Last week we released Claude Sonnet 4.5. As part of our alignment testing, we used a new tool to run automated audits for behaviors like sycophancy and deception.Now we’re open-sourcing the tool to run those audits. https://t.co/cCJGNaVFrl ...

We’re at an inflection point in AI’s impact on cybersecurity.Claude now outperforms human teams in some cybersecurity competitions, and helps teams discover and fix code vulnerabilities.At the same time, attackers are using AI to expand their operations. https://t.co/odoTuPpJXe ...

Cybersecurity Performance - Claude Sonnet 4.5 is comparable or superior to Opus 4.1 in defensive cybersecurity tasks [1] - Claude Sonnet 4.5 is faster and cheaper in cybersecurity tasks [1]

AI Agent Development - Anthropic Engineering Blog introduces "context engineering" for maximizing AI agent performance, going beyond traditional prompt engineering [1] - The blog post explains how context engineering works [1]

RT Jack Clark (@jackclarkSF)We applaud @CAgovernor for signing @Scott_Wiener's SB 53, establishing transparency requirements for frontier AI companies that will help us all have better data about these systems and the companies building them. Anthropic is proud to have supported this bill. ...

RT Claude (@claudeai)Introducing Claude Sonnet 4.5—the best coding model in the world.It's the strongest model for building complex agents. It's the best model at using computers. And it shows substantial gains on tests of reasoning and math. https://t.co/7LwV9WPNAv ...

Chris Ciauri is joining Anthropic as our Managing Director of International.He joins during a period of rapid global expansion for Anthropic, as we triple our international headcount across Dublin, Tokyo, London, and Zurich.Read more: https://t.co/SeFIXPd53x ...

Claude Sonnet 4 and Opus 4.1 are now available in Microsoft 365 Copilot, bringing Claude’s advanced reasoning capabilities to millions of enterprise users.Read more: https://t.co/3UTzA9A2Yk ...

We're partnering with Learning Commons from the Chan Zuckerberg Initiative—addressing some of the biggest challenges we hear about from K–12 teachers about AI in the classroom: https://t.co/m3A2eQYbUzChan Zuckerberg Initiative (@ChanZuckerberg):Fall is here 🍎 and we’re sharing big AI releases:✔️ Knowledge Graph✔️ Knowledge Graph’s Claude Connector✔️ EvaluatorsWith tools like Knowledge Graph + Evaluators we are laying a foundation teachers can trust 🔽 https://t.co/MSTDxiJnmI ...

Social Media Activity - The tweet encourages continued thinking [1]