Stack Knowledge

This skill provides stack-specific patterns for agents making architectural and implementation decisions.

Neon Postgres

• Use @neondatabase/serverless driver with Drizzle ORM
• Connection: DATABASE_URL env var pointing to Neon's pooled connection string
• Neon branching: each Vercel preview deployment can get its own database branch
• No Row-Level Security — authorization happens in the application layer via Better Auth middleware
• Migrations: drizzle-kit push for development, drizzle-kit migrate for production
• Always use connection pooling in serverless environments

Drizzle ORM

• All database access goes through Drizzle — no raw SQL in application code
• Define schemas in src/db/schema/ with one file per entity
• Index every column used in WHERE, JOIN, or ORDER BY
• Use partial indexes when filtering on constant conditions (e.g., status = 'active')
• Infer types from schema: type User = typeof users.$inferSelect

Better Auth

• Configure with Drizzle adapter pointing at Neon
• After adding/changing plugins, always run: npx @better-auth/cli@latest generate
• Import plugins from dedicated paths: import { twoFactor } from "better-auth/plugins/two-factor"
• Infer session types: typeof auth.$Infer.Session
• Environment variables: BETTER_AUTH_SECRET, BETTER_AUTH_URL
• Server-side auth: auth.api.getSession()

Next.js App Router

• Server Components by default — only add "use client" for interactivity/hooks/browser APIs
• Server actions for mutations, route handlers for webhooks/external integrations
• Parallel data fetching with Promise.all() — never sequential awaits
• Wrap async server components in <Suspense> with meaningful fallbacks
• Dynamic imports via next/dynamic for heavy components not needed on first paint

Tailwind CSS

• Utility-first — avoid custom CSS unless absolutely necessary
• Use cn() utility (clsx + tailwind-merge) for conditional classes
• Design tokens via CSS custom properties in globals.css