awesome-agents-md: Instructions file for GitHub Copilot

GitHub Copilot — Custom Instructions for Next.js 15

This is a Next.js 15 application using the App Router, React 19, TypeScript (strict), Drizzle ORM, and Tailwind CSS 4. Always default to Server Components — only use "use client" when state, effects, browser APIs, or a client-only library is genuinely required.

Conventions

• Package manager: pnpm. Never use npm or yarn commands in suggestions.
• Imports: Use the @/* path alias for any cross-directory import. Named exports only — default exports are reserved for Next's special files (page.tsx, layout.tsx, loading.tsx, error.tsx).
• Mutations: Server Actions, not API routes. Use revalidatePath or revalidateTag after mutations.
• Database: Drizzle in Server Components directly. No intermediate API layer.
• Styling: Tailwind 4 with CSS-first config in app/globals.css. Use the cn() utility from @/lib/utils for conditional classNames. Use design tokens (CSS variables), not hardcoded hex values.
• UI primitives: shadcn components in components/ui/. Do not edit them — re-run the shadcn CLI to update.
• Forms: React Hook Form + Zod. Re-validate server-side with the same Zod schema.
• Tests: Vitest + Testing Library for unit/component, Playwright for end-to-end. Test user-visible behavior, not implementation details.

Forbidden patterns

• useEffect for data fetching (use Server Components or use())
• any type (use unknown and narrow)
• getServerSideProps / getStaticProps (Pages Router — we're App Router only)
• Inline style={{ }} except for dynamic CSS variable assignment
• Default exports for components

Cache and hydration awareness

• fetch is cached aggressively in Server Components. Use cache: "no-store" for user-specific data, or next: { tags } + revalidateTag for invalidation.
• Avoid Date, Math.random, window, document, localStorage during render in components reachable from the server tree — they cause hydration mismatches.