How to integrate Constant Contact MCP with Mastra AI

This guide walks you through connecting Constant Contact to Mastra AI using the Composio tool router. By the end, you'll have a working Constant Contact agent that can create newsletter draft for new subscribers, list contacts added this week, segment inactive constant contact subscribers through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Constant Contact account through Composio's Constant Contact MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Constant Contact is an email marketing and automation platform for small businesses. It helps teams build campaigns, manage contacts, and grow customer relationships.

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Introduction

This guide walks you through connecting Constant Contact to Mastra AI using the Composio tool router. By the end, you'll have a working Constant Contact agent that can create newsletter draft for new subscribers, list contacts added this week, segment inactive constant contact subscribers through natural language commands.

This guide will help you understand how to give your Mastra AI agent real control over a Constant Contact account through Composio's Constant Contact MCP server.

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

Also integrate Constant Contact with

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TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Constant Contact tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Constant Contact tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your Constant Contact agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

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

The Constant Contact MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Constant Contact account. It provides structured and secure access so your agent can perform Constant Contact 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 step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach Constant Contact through MCP.
3

Install dependencies

bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_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
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models
5

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session
6

Create a Tool Router session for Constant Contact

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["constant_contact"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Constant Contact MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "constant_contact" for Constant Contact access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
7

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the Constant Contact toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "constant_contact-mastra-agent",
    instructions: "You are an AI agent with Constant Contact tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM
9

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\n");

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

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;
  }

  messages.push({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        constant_contact: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and Constant Contact toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with Constant Contact and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({ apiKey: composioAPIKey as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["constant_contact"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      constant_contact: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "constant_contact-mastra-agent",
    instructions: "You are an AI agent with Constant Contact tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

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

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { constant_contact: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with Constant Contact through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows
TOOLS

Supported Tools

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

Add Account Email Address

Add a new email address to a Constant Contact account.

Add Contact Taggings

Add Tags to Contacts.

Add list memberships

Add Contacts to Lists creates an activity to add contacts to one or more contact lists.

Copy Event

POST (copy) an existing event in Constant Contact.

Count Contact Consents

GET contact consent counts for a Constant Contact account.

Create Contact

Create a new contact in Constant Contact.

Create contact from sign-up form

Create or Update a Contact via sign-up form.

Create Contact List

Create a new contact list in Constant Contact.

Create contact tag

POST (Create) a Tag.

Create Custom Field

Create a new custom field for contacts in Constant Contact.

Create Email Campaign

Create a new email campaign in Constant Contact.

Create Event

Create a new event with default settings in Constant Contact.

Create Resend to Non-openers

Create a resend to non-openers campaign activity for an email campaign.

Create Social Post

Create a new social media post campaign.

Delete contact

DELETE a specific contact from your Constant Contact account.

Delete Contact List

Permanently deletes a contact list from Constant Contact by its ID.

Create contact delete activity

Delete multiple contacts in bulk by submitting a contact_delete activity.

Delete contact tag

Delete a specific contact tag from your Constant Contact account.

Delete contact tags

Delete one or more tags from contacts in Constant Contact.

Delete custom field

DELETE a specific contact custom field from your Constant Contact account.

Delete custom fields

Delete one or more custom fields from a Constant Contact account.

Delete Email Campaign

DELETE an Email Campaign from your Constant Contact account.

Delete contact list activity

Delete one or more contact lists from your Constant Contact account by submitting a list delete activity.

Delete Segment

Permanently deletes a segment from Constant Contact by its ID.

Export Contacts

Create a bulk activity that exports contacts to a CSV file.

Get account physical address

GET the Physical Address for the Account.

Get account summary

GET a summary of account details for a Constant Contact account.

Get activity status

GET the status of a specific bulk activity.

Get contact

GET a contact by their unique ID.

Get contact activity summary report

GET contact tracking activity summary for a specific contact.

Get Contact List

GET details for a specific contact list by its ID.

Get Contact Open and Click Rates Report

GET average open and click rates for a contact.

Get Contacts Export File

Retrieve the exported contacts file from a completed export contacts activity.

Get Contact SMS Engagement History

GET SMS Engagement History for a Contact.

Get contact tag details

GET Tag Details - Retrieves detailed information about a specific contact tag.

Get custom field

GET a custom field by its unique ID.

Get email campaign details

GET details for a single email campaign using its campaign ID.

Get Email Campaign Activity

GET details for a specific email campaign activity by its ID.

Get email campaign activity preview

GET the HTML Preview of an Email Campaign Activity.

Get Email Campaign Activity Schedule

GET an email campaign activity schedule.

Get email campaign activity send history

GET the send history of an email campaign activity.

Get email campaign ID cross-references

GET a collection of V2 and V3 API Email Campaign ID cross-references.

Get Email Campaign Statistics Report

GET statistics for one or more email campaigns.

Get Event

GET details for a single event by its unique ID.

Get list ID cross-references

GET a collection of V2 and V3 API List IDs cross-references.

Get Partner Webhook Subscription

GET details for a specific Partner Webhook Topic Subscription by its ID.

Get resend to non-openers

GET Details for a Resend to Non-openers Campaign Activity.

Get Segment

GET details for a specific segment by its unique ID.

Import contacts from CSV file

Import contacts into Constant Contact from a CSV file.

Import contacts from JSON

Bulk import contacts into Constant Contact using JSON format.

List account email addresses

GET a Collection of Account Email Addresses.

List account user privileges

Get the user privileges associated with your access token.

List activity statuses

GET a collection of bulk activities.

List Contact Lists

GET all contact lists for the Constant Contact account.

List contacts

GET Contacts Collection to retrieve a list of contacts from Constant Contact.

List contact tags

GET Details for All Tags - Retrieves all contact tags for the account.

List contact custom fields

GET custom_fields Collection to retrieve all contact custom field definitions.

List Email Campaigns

GET a collection of email campaigns from Constant Contact.

List Email Campaign Summaries Report

GET an Email Campaigns Summary Report from Constant Contact.

List Email Did Not Opens Report

GET an Email Did Not Opens Report to retrieve a list of contacts who did not open a specific email campaign.

List email forwards report

GET an Email Forwards Report for a specific email campaign activity.

List email opt-outs report

GET an Email Opt-outs Report for a specific email campaign activity.

List Email Unique Opens Report

GET an email unique opens report for a campaign activity.

List Events

GET a collection of events from Constant Contact.

List event track registrations

GET registrations for an event track to retrieve a list of registrations.

List Landing Page Contact Opens Report

GET a Contacts Opens Landing Page Report.

List Landing Page Unique Contact Adds Report

GET a Unique Contacts Adds Landing Page Report for a specific landing page campaign activity.

List Landing Page Unique Contact Clicks Report

GET unique contact clicks data for a landing page campaign.

List Landing Page Unique Contact Opens Report

GET a Unique Contacts Opens Landing Page Report to retrieve a list of contacts who uniquely opened a specific landing page campaign.

List landing page unique contact updates report

GET a Unique Contacts Updates Landing Page Report for a specific landing page campaign activity.

List Segments

GET all segments for the Constant Contact account.

List SMS Campaign Summaries Report

GET an SMS Campaigns Summary Report.

List Social Connections

GET social network connections for a Constant Contact account.

List Social Hashtag Groups

GET hashtag groups - Retrieves a paginated list of social hashtag groups.

List Social Profiles

GET social media profiles from Constant Contact.

Remove Contact Tagging

Remove tagging from contacts in Constant Contact.

Remove Tags from Contacts

Remove tags from contacts in Constant Contact.

Remove contacts from lists

Create a Remove Contacts from Lists activity to remove contacts from one or more lists.

Rename Email Campaign

PATCH (Update) the name of an existing email campaign in Constant Contact.

Rename Segment

PATCH (rename) an existing segment in Constant Contact.

Resubscribe Contact

Resubscribe an unsubscribed contact to one or more contact lists.

Undo Event Ticket Check-In

Undo check-in for event tickets.

Update Account Details

PUT (update) Account Details for the authenticated user.

Update Account Physical Address

PUT (update) the Physical Address for an Account.

Update Contact

PUT (update) an existing contact in Constant Contact.

Update Contact List

PUT (update) an existing contact list in Constant Contact.

Update Contact Tag

PUT (Update) a Tag.

Update Custom Field

Update an existing contact custom field in Constant Contact.

Update Email Campaign Activity

PUT (Update) an Email Campaign Activity in Constant Contact.

Update Event

PATCH (update) an existing event in Constant Contact.

Update Event Track Registration Payment Status

Update the payment status for event track registrations in Constant Contact.

Update Event Track Registrations

PUT (update) registration status for event track registrations.

Update Segment

PUT (update) an existing segment in Constant Contact.

FRAMEWORKS

How to build Constant Contact MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Constant Contact MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Constant Contact MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Constant Contact MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Constant Contact MCP with Claude Cowork

Codex logo

Codex

Use Constant Contact MCP with Codex

OpenClaw logo

OpenClaw

Use Constant Contact MCP with OpenClaw

Hermes logo

Hermes

Use Constant Contact MCP with Hermes

CLI logo

CLI

Use Constant Contact MCP with CLI

Google ADK logo

Google ADK

Use Constant Contact MCP with Google ADK

LangChain logo

LangChain

Use Constant Contact MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Constant Contact MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Constant Contact MCP with LlamaIndex

CrewAI logo

CrewAI

Use Constant Contact MCP with CrewAI

FAQ

Frequently asked questions

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

Yes, you can. Mastra AI 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 Constant Contact tools.

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

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Co-founder, Slashy

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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Co-founder, Opennote

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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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