How to integrate Heygen MCP with Pydantic AI

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Introduction

This guide walks you through connecting Heygen to Pydantic AI using the Composio tool router. By the end, you'll have a working Heygen agent that can create a talking photo from my selfie, add new contacts to my video project, list all available streaming avatars for today, fetch details of my latest personalized video project through natural language commands.

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

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

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

The Heygen MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Heygen account. It provides structured and secure access to your Heygen video platform, so your agent can perform actions like creating talking photos, managing video assets, personalizing video projects, and controlling streaming avatars on your behalf.

  • AI-powered video asset creation: Add new avatars, backgrounds, or other content elements directly into your Heygen library for use in video generation workflows.
  • Personalized video project management: Let your agent add contacts to personalized video projects and fetch detailed project information to streamline large-scale video personalization efforts.
  • Dynamic talking photo generation: Instantly create engaging talking photos from uploaded images, transforming static pictures into interactive, speaking content for marketing or educational use.
  • Real-time avatar streaming control: Retrieve a list of streaming avatars, generate streaming tokens, and manage live avatar sessions—including interrupting or monitoring ongoing streams for responsive, interactive experiences.
  • Audience insights and analytics: Fetch detailed audience engagement and preference data for personalized video campaigns, helping you optimize your content and targeting strategies.

Supported Tools & Triggers

Tools
Add new assetCreates a new asset in the heygen platform.
Add contact to personalized video projectThis endpoint allows you to add one or more contacts to a specific personalized video project in the heygen platform.
Retrieve audience video detailsRetrieves detailed information about the audience for personalized videos.
Fetch personalized video project detailRetrieves detailed information about a specific personalized video project in the heygen platform.
Post talking photo binary imageCreates a talking photo by processing an uploaded image file.
List streaming avatarsRetrieves a list of available avatars for streaming purposes in the heygen platform.
Create streaming token with expiryCreates a new streaming token for use with heygen's real-time avatar and voice chat services.
Post streaming ice candidatesThis endpoint is used to submit ice (interactive connectivity establishment) candidate information for a specific streaming session in the heygen platform.
Interrupt streaming sessionInterrupts an ongoing streaming session with an interactive avatar.
Retrieve streaming listRetrieves a list of active or available streaming sessions or content within the heygen platform.
Set streaming quality endpointInitiates a new streaming session with heygen, allowing users to start an avatar-based stream with specified quality settings.
Start streaming sessionInitiates a new streaming session for real-time communication in the heygen platform.
Stop streaming sessionThe streaming.
Post streaming task sessionThe streamingtask endpoint initiates a real-time speaking task for an ai-driven avatar within an active streaming session.
List avatars endpointRetrieves a list of available avatars from the heygen platform.
List talking photo entriesRetrieves a list of talking photos created using the heygen platform.
Delete videoThe video.
List videosRetrieves a list of videos associated with the user's account on the heygen platform.
Retrieve video statusRetrieves the current status of a video in the heygen platform.
List voice endpointsRetrieves a comprehensive list of all available voices in the heygen platform.
Add webhook endpointAdds a new webhook endpoint to receive real-time notifications for specified heygen events.
Delete webhook endpointDeletes a specific webhook endpoint from the heygen system.
List webhook endpointsRetrieves a list of all webhook endpoints configured for your heygen account.
List webhooksRetrieves a list of all webhooks configured for your heygen account.
Retrieve avatars collectionRetrieves a list of available avatars from the heygen platform.
Delete talking photo by idDeletes a specific talking photo from the heygen platform using its unique identifier.
Generate video template with variablesThis endpoint generates a customized video based on a pre-existing template using heygen's ai-driven platform.
Get template by idRetrieves a specific template from the heygen platform using its unique identifier.
Retrieve all templatesRetrieves a list of available avatar templates from the heygen platform.
Retrieve user remaining quotaRetrieves the current remaining quota for the authenticated user on the heygen platform.
Generate video with inputsGenerates a customized video using heygen's ai-driven platform.
Post video translate requestThe translatevideo endpoint enables the translation of video content from one language to another.
Retrieve video translation by idRetrieves the current status of a video translation job in the heygen platform.
Retrieve video translation target languagesRetrieves a list of all available target languages supported by heygen's video translation feature.
List available voicesRetrieves a list of available voice models and options that can be used with heygen's ai-driven video creation platform.

What is the Composio tool router, and how does it fit here?

What is Tool Router?

Composio's Tool Router 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 Tool Router

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Tool Router works

The Tool Router 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

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 Heygen
  • 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 Heygen
  • MCPServerStreamableHTTP connects to the Heygen 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 Heygen
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["heygen"],
    )
    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 Heygen 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
heygen_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[heygen_mcp],
    instructions=(
        "You are a Heygen assistant. Use Heygen tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Heygen endpoint
  • The agent uses GPT-5 to interpret user commands and perform Heygen 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 Heygen.\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
  • Heygen 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 Heygen 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 Heygen
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["heygen"],
    )
    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
    heygen_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[heygen_mcp],
        instructions=(
            "You are a Heygen assistant. Use Heygen 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 Heygen.\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 Heygen through Composio's Tool Router. With this setup, your agent can perform real Heygen 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 + Heygen 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 Heygen MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Heygen MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Heygen MCP with Claude Agent SDK

Google ADK

Google ADK

Use Heygen MCP with Google ADK

LangChain

LangChain

Use Heygen MCP with LangChain

Vercel AI SDK

Vercel AI SDK

Use Heygen MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Heygen MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Heygen MCP with LlamaIndex

CrewAI

CrewAI

Use Heygen MCP with CrewAI

FAQ

What are the differences in Tool Router MCP and Heygen MCP?

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

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

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

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