Responsive Screenshots

Screenshot a page at every common viewport and mechanically check each one for layout breakage. No signup required.

Prerequisites

• Playwright MCP (ships with Claude Code)

Trigger

• "Responsive screenshots of https://...";
• "How does my site look on mobile and tablet?"
• "Screenshot this page at different sizes"
• "Does my layout break anywhere between phone and desktop?"

Workflow

1. mcpplaywrightbrowser_navigate to the URL once, then loop these viewports:

1. Per viewport: mcpplaywrightbrowserresize, wait ~1s for reflow, then run step 3, then mcpplaywrightbrowsertake_screenshot (filename like shot-360x800.png).
2. mcpplaywrightbrowser_evaluate layout probe at each size:

() => {
  const vw = window.innerWidth, vh = window.innerHeight;
  const out = { viewport: `${vw}x${vh}`,
    horizontalOverflow: document.scrollingElement.scrollWidth > vw,
    overflowPx: Math.max(0, document.scrollingElement.scrollWidth - vw), covered: [] };
  // Overlap probe: an element whose center hit-tests to an unrelated element is covered by it
  for (const el of document.querySelectorAll('a[href],button,input,select,h1,h2,h3,nav,[role=button]')) {
    const b = el.getBoundingClientRect();
    if (b.width < 4 || b.height < 4 || b.bottom < 0 || b.top > vh) continue;
    const x = Math.min(Math.max(b.left + b.width / 2, 0), vw - 1);
    const y = Math.min(Math.max(b.top + b.height / 2, 0), vh - 1);
    const hit = document.elementFromPoint(x, y);
    if (hit && hit !== el && !el.contains(hit) && !hit.contains(el))
      out.covered.push({ el: `${el.tagName}${el.id ? '#' + el.id : ''} "${(el.textContent || '').trim().slice(0, 25)}"`,
        by: hit.tagName + (hit.id ? '#' + hit.id : '') });
  }
  out.covered = out.covered.slice(0, 10);
  return out;
}

1. Interpret the probe honestly: it only sees the current scroll position (above the fold), and legitimate overlays (open menus, sticky headers over anchors, cookie banners) appear in covered — call those out separately from genuine collisions.
2. Visually scan every screenshot for what the probe can't measure: truncated text, images spilling containers, nav failing to collapse to a hamburger, giant whitespace gaps at wide sizes.
3. Verdict per viewport: pass = no overflow, no unexplained covered elements, screenshot looks correct; fail otherwise. Overall grade: A = 5/5 pass · B = 4/5 · C = 3/5 · D = 2/5 · F = worse.

Report

## Responsive Report: [URL]

**Grade: B** — 4/5 viewports pass

| Viewport | Overflow | Overlaps | Visual scan | Verdict |
|---|---|---|---|---|
| 360x800 (Mobile) | ❌ 18px | H1 covered by NAV | nav doesn't collapse | FAIL |
| 768x1024 (Tablet) | ✅ | — | ok | PASS |
| 1280x800 (Laptop) | ✅ | — | ok | PASS |
| 1440x900 (Desktop) | ✅ | — | ok | PASS |
| 1920x1080 (Full HD) | ✅ | — | hero image slightly soft | PASS |

### Screenshots
shot-360x800.png · shot-768x1024.png · shot-1280x800.png · shot-1440x900.png · shot-1920x1080.png

### Issues to fix
1. [360px] Hero section forces 18px of horizontal scroll — likely a fixed-width child.
2. [360px] Nav bar overlaps the H1; it never collapses to a mobile menu.

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