I just ran a couple of my stories through Copyleaks.com’s AI Content Detector and wasn't stoked with the results. The story "10 AI-Generated Plot Twists" (for which I used AI to write plots twists, https://medium.com/promptly-written/10-ai-generated-plot-twists-d4f7663205ad) came back as human, as did the AI-generated sections of "I Asked AI To Review My Books" (https://medium.com/youve-been-informed/i-asked-ai-to-review-my-books-f0ff82df762d). I wrote the rest of the articles (the majority), so I expected to get the AI + human result with the AI parts highlighted, but nope. It gave passing human results for both. Granted, it gave those articles a ~60% probability of being human, and another article I just tested (which I wrote in its entirety, using no AI) got a 94% probability of being human. But the tech definitely isn't foolproof yet!