Why Your Vibe-Coded App Keeps Breaking Every Time You Fix Something

You ship a working feature on Monday. Tuesday morning a small cosmetic bug appears. You ask the AI to fix it. The fix works but the login flow now throws a 500. You paste the stack trace back in. The login comes back, but the payment webhook is silent. Eight prompts later, the UI is half-broken in three new places and you can no longer remember which version of the app actually worked. This is not bad luck, and it is not a skill issue. It is the predictable output of four compounding technical limitations in how today's AI coding agents understand code.