It may be easier to constantly test for humanity. Given models change rapidly and can be trained, you could focus on some lower level interactions that cant be

It may be easier to constantly test for humanity. Given models change rapidly and can be trained, you could focus on some lower level interactions that cant be as easily changed. Speed is one mentioned below, but also cadence in responses could be measured similar to looking at keystrokes. This could be by token/word or perhaps answer-cadence, for example asking a challenge-response mix of complex questions and simple questions and measuring response times. Whatever you choose it would need to be done constantly in the background or mixed with regular traffic while interacting with your site though as a human could use an AI to get through the front door but then take over. Really cool question!