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How to integrate Customerio MCP with Mastra AI

Connect Mastra AI to Customerio MCP. List all segments in your workspace, get delivery metrics for last week's emails, and more using natural language, with authentication handled for you.

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Customerio

Api Key

Customer.io is a customer engagement platform for targeted messaging across email, SMS, and push. Easily automate, segment, and track communications with your audience.

39 Tools

Managed auth

Connect Customerio without auth hassles

We manage OAuth, API keys, token refresh, and scopes — you just build.

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Explore the MCP Gateway

Introduction

This guide walks you through connecting Customerio to Mastra AI using the Composio tool router. By the end, you'll have a working Customerio agent that can identify people, track events and page views, trigger broadcasts, review segments and metrics, and suppress or unsubscribe customers through natural language commands.

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

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

For exact tool slugs and parameter tables, see the tool catalog in the Composio docs.

Also integrate Customerio with

Claude Code ChatGPT Claude Cowork Antigravity OpenAI Agents SDK Claude Agent SDK Grok Bot Codex OpenClaw Hermes Atomic Agent Google ADK LangChain Vercel AI SDK LlamaIndex CrewAI Pydantic AI AutoGen

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 Customerio tools
Connect Mastra's MCP client to the Composio generated MCP URL
Fetch Customerio 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 Customerio 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 Customerio MCP server, and what's possible with it?

The Customerio MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Customer.io account. It provides structured and secure access to your customer engagement workspace, allowing your agent to send targeted communications, manage segments, retrieve messaging analytics, and automate customer data management on your behalf.

Targeted message analytics and tracking: Retrieve detailed lists of messages sent, including delivery metrics, to monitor campaign performance and engagement.
Segment discovery and membership management: Let your agent fetch all segments, get details for a specific segment, and list all customers in a segment for precise audience targeting.
Integration and webhook management: Have your agent list and review all integrations and webhooks in your workspace to streamline system connectivity and reporting.
Customer profile suppression: Direct your agent to permanently suppress (delete and block) customer profiles, ensuring compliance and data privacy.
Collection metadata retrieval: Retrieve up-to-date details for all collections in your workspace, keeping your AI-powered workflows and automations in sync with your data sources.

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:

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

Step-by-step Guide

Step by step09 STEPS

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

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 Customerio through MCP.

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

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

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

Create a Tool Router session for Customerio

typescript

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

  const composioMCPUrl = session.mcp.url;
  console.log("Customerio MCP URL:", composioMCPUrl);

What's happening:

create spins up a short-lived MCP HTTP endpoint for this user
The toolkits array contains "customerio" for Customerio access
session.mcp.url is the MCP URL that Mastra's MCPClient will connect to

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 Customerio toolkit

Create the Mastra agent

typescript

const agent = new Agent({
    name: "customerio-mastra-agent",
    instructions: "You are an AI agent with Customerio 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

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: {
        customerio: 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 Customerio 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 Customerio 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: ["customerio"],
  });

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "customerio-mastra-agent",
    instructions: "You are an AI agent with Customerio 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: { customerio: 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 Customerio 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 Customerio action and event your agent gets out of the box.

Add Person to Group

Add a person to a Customer.

Author, Version, and Publish Email

Update and version a linked Design Studio email, then publish it.

Create Profile Alias

Create an alias to merge Customer.

Create Segment

Create an empty manual segment in Customer.

Suppress Customer Profile

Suppress a customer profile to permanently delete it and prevent re-adding with the same identifier.

Find Customers by Email

Return Customer.

Get Account Region

Return the region and Track API URL for the connected Customer.

Get Customer Attributes

Return one Customer.

Get Integrations

Retrieve a list of integrations in your workspace to discover configured integrations.

Get Messages

Tool to retrieve a list of messages sent from your workspace.

Get Newsletter Content Metrics

Retrieve engagement metrics for a Customer.

Get Newsletter Metrics

Retrieve aggregate engagement metrics for a Customer.

Get Segment Customer Count

Return the current number of profiles in a Customer.

Get Segment Details

Tool to retrieve details of a specific segment.

Get Segment Membership

Tool to retrieve people in a specific segment.

Get Segments

Tool to retrieve a list of segments in your workspace.

Get Transactional Metrics

Return aggregate engagement metrics for a transactional message template.

Get Trigger

Retrieves details about a specific API-triggered broadcast, including trigger ID, campaign ID, creation timestamp, recipient filter criteria, and personalization data.

Get Broadcast Triggers

Retrieve all API trigger instances for a specific broadcast/campaign.

Get Customer.io Workspace Webhooks

Retrieves all reporting webhook configurations from the Customer.

Identify Person

Identify a person in Customer.

List Activities

Return recent workspace activity-log entries with optional filters.

List Campaigns

Return Customer.

List Collections

Tool to list all Collections metadata.

List Customer Attributes

Return attributes and devices for up to 100 Customer.

List IP Addresses

Tool to retrieve the list of IP addresses used by Customer.

List Newsletters

Tool to list all newsletters.

List Snippets

Tool to list all snippets in your workspace.

List Transactional Contents

Return every language and content variant of a transactional template.

List Transactional Messages

Lists all transactional message templates in your Customer.

List Workspaces

List Customer.

Preview Email

Evaluate a Design Studio email against sample Liquid data without sending.

Search Customers

Search Customer.

Send Batch CDP Calls

Send multiple CDP calls (identify, track, page, screen, group, alias) in a single batch request.

Track Event

Tool to send an event associated with a person in Customer.

Track Page View

Track page views for website visitors through the Customer.

Track Screen View

Track mobile screen views in Customer.

Trigger Broadcast

Manually trigger a Customer.

Unsubscribe from Delivery

Tool to handle custom unsubscribe requests for email deliveries in Customer.

FRAMEWORKS

How to build Customerio MCP Agent with another framework

Claude Code

Use Customerio MCP with Claude Code

ChatGPT

Use Customerio MCP with ChatGPT

Claude Cowork

Use Customerio MCP with Claude Cowork

Antigravity

Use Customerio MCP with Antigravity

OpenAI Agents SDK

Use Customerio MCP with OpenAI Agents SDK

Claude Agent SDK

Use Customerio MCP with Claude Agent SDK

Grok Bot

Use Customerio MCP with Grok Bot

Codex

Use Customerio MCP with Codex

OpenClaw

Use Customerio MCP with OpenClaw

Hermes

Use Customerio MCP with Hermes

Atomic Agent

Use Customerio MCP with Atomic Agent

Google ADK

Use Customerio MCP with Google ADK

LangChain

Use Customerio MCP with LangChain

Vercel AI SDK

Use Customerio MCP with Vercel AI SDK

LlamaIndex

Use Customerio MCP with LlamaIndex

CrewAI

Use Customerio MCP with CrewAI

Pydantic AI

Use Customerio MCP with Pydantic AI

AutoGen

Use Customerio MCP with AutoGen

MORE TOOLKITS

Explore Other Toolkits

Toolkit marketplace

Oauth2

Reddit is a social news platform with thriving user-driven communities (subreddits). It's the go-to place for discussion, content sharing, and viral marketing.

Facebook

Oauth2

Facebook is a social media and advertising platform for businesses and creators. It helps you connect, share, and manage content across your public Facebook Pages.

Oauth2

LinkedIn is a professional networking platform for connecting, sharing content, and engaging with business opportunities. It's the go-to place for building your professional brand and unlocking new career connections.

Active campaign

Api Key

ActiveCampaign is a marketing automation and CRM platform for managing email campaigns, sales pipelines, and customer segmentation. It helps businesses engage customers and drive growth through smart automation and targeted outreach.

FAQ

Frequently asked questions

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

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

Start with Customerio.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Customerio tool your agent needs.Free to start.

Start building

How to integrate Customerio MCP with Mastra AI

Connect Customerio without auth hassles

Introduction

Also integrate Customerio with

TL;DR

What is Mastra AI?

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

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

What is Composio SDK?

How the Composio SDK works

Step-by-step Guide

Prerequisites

Getting API Keys for OpenAI and Composio

Install dependencies

Set up environment variables

Import libraries and validate environment

Create a Tool Router session for Customerio

Configure Mastra MCP client and fetch tools

Create the Mastra agent

Set up interactive chat interface

Complete Code

Conclusion

Supported Tools

How to build Customerio MCP Agent with another framework

Claude Code

ChatGPT

Claude Cowork

Antigravity

OpenAI Agents SDK

Claude Agent SDK

Grok Bot

Codex

OpenClaw

Hermes

Atomic Agent

Google ADK

LangChain

Vercel AI SDK

LlamaIndex

CrewAI

Pydantic AI

AutoGen

Explore Other Toolkits

Reddit

Facebook

Linkedin

Active campaign

Frequently asked questions

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

Can I use Tool Router MCP with Mastra AI?

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

How safe is my data with Composio Tool Router?

Start with Customerio.It takes 30 seconds.