How to install the Impeccable skill in Claude Code and audit the design of an Electron desktop app

Impeccable is a design skill you add to coding agents such as Claude Code and Codex. Since 4.7.0, released October 19, its audit and critique commands can also check desktop app windows built with Electron, NW.js, CEF or WebView2. It reads the open window as it stands and leaves it as it found it.

1. Install it from your project folder, then reopen Claude Code. The first time, run /impeccable init to write PRODUCT.md.

npx impeccable install

1. Launch the app with a debugging port. For Electron, NW.js and CEF add the --remote-debugging-port=9222 argument; for WebView2 put the same value in the WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS environment variable. Keep the port on 127.0.0.1 only, and prefer a test profile and test data.

npx electron . --remote-debugging-port=9222

1. Set up the state you want reviewed (route, open panel, theme, data) and keep the window on screen. A minimized or hidden window skips the pixel contrast checks.

2. Invoke it from Claude Code.

/impeccable audit <screen to check>
/impeccable critique <screen to check>

The skill reads the window with impeccable detect --cdp 9222, which you can also run yourself. With several pages open it fails and lists them, so pass part of the page URL or title to --target to pick one.

.claude/skills/impeccable/scripts/impeccable detect --cdp 9222 --target <part of URL or title> --json

critique has its two sub-agents take turns in the single window (on web pages they run in parallel). Tauri apps on macOS and Linux expose no CDP, so only the source scan runs. It's Apache-2.0 licensed.