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chrome-cdp

chrome-cdp

github.com/paskyDevelopment3.3k2.1k installsUpdated 17w ago
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About chrome-cdp

chrome-cdp is a lightweight Node.js CLI for controlling browsers through Chrome DevTools Protocol. It helps developers inspect pages and automate browser actions through a direct WebSocket connection, without Puppeteer.

Key features

  1. 01List open browser pages
  2. 02Capture viewport screenshots
  3. 03Inspect accessibility tree
  4. 04Evaluate JavaScript and retrieve HTML
  5. 05Navigate, click, type, and inspect network timing

Use cases

  1. 01Inspect page structure while debugging
  2. 02Capture a browser viewport for review
  3. 03Interact with elements in cross-origin iframes
  4. 04Collect resource timing data

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/pasky/chrome-cdp-skill --skill chrome-cdp

After installing, type/chrome-cdpin Claude Code to confirm it loaded.

Bundled filesscripts/cdp.mjs

Details

From the project README

Chrome CDP

Lightweight Chrome DevTools Protocol CLI. Connects directly via WebSocket — no Puppeteer, works with 100+ tabs, instant connection.

Prerequisites

  • Chrome (or Chromium, Brave, Edge, Vivaldi) with remote debugging enabled: open chrome://inspect/#remote-debugging and toggle the switch
  • Node.js 22+ (uses built-in WebSocket)
  • If your browser's DevToolsActivePort is in a non-standard location, set CDP_PORT_FILE to its full path

Commands

All commands use scripts/cdp.mjs. The <target> is a unique targetId prefix from list; copy the full prefix shown in the list output (for example 6BE827FA). The CLI rejects ambiguous prefixes.

List open pages
scripts/cdp.mjs list
Take a screenshot
scripts/cdp.mjs shot <target> [file]    # default: screenshot-<target>.png in runtime dir

Captures the viewport only. Scroll first with eval if you need content below the fold. Output includes the page's DPR and coordinate conversion hint (see Coordinates below).

Accessibility tree snapshot
scripts/cdp.mjs snap <target>
Evaluate JavaScript
scripts/cdp.mjs eval <target> <expr>

Watch out: avoid index-based selection (querySelectorAll(...)[i]) across multiple eval calls when the DOM can change between them (e.g. after clicking Ignore, card indices shift). Collect all data in one eval or use stable selectors.

Other commands
scripts/cdp.mjs html    <target> [selector]   # full page or element HTML
scripts/cdp.mjs nav     <target> <url>         # navigate and wait for load
scripts/cdp.mjs net     <target>               # resource timing entries
scripts/cdp.mjs click   <target> <selector>    # click element by CSS selector
scripts/cdp.mjs clickxy <target> <x> <y>       # click at CSS pixel coords
scripts/cdp.mjs type    <target> <text>         # Input.insertText at current focus; works in cross-origin iframes unlike eval
scripts/cdp.mjs loadall <target> <selector> [ms]  # click "load more" until gone (default 1500ms between clicks)
scripts/cdp.mjs evalraw <target> <method> [json]  # raw CDP command passthrough
scripts/cdp.mjs open    [url]                  # open new tab (each triggers Allow prompt)
scripts/cdp.mjs stop    [target]               # stop daemon(s)

Coordinates

shot saves an image at native resolution: image pixels = CSS pixels × DPR. CDP Input events (clickxy etc.) take CSS pixels.

CSS px = screenshot image px / DPR

shot prints the DPR for the current page. Typical Retina (DPR=2): divide screenshot coords by 2.

Tips

  • Prefer snap --compact over html for page structure.
  • Use type (not eval) to enter text in cross-origin iframes — click/clickxy to focus first, then type.
  • Chrome shows an "Allow debugging" modal once per tab on first access. A background daemon keeps the session alive so subsequent commands need no further approval. Daemons auto-exit after 20 minutes of inactivity.

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