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How to integrate Resend MCP with OpenAI Agents SDK

Connect OpenAI Agents SDK to Resend MCP. Create a new contact for your newsletter, list all domains connected to your account, and more using natural language, with authentication handled for you.

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Resend is a universal API for sending emails using a single, modern endpoint. It streamlines transactional and marketing email delivery for developers and teams.

113 Tools

Introduction

This guide walks you through connecting Resend to the OpenAI Agents SDK using the Composio tool router. By the end, you'll have a working Resend agent that can send transactional and batch emails, run broadcasts, manage contacts and segments, verify sending domains, and edit email templates through natural language commands.

This guide will help you understand how to give your OpenAI Agents SDK agent real control over a Resend account through Composio's Resend MCP server.

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

Also integrate Resend with

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TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Install the necessary dependencies
  • Initialize Composio and create a Tool Router session for Resend
  • Configure an AI agent that can use Resend as a tool
  • Run a live chat session where you can ask the agent to perform Resend operations

What is OpenAI Agents SDK?

The OpenAI Agents SDK is a lightweight framework for building AI agents that can use tools and maintain conversation state. It provides a simple interface for creating agents with hosted MCP tool support.

Key features include:

  • Hosted MCP Tools: Connect to external services through hosted MCP endpoints
  • SQLite Sessions: Persist conversation history across interactions
  • Simple API: Clean interface with Agent, Runner, and tool configuration
  • Streaming Support: Real-time response streaming for interactive applications

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

The Resend MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Resend account. It provides structured and secure access to your email sending and contact management capabilities, so your agent can perform actions like sending emails, managing audiences, creating domains, and handling contacts on your behalf.

  • Automated email delivery and scheduling: Ask your agent to send emails instantly or schedule them for later, and even cancel scheduled messages if needed.
  • Audience and contact management: Let your agent create, list, or delete audiences and individual contacts, keeping your recipient lists organized without manual effort.
  • Domain administration: Easily have your agent set up, list, or remove email sending domains, streamlining onboarding or maintenance for your email infrastructure.
  • Seamless recipient segmentation: Direct your agent to group contacts into audiences for targeted campaigns or communications, improving personalization and reach.
  • Bulk operations and cleanups: Enable your agent to quickly list, update, or delete multiple contacts, audiences, or domains to maintain a tidy and up-to-date email system.

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:
  • Composio API Key and OpenAI API Key
  • Primary know-how of OpenAI Agents SDK
  • A live Resend project
  • Some knowledge of Python or Typescript
2

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
3

Install dependencies

npm install @composio/openai-agents @openai/agents dotenv

Install the Composio SDK and the OpenAI Agents SDK.

4

Set up environment variables

bash
OPENAI_API_KEY=sk-...your-api-key
COMPOSIO_API_KEY=your-api-key
USER_ID=composio_user@gmail.com

Create a .env file and add your OpenAI and Composio API keys.

5

Import dependencies

import 'dotenv/config';
import { Composio } from '@composio/core';
import { OpenAIAgentsProvider } from '@composio/openai-agents';
import { Agent, hostedMcpTool, run, OpenAIConversationsSession } from '@openai/agents';
import * as readline from 'readline';
What's happening:
  • You're importing all necessary libraries.
  • The Composio and OpenAIAgentsProvider classes are imported to connect your OpenAI agent to Composio tools like Resend.
6

Set up the Composio instance

dotenv.config();

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.USER_ID;

if (!composioApiKey) {
  throw new Error('COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key');
}
if (!userId) {
  throw new Error('USER_ID is not set');
}

// Initialize Composio
const composio = new Composio({
  apiKey: composioApiKey,
  provider: new OpenAIAgentsProvider(),
});
What's happening:
  • dotenv.config() loads your .env file so COMPOSIO_API_KEY and USER_ID are available as environment variables.
  • Creating a Composio instance using the API Key and OpenAIAgentsProvider class.
7

Create a Tool Router session

// Create Tool Router session for Resend
const session = await composio.create(userId as string, {
  toolkits: ['resend'],
});
const mcpUrl = session.mcp.url;

What is happening:

  • You give the Tool Router the user id and the toolkits you want available. Here, it is only resend.
  • The router checks the user's Resend connection and prepares the MCP endpoint.
  • The returned session.mcp.url is the MCP URL that your agent will use to access Resend.
  • This approach keeps things lightweight and lets the agent request Resend tools only when needed during the conversation.
8

Configure the agent

// Configure agent with MCP tool
const agent = new Agent({
  name: 'Assistant',
  model: 'gpt-5',
  instructions:
    'You are a helpful assistant that can access Resend. Help users perform Resend operations through natural language.',
  tools: [
    hostedMcpTool({
      serverLabel: 'tool_router',
      serverUrl: mcpUrl,
      headers: { 'x-api-key': composioApiKey },
      requireApproval: 'never',
    }),
  ],
});
What's happening:
  • We're creating an Agent instance with a name, model (gpt-5), and clear instructions about its purpose.
  • The agent's instructions tell it that it can access Resend and help with queries, inserts, updates, authentication, and fetching database information.
  • The tools array includes a hostedMcpTool that connects to the MCP server URL we created earlier.
  • The headers object includes the Composio API key for secure authentication with the MCP server.
  • requireApproval: 'never' means the agent can execute Resend operations without asking for permission each time, making interactions smoother.
9

Start chat loop and handle conversation

// Keep conversation state across turns
const conversationSession = new OpenAIConversationsSession();

// Simple CLI
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: 'You: ',
});

console.log('\nComposio Tool Router session created.');
console.log('\nChat started. Type your requests below.');
console.log("Commands: 'exit', 'quit', or 'q' to end\n");

try {
  const first = await run(agent, 'What can you help me with?', { session: conversationSession });
  console.log(`Assistant: ${first.finalOutput}\n`);
} catch (e) {
  console.error('Error:', e instanceof Error ? e.message : e, '\n');
}

rl.prompt();

rl.on('line', async (userInput) => {
  const text = userInput.trim();

  if (['exit', 'quit', 'q'].includes(text.toLowerCase())) {
    console.log('Goodbye!');
    rl.close();
    process.exit(0);
  }

  if (!text) {
    rl.prompt();
    return;
  }

  try {
    const result = await run(agent, text, { session: conversationSession });
    console.log(`\nAssistant: ${result.finalOutput}\n`);
  } catch (e) {
    console.error('Error:', e instanceof Error ? e.message : e, '\n');
  }

  rl.prompt();
});

rl.on('close', () => {
  console.log('\n👋 Session ended.');
  process.exit(0);
});
What's happening:
  • The program prints a session URL that you visit to authorize Resend.
  • After authorization, the chat begins.
  • Each message you type is processed by the agent using run().
  • The responses are printed to the console.
  • Typing exit, quit, or q cleanly ends the chat.

Complete Code

Here's the complete code to get you started with Resend and OpenAI Agents SDK:

import 'dotenv/config';
import { Composio } from '@composio/core';
import { OpenAIAgentsProvider } from '@composio/openai-agents';
import { Agent, hostedMcpTool, run, OpenAIConversationsSession } from '@openai/agents';
import * as readline from 'readline';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.USER_ID;

if (!composioApiKey) {
  throw new Error('COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key');
}
if (!userId) {
  throw new Error('USER_ID is not set');
}

// Initialize Composio
const composio = new Composio({
  apiKey: composioApiKey,
  provider: new OpenAIAgentsProvider(),
});

async function main() {
  // Create Tool Router session
  const session = await composio.create(userId as string, {
    toolkits: ['resend'],
  });
  const mcpUrl = session.mcp.url;

  // Configure agent with MCP tool
  const agent = new Agent({
    name: 'Assistant',
    model: 'gpt-5',
    instructions:
      'You are a helpful assistant that can access Resend. Help users perform Resend operations through natural language.',
    tools: [
      hostedMcpTool({
        serverLabel: 'tool_router',
        serverUrl: mcpUrl,
        headers: { 'x-api-key': composioApiKey },
        requireApproval: 'never',
      }),
    ],
  });

  // Keep conversation state across turns
  const conversationSession = new OpenAIConversationsSession();

  // Simple CLI
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: ',
  });

  console.log('\nComposio Tool Router session created.');
  console.log('\nChat started. Type your requests below.');
  console.log("Commands: 'exit', 'quit', or 'q' to end\n");

  try {
    const first = await run(agent, 'What can you help me with?', { session: conversationSession });
    console.log(`Assistant: ${first.finalOutput}\n`);
  } catch (e) {
    console.error('Error:', e instanceof Error ? e.message : e, '\n');
  }

  rl.prompt();

  rl.on('line', async (userInput) => {
    const text = userInput.trim();

    if (['exit', 'quit', 'q'].includes(text.toLowerCase())) {
      console.log('Goodbye!');
      rl.close();
      process.exit(0);
    }

    if (!text) {
      rl.prompt();
      return;
    }

    try {
      const result = await run(agent, text, { session: conversationSession });
      console.log(`\nAssistant: ${result.finalOutput}\n`);
    } catch (e) {
      console.error('Error:', e instanceof Error ? e.message : e, '\n');
    }

    rl.prompt();
  });

  rl.on('close', () => {
    console.log('\nSession ended.');
    process.exit(0);
  });
}

main().catch((err) => {
  console.error('Fatal error:', err);
  process.exit(1);
});

Conclusion

This was a starter code for integrating Resend MCP with OpenAI Agents SDK to build a functional AI agent that can interact with Resend.

Key features:

  • Hosted MCP tool integration through Composio's Tool Router
  • SQLite session persistence for conversation history
  • Simple async chat loop for interactive testing
You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.
TOOLS

Supported Tools

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

Add Contact To Segment

Add an existing contact to a segment in Resend.

Batch Add Suppressions

Add between 1 and 100 Resend suppressions to prevent sending to those emails.

Batch Remove Suppressions

Remove 1–100 Resend suppressions by email addresses or suppression IDs, but not both.

Cancel Broadcast

Cancel a queued or scheduled broadcast.

Cancel Email

Cancel a scheduled email.

Create API Key

Create a new API key to authenticate communications with Resend.

Create Audience

Create a segment using the legacy audience action and response shape.

Create Automation

Create a Resend automation from workflow steps and connections.

Create Contact

Create a global contact and add it to the segment identified by audienceId.

Create Contact Import

Create a contact import from a CSV file, optionally mapping columns and applying segments and topic subscriptions.

Create Contact Property

Tool to create a new contact property in Resend.

Create Contact V2

Tool to create a new contact in Resend.

Create Domain

Create a domain through the Resend Email API.

Create Domain Claim

Start a claim for a domain another Resend account has already verified.

Create Draft Broadcast

Create a broadcast and leave it as an unsent draft.

Create Event

Create a Resend event definition, optionally with a typed payload schema.

Create Segment

Create a new segment for contacts to be added to.

Create Suppression

Create a Resend suppression for an email address to prevent sending to it.

Create Template

Tool to create a new email template in Resend.

Create Topic

Tool to create a new topic to segment your audience.

Create Webhook

Tool to create a webhook to receive real-time notifications about email events.

Delete API Key

Remove an existing API key from Resend.

Delete Audience

Remove a segment using the legacy audience action and response shape.

Delete Automation

Remove an existing automation from Resend using its automation ID.

Delete Broadcast

Remove an existing broadcast that is in draft status.

Delete Contact

Remove a contact from the segment identified by audienceId, preserving the global contact.

Delete Contact By ID

Tool to remove an existing contact by its ID.

Delete Contact Property

Remove an existing contact property from Resend.

Delete Domain

Delete a domain through the Resend Email API.

Delete Event

Delete an existing Resend event using its event ID (UUID) or event name.

Delete Segment

Remove an existing segment.

Delete Suppression

Remove a Resend suppression using its suppression ID or email address.

Delete Template

Remove an existing template.

Delete Topic

Delete an existing Resend topic by its topic ID.

Delete Webhook

Remove an existing webhook by ID.

Duplicate Automation

Duplicate an existing automation by its ID and return the new automation's ID.

Duplicate Broadcast

Create a new draft broadcast from an existing broadcast.

Duplicate Template

Duplicate an existing template through the Resend Email API.

Get Automation

Retrieve a Resend automation by ID, including its active workflow steps and connections.

Get Automation Run

Retrieve a Resend automation run by automation and run IDs, including its status and step executions in graph order.

Get Broadcast

Retrieve a single broadcast by its ID.

Get Contact

Tool to retrieve a single contact from Resend by ID or email.

Get Contact Import

Retrieve a contact import by ID to check its status, timestamps, and processed row counts.

Get Contact Property

Tool to retrieve a single contact property from Resend.

Get Domain Claim

Retrieve the latest claim for a placeholder domain created by a claim.

Get Email Attachment

Retrieve a single attachment from a sent email.

Get Email Metrics

Retrieve account-level email metrics over a date range, with optional filters and dimension breakdowns.

Get Event

Retrieve a Resend event definition by UUID or event name.

Get Log

Retrieve a single Resend API log by its ID.

Get Received Email

Retrieve a single received email by ID, including its content, headers, recipients, and attachment metadata.

Get Received Email Attachment

Retrieve a single attachment from a received email, including its metadata and signed download URL.

Get Segment

Retrieve a single segment by its ID.

Get Suppression

Retrieve a Resend suppression by ID or email address.

Get Template

Retrieve a single template by ID or alias from Resend.

Get Topic

Tool to retrieve a single topic by its ID in Resend.

Get Usage

Retrieve the account's current usage and plan limits for emails, contacts, segments, broadcasts, AI credits, automation runs, domains, and API requests.

Get Webhook

Retrieve a single webhook for the authenticated user.

Get Webhook Event

Retrieve a single webhook event by webhook ID and event ID.

List All Contacts

Tool to retrieve a list of all contacts from Resend.

List API Keys

Tool to retrieve a list of API keys for the authenticated user.

List Audiences

List segments using the legacy audience action and response shape.

List Automation Runs

Retrieve a page of runs for a Resend automation.

List Automations

Retrieve a page of Resend automations.

List Broadcast Clicked Links

Retrieve one page of a broadcast's clicked URLs and total and unique click counts.

List Broadcast Recipients

Retrieve a page of broadcast recipients filtered by a required event type.

List Broadcasts

Tool to retrieve a list of broadcasts.

List Contact Imports

Retrieve a page of Resend contact imports, optionally filtered by status.

List Contact Properties

Tool to retrieve a list of contact properties from Resend.

List Contacts

List contacts belonging to the segment identified by the legacy audienceId parameter.

List Contact Segments

Retrieve a list of segments that a contact is part of.

List Contact Topics

Retrieve a list of topic subscriptions for a contact in Resend.

List Domains

List all domains.

List Email Attachments

Tool to retrieve a list of attachments from a sent email.

List Emails

Tool to retrieve a list of emails sent by your team.

List Events

Retrieve a page of Resend event definitions and their payload schemas.

List Logs

Retrieve a page of Resend API request logs with optional cursor pagination.

List Received Email Attachments

Retrieve a paginated list of attachments for a received email, including metadata and signed download URLs.

List Received Emails

Tool to retrieve a list of received emails for the authenticated user.

List Segments

Retrieve a page of Resend segments for audience management.

List Suppressions

Retrieve a page of suppressed email addresses from Resend, optionally filtered by bounce, complaint, or manual origin.

List Templates

Tool to retrieve a list of templates from Resend.

List Topics

Tool to retrieve a list of topics for the authenticated user.

List Webhook Event Attempts

Retrieve a page of delivery attempts for an event on a Resend webhook, including HTTP status codes, response bodies, and send timestamps.

List Webhook Events

Retrieve a page of events for a Resend webhook, including delivery status.

List Webhooks

Retrieve a list of webhooks for the authenticated user.

Publish Template

Publish a template through the Resend Email API.

Remove Contact From Segment

Remove an existing contact from a segment.

Replay Webhook Event

Queue one more delivery of an event to an enabled webhook.

Retrieve Audience

Retrieve a segment using the legacy audience action and response shape.

Retrieve Contact

Retrieve a global contact by ID.

Retrieve Domain

Retrieve a single domain.

Retrieve Email

Retrieve a single email.

Send Batch Emails

Trigger up to 100 batch emails at once.

Send Broadcast

Send an existing Resend broadcast immediately or schedule it for a later ISO 8601 date.

Send Email

Send an email using Resend.

Send Event

Send an event associated with a contact ID or email, with an optional payload.

Share Email

Create a shareable link for a sent or received Resend email.

Stop Automation

Stop an automation by its ID and return its status after stopping.

Update Automation

Update a Resend automation's name, status, or workflow graph.

Update Broadcast

Update an existing broadcast in Resend.

Update Contact

Tool to update an existing contact in Resend by ID or email.

Update Contact Property

Update an existing contact property in Resend.

Update Contact Topics

Update topic subscriptions for a Resend contact by ID or email address.

Update Domain

Update an existing domain's click tracking, open tracking, and TLS settings.

Update Draft Broadcast

Update a broadcast that is still an unsent draft.

Update Email

Update the scheduled send time of a scheduled email by ID.

Update Event

Update a Resend event definition's payload schema by UUID or event name.

Update Segment

Update an existing segment in Resend.

Update Template

Tool to update an existing email template in Resend.

Update Topic

Tool to update an existing topic in Resend.

Update Webhook

Tool to update an existing webhook configuration.

Verify Domain

Verify a domain through the Resend Email API.

Verify Domain Claim

Trigger asynchronous DNS verification and ownership transfer for a domain claim.

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AutoGen

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FAQ

Frequently asked questions

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

Yes, you can. OpenAI Agents SDK 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 Resend tools.

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

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