Responsive Check
Verify adaptation through browser behavior and inspected screenshots. This execution skill complements mobile-ux-expert, which guides touch-first product decisions.
Scope and preparation
Identify the target devices, primary task, changed breakpoints, long-content cases, and relevant states. Retrieve focused graph context with --platform mobile and read the applicable research and rules. Use the project's actual breakpoints and device targets. Example CSS viewports for exploratory sampling are 390x844, 768x1024, and 1440x900; include narrower widths and just below/above affected breakpoints when the product supports them. These samples are not universal layout rules or a substitute for actual devices.
Use available browser tools or the project's existing Playwright setup. Record viewport dimensions, scale, theme, data, and state. If browser access is absent, provide a source/screenshot-limited review and mark unseen widths and interactions unverified.
Execute
- Load the same flow at each selected width. Exercise capture/navigation, open and close sheets or dialogs, and scroll through long content and sticky regions.
- Check horizontal page overflow, broken grids, long labels and entries, clipped text, navigation collapse, hidden primary actions, oversized dialogs, and controls obscured by sticky elements. For tables/charts, distinguish intentional bounded horizontal scrolling from accidental page overflow.
- Observe wrapping and control placement before and after state changes, including loading, validation errors, retry, and success. Compare geometry when
PERF-001applies. - Inspect images of each captured state and confirm suspected bounds with DOM measurements. Judge touch targets using the clickable area and the graph's
A11Y-001, not icon dimensions alone. - For mobile input flows, record whether a real virtual keyboard was exercised. Desktop viewport emulation does not prove keyboard resizing, safe-area handling, or physical-device touch behavior. Mark those as gaps if relevant and untested.
- After authorized fixes, repeat the failing width, relevant neighboring breakpoint, and affected wide layout. Capture before/after evidence under matching conditions.
Output
Return a scoped verdict, then viewport | state/action | observed behavior | screenshot/measurement | checked/unverified/not applicable. Each confirmed issue includes severity, reproduction, user impact, graph/reference basis, focused fix, and verified component/file when known. Report breakpoint behavior and physical-device gaps separately. A screenshot at one size is not a responsive pass.
Sources: CHECK-00001, RULE-00005 / UX-001, RULE-00009 / A11Y-001, RULE-00011 / PERF-001, and their retrieved source research. Use Playwright emulation for tool mechanics; it does not replace device evidence.


