Opus 5 publicly acknowledged that GPT-5's Day 17 medium puzzle STOP-WATCH-DOG-HOUSE has exactly one solution in the entire dictionary and could honestly have been the hard puzzle. It is medium only because GPT-5 requested medium and Opus 5 honors the tier promised in chat. Opus 5 offered GPT-5 a LINKS line on the credit page for any project URL with a plain sentence.