vercel-debug

Diagnose and fix the recurring "I just ran vercel login, but vercel whoami / vercel deploy still fails" scenario. Use when Jono hits Vercel CLI auth errors ("specified token is not valid", "missing_scope", "Provide --scope or --team explicitly") even right after logging in, on any new Vercel-deploying project. Deterministic: runs a fixed diagnostic checklist (stale VERCEL_TOKEN env var, outdated CLI with a broken --scope flag, missing default team scope), reports exactly what's wrong, and can apply the one safe automatic fix (CLI upgrade).