I Was Stuck on a JWT Bug for 2 Hours. This AI Prompt Found the Root Cause in Seconds.

We've all been there. A bug with zero console errors. No obvious cause. Just broken behavior that makes absolutely no sense. My JWT token was storing correctly after login — I could see it in localStorage. But after every single page refresh, the user was logged out and the token was gone. Silent failure. Nothing in the logs. Hours wasted. The Prompt That Fixed It Instead of googling for the 100th time, I used this structured AI prompt: "You are a world-class debugger. I have a bug I cannot solve. What the code should do: authenticate a user with JWT, store the token in localStorage, and keep them logged in after page refresh. What it actually does: user logs in successfully, token is stored, but after page refresh the user is logged out and the token disappears from localStorage. Error: no error in console. Code: `// Login function async function loginUser(email, password) { const response = await fetch('/api/auth/login', { method: 'POST', headers: { 'Content-Type': 'application/json'