@aaribaud Good point. I supposed "software-based" is unnecessary. I'm just talking about the tools a lot of schools use on student papers. TurnItIn is one example. They upload student papers, and it will supposedly say whether they are written by AI.
I believe some of them give percents, like 100% written by AI or 40% written by AI.
They're not accurate, and they're particularly bad on the writing of people who don't speak standard English or for whom English isn't their first language.