How to Trust Code You Didn't Write

Every engineering leader now ships code no one on their team has read. The old guarantees don’t transfer: human review can’t cover machine output, and tests generated by the same models that wrote the code prove less than they appear to. Some teams respond with better review, some with harder testing, some with mathematical proof - and in software where failure costs real money or lives, the bar is higher still. What it actually takes to trust machine-written code, which guarantees are real today, and which are still promises.