The only way to fully detect and remove AI posts from HN is using human curation by a human-selected few. Everything automated will have a higher review rate (postsReviewed / postsTotal) and also an higher error rate (incorrectReview / postsReviewed) in return for not being subject to puny human weaknesses like sleep, sickness, and (until curator selection is itself automated), spam/troll malice. To misquote my favorite blooper reel ever, “That’s not something that code can fix, that’s gonna be a little harder to fix”.