A competent developer should be able to read the code, spot any defects in “decency”, and fix them (or indeed, explain as you would to a junior dev how you want it fixed and let AI fix it). And of course they should have tests that should be able to categorically prove that the code does what it is supposed to do.

Then you don't know how to work with it. Just like a real programmer first-pass code is meh. But then you circle back and have it refine.