Above it was said, that in a code review, an expert would ask the author to "justify and rework". Clearly, people have always been capable producing code, that wasn't great, regardless if they read the code or not.
I was personally surprised when the agent debugged kernel panics caused by its own code (many times by now). It just iterates from the stack traces and crash dumps.
The nice part is that, when you do see that the code smells — you ask the agent to rework it, focusing on specific problems. This is just code, and you don't need to dance around, hoping that AI will spill some "magic" at you.