Connect CDP Browser

Connect to an already running browser via its Chrome DevTools Protocol (CDP) debugging port.

Overview

This skill enables connecting to externally launched browser instances using Playwright's connect_over_cdp() method. Useful when:

• A browser is launched by external software/tool
• You need to connect to an existing browser without starting a new one
• The browser exposes a CDP debugging port

Quick Start

When user provides a CDP port (e.g., "port 37194"):

1. Use the provided script to connect:

python scripts/connect_cdp.py --port 37194

2. Or execute Python code directly:

from playwright.sync_api import sync_playwright

port = 37194  # User-provided port
cdp_url = f"http://127.0.0.1:{port}"

with sync_playwright() as p:
    browser = p.chromium.connect_over_cdp(cdp_url)
    context = browser.contexts[0] if browser.contexts else browser.new_context()
    page = context.pages[0] if context.pages else context.new_page()
    
    print(f"Connected to browser")
    print(f"Page title: {page.title()}")
    print(f"Page URL: {page.url}")
    
    browser.close()

Common Operations

Get Page Information

print(f"Title: {page.title()}")
print(f"URL: {page.url}")
print(f"Content length: {len(page.content())}")

Navigate to URL

page.goto("https://example.com")

Take Screenshot

page.screenshot(path="screenshot.png", full_page=True)

Click Element

page.click("selector")

Type Text

page.fill("input[name='q']", "search query")

Troubleshooting

• Connection refused: Ensure the browser is running and CDP port is correct
• Timeout: Check if port is accessible from current environment
• Browser closed: The browser must remain running during the session

Resources

scripts/

• connect_cdp.py - Helper script for connecting to CDP browsers