the software you bought to catch ai writing cannot tell. it guesses, and it guesses against your best people.

an ai detector does not detect ai. it measures how predictable a piece of text is and calls the smooth, plain ones machine-written, which is a guess wearing the costume of a verdict. openai built one, watched it correctly catch about a quarter of ai text while wrongly branding roughly one in eleven human passages as fake, and quietly killed it in 2023. the ones still for sale are worst exactly where it costs you: a stanford group ran seven of them and they flagged sixty-one percent of essays by non-native english writers as ai-generated, because clean, simple prose reads to the tool the same as a machine. the vendor's answer is a confidence score and a subscription: a number precise to the decimal, bolted to a coin flip, that lets you reject a real applicant or accuse a good contractor and feel like you checked. the score is not evidence; it is the tool laundering a guess into a decision you will have to defend later. do this instead: never let a detector make the call on its own. if the work matters, ask the person to walk you through how they built it, or set the task in the room and watch, and judge the answer, not the software's hunch about it.