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How to integrate Omnisend MCP with Pydantic AI

Connect Pydantic AI to Omnisend MCP. Add new subscribers from latest signups, update contact email preferences in bulk, and more using natural language, with authentication handled for you.

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Omnisend is a marketing automation platform for ecommerce, specializing in email and SMS campaigns. It helps online businesses engage customers and boost sales with targeted, automated messaging.

43 Tools

Introduction

This guide walks you through connecting Omnisend to Pydantic AI using the Composio tool router. By the end, you'll have a working Omnisend agent that can create and update contacts, sync products and categories, manage carts and orders, send custom events, and list campaigns through natural language commands.

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

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

Also integrate Omnisend with

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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 Omnisend
  • 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 Omnisend 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 Omnisend MCP server, and what's possible with it?

The Omnisend MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Omnisend account. It provides structured and secure access to your ecommerce marketing data, so your agent can manage contacts, automate batch operations, update products, and streamline campaign preparation for your store.

  • Bulk contact and product management: Effortlessly create or update large sets of contacts or products in one go, perfect for onboarding new subscribers or syncing your catalog.
  • Individual contact handling: Retrieve, update, or enrich detailed contact profiles, making it easy for your agent to personalize outreach or manage subscriptions.
  • Batch job automation and tracking: Initiate batch operations and monitor their progress, status, and results to ensure smooth processing of large datasets.
  • Product catalog maintenance: List, review, or delete products directly from your Omnisend account, keeping your store's offerings up to date for campaigns.
  • Contact segmentation and filtering: Fetch paginated and filtered contact lists, enabling targeted marketing actions and smarter audience management.

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:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming
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
  • 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.
3

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 Omnisend
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file
4

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
5

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 Omnisend
  • MCPServerStreamableHTTP connects to the Omnisend MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant
6

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 Omnisend
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["omnisend"],
    )
    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 Omnisend 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
7

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
omnisend_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[omnisend_mcp],
    instructions=(
        "You are a Omnisend assistant. Use Omnisend tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Omnisend endpoint
  • The agent uses GPT-5 to interpret user commands and perform Omnisend operations
  • The instructions field defines the agent's role and behavior
8

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 Omnisend.\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
  • Omnisend API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns
9

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 Omnisend 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 Omnisend
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["omnisend"],
    )
    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
    omnisend_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[omnisend_mcp],
        instructions=(
            "You are a Omnisend assistant. Use Omnisend 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 Omnisend.\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 Omnisend through Composio's Tool Router. With this setup, your agent can perform real Omnisend 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 + Omnisend 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 Omnisend action and event your agent gets out of the box.

Add Cart Product

Tool to add a product to a cart in Omnisend (v3 API).

Create Batch

Tool to create a new batch operation for multiple items.

Create Cart

Tool to create a new shopping cart in Omnisend.

Create Category

Tool to create a new category in Omnisend.

Create Order

Tool to create a new order in Omnisend v3 API.

Create or Update Contact

Create or update an Omnisend contact using email identifiers and subscriber details.

Create Product

Tool to create a new product in the Omnisend product catalog.

Create Product Category

Tool to create a new product category in the Omnisend catalog.

Delete Cart

Tool to delete a cart from Omnisend by its ID (v3 API).

Delete Category

Tool to remove a category from Omnisend by its ID.

Delete Order

Tool to delete an order from Omnisend by its ID.

Delete Product

Tool to remove a product from Omnisend by its ID.

Delete Product Category

Tool to remove a product category from Omnisend by its ID.

Get Batches

Retrieve a list of batch operations for a required target endpoint: contacts, orders, products, events, or categories.

Get Batch Information

Tool to retrieve information about a specific batch by ID.

Get Batch Item

Tool to retrieve a specific item within a batch by batchID and itemID.

Get Batch Items

Retrieve items for a specific Omnisend batch by ID to inspect individual batch operation results.

Get Brand

Tool to retrieve information about the current authenticated brand.

Get Cart

Tool to retrieve a specific cart by ID from Omnisend v3 API.

Get Category

Tool to retrieve details of a specific category by ID.

Get Contact

Tool to retrieve details of a single contact by ID.

Get Order

Tool to retrieve details of a specific order by ID.

Get Product

Tool to retrieve details of a specific product by ID from Omnisend.

Get Product Category

Tool to retrieve a specific product category by ID.

List Campaigns

Tool to retrieve a paginated list of campaigns with optional filtering by status and type.

List Carts

Tool to retrieve a paginated list of carts with optional filtering.

List Categories

Tool to retrieve a paginated list of product categories.

List Contacts

Tool to retrieve a paginated list of contacts with optional filtering.

List Events

Tool to retrieve all custom events created in Omnisend app.

List Product Categories

Tool to retrieve a paginated list of product categories from the Omnisend catalog.

List Products

Tool to retrieve a paginated list of products.

Remove Cart Product

Tool to remove a product from a cart in Omnisend.

Replace Cart

Tool to replace an existing cart in Omnisend using the v3 API.

Replace Cart Product

Tool to replace a product in a cart using Omnisend v3 API.

Replace Category

Tool to replace a category's title by ID.

Replace Order

Tool to completely replace an existing order in Omnisend.

Replace Product

Tool to replace an existing product in the Omnisend catalog.

Send Event

Tool to send a customer event to Omnisend.

Update Cart

Partially update a cart in Omnisend's v3 API, including its recovery URL or products.

Update Cart Product

Tool to update a product in a cart (v3 API).

Update Contact

Tool to update fields of an existing contact by ID.

Update Order Status

Tool to partially update an order status in Omnisend (v3 API).

Update Product Category

Tool to update an existing product category title in Omnisend.

FRAMEWORKS

How to build Omnisend MCP Agent with another framework

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OpenAI Agents SDK

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Claude Agent SDK

Use Omnisend MCP with Claude Agent SDK

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Codex

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OpenClaw logo

OpenClaw

Use Omnisend MCP with OpenClaw

Hermes logo

Hermes

Use Omnisend MCP with Hermes

Atomic Agent logo

Atomic Agent

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Google ADK logo

Google ADK

Use Omnisend MCP with Google ADK

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LangChain

Use Omnisend MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Omnisend MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Omnisend MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Omnisend MCP with LlamaIndex

CrewAI logo

CrewAI

Use Omnisend MCP with CrewAI

AutoGen logo

AutoGen

Use Omnisend MCP with AutoGen

FAQ

Frequently asked questions

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

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

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