Agent skill · software engineering · erichowens
fullstack-debugger
Expert debugger for Next.js + Cloudflare Workers + Supabase stacks. Systematic troubleshooting for auth, caching, workers, RLS, CORS, and build issues. Activate on: ''debug'', ''not working'',
Why this skill is useful
Provides systematic troubleshooting techniques and specific commands for debugging Next.js, Cloudflare Workers, and Supabase that the AI wouldn't reliably generate on its own.
What it needs
Requires npm installed locally. About 8k tokens when loaded. Last updated 2026-07-14. 180 stars on the source repository.
What this skill does
Fullstack Debugger Expert debugger for modern web stacks: Next.js 15, Cloudflare Workers, Supabase, and edge deployments. Systematic, evidence-based troubleshooting. Activation Triggers Activate on: "debug", "not working", "broken", "error", "500 error", "401", "403", "cache issue", "CORS error", "RLS policy", "auth not working", "blank page", "hydration error", "build failed", "worker not responding" NOT for: Feature development → language skills Architecture → system-architect Performance optimization → performance-engineer Debug Philosophy Architecture Layers Quick Diagnosis Commands Check Everything At Once Supabase RLS Diagnosis Worker Health Check Cache Inspection Common Issues & Solutions 1. RLS Policy Blocking Data (Most Common!) Symptoms: Query returns empty array but no error Works in Supabase dashboard but not in app Works for some users but not others Diagnosis: Common Fixes: 2. CORS Errors Symptoms: "Access to fetch blocked by CORS policy" Works in Postman but not in browser Preflight request fails Diagnosis: Fix in Cloudflare Worker: 3. Auth State Not Persisting Symptoms: User logged in but shows as logged out on refresh Auth works locally but not in production Session disappears randomly Diagnosis: Common Fixes: Check Supabase URL matches (http vs https, trailing slash) Verify site URL in Supabase Auth settings Check for cookie blocking (Safari, incognito) Ensure AuthContext wraps all components needing auth 4. Hydration Mismatch Symptoms: "Hydration failed because the initial UI does not match" Content flashes on page load Different content on server vs client Diagnosis: Common Fixes: 5. Worker Not Deploying Symptoms: Deploy command succeeds but changes not reflected Old code still running Intermittent old/new behavior Diagnosis: Fixes: 6. TypeScript Cache Haunting Symptoms: Errors reference deleted/changed code Types don't match current code "Cannot find module" for existing files Fix: 7. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills erichowens/fullstack-debugger