How to integrate Enginemailer MCP with Pydantic AI

This guide walks you through connecting Enginemailer to Pydantic AI using the Composio tool router. By the end, you'll have a working Enginemailer agent that can add new subscriber to newsletter list, pause tomorrow's scheduled marketing campaign, export email delivery report from last week through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Enginemailer account through Composio's Enginemailer MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Enginemailer

Api Key

Enginemailer is an email marketing platform for managing contacts, campaigns, and sending personalized emails. It helps businesses automate outreach and boost engagement with targeted messaging.

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Introduction

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

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

Also integrate Enginemailer with

OpenAI Agents SDK Claude Agent SDK Claude Code Claude Cowork Codex OpenClaw Hermes CLI Google ADK LangChain Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

How to set up your Composio API key and User ID
How to create a Composio Tool Router session for Enginemailer
How to attach an MCP Server to a Pydantic AI agent
How to stream responses and maintain chat history
How to build a simple REPL-style chat interface to test your Enginemailer workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

Type Safety: Built on Pydantic for automatic data validation
MCP Support: Native support for Model Context Protocol servers
Streaming: Built-in support for streaming responses
Async First: Designed for async/await patterns

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

The Enginemailer MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Enginemailer account. It provides structured and secure access to your email marketing platform, so your agent can perform actions like creating campaigns, managing subscriber lists, exporting reports, and sending personalized email campaigns on your behalf.

Campaign creation and scheduling: Direct your agent to set up new email campaigns, configure content, and schedule delivery to your audience.
Subscriber management: Have your agent add new subscribers to your lists, including custom fields and segmentation for targeted outreach.
Instant campaign delivery and controls: Command your agent to send campaigns immediately or pause scheduled campaigns for last-minute adjustments.
Campaign monitoring and reporting: Let your agent export detailed email campaign reports as CSV files and check the status of ongoing exports.
Audience segmentation and subcategory retrieval: Guide your agent to fetch subcategories and organize recipients for more personalized and effective campaigns.

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:

Python 3.9 or higher
A Composio account with an active API key
Basic familiarity with Python and async programming

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

Log in to the Composio dashboard.
Navigate to your API settings and generate a new API key.
Store this key securely as you'll need it for authentication.

Install dependencies

bash

pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

composio connects your agent to external SaaS tools like Enginemailer
pydantic-ai lets you create structured AI agents with tool support
python-dotenv loads your environment variables securely from a .env file

Set up environment variables

bash

COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

COMPOSIO_API_KEY authenticates your agent to Composio's API
USER_ID associates your session with your account for secure tool access
OPENAI_API_KEY to access OpenAI LLMs

Import dependencies

python

import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

What's happening:

We load environment variables and import required modules
Composio manages connections to Enginemailer
MCPServerStreamableHTTP connects to the Enginemailer MCP server endpoint
Agent from Pydantic AI lets you define and run the AI assistant

Create a Tool Router Session

python

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Enginemailer
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["enginemailer"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

What's happening:

We're creating a Tool Router session that gives your agent access to Enginemailer tools
The create method takes the user ID and specifies which toolkits should be available
The returned session.mcp.url is the MCP server URL that your agent will use

Initialize the Pydantic AI Agent

python

# Attach the MCP server to a Pydantic AI Agent
enginemailer_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[enginemailer_mcp],
    instructions=(
        "You are a Enginemailer assistant. Use Enginemailer tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)

What's happening:

The MCP client connects to the Enginemailer endpoint
The agent uses GPT-5 to interpret user commands and perform Enginemailer operations
The instructions field defines the agent's role and behavior

Build the chat interface

python

# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Enginemailer.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()

What's happening:

The agent reads input from the terminal and streams its response
Enginemailer API calls happen automatically under the hood
The model keeps conversation history to maintain context across turns

Run the application

python

if __name__ == "__main__":
    asyncio.run(main())

What's happening:

The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Enginemailer and Pydantic AI:

python

import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Enginemailer
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["enginemailer"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    enginemailer_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[enginemailer_mcp],
        instructions=(
            "You are a Enginemailer assistant. Use Enginemailer tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Enginemailer.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've built a Pydantic AI agent that can interact with Enginemailer through Composio's Tool Router. With this setup, your agent can perform real Enginemailer actions through natural language. You can extend this further by:

Adding other toolkits like Gmail, HubSpot, or Salesforce
Building a web-based chat interface around this agent
Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Enginemailer for workflow automation)

This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.

TOOLS

Supported Tools

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

Activate Subscriber

Tool to activate an inactive subscriber in EngineMailer.

Add or Update Subscriber

Tool to add or update a subscriber with custom fields via N8N integration.

Check Batch Update Status

Tool to check the status of a batch subscriber update operation.

Batch Update Subscribers

Tool to add or update multiple subscribers with custom fields in a single batch operation.

Check Export Status V2

Tool to check status of a previously requested CSV report export.

Test API Connection

Tool to test API connection and verify authentication.

Create Campaign

Tool to create a new email campaign.

Delete Campaign

Tool to delete an undelivered email campaign.

Delete Recipient List

Tool to delete an existing recipient list from a targeted campaign.

Delete Subscriber

Tool to remove a subscriber from the system by email address.

Export CSV Report V2

Tool to export a transactional email report as CSV.

Find Subscriber

Tool to find a subscriber by email address via N8N integration.

Get Custom Field List

Tool to retrieve the list of custom fields configured for subscribers.

Get List Campaign

Tool to get a list of undelivered campaigns.

Get New Subscribers

Tool to retrieve new subscribers with optional filtering by source, form, page, or popup.

Get Subcategories

Tool to retrieve subcategories for a given category.

Get Subscriber

Tool to retrieve subscriber information by email address.

Get Subscriber Autoresponder Completed

Tool to retrieve subscribers who completed autoresponders with optional filtering by autoresponder ID.

Get Subscriber Autoresponder Triggered

Tool to retrieve subscribers who triggered autoresponders with optional filtering by autoresponder ID.

Get Deleted Subscribers

Tool to retrieve deleted subscribers since last polling date.

Get Subscribers Modified

Tool to retrieve modified subscribers since last polling date with optional limit.

Get Subscribers Tagged

Tool to retrieve subscribers who were tagged with optional filtering by subcategory.

Get Untagged Subscribers

Tool to retrieve subscribers who were untagged from subcategories.

Get Unsubscribe Events

Tool to retrieve unsubscribe events with optional filtering by campaign or autoresponder.

Insert Subscriber

Tool to add a new subscriber with optional custom fields.

List Autoresponders

Tool to retrieve a list of all autoresponders.

List Campaigns

Tool to retrieve a list of all campaigns.

List Forms

Tool to retrieve a list of available forms in Enginemailer.

List Pages

Tool to retrieve a list of all pages.

List Popups

Tool to retrieve a list of popups from Enginemailer.

List Templates

Tool to retrieve a list of all email templates.

Pause Campaign

Tool to pause a scheduled email campaign.

Create/Update Category

Tool to create or update a category for subscriber segmentation.

Update Subscriber

Tool to update data for an existing subscriber in EngineMailer.

Send Campaign

Tool to send an email campaign immediately.

Tag Subscriber to Subcategory

Tool to tag a subscriber to a specific subcategory via N8N API endpoint.

Unsubscribe (N8N)

Tool to unsubscribe a subscriber via N8N API endpoint.

Unsubscribe Subscriber

Tool to unsubscribe a subscriber from the email list.

FRAMEWORKS

How to build Enginemailer MCP Agent with another framework

OpenAI Agents SDK

Use Enginemailer MCP with OpenAI Agents SDK

Claude Agent SDK

Use Enginemailer MCP with Claude Agent SDK

Claude Code

Use Enginemailer MCP with Claude Code

Claude Cowork

Use Enginemailer MCP with Claude Cowork

Codex

Use Enginemailer MCP with Codex

OpenClaw

Use Enginemailer MCP with OpenClaw

Hermes

Use Enginemailer MCP with Hermes

CLI

Use Enginemailer MCP with CLI

Google ADK

Use Enginemailer MCP with Google ADK

LangChain

Use Enginemailer MCP with LangChain

Vercel AI SDK

Use Enginemailer MCP with Vercel AI SDK

Mastra AI

Use Enginemailer MCP with Mastra AI

LlamaIndex

Use Enginemailer MCP with LlamaIndex

CrewAI

Use Enginemailer MCP with CrewAI

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FAQ

Frequently asked questions

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

Yes, you can. Pydantic 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 Enginemailer tools.

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

Start with Enginemailer.It takes 30 seconds.

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

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Customer stories

Teams ship real agents on Composio

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Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati

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.

Abhi Arya

Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

Nirman Dave

CEO, Zams

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

Ryan Yu

Founder, Extra Thursday

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.

Tomisin Jenrola

Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Jerome Leclanche

Co-Founder, Ingram Technologies

How to integrate Enginemailer MCP with Pydantic AI

Connect Enginemailer without auth hassles

Introduction

Also integrate Enginemailer with

TL;DR

What is Pydantic AI?

What is the Enginemailer 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 dependencies

Create a Tool Router Session

Initialize the Pydantic AI Agent

Build the chat interface

Run the application

Complete Code

Conclusion

Supported Tools

How to build Enginemailer MCP Agent with another framework

OpenAI Agents SDK

Claude Agent SDK

Claude Code

Claude Cowork

Codex

OpenClaw

Hermes

CLI

Google ADK

LangChain

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

Explore Other Toolkits

Reddit

Facebook

Linkedin

Active campaign

Frequently asked questions

What are the differences in Tool Router MCP and Enginemailer MCP?+

Can I use Tool Router MCP with Pydantic AI?+

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

How safe is my data with Composio Tool Router?+

Start with Enginemailer.It takes 30 seconds.

Teams ship real agents on Composio