Chrome CDP#

Lightweight Chrome DevTools Protocol CLI. Connects directly via WebSocket, does not need Puppeteer, and works well with large tab counts.

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)
• No Python or pip packages are required
• No npm install step is required
• If your browser's DevToolsActivePort is in a non-standard location, set CDP_PORT_FILE to its full path

Quick setup#

1. Open Chrome and keep it running.
2. Open chrome://inspect/#remote-debugging.
3. Turn on remote debugging.
4. Keep the browser open while using this skill.
5. Run {baseDir}/scripts/cdp.mjs list to confirm that tabs are visible.

On first access to a tab, Chrome may ask the user to approve debugging access.

Installation#

• Recommended: clawhub install chrome-cdp-skill
• Manual: place this skill directory in your OpenClaw workspace skills/ folder
• This skill does not require npm install, Python, or pip packages

Safety#

This skill can inspect and control a real local browser session. Commands such as eval, evalraw, click, type, and nav are intentionally powerful and may trigger warnings from security scanners.

Only use this skill when the user explicitly wants you to inspect or operate pages they already have open. Assume those tabs may contain sensitive logged-in content.

The skill only works after the user enables Chrome remote debugging. On first access to a tab, Chrome may ask the user to approve debugging access.

Commands#

All commands use {baseDir}/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#

bash

{baseDir}/scripts/cdp.mjs list

Take a screenshot#

bash

{baseDir}/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#

bash

{baseDir}/scripts/cdp.mjs snap <target>

Evaluate JavaScript#

bash

{baseDir}/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#

bash

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

text

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.