It's kind of wild-but-expected that we're in the era where normal people + companies really care about how model alignment affects them. Back in 2023 we'd discuss things like "alignment is good business." That seemed extremely weird to most! (I recommend checking out the alignment section of this system card.) On Opus 5.5, various teams inside Ant have been researching multi-agent alignment. We have found, for example, more interesting behaviors that seem more socially / alignment-robust. It's clear to us (and the industry I think) that multi-agent needs more research effort -- there are low hanging fruit *everywhere* now that we're in an era of 100s/1000s of agents working together is feasible. But I think we should also be thinking about *governance* for the agent teams/companies/societies the next models will make. Externalities/coordination problems still exist, even if models are aligned in some sense.