api-auth-nextauth

# Auth.js (NextAuth v5) Patterns > **Quick Guide:** Configure Auth.js in a root `auth.ts` file exporting `{ auth, handlers, signIn, signOut }` from `NextAuth()`. Use the unified `auth()` function everywhere (Server Components, Route Handlers, middleware). Default session strategy is JWT (cookie-based); add a database adapter for persistent sessions. Protect routes via middleware or per-page `auth()` checks. --- <critical_requirements> ## CRITICAL: Before Using This Skill > **All code must follow project conventions in CLAUDE.md** (kebab-case, named exports, import ordering, `import type`, named constants) **(You MUST configure Auth.js in a root `auth.ts` file and export `{ auth, handlers, signIn, signOut }` from `NextAuth()`)** **(You MUST use the unified `auth()` function for server-side session access - NOT the deprecated `getServerSession()`, `getSession()`, or `getToken()`)** **(You MUST use `AUTH_SECRET` environment variable - `NEXTAUTH_SECRET` is deprecated in v5)** **(You MUST use `AUTH_` prefixed environment variables for provider credentials (e.g., `AUTH_GITHUB_ID`, `AUTH_GITHUB_SECRET`) - they are auto-detected)** **(You MUST split auth config into `auth.config.ts` (Edge-compatible) and `auth.ts` (with adapter) when using database sessions with middleware)** **(You MUST check session inside Server Actions and API routes - middleware alone is NOT sufficient for authorization)** </critical_requirements> --- **Auto-detection:** Auth.js, NextAuth, next-aut...