my guess is for some applications they can, but even reasoning models (o3-mini-high, grok3, sonnet 3.7, o1, deepseek, etc.) often fail to fix logic bugs. note that this isn't necessarily a form validation logic bug I'm referring to but, say, a pretty in-the-weeds tool for cleaning and pre-processing data for ML purposes. my guess is basic business-logic-y type stuff is much more doable.
i haven't really found a good way around cases where it either just adds printfs or loops through the same, non-working fixes repeatedly. they keep getting better, they're just not yet below my epsilon for unreliability.