Petri is open-source and available now: https://t.co/X2h1O0t8t8Read the full technical report: https://t.co/fKXxbYtItn ...

As a pilot demonstration of Petri’s capabilities, we tested it with 14 frontier models across 111 diverse scenarios. https://t.co/xdqSLiUs4w ...

It’s called Petri: Parallel Exploration Tool for Risky Interactions. It uses automated agents to audit models across diverse scenarios.Describe a scenario, and Petri handles the environment simulation, conversations, and analyses in minutes.Read more: https://t.co/inztNkrXMh ...

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 ...

AI in Cybersecurity - Overview - AI's impact on cybersecurity is at an inflection point [1] - Claude AI outperforms human teams in some cybersecurity competitions [1] - AI assists in discovering and fixing code vulnerabilities [1] - Attackers are leveraging AI to scale their operations [1]

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 ...