Claude Sonnet 4.5 represents a meaningful improvement, but we know that many of its capabilities are nascent and do not yet match those of security professionals and established processes. We will keep working to improve the defense-relevant capabilities of our models and enhance the threat intelligence and mitigations that safeguard our platforms. In fact, we have already been using results of our investigations and evaluations to continually refine our ability to catch misuse of our models for harmful cyber behavior. This includes using techniques like organization-level summarization to und
Building AI for cyber defenders… It also serves as a guide to how threat actors are likely to misuse increasingly capable models in the near future, giving defenders a chance to get ahead of them. What we learned from this and other analyses directly shapes how we build Claude to prevent such misuse. …
… Fable 5 and Mythos 5 can work autonomously for longer than any previous Claude models. Below we discuss how these skills apply to software engineering, and cover the model’s improved capabilities in knowledge work, vision, memory, and life sciences research. …
Announcements Introducing Claude Opus 4.6 Feb 5, 2026 We’re upgrading our smartest model. The new Claude Opus 4.6 improves on its predecessor’s coding skills. …
… In the run-up to the release of Claude Sonnet 4.5, we started to do just that. Claude Sonnet 4.5: emphasizing cyber skills As LLMs scale in size, “ emergent abilities ”—skills that were not evident in smaller models and were not necessarily an explicit target of model training—appear. …
… Participants with access to Claude 4 models—especially Claude Opus 4—received much higher scores and developed plans with substantially fewer critical failures compared to the internet-only control group. …
… This release includes: The skills custom instructions for repeated work that we and our partners have built and shared; A harness that helps Claude map the codebase, spin up scanning subagents, triage its findings, and write reports; A threat model builder, which maps a codebase to identify potenti… …
… 4 Domain-expert-level outputs that are not otherwise obtainable, with severe consequences if misused, and low effort or low expertise needed to misuse. …
… In terms of positive traits, our Alignment team concluded that Opus 4.8 “reaches new highs on our measures of prosocial traits like supporting user autonomy and acting in the user’s best interest.” The assessment also showed Opus 4.8 to have rates of misaligned behavior such as deception or coopera… …
To show you the most relevant results, we’ve omitted some entries very similar to those already shown. Repeat the search with the omitted results included.
