loop continuously accepts 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 ainvoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully

Run the application

if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • We call the main() function using asyncio.run() to start the application

Complete Code

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

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
    
    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
    
    session = composio.create(
        user_id=os.getenv("COMPOSIO_USER_ID"),
        toolkits=['instantly']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "instantly-agent": {
            "transport": "streamable_http",
            "url": url,
            "headers": {
                "x-api-key": os.getenv("COMPOSIO_API_KEY")
            }
        }
    })
    
    tools = await client.get_tools()
  
    agent = create_agent("gpt-5", tools)
    
    conversation_history = []
    
    print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
    print("Ask any Instantly related question or task to the agent.\n")
    
    while True:
        user_input = input("You: ").strip()
        
        if user_input.lower() in ['exit', 'quit', 'bye']:
            print("\nGoodbye!")
            break
        
        if not user_input:
            continue
        
        conversation_history.append({"role": "user", "content": user_input})
        print("\nAgent is thinking...\n")
        
        response = await agent.ainvoke({"messages": conversation_history})
        conversation_history = response['messages']
        final_response = response['messages'][-1].content
        print(f"Agent: {final_response}\n")

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've successfully built a LangChain agent that can interact with Instantly 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.

How to build Instantly MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Instantly MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Instantly MCP with Claude Agent SDK

Google ADK

Google ADK

Use Instantly MCP with Google ADK

Vercel AI SDK

Vercel AI SDK

Use Instantly MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Instantly MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Instantly MCP with LlamaIndex

CrewAI

CrewAI

Use Instantly MCP with CrewAI

FAQ

What are the differences in Tool Router MCP and Instantly MCP?

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

Can I use Tool Router MCP with LangChain?

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 Instantly tools.

Can I manage the permissions and scopes for Instantly while using Tool Router?

Yes, absolutely. You can configure which Instantly 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.

How safe is my data with Composio Tool Router?

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 Instantly data and credentials are handled as safely as possible.

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