browser-screenshot

name	browser-screenshot
description	Take a screenshot of the running web application for visual verification of UI/CSS changes. Use when iterating on frontend changes and need to see the result.
allowed-tools	Read,Bash(npm:*),Bash(npx:*),Bash(scripts/screenshot:*),Bash(ln:*)
model-tier	economy
model	haiku
effort	medium
version	1.0.0
author	flurdy

Browser Screenshot

Capture screenshots of the web application for visual verification during UI/CSS iteration.

Setup

1. Install playwright in the project (if not already):

npm install playwright
npx playwright install chromium

2. Symlink the screenshot script into the project's scripts/ directory:

SKILLS_DIR="${SKILLS_DIR:-${CODEX_HOME:-$HOME/.codex}/skills}"
if [[ ! -d "$SKILLS_DIR" ]]; then
  SKILLS_DIR="${CLAUDE_HOME:-$HOME/.claude}/skills"
fi
ln -sfn "$SKILLS_DIR/browser-screenshot/scripts/screenshot.sh" scripts/screenshot

Usage

/browser-screenshot
/browser-screenshot http://localhost:3000
/browser-screenshot http://localhost:3000 mobile

Instructions

1. Determine the URL to screenshot:

   • If $ARGUMENTS contains a URL, use it
   • Otherwise use the SCREENSHOT_URL env var if set
   • Default: http://localhost:3000

2. Determine the viewport:

   • If $ARGUMENTS contains mobile, use mobile viewport (375x812)
   • If $ARGUMENTS contains tablet, use tablet viewport (768x1024)
   • If $ARGUMENTS contains a custom size like 1024x768, use those dimensions
   • Default: desktop viewport (1280x900)
   • If $ARGUMENTS contains both, take two screenshots (desktop and mobile)
   • Keep both dimensions under 2000px to avoid image limit errors

3. Run the screenshot script via the project symlink:

scripts/screenshot <url> <viewport>

If the symlink doesn't exist yet, create it first (see Setup above).

Screenshots are saved to /tmp/claude-screenshots/screenshot-<viewport>.png by default (e.g. screenshot-desktop.png, screenshot-mobile.png). Each run overwrites the previous screenshot for that viewport.

4. Read the screenshot using the available image-reading tool to view the captured image. This is the critical step because the model can inspect the captured UI directly.

5. Analyze the screenshot and report what you see, especially:

   • Layout issues (overlapping elements, alignment problems)
   • Spacing/margin problems
   • Color or styling discrepancies
   • Responsive behavior (if both viewports captured)

6. If the user asked you to fix a specific CSS issue, compare what you see against their description and suggest or apply fixes.

Notes

• The script uses waitUntil: 'networkidle' with a 15s timeout — if the page loads async content, the screenshot will wait for it.
• Screenshots capture the viewport only (not full-page scroll) to stay within the 2000px image dimension limit.
• For rapid iteration: make the CSS change, then run /browser-screenshot to verify, repeat.