This walks you through Next.js environment variable management with the kind of detail you actually need. It covers the file precedence order (like how .env.production.local beats .env), explains when to use NEXT_PUBLIC_ prefixes versus server-only vars, and shows concrete examples for each file type. The deployment section is especially useful because it emphasizes that NEXT_PUBLIC_ variables are baked into the build, so you need to redeploy after changing them in Vercel. It also includes validation workflows and a troubleshooting section for the usual gotchas, like forgetting the prefix or wondering why your changes aren't showing up. Good for initial setup or when you're debugging why something works locally but fails in production.
npx skills add https://github.com/bobmatnyc/claude-mpm-skills --skill nextjs-env-variables