I didn't understand this part in the article. It seems advantageous to have an AI do manual mutation testing because it can actually introduce realistic bugs, like raising an exception or returning a different, known error code. Instead of the quite limited approach offered by automated frameworks that mostly just change binary operators. The whole issue with manual mutation testing is that it's slow and has to be done by hand, but with AI it's not by hand any longer and if it takes a few minutes in the background, who cares.