CDP Use

A type-safe Python client generator for the Chrome DevTools Protocol (CDP). This library automatically generates Python bindings with full TypeScript-like type safety from the official CDP protocol specifications.

🚀 Features

🔒 Type Safety: Full type hints with TypedDict classes for all CDP commands, parameters, and return types
🎯 Event Registration: Typesafe event handlers with full IDE support
🏗️ Auto-Generated: Code generated directly from official Chrome DevTools Protocol specifications
🎯 IntelliSense Support: Perfect IDE autocompletion and type checking
📦 Domain Separation: Clean organization with separate modules for each CDP domain
🔄 Always Up-to-Date: Easy regeneration from latest protocol specs

🛠️ Installation & Setup

Clone and install dependencies:

git clone https://github.com/browser-use/cdp-use
cd cdp-use
uv sync  # or pip install -r requirements.txt

Generate the CDP client library:

python -m cdp_use.generator

This automatically downloads the latest protocol specifications and generates all type-safe bindings.

📖 Usage Examples

Basic Usage

import asyncio
from cdp_use.client import CDPClient

async def main():
    # Connect to Chrome DevTools
    async with CDPClient("ws://localhost:9222/devtools/browser/...") as cdp:
        # Get all browser targets with full type safety
        targets = await cdp.send.Target.getTargets()
        print(f"Found {len(targets['targetInfos'])} targets")

        # Navigate to a page
        await cdp.send.Page.navigate({"url": "https://example.com"})

asyncio.run(main())

Type Safety in Action

# ✅ Fully typed parameters
await cdp.send.Runtime.evaluate(params={
    "expression": "document.title",
    "returnByValue": True
})

# ✅ Return types are fully typed
result = await cdp.send.DOM.getDocument(params={"depth": 1})
node_id: int = result["root"]["nodeId"]  # Full IntelliSense support

# ❌ Type errors caught at development time
await cdp.send.DOM.getDocument(params={"invalid": "param"})  # Type error!

🎧 Event Registration

The library provides typesafe event registration with full IDE support:

Basic Event Registration

import asyncio
from cdp_use.client import CDPClient
from cdp_use.cdp.page.events import FrameAttachedEvent, DomContentEventFiredEvent
from cdp_use.cdp.runtime.events import ConsoleAPICalledEvent
from typing import Optional

def on_frame_attached(event: FrameAttachedEvent, session_id: Optional[str]) -> None:
    print(f"Frame {event['frameId']} attached to {event['parentFrameId']}")

def on_dom_content_loaded(event: DomContentEventFiredEvent, session_id: Optional[str]) -> None:
    print(f"DOM content loaded at: {event['timestamp']}")

def on_console_message(event: ConsoleAPICalledEvent, session_id: Optional[str]) -> None:
    print(f"Console: {event['type']}")

async def main():
    async with CDPClient("ws://localhost:9222/devtools/page/...") as client:
        # Register event handlers with camelCase method names (matching CDP)
        client.register.Page.frameAttached(on_frame_attached)
        client.register.Page.domContentEventFired(on_dom_content_loaded)
        client.register.Runtime.consoleAPICalled(on_console_message)

        # Enable domains to start receiving events
        await client.send.Page.enable()
        await client.send.Runtime.enable()

        # Navigate and receive events
        await client.send.Page.navigate({"url": "https://example.com"})
        await asyncio.sleep(5)  # Keep listening for events

Event Registration Features

✅ Type Safety: Event handlers are validated at compile time
✅ IDE Support: Full autocomplete for domains and event methods
✅ Parameter Validation: Callback signatures are type-checked
✅ Event Type Definitions: Each event has its own TypedDict interface

Registration Syntax

client.register.Domain.eventName(callback_function)

Where:

Domain is any CDP domain (Page, Runtime, Network, etc.)
eventName is the camelCase CDP event name (matching CDP specs)
callback_function must accept (event_data, session_id) parameters

Available Event Domains

Page: client.register.Page.* - Page lifecycle, navigation, frames
Runtime: client.register.Runtime.* - JavaScript execution, console, exceptions
Network: client.register.Network.* - HTTP requests, responses, WebSocket
DOM: client.register.DOM.* - DOM tree changes, attributes
CSS: client.register.CSS.* - Stylesheet changes, media queries
Debugger: client.register.Debugger.* - Breakpoints, script parsing
Performance: client.register.Performance.* - Performance metrics
Security: client.register.Security.* - Security state changes
And many more...

Type Safety Examples

✅ Correct Usage:

def handle_console(event: ConsoleAPICalledEvent, session_id: Optional[str]) -> None:
    print(f"Console: {event['type']}")

client.register.Runtime.consoleAPICalled(handle_console)

❌ Type Error - Wrong signature:

def bad_handler(event):  # Missing session_id parameter
    pass

client.register.Runtime.consoleAPICalled(bad_handler)  # Type error!

📋 What Gets Generated

cdp_use/cdp/
├── library.py                    # Main CDPLibrary class
├── registry.py                   # Event registry system
├── registration_library.py       # Event registration interface
├── dom/                          # DOM domain
│   ├── types.py                 # DOM-specific types
│   ├── commands.py              # Command parameter/return types
│   ├── events.py                # Event types
│   ├── library.py               # DOMClient class
│   └── registration.py          # DOM event registration
├── page/                         # Page domain
│   └── ...
└── ... (50+ domains total)

🏛️ Architecture

Main Components

class CDPClient:
    def __init__(self, url: str):
        self.send: CDPLibrary                    # Send commands
        self.register: CDPRegistrationLibrary    # Register events

# Domain-specific clients
class CDPLibrary:
    def __init__(self, client: CDPClient):
        self.DOM = DOMClient(client)           # DOM operations
        self.Network = NetworkClient(client)   # Network monitoring
        self.Runtime = RuntimeClient(client)   # JavaScript execution
        # ... 50+ more domains

# Event registration
class CDPRegistrationLibrary:
    def __init__(self, registry: EventRegistry):
        self.Page = PageRegistration(registry)
        self.Runtime = RuntimeRegistration(registry)
        # ... all domains with events

🔧 Development

Regenerating Types

# Using task (recommended)
task generate

# Or directly with uv
uv run python -m cdp_use.generator

# Or with python
python -m cdp_use.generator

This will:

Download the latest protocol files from Chrome DevTools repository
Generate all Python type definitions and event registrations
Create domain-specific client classes
Format the code

Version Pinning

By default, the generator downloads the latest CDP specification from the master branch. To pin a specific version, edit cdp_use/generator/constants.py:

# Pin to a specific commit
CDP_VERSION = "4b0c3f2e8c5d6a7b9e1f2a3c4d5e6f7a8b9c0d1e"

# Or use master for latest
CDP_VERSION = "refs/heads/master"

To find specific commits, visit: https://github.com/ChromeDevTools/devtools-protocol/commits/master

Available Tasks

task generate    # Regenerate CDP types from protocol definitions
task build       # Build the distribution package
task lint        # Run ruff linter
task format      # Format code with ruff
task format-json # Format JSON protocol files
task example     # Run the simple example
task clean       # Clean generated files and build artifacts

Project Structure

cdp-use/
├── cdp_use/
│   ├── client.py              # Core CDP WebSocket client
│   ├── generator/             # Code generation tools
│   └── cdp/                   # Generated CDP library (auto-generated)
├── simple.py                  # Example usage
└── README.md

🤝 Contributing

Fork the repository
Make changes to generator code (not the generated cdp_use/cdp/ directory)
Run python -m cdp_use.generator to regenerate
Test with python simple.py
Submit a pull request

🔗 Related

Generated from Chrome DevTools Protocol specifications • Type-safe • Zero runtime overhead

browser-use/cdp-use

README