# How to integrate Smtp2go MCP with Pydantic AI ```json { "title": "How to integrate Smtp2go MCP with Pydantic AI", "toolkit": "Smtp2go", "toolkit_slug": "smtp2go", "framework": "Pydantic AI", "framework_slug": "pydantic-ai", "url": "https://composio.dev/toolkits/smtp2go/framework/pydantic-ai", "markdown_url": "https://composio.dev/toolkits/smtp2go/framework/pydantic-ai.md", "updated_at": "2026-09-24T11:25:26.622Z" } ``` ## Introduction This guide walks you through connecting Smtp2go to Pydantic AI using the Composio tool router. By the end, you'll have a working Smtp2go agent that can search for bounced emails this week, add marketing@mydomain.com as allowed sender, list all verified sender domains through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Smtp2go account through Composio's Smtp2go MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Smtp2go with - [Claude Code](https://composio.dev/toolkits/smtp2go/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/smtp2go/framework/claude-cowork) - [OpenAI Agents SDK](https://composio.dev/toolkits/smtp2go/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/smtp2go/framework/claude-agents-sdk) - [Codex](https://composio.dev/toolkits/smtp2go/framework/codex) - [OpenClaw](https://composio.dev/toolkits/smtp2go/framework/openclaw) - [Hermes](https://composio.dev/toolkits/smtp2go/framework/hermes-agent) - [Atomic Agent](https://composio.dev/toolkits/smtp2go/framework/atomic-agent) - [Google ADK](https://composio.dev/toolkits/smtp2go/framework/google-adk) - [LangChain](https://composio.dev/toolkits/smtp2go/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/smtp2go/framework/ai-sdk) - [Mastra AI](https://composio.dev/toolkits/smtp2go/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/smtp2go/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/smtp2go/framework/crew-ai) - [AutoGen](https://composio.dev/toolkits/smtp2go/framework/autogen) ## 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 Smtp2go - 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 Smtp2go 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 Smtp2go MCP server, and what's possible with it? The Smtp2go MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Smtp2go account. It provides structured and secure access to your email sending and management infrastructure, so your agent can perform actions like searching email activity, managing allowed senders, updating sender domains, and controlling IP allow lists on your behalf. - Comprehensive email activity search: Ask your agent to filter and retrieve email events such as sends, opens, clicks, and bounces by recipient, date, or message ID. - Allowed sender management: Have your agent add, update, remove, or view allowed sender email addresses to control who can send emails from your account. - Sender domain configuration: Let the agent register new sender domains for SPF/DKIM verification and manage domain-related settings seamlessly. - IP allow list control: Direct your agent to add or remove IP addresses or CIDR ranges in your account’s IP allow list, enhancing security for sending sources. - Email delivery monitoring: Enable your agent to search and analyze sent emails, helping you monitor delivery, troubleshoot issues, and ensure reliable communication. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `SMTP2GO_ACTIVITY_SEARCH` | Search Email Activity | Tool to search activity events like sends, opens, clicks, and bounces. Use when you need to filter account email activity by date, event, recipient, or message ID. | | `SMTP2GO_ALLOWED_SENDERS_ADD` | Add Allowed Sender | Tool to add a new allowed sender email address. Use when you need to whitelist a sender before sending email. Example: Add "user@example.com" to allowed senders list. | | `SMTP2GO_ALLOWED_SENDERS_REMOVE` | Remove Allowed Sender | Tool to remove a sender email address from the allowed senders list. Use when you need to revoke send permissions for a validated address. | | `SMTP2GO_ALLOWED_SENDERS_UPDATE` | Update Allowed Senders | Tool to update (replace) the entire allowed senders list in your SMTP2GO account. This action overwrites the current list with the provided email addresses and domain names. Use when you need to set or update who can send emails through your account. Example: 'Update allowed senders to include user@example.com and admin@company.com in whitelist mode.' | | `SMTP2GO_ALLOWED_SENDERS_VIEW` | View Allowed Senders | Tool to view the list of allowed senders configured in your account. Use after setting up SMTP2GO authentication to retrieve your allowed-senders list. Example: 'Show me all verified allowed senders.' | | `SMTP2GO_DOMAIN_ADD` | Add Sender Domain | Tool to add a new sender domain for SPF/DKIM verification. Use when you need to register a domain and optionally set tracking/return-path subdomains. | | `SMTP2GO_EMAIL_SEARCH` | Search SMTP2GO Emails | Tool to search sent emails. Use when filtering your SMTP2GO account's email activity by criteria like date, sender, or recipient. Call after authentication. | | `SMTP2GO_IP_ALLOW_LIST_ADD` | Add IP Allow List | Tool to add a public IP address to your account's IP allow list. Use when you need to whitelist specific sending sources by IP after confirming accuracy. Note: Only plain IP addresses are supported (no CIDR notation). Private/reserved IP ranges are rejected. | | `SMTP2GO_IP_ALLOW_LIST_REMOVE` | Remove IP from Allow List | Tool to remove an IP address from your account's IP allow list. Use after identifying the IP you wish to revoke. | | `SMTP2GO_IP_ALLOW_LIST_VIEW` | View IP Allow List | Tool to view the list of IP addresses in your IP allow list. Use after confirming your SMTP2GO API key is set. | | `SMTP2GO_SMS_VIEW_RECEIVED` | View Received SMS | Tool to retrieve received SMS replies for your SMTP2GO account. Use when you need to fetch incoming SMS messages for analysis or display. Pagination supported via limit and offset. | | `SMTP2GO_STATS_EMAIL_BOUNCES` | Get Email Bounces Stats | Tool to retrieve email bounces statistics. Use after sending emails to analyze bounce metrics over a time period. | | `SMTP2GO_STATS_EMAIL_CYCLE` | Email Cycle Statistics | Tool to retrieve current email cycle/quota statistics. Use when you need to check the account's monthly email allowance, usage, and remaining quota for the current billing cycle. | | `SMTP2GO_STATS_EMAIL_HISTORY` | Email History Statistics | Tool to retrieve email history statistics. Use when you need detailed delivery metrics within a date range. | | `SMTP2GO_STATS_EMAIL_SPAM` | Email Spam Statistics | Tool to retrieve email spam report statistics. Use when analyzing spam trends for sent emails. | | `SMTP2GO_STATS_EMAIL_UNSUBS` | Email Unsubscription Stats | Tool to retrieve email unsubscribe statistics. Use when you need unsubscribe data for your account over a date range. | | `SMTP2GO_SUBACCOUNTS_SEARCH` | Search Subaccounts | Tool to search subaccounts. Use after authenticating to filter and paginate your subaccounts by name, email, or status. | | `SMTP2GO_SUBACCOUNTS_USAGE` | Subaccounts Usage | Tool to retrieve usage statistics for subaccounts. Use when you need to monitor per-subaccount email usage. | | `SMTP2GO_SUPPRESSION_ADD` | Add to Suppression List | Tool to add email addresses or domains to the suppression list. Use when you need to block sending emails to specific recipients or entire domains after unsubscribes or bounces. | | `SMTP2GO_SUPPRESSION_REMOVE` | Remove suppression entry | Tool to remove an email address or domain from the suppression list. Use when you want to resume sending to the address or domain. | | `SMTP2GO_SUPPRESSION_VIEW` | View Suppression List | Tool to view the suppression list. Use when you need to inspect suppressed email addresses in your account. | | `SMTP2GO_TEMPLATE_EDIT` | Edit Email Template | Tool to edit details of an existing email template. Use when you need to update template properties after confirming its ID. | | `SMTP2GO_TEMPLATE_SEARCH` | Search Email Templates | Tool to search your collection of email templates by ID or name. Use when you need to find templates matching specific criteria after authentication. | | `SMTP2GO_TEMPLATE_VIEW` | View Email Template | Tool to view details of a specific email template. Use after you have the template ID to inspect. | | `SMTP2GO_USERS_SMTP_ADD` | Add SMTP User | Tool to add a new SMTP user. Use when you need to provision a fresh SMTP credential after collecting username and password. | | `SMTP2GO_USERS_SMTP_EDIT` | Edit SMTP User | Tool to edit details of an existing SMTP user. Use when you need to update username, password, sender restrictions, or enable/disable a user after confirming the target username. | | `SMTP2GO_USERS_SMTP_REMOVE` | Remove SMTP User | Tool to remove an SMTP user from your account. Use when you need to revoke SMTP access for a user. | | `SMTP2GO_USERS_SMTP_VIEW` | View SMTP Users | Tool to list all SMTP users configured on your account. Use when you need to retrieve SMTP user configurations. | | `SMTP2GO_WEBHOOK_ADD` | Add Webhook | Tool to create a new webhook. Use when you need real-time notifications of email or SMS events. | | `SMTP2GO_WEBHOOK_EDIT` | Edit Webhook | Tool to edit an existing webhook’s settings. Use when you need to update a webhook's configuration after creation. | | `SMTP2GO_WEBHOOK_REMOVE` | Remove webhook | Tool to remove a webhook. Use when you want to delete a webhook by its ID from your SMTP2GO account. | | `SMTP2GO_WEBHOOK_VIEW` | View Webhooks | Tool to view all webhooks configured in your account. Use when you need to inspect existing webhook configurations after setup. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Smtp2go MCP server is an implementation of the Model Context Protocol that connects your AI agent to Smtp2go. It provides structured and secure access so your agent can perform Smtp2go operations on your behalf through a secure, permission-based interface. With Composio's managed implementation, you don't have to create your own developer app. For production, if you're building an end product, we recommend using your own credentials. The managed server helps you prototype fast and go from 0-1 faster. ## Step-by-step Guide ### 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 ### 1. Getting API Keys for OpenAI and Composio OpenAI API Key - Go to the [OpenAI dashboard](https://platform.openai.com/settings/organization/api-keys) 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](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs). - Navigate to your API settings and generate a new API key. - Store this key securely as you'll need it for authentication. ### 2. Install dependencies Install the required libraries. What's happening: - composio connects your agent to external SaaS tools like Smtp2go - pydantic-ai lets you create structured AI agents with tool support - python-dotenv loads your environment variables securely from a .env file ```bash pip install composio pydantic-ai python-dotenv ``` ### 3. Set up environment variables 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 ```bash COMPOSIO_API_KEY=your_composio_api_key_here USER_ID=your_user_id_here OPENAI_API_KEY=your_openai_api_key ``` ### 4. Import dependencies What's happening: - We load environment variables and import required modules - Composio manages connections to Smtp2go - MCPServerStreamableHTTP connects to the Smtp2go MCP server endpoint - Agent from Pydantic AI lets you define and run the AI assistant ```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() ``` ### 5. Create a Tool Router Session What's happening: - We're creating a Tool Router session that gives your agent access to Smtp2go 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 ```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 Smtp2go composio = Composio(api_key=api_key) session = composio.create( user_id=user_id, toolkits=["smtp2go"], ) url = session.mcp.url if not url: raise ValueError("Composio session did not return an MCP URL") ``` ### 6. Initialize the Pydantic AI Agent What's happening: - The MCP client connects to the Smtp2go endpoint - The agent uses GPT-5 to interpret user commands and perform Smtp2go operations - The instructions field defines the agent's role and behavior ```python # Attach the MCP server to a Pydantic AI Agent smtp2go_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY}) agent = Agent( "openai:gpt-5", toolsets=[smtp2go_mcp], instructions=( "You are a Smtp2go assistant. Use Smtp2go tools to help users " "with their requests. Ask clarifying questions when needed." ), ) ``` ### 7. Build the chat interface What's happening: - The agent reads input from the terminal and streams its response - Smtp2go API calls happen automatically under the hood - The model keeps conversation history to maintain context across turns ```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 Smtp2go.\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() ``` ### 8. Run the application What's happening: - The asyncio loop launches the agent and keeps it running until you exit ```python if __name__ == "__main__": asyncio.run(main()) ``` ## Complete Code ```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 Smtp2go composio = Composio(api_key=api_key) session = composio.create( user_id=user_id, toolkits=["smtp2go"], ) 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 smtp2go_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY}) agent = Agent( "openai:gpt-5", toolsets=[smtp2go_mcp], instructions=( "You are a Smtp2go assistant. Use Smtp2go 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 Smtp2go.\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 Smtp2go through Composio's Tool Router. With this setup, your agent can perform real Smtp2go 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 + Smtp2go for workflow automation) This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations. ## How to build Smtp2go MCP Agent with another framework - [Claude Code](https://composio.dev/toolkits/smtp2go/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/smtp2go/framework/claude-cowork) - [OpenAI Agents SDK](https://composio.dev/toolkits/smtp2go/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/smtp2go/framework/claude-agents-sdk) - [Codex](https://composio.dev/toolkits/smtp2go/framework/codex) - [OpenClaw](https://composio.dev/toolkits/smtp2go/framework/openclaw) - [Hermes](https://composio.dev/toolkits/smtp2go/framework/hermes-agent) - [Atomic Agent](https://composio.dev/toolkits/smtp2go/framework/atomic-agent) - [Google ADK](https://composio.dev/toolkits/smtp2go/framework/google-adk) - [LangChain](https://composio.dev/toolkits/smtp2go/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/smtp2go/framework/ai-sdk) - [Mastra AI](https://composio.dev/toolkits/smtp2go/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/smtp2go/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/smtp2go/framework/crew-ai) - [AutoGen](https://composio.dev/toolkits/smtp2go/framework/autogen) ## Related Toolkits - [0CodeKit](https://composio.dev/toolkits/0codekit) - 0CodeKit is a utility API platform for AI, document, image, and data workflows. Use it to convert, validate, generate, store, and automate data without custom backend code. - [Airtop](https://composio.dev/toolkits/airtop) - Airtop is a cloud browser platform for AI-powered web automation. Use it to navigate sites, extract data, and run reusable browser workflows. - [Apify MCP](https://composio.dev/toolkits/apify_mcp) - Apify MCP is the official MCP server for Apify's web scraping and browser automation platform. Use it to run actors, collect structured web data, and automate crawling workflows. - [Apilio](https://composio.dev/toolkits/apilio) - Apilio is a home automation platform that lets you connect and control smart devices from different brands. It helps you build flexible automations with complex conditions, schedules, and integrations. - [Basin](https://composio.dev/toolkits/basin) - Basin is a no-code form backend for quickly setting up reliable contact forms. It lets you collect and manage form submissions without writing any server-side code. - [Bika.ai](https://composio.dev/toolkits/bika) - Bika.ai is an AI automation database platform for managing spaces, teams, records, automations, and outgoing webhooks. It helps teams organize structured data and automate database-driven workflows in one place. - [Botster](https://composio.dev/toolkits/botster) - Botster is a web automation service for running configurable data collection bots. Use it to collect structured web data without building and maintaining scrapers yourself. - [Bouncer](https://composio.dev/toolkits/bouncer) - Bouncer is an email validation platform that verifies the authenticity of email addresses in real-time and batch. It helps boost deliverability and reduce bounce rates for your communications. - [BrowserAct](https://composio.dev/toolkits/browseract) - BrowserAct is a hosted browser-automation service for running web workflows. Use it to execute repeatable browser tasks with templates, proxies, and APIs. - [Celigo](https://composio.dev/toolkits/celigo) - Celigo is an integration platform as a service for connecting apps, data, and business workflows. It helps teams automate cross-system processes without building every integration from scratch. - [CheckFlow](https://composio.dev/toolkits/checkflow) - CheckFlow is a workflow and checklist platform for repeatable processes, tasks, templates, teams, data sets, and automation. Use it to standardize operations, track process execution, and keep teams aligned. - [Conveyor](https://composio.dev/toolkits/conveyor) - Conveyor is a platform that automates security reviews with a Trust Center and AI-driven questionnaire automation. It streamlines compliance and vendor security processes for faster, hassle-free reviews. - [CrewAI](https://composio.dev/toolkits/crew_ai) - CrewAI is a platform for running deployed automations and managing AMP control-plane resources. Use it to automate workflows and centrally control SaaS automation resources. - [Cronfree Time Scheduler](https://composio.dev/toolkits/cronfree_time_scheduler) - Cronfree Time Scheduler is an API-based scheduler for recurring webhook calls. Use it to create and remove timezone-aware schedules without running cron. - [Crowdin](https://composio.dev/toolkits/crowdin) - Crowdin is a localization management platform that streamlines translation workflows and collaboration. It helps teams centralize multilingual content, boost productivity, and automate translation processes. - [Databox](https://composio.dev/toolkits/databox) - Databox is a business analytics platform that connects your data from any tool and device. It helps you track KPIs, build dashboards, and discover actionable insights. - [Detrack](https://composio.dev/toolkits/detrack) - Detrack is a delivery management platform for real-time tracking and proof of delivery. It helps businesses automate notifications and keep customers updated every step of the way. - [Dify](https://composio.dev/toolkits/dify) - Dify is a platform for running and managing published workflow apps via a Service API. Use it to execute workflows and inspect configuration and run history quickly. - [Digital Humani](https://composio.dev/toolkits/digital_humani) - Digital Humani is a reforestation API for browsing planting projects, submitting tree requests, and tracking planted trees. It helps teams connect climate action directly to products, campaigns, and customer experiences. - [Dnsfilter](https://composio.dev/toolkits/dnsfilter) - Dnsfilter is a cloud-based DNS security and content filtering solution. It helps organizations block online threats and manage safe internet access with ease. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Smtp2go MCP? With a standalone Smtp2go MCP server, the agents and LLMs can only access a fixed set of Smtp2go tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Smtp2go and many other apps based on the task at hand, all through a single MCP endpoint. ### Can I use Tool Router MCP with Pydantic AI? 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 Smtp2go tools. ### Can I manage the permissions and scopes for Smtp2go while using Tool Router? Yes, absolutely. You can configure which Smtp2go 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 Smtp2go data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)