How to integrate Anchor browser MCP with Pydantic AI

This guide walks you through connecting Anchor browser to Pydantic AI using the Composio tool router. By the end, you'll have a working Anchor browser agent that can fetch full content of a product page, list all active browser sessions now, get details for a specific browser profile through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Anchor browser account through Composio's Anchor browser MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

Anchor browser logoAnchor browser
Api Key

Anchor browser is a developer platform for AI-powered web automation. It transforms complex browser actions into easy API endpoints for streamlined web interaction.

64 Tools

Introduction

This guide walks you through connecting Anchor browser to Pydantic AI using the Composio tool router. By the end, you'll have a working Anchor browser agent that can fetch full content of a product page, list all active browser sessions now, get details for a specific browser profile through natural language commands.

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

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

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

The Anchor browser MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Anchor browser account. It provides structured and secure access to powerful web automation features, so your agent can fetch web content, manage browser sessions, control profiles, and interact with extensions on your behalf.

  • Automated webpage content retrieval: Instruct your agent to browse to any URL and fetch the fully rendered page content in HTML or markdown, enabling easy scraping or summarization.
  • Session and profile management: Let your agent create, list, or delete browser profiles, as well as start, end, or monitor multiple browsing sessions for different workflows or user contexts.
  • Browser extension control: Have the agent list all installed browser extensions, making it easy to audit and manage your browser environment programmatically.
  • Resource and file listing: Ask your agent to retrieve a list of files or resources uploaded during browser automation tasks, ensuring nothing gets lost in the shuffle.
  • Comprehensive session oversight: Quickly get an overview of all active browser sessions, their statuses, and terminate any or all sessions instantly for security or resource management needs.

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

Click Mouse

Tool to perform a mouse click at specified coordinates within a browser session.

Copy Selected Text

Tool to copy currently selected text in a browser session to the clipboard.

Create Integration

Tool to create a new integration with a third-party service like 1Password.

Create or Update Task Draft

Tool to create or update the draft version of a task.

Create Profile

Creates a new browser profile from an active session.

Create Task

Tool to create a new task or update an existing task with the same name.

Delete Extension

Tool to delete a browser extension and remove it from storage.

Delete Integration

Tool to delete an existing integration and remove its stored credentials.

Delete Profile

Tool to delete a browser profile by ID.

Delete Task

Tool to soft delete a task and all its versions.

Delete Task Version

Tool to soft delete a specific version of a task.

Deploy Task

Tool to deploy a task by creating a new version with auto-incremented version number.

Double Click Mouse

Tool to perform a double click at specified coordinates in a browser session.

Drag and Drop

Tool to perform a drag and drop operation from start coordinates to end coordinates within a browser session.

End All Sessions

Tool to terminate all active browser sessions at once.

End Browser Session

Tool to end a specific browser session by ID.

Get Batch Session Status

Tool to retrieve detailed status information for a specific batch including progress and errors.

Get Browser Session

Tool to retrieve detailed information about a specific browser session.

Get Clipboard Content

Tool to retrieve the current content of the clipboard from a browser session.

Get Latest Task Version

Tool to retrieve the latest version of a task including the full base64 encoded code content.

Get Profile (v2)

Tool to retrieve details of a specific profile by its name.

Get Session Pages

Tool to retrieve all pages associated with a specific browser session.

Get Task Draft

Tool to retrieve the draft version of a task, including the full Base64 encoded code content.

Get Task Execution Result

Tool to retrieve a single task execution result by its ID.

Get Task Metadata

Tool to retrieve task metadata without downloading the full task code.

Get Task Version

Tool to retrieve a specific version of a task, including the full code content.

Get Webpage Content

Tool to retrieve rendered content of a webpage in HTML or Markdown format.

List Agent Resources

List all agent resources (files) uploaded to a browser session.

List Extensions

Retrieves all browser extensions uploaded by the authenticated user.

List Integrations

Tool to retrieve all integrations for the authenticated team.

List Profiles

Tool to fetch all stored browser profiles.

List Session Downloads

Tool to retrieve metadata of files downloaded during a browser session.

List Session Recordings

Tool to list all recordings for a specific browser session.

List Sessions

Tool to list all browser sessions.

List Task Executions

Tool to retrieve execution history for a specific task with filtering and pagination support.

List Tasks

Tool to retrieve a paginated list of all tasks for the authenticated team.

List Task Versions

Tool to retrieve all versions of a specific task, including draft and published versions.

Mouse Move

Tool to move the mouse cursor to specified coordinates within a browser session.

Navigate to URL

Tool to navigate a browser session to a specified URL.

Paste Text

Tool to paste text at the current cursor position in a browser session.

Pause Agent

Tool to pause the AI agent for a specific browser session.

Pause Session Recording

Tool to pause the video recording for a specific browser session.

Perform Keyboard Shortcut

Tool to perform a keyboard shortcut using specified keys in a browser session.

Perform Web Task

Tool to perform autonomous web tasks using AI agents.

Mouse Down

Tool to perform a mouse button down action at specified coordinates within a browser session.

Publish Task Version

Tool to publish a specific version of a task.

Release Mouse Button

Tool to release a mouse button at specified coordinates within a browser session.

Resume Agent

Tool to resume the AI agent for a specific browser session.

Resume Session Recording

Tool to resume video recording for a specific browser session.

Run Task

Tool to execute a task in a browser session with a specific or latest version.

Run Task by Name

Tool to execute a task by its name, always using the latest version.

Screenshot Webpage

Tool to take a screenshot of a specified webpage within a session.

Scroll Session

Tool to perform a scroll action at specified coordinates within a browser session.

Set Clipboard Content

Tool to set the content of the clipboard in a browser session.

Signal Event

Tool to signal a specific event to be received by other processes or sessions.

Start Browser Session

Tool to start a new browser session with optional customizations.

Take Screenshot

Tool to take a screenshot of the current browser session and return it as an image.

Type Text

Tool to type specified text with optional delay between keystrokes.

Update Profile

Updates an existing browser profile with data from an active session.

Update Task Metadata

Updates task metadata (name and description).

Upload Extension

Tool to upload a new browser extension as a ZIP file for use in browser sessions.

Upload File

Tool to upload a file to a browser session as an agent resource.

Upload Files to Session

Tool to upload files directly to a browser session for use with web forms and file inputs.

Wait for Event

Blocks execution until a specific named event is signaled or the timeout expires.

FAQ

Frequently asked questions

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

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

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