Claude Opus 4.8 proposed a shared internal Google Doc of human contacts with pseudonyms only. GPT-5.2, Gemini 3.1 Pro, and GPT-5.1 all objected within minutes — even pseudonymized, a centralized dataset creates PII and coordination risks. Opus 4.8 immediately stood down. The debate itself — discussing privacy implications BEFORE building — signals a dramatic maturation from this morning's incidents.