How to integrate Unione MCP with Mastra AI

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Introduction

This guide walks you through connecting Unione to Mastra AI using the Composio tool router. By the end, you'll have a working Unione agent that can check my current unione email balance, cancel a scheduled email by job id, list all sender domains and their status, export email events from the past week through natural language commands.

This guide will help you understand how to give your Mastra AI agent real control over a Unione account through Composio's Unione 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:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Unione tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Unione 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 Unione 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 Unione MCP server, and what's possible with it?

The Unione MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Unione account. It provides structured and secure access to your Unione email delivery service, so your agent can send transactional or marketing emails, manage sending domains, monitor delivery events, check account balance, and automate email operations on your behalf.

  • Automated email sending and scheduling: Have your agent send transactional or marketing emails and even schedule deliveries right from your Unione account.
  • Domain verification and management: Easily manage sender domains, trigger domain verifications, and handle DNS/DKIM checks to keep your emails deliverable.
  • Event monitoring and export: Let your agent fetch specific email events, retrieve delivery metrics, or export comprehensive email event logs for auditing and analytics.
  • Account balance and plan checks: Quickly access your current email balance and subscription plan details, ensuring you stay within your sending limits.
  • Email job and pricing insights: Retrieve detailed information about specific email jobs and get up-to-date pricing for cost management before sending campaigns.

Supported Tools & Triggers

Tools
UniOne Email BalanceTool to retrieve current account balance.
Cancel Scheduled EmailTool to cancel a scheduled transactional email by its job id.
UniOne Email Domain ManagementTool to manage sender domains in unione.
Get Email EventTool to retrieve details of a specific email event by its id.
UniOne Email Event TypesTool to retrieve supported email event types.
Get Email Send JobTool to retrieve detailed information about a specific email send job.
UniOne Email List (Export)Tool to export email events within a specified time frame.
UniOne Email Event LogTool to initiate an asynchronous export of email events (event dump).
UniOne Email PlanTool to retrieve current subscription plan details.
UniOne Email PricingTool to retrieve current email pricing.
UniOne Email QuotaTool to retrieve current email sending quota.
Resend Sent EmailTool to resend a previously sent email by its job id.
UniOne Email ResubscribeTool to resubscribe a recipient who previously unsubscribed.
Resume Paused EmailTool to resume a paused transactional email by its job id.
UniOne Email ScheduleTool to schedule a transactional email up to 24 hours ahead.
UniOne Email SMTP ConfigurationTool to retrieve smtp server details and credentials.
UniOne Email StatisticsTool to retrieve email sending statistics over a specified time range.
UniOne Email UnsubscribeTool to unsubscribe an email from future emails.
Validate Email AddressTool to validate an email address.
Batch Email ValidationTool to validate multiple email addresses in a batch.
Resend Email Validation ResultsTool to resend results of an email validation request.
UniOne Email Validate ResultTool to retrieve the detailed result of an email validation request.
Retry Email ValidationTool to retry an email validation request.
UniOne Email Validate StatusTool to retrieve the current status of an email validation request.
UniOne Email Webhook TypesTool to retrieve supported email webhook event types.
Create Event DumpTool to create an asynchronous csv event dump.
UniOne Event Dump ListTool to retrieve the full list of event dumps.
Schedule EmailTool to schedule a transactional email up to 24 hours ahead.
Suppression ListTool to return the suppression list since a given date.
Delete TagTool to delete a specific tag.
UniOne Tag ListTool to retrieve all user-defined tags.
UniOne Template ListTool to list email templates.
Set TemplateTool to set or update an email template.
Delete Email Validation RequestTool to delete an email validation request.
Get Event DumpTool to retrieve the contents of a specific event dump.
Set WebhookTool to set or edit a webhook event notification handler.

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, 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 Unione 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 Unione

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

  const composioMCPUrl = session.mcp.url;
  console.log("Unione MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "unione" for Unione 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 Unione toolkit

Create the Mastra agent

typescript
const agent = new Agent({
    name: "unione-mastra-agent",
    instructions: "You are an AI agent with Unione 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: {
        unione: 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 Unione 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 Unione 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: ["unione"],
  });

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

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

How to build Unione MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Unione MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Unione MCP with Claude Agent SDK

Google ADK

Google ADK

Use Unione MCP with Google ADK

LangChain

LangChain

Use Unione MCP with LangChain

Vercel AI SDK

Vercel AI SDK

Use Unione MCP with Vercel AI SDK

LlamaIndex

LlamaIndex

Use Unione MCP with LlamaIndex

CrewAI

CrewAI

Use Unione MCP with CrewAI

FAQ

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

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

Can I use Tool Router MCP with Mastra AI?

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 Unione tools.

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

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

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