How to integrate Dynosend MCP with Mastra AI

This guide walks you through connecting Dynosend to Mastra AI using the Composio tool router. By the end, you'll have a working Dynosend agent that can add contact to newsletter audience, summarize latest campaign engagement metrics, track signup event for customer through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Dynosend account through Composio's Dynosend MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

Dynosend logoDynosend
Api Key

Dynosend is an email marketing platform for audiences, contacts, campaigns, transactional messages, and customer events. Use it to manage lifecycle email, track engagement, and keep customer communication organized.

18 Tools

Introduction

This guide walks you through connecting Dynosend to Mastra AI using the Composio tool router. By the end, you'll have a working Dynosend agent that can add contact to newsletter audience, summarize latest campaign engagement metrics, track signup event for customer through natural language commands.

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

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

Also integrate Dynosend with

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

The Dynosend MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Dynosend account. It provides structured and secure access to your audiences, contacts, campaigns, transactional messages, and customer events, so your agent can manage contacts, operate campaigns, send transactional messages, track customer activity, and maintain your blacklist on your behalf.

  • Audience and contact management: Have your agent list audiences, create or update contacts, manage tags and custom fields, find duplicate contacts, and delete contacts when required for privacy compliance.
  • Subscription and blacklist control: Let the agent subscribe or unsubscribe contacts, check whether an email is blacklisted, and add addresses to the blacklist when needed.
  • Campaign operations and insights: Direct your agent to list campaigns, review delivery and engagement results, start ready campaigns, or pause and resume campaign delivery.
  • Transactional email delivery: Instruct your agent to send configured transactional messages through your Dynosend account.
  • Customer event tracking: Have your agent record application events for contacts to keep customer activity available in Dynosend.

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 Dynosend 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 Dynosend

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

  const composioMCPUrl = session.mcp.url;
  console.log("Dynosend MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "dynosend" for Dynosend 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 Dynosend toolkit
8

Create the Mastra agent

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

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

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

Add Email To Blacklist

Permanently add an email address to the Dynosend blacklist.

Add Tags To Contact

Append one or more tags to a contact without replacing its existing tags.

Check Blacklist

Check whether an email address is on the connected Dynosend account's blacklist and return its timestamp and reason when available.

Create Contact

Create a contact in an audience, optionally assigning tags and audience-defined custom fields.

Delete Contact

Permanently delete one contact from an audience for GDPR/CCPA erasure.

Find Duplicate Contacts

Find contacts that use the same email address across all audiences in the connected Dynosend account.

Get Audience

Get one audience's configuration, custom-field definitions, contact information, and subscription statistics by audience UID.

Get Campaign

Get one campaign's configuration and delivery, open, click, spam, bounce, and unsubscribe insights.

Get Contact

Get one contact in an audience by contact UID or email address.

List Audiences

List audiences available to the connected Dynosend account, including the UID needed by audience and contact tools.

List Campaigns

List campaigns in the connected Dynosend account, including status and the campaign UID used by campaign tools.

List Contacts

Return one page of contacts in a Dynosend audience, including contact UIDs, subscription status, tags, and audience-defined custom-field values.

Record Contact Event

Record an application event for a contact in an audience.

Send Transactional Message

Send a configured Dynosend transactional message.

Set Campaign Delivery State

Pause a sending campaign or resume a paused campaign by setting its delivery state to paused or sending.

Set Contact Subscription Status

Set a contact's subscription status to subscribed or unsubscribed in an audience.

Start Campaign

Start a ready broadcast campaign.

Update Contact

Update a contact's email, replace its complete tag set, or set audience-defined custom fields.

FAQ

Frequently asked questions

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

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

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