Covers Next.js 16's environment variable system with the file precedence rules, NEXT_PUBLIC_ prefixing for client-side exposure, and deployment patterns for Vercel. You'll reach for this when setting up a new Next.js project or debugging why your API keys work locally but not in production. The source walks through the seven different .env file types and their load order, which is genuinely helpful since Next.js's precedence chain trips people up constantly. Includes validation scripts and a practical checklist for catching the classic mistake of putting secrets in NEXT_PUBLIC_ variables where they'll get baked into your browser bundle.
npx skills add https://github.com/bobmatnyc/claude-mpm-skills --skill nextjs-v16