I have been building an interview practice tool for the last two months, writing it alongside Claude. Not "generate me an app" — ordinary daily work where I set a task, look at the result, argue with it and rewrite.
Plenty has been written about how fast AI writes code. I find the other question more interesting: what does it break in a way you cannot see?
All four bugs below are real, from my own project. What they have in common is that none of them throws. No exception, no 500, no red line in the logs. Every one of them looks correct in review. You find out when a user tells you — or you never find out at all.
1. The counter that never counted
Free plan, three interviews a month. Simple logic: questions generated, counter goes up.
