# Before And After

Captures before/after screenshots of web pages or elements for visual comparison.

- Repository: https://github.com/michaelshimeles/rstack (1423 stars)
- Category: Design
- License: see repository
- Last updated: 2026-10-26
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add michaelshimeles/rstack --skill before-and-after -g -a claude-code -y`
Codex: `npx skills add michaelshimeles/rstack --skill before-and-after -g -a codex -y`
Cursor: `npx skills add michaelshimeles/rstack --skill before-and-after -g -a cursor -y`
Gemini CLI: `npx skills add michaelshimeles/rstack --skill before-and-after -g -a gemini-cli -y`

## Description

Captures before/after screenshots of web pages or elements for visual comparison. Use when user says "take before and after", "screenshot comparison", "visual diff", "PR screenshots", "compare old and new", or needs to document UI changes. Accepts two URLs (file://, http://, https://) or two image paths.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Before-After Screenshot Skill

> **Package:** `@vercel/before-and-after`
> Never use `before-and-after` (wrong package).

## Agent Behavior Rules

**DO NOT:**
- Switch branches or stash another task's changes. Use an isolated worktree for
  any baseline server already authorized by the task.
- Use `--full` unless user explicitly asks for full page / full scroll capture

**DO:**
- Use `--markdown` when user wants PR integration or markdown output
- Use `--mobile` / `--tablet` if user mentions phone, mobile, tablet, responsive, etc.
- Reuse before captures, baseline URLs, and revision information already
  established in the task. Confirm that they show the relevant behavior and
  match the after capture's viewport and starting state.
- Treat the current state as after only when the task context establishes it.
  If the before state remains ambiguous after checking available context, ask
  for the missing baseline. Do not ask again for a URL when a valid image pair
  or earlier baseline is already available.

## Capture and delivery

1. Use an installed `before-and-after` CLI or `npx @vercel/before-and-after`.
2. For remote URLs, check access when needed. A 401/403 indicates protection.
   Existing image pairs do not require a URL or deployment access check.
3. Capture missing images with `before-and-after "<before-url>" "<after-url>"`.
4. When the task calls for uploaded evidence or PR markdown, run
   `before-and-after before.png after.png --markdown` once. For local capture
   requests, deliver the files without uploading them.
5. Append the markdown to the PR when PR integration is part of the task.

Resolve bundled script paths relative to this skill's directory, not the
project working directory. Reuse earlier evidence instead of recapturing it.

## Quick Reference

```bash
# Basic usage
before-and-after <before-url> <after-url>

# With selector
before-and-after url1 url2 ".hero-section"

The rest: https://github.com/michaelshimeles/rstack/blob/HEAD/before-and-after/SKILL.md