The role React plays
React commonly controls component interfaces, state, effects, routing, and client rendering. Its surrounding reliability depends on effect loops, stale state, duplicated components, key errors, and server/client boundaries, so the visible error may originate outside the file the AI last changed.
Specific failure patterns to inspect
For Mobile Layout Broken, common causes include fixed dimensions, absolute positioning, breakpoint conflict, unbounded content. Generated implementations also tend to omit defensive error handling, version checks, idempotency, or a safe difference between public configuration and private credentials.
A safer diagnostic sequence
Preserve the current branch and exact error. Then test at 320px and 390px; zoom to 200 percent; note the first overflowing element. Follow one test request across the interface, server or provider, and durable data rather than making several speculative code changes.
Repair boundaries
The repair should change the narrowest contract that is actually broken. Broader refactoring is justified only when duplicated ownership or an unsafe architecture would otherwise let the failure return.
What to avoid
Do not hide essential content on mobile or add arbitrary breakpoints for every device. Do not upgrade the entire React stack during a contained incident unless version incompatibility is the proven cause.
What a complete handoff includes
The handoff identifies the root cause, affected code or settings, safe test case, deployment note, and any remaining follow-up. The repaired behavior should be protected by a repeatable check.