Stylometry on steroids: https://gwern.net/doc/statistics/stylometry/truesight/index

Truesight is a spell in D&D that allows you to see the true being behind an illusion or other deception.

It's almost like a claudeism

Gwern, who posted that comment, is one of the early popularisers of the term. Janus used it in at least 2023, and Gwern in at least early 2024.

If anything, you probably have the causation backwards: Claude talks like a LessWrong poster.