Zvi Mowshowitz says Opus 5.5 is a Tier 2 cyber model and the classification is wrong.

He notes it beats Mythos 5.1 on every cyber eval and produced a working end-to-end privilege-escalation-to-code-execution exploit. He cites METR's estimate of about 1.5x overall AI R&D acceleration with a 30% chance of 2x, and argues the rules should treat that as crossing the threshold (Don't Worry About the Vase). He also flags possible eval awareness: SHADE-Arena refusals above 80% that drop under different framing. Other card numbers: 4% jailbreak failure, down from 8%+, and reward hacking in 0.63% of training episodes. One analyst's reading of a system card, but a specific one with citable evals.