responsiveness-check

Test website responsiveness across viewport widths, detect layout transitions, and report where layouts break. Test how a website's layout responds to viewport width changes. Resizes through breakpoints in a single browser session, screenshots each width, compares adjacent sizes, and reports where layouts break. What this tests : Layout responsiveness — overflow, stacking, navigation transitions, content reflow. What this does NOT test : General accessibility (ARIA, semantic HTML, heading hierarchy, colour contrast). Those don't vary by viewport width — use the ux-audit skill instead. Before starting, detect available browser tools: If none are available, inform the user and suggest installing playwright-cli or Playwright MCP. When : "check responsive", "responsiveness check", "test breakpoints" Test 8 key breakpoints that cover the device spectrum: Process : When : "responsive sweep", "sweep all breakpoints", "find where it breaks" Test every 160px from 320 to 2560 (15 widths total).