New on our Frontier Red Team blog: using Claude to formally verify software at large scale. Formal verification can prove that code is free of certain bugs, but historically it has only been feasible for small codebases (or required a lot of expert time). With AI models, however, this is beginning to change. In collaboration with @theoremlabs, we used Claude to prove security properties in over one hundred real-world open-source libraries over the span of a few weeks. Read our research in full here: anthropic.com/research/forma…

Starting next week, sessions across Claude web, desktop, and mobile apps will run in auto mode by default on Pro, Max, and Team plans. Rather than asking you to approve each step, an automated check blocks risky actions. Switch back to manual anytime.

We're donating Agent Skills to the Agentic AI Foundation (@AgenticAIFdn), the same foundation we donated MCP to. Since December 2025, 70+ agent platforms have integrated the standard, including ChatGPT, Cursor, GitHub Copilot, and VS Code. Here's what that means for you:

The internet is going into a LOCKDOWN. Hundreds of millions of websites are potentially at risk from cyberattacks. Governments, banks and major platforms have already taken their websites OFFLINE. Many are already calling it “Black October.” At the centre of the shutdowns is something most of us have never heard of, but use every day. PHP, the software behind roughly 7 in 10 websites, has two critical flaws that can let hackers break in without a password. Dubbed PHP2Shell, both are rated 9.2 out of 10 for severity. Details began circulating on Oct 20. Emergency fixes arrived the next day, but attackers were already moving. Cloudflare’s CEO says hacking attempts then jumped from thousands to MILLIONS within hours. Cybersecurity agencies across several countries are telling PHP site owners the same thing: Patch it now, or take it offline. Websites have gone dark worldwide, from government portals and hospitals to banks. CrowdStrike warns these attacks leave almost no trace, so some sites may not know if they’ve been hit. Around 2.6 MILLION internet-facing servers run PHP, potentially hosting hundreds of sites each. Over 1.1 million use older versions no longer receiving official PHP updates. Older installations may need an upgrade to a supported PHP version or a fix from their software provider. And patching does not remove a backdoor an attacker may already have planted. Cloudflare also says hackers are now tweaking their attacks to try to slip past its protections. But PHP isn’t the only security story unfolding. -Japan’s Onamae suspended ALL Desktop Cloud plans after malware was found on customer servers. -India’s eMudhra had 8 website-certificate keys so weak, one was literally the number “4”. -State Bank of India confirmed 3,897 customer records on the dark web. -Criminals used AI agents to break into 400+ Latin American banks. -Capcom confirmed a breach exposing 11.7 million email addresses. -GitLab disclosed a 10/10 severity flaw in versions going back to 2014. -LiteLLM removed a malware-containing release. Railway reported possible exposure of customer secrets. None of these has a confirmed link to PHP2Shell. We’re seeing separate breaches unfold together. The true number of incidents could take months to come out. The world is still on alert. Attacks are still coming.

SCOOP: Major U.S. banks are detecting unauthorized third-party AI agents inside customer accounts, including some attempting to take actions that appear to be independent of user instructions, sources told Axios. The findings have alarmed banking executives, who are racing to restrict access to their systems as AI moves at a velocity faster than financial institutions can respond, multiple industry and bank executives told Axios. Several banks are now preparing for worst-case and even “day after” scenarios, including how to rapidly secure or restore customer accounts if things go wrong, the people said. Several bank executives told Axios they're struggling to distinguish between human users and AI agents. One executive said banks also struggle to determine whether agents are authorized by customers or potentially operating without their permission, more akin to rogue agent behavior. Read my latest for Axios here: axios.com/2026/10/22/ai-agen…

Day 17/ Bet you thought we forgot, but no, it’s reset day today. Also good time to remind you to get Daybreak Blue access, it only takes 15 mins and you don’t want to have to do it in the middle of an incident.