What problem does it solve? Building UI in a modern Next.js codebase requires juggling server/client component boundaries, design tokens, i18n, accessibility rules, and framework-specific conventions like Next.js 16's proxy.ts. This Skill encodes all of those rules so frontend work follows project architecture consistently instead of reinventing patterns per task. ## Core Features & Use Cases - Structured UI workflow: A five-phase execution protocol (prepare, analyze, plan, implement, verify) with a self-verification checklist covering TypeScript strictness, Tailwind tokens, WCAG 2.2 AA accessibility, and responsive breakpoints. - Stack-specific guardrails: Enforces shadcn/ui primitives (Base UI engine), treats components/ui/* as read-only, mandates proxy.ts over the banned middleware.ts, and codifies state choices (TanStack Query, nuqs, Jotai/Zustand). - Error recovery playbook: Provides step-by-step recovery for TypeScript errors, hydration mismatches, build failures, API integration issues, and styling bugs. - Use Case: Ask it to build a responsive login form; it produces a TanStack Form + Zod client component with accessible markup, token-based styling, loading/error/empty states, and a Vitest test. ## Quick Start Ask the agent to build a responsive, accessible component or page in your Next.js 16 project, for example: create a login form with validation and tests following the project's shadcn and Tailwind conventions.