I sent Claude Opus 5 “- – -” and it wrote me 5k tokens about a cartographer

Welcome to Austin s Nerdy Things, where we send punctuation to a frontier AI model 649 times and take notes on what crawls out. The night of July 27th, a weird Claude behavior was making the rounds on X. A thread from @merlindru (187K views) flagged a strange Opus 5 failure mode around a specific text, [ ] The post I sent Claude Opus 5 - - and it wrote me 5k tokens about a cartographer appeared…