# How to integrate Bouncer MCP with Pydantic AI ```json { "title": "How to integrate Bouncer MCP with Pydantic AI", "toolkit": "Bouncer", "toolkit_slug": "bouncer", "framework": "Pydantic AI", "framework_slug": "pydantic-ai", "url": "https://composio.dev/toolkits/bouncer/framework/pydantic-ai", "markdown_url": "https://composio.dev/toolkits/bouncer/framework/pydantic-ai.md", "updated_at": "2026-05-06T08:03:42.497Z" } ``` ## Introduction This guide walks you through connecting Bouncer to Pydantic AI using the Composio tool router. By the end, you'll have a working Bouncer agent that can verify this email address instantly, check domain validity for new signups, batch-verify a list of customer emails through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Bouncer account through Composio's Bouncer MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Bouncer with - [OpenAI Agents SDK](https://composio.dev/toolkits/bouncer/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/bouncer/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/bouncer/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/bouncer/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/bouncer/framework/codex) - [OpenClaw](https://composio.dev/toolkits/bouncer/framework/openclaw) - [Hermes](https://composio.dev/toolkits/bouncer/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/bouncer/framework/cli) - [Google ADK](https://composio.dev/toolkits/bouncer/framework/google-adk) - [LangChain](https://composio.dev/toolkits/bouncer/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/bouncer/framework/ai-sdk) - [Mastra AI](https://composio.dev/toolkits/bouncer/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/bouncer/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/bouncer/framework/crew-ai) ## 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 Bouncer - 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 Bouncer 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 Bouncer MCP server, and what's possible with it? The Bouncer MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Bouncer account. It provides structured and secure access to your email verification and validation tools, so your agent can perform actions like real-time email validation, bulk verification, domain checks, and toxicity analysis for improved email deliverability. - Real-time email verification: Instantly validate single email addresses to check deliverability and reduce bounce rates before sending messages. - Bulk batch verification: Initiate, manage, and retrieve results from batch email verification jobs to clean and maintain large email lists efficiently. - Toxicity analysis of email lists: Start and monitor toxicity analysis jobs to identify potentially harmful or problematic email addresses in your database. - Domain verification: Check the validity and configuration of email domains, including MX records and catch-all status, to ensure emails reach their intended targets. - Automated batch management: Finish, delete, or update batch verification and toxicity jobs to keep your verification workflows tidy and up-to-date. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `BOUNCER_CHECK_TOXICITY_LIST_JOB_STATUS` | Check Toxicity List Job Status | Tool to check the status of a specific toxicity list job. use after creating a toxicity list job to poll its status until completion. | | `BOUNCER_CREATE_BATCH_REQUEST` | Create Batch Request | Tool to initiate a batch email verification request. use when you have multiple emails to verify in one api call. returns a batch id and initial status. | | `BOUNCER_CREATE_TOXICITY_LIST_JOB` | Create Toxicity List Job | Tool to create a toxicity analysis job for a list of email addresses. use when you need to batch-process toxicity checks for multiple emails at once. | | `BOUNCER_DELETE_BATCH_REQUEST` | Delete batch request | Tool to delete a batch verification request. use when you need to remove all associated emails and results for a specific batch after confirming that the batch data is no longer required. | | `BOUNCER_DELETE_TOXICITY_LIST_JOB` | Delete Toxicity List Job | Tool to delete a specific toxicity list job. use when you need to remove a completed or unwanted toxicity analysis job after confirming its id. | | `BOUNCER_FINISH_BATCH` | Finish Batch | Tool to mark a batch verification process as finished. use after batch processing completes to stop further verifications and reclaim unused credits. | | `BOUNCER_GET_BATCH_RESULTS` | Get Batch Results | Tool to retrieve the results of a batch verification process. use after submitting a batch to fetch all processed email verification outcomes. | | `BOUNCER_VERIFY_DOMAIN` | Verify Domain | Tool to verify the validity and configuration of a domain. use when you need to confirm the domain's mx records and catch-all behavior. | | `BOUNCER_VERIFY_EMAIL` | Verify Email | Tool to verify a single email address in real-time. use when validating email entry form inputs instantly. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Bouncer MCP server is an implementation of the Model Context Protocol that connects your AI agent to Bouncer. It provides structured and secure access so your agent can perform Bouncer 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 Bouncer - 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 Bouncer - MCPServerStreamableHTTP connects to the Bouncer 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 Bouncer 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 Bouncer composio = Composio(api_key=api_key) session = composio.create( user_id=user_id, toolkits=["bouncer"], ) 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 Bouncer endpoint - The agent uses GPT-5 to interpret user commands and perform Bouncer operations - The instructions field defines the agent's role and behavior ```python # Attach the MCP server to a Pydantic AI Agent bouncer_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY}) agent = Agent( "openai:gpt-5", toolsets=[bouncer_mcp], instructions=( "You are a Bouncer assistant. Use Bouncer 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 - Bouncer 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 Bouncer.\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 Bouncer composio = Composio(api_key=api_key) session = composio.create( user_id=user_id, toolkits=["bouncer"], ) 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 bouncer_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY}) agent = Agent( "openai:gpt-5", toolsets=[bouncer_mcp], instructions=( "You are a Bouncer assistant. Use Bouncer 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 Bouncer.\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 Bouncer through Composio's Tool Router. With this setup, your agent can perform real Bouncer 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 + Bouncer 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 Bouncer MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/bouncer/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/bouncer/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/bouncer/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/bouncer/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/bouncer/framework/codex) - [OpenClaw](https://composio.dev/toolkits/bouncer/framework/openclaw) - [Hermes](https://composio.dev/toolkits/bouncer/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/bouncer/framework/cli) - [Google ADK](https://composio.dev/toolkits/bouncer/framework/google-adk) - [LangChain](https://composio.dev/toolkits/bouncer/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/bouncer/framework/ai-sdk) - [Mastra AI](https://composio.dev/toolkits/bouncer/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/bouncer/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/bouncer/framework/crew-ai) ## Related Toolkits - [Apilio](https://composio.dev/toolkits/apilio) - Apilio is a home automation platform that lets you connect and control smart devices from different brands. 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It helps organizations streamline maintenance operations and improve team coordination. - [Make](https://composio.dev/toolkits/make) - Make is an automation platform that connects your favorite apps and services. Build powerful, custom workflows without writing code. - [Ntfy](https://composio.dev/toolkits/ntfy) - Ntfy is a notification service to send push messages to phones or desktops. Instantly deliver alerts and updates to users, devices, or teams. - [Persona](https://composio.dev/toolkits/persona) - Persona offers identity infrastructure to automate user verification and compliance. It helps organizations securely verify users and reduce fraud risk. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Bouncer MCP? With a standalone Bouncer MCP server, the agents and LLMs can only access a fixed set of Bouncer tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Bouncer 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 Bouncer tools. ### Can I manage the permissions and scopes for Bouncer while using Tool Router? Yes, absolutely. You can configure which Bouncer 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 Bouncer data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) ยท [Composio docs](https://docs.composio.dev/llms.txt)