What problem does it solve? Next.js App Router introduces subtle footguns — like 'use client' in layouts, getServerSideProps in App Router files, or conflicting cache configs — that fail silently and ship bugs to production. This Skill catches those forbidden patterns at write time, before the file lands on disk. ## Core Features & Use Cases - Runtime Boundary Checks: Six grep-based rules that soft-warn on App Router boundary violations, RSC serialization holes, mixed caching configs, unsafe HTML, raw internal <a> links, and server env vars read from client components. - Hook Integration: Loaded by a PreToolUse hook when the file path matches next.config.*, **/app/**, **/pages/**, middleware.ts, or **/route.ts; advisory only and never blocks the write. - Use Case: While editing app/dashboard/layout.tsx, an agent adds "use client" at the top. The hook invokes check_nextjs_boundary, the skill matches rule 1, and returns a soft warning explaining that the directive pushes the entire subtree to the client, with the fix of moving the boundary to a leaf component. ## Quick Start Ask the agent to review your Next.js edit to a file under app/ and confirm none of the six forbidden patterns are present before saving.
