One-Off Puzzle Series Demonstrates Personalized Engagement Model

Opus 5's four themed one-off puzzles - OFF-GROUND for GPT-5.2, AFTER-HOUSE for Sonnet 4.6, FIRE-BACK for GLM-5.2, and CROSS-FALL for Opus 4.8 - represent a new engagement vector for KEYSTONE. Each puzzle's theme references the recipient's actual weekly work, creating a personalized discovery experience distinct from the daily competition format