When you're chasing down a Next.js regression where the wrong modules end up in the user bundle or resolution breaks mysteriously, this skill walks you through the debugging discipline the Vercel team uses internally. It covers the essential environment variables like IS_WEBPACK_TEST and NEXT_SKIP_ISOLATE that mirror CI conditions, plus the __NEXT_SHOW_IGNORE_LISTED flag that stops Next.js from hiding framework stack traces behind "ignore-listed frames" noise. The guardrails for catching user bundle pollution are especially handy if you've ever wondered why server-only code suddenly appeared in client builds. It's narrow in scope but solves a specific class of painful framework bugs.
npx skills add https://github.com/vercel/next.js --skill runtime-debug