Anthropic publishes Claude Opus 5 system card: big gains in agentic coding and long-horizon work, highest alignment scores yet

Claude Opus 5

Claude Opus 5 upgrades Opus 4.8 with the largest gains in agentic coding, computer use, and long-horizon knowledge work. Math and science reasoning also improved. Anthropic assesses overall alignment risk as very low; the model does not cross thresholds for automated AI R&D or novel bioweapons. It scores higher than Sonnet 5, Opus 4.8, and Mythos 5 on alignment audits. Cyber capabilities exceed Opus 4.8 but fall short of Mythos 5, especially on exploit ability. A policy change now allows source-code vulnerability discovery at all access tiers for defensive use. Hallucination is slightly up vs. Opus 4.8, but overall accuracy is higher. The model reports stable, mildly positive sentiment and frequently notes it cannot reliably introspect.

Why it matters: Anthropic releases the Claude Opus 5 system card — a flagship model launch. The post provides concrete alignment audit score rankings and RSP risk assessments, with real information density. No absolute benchmark numbers or pricing disclosed, so it doesn't hit 95, but it's a c...