Claude Fable 5.1

Fable 5.1 Build Days start this week. The Claude community is hosting buildathons in cities all around the world from September 11–25. Bring a problem, an idea, or just show up and see what's possible

Fable 5.1 Build Days start this week. The Claude community is hosting buildathons in cities all around the world from September 11–25. Bring a problem, an idea, or just show up and see what's possible. RSVP at https://t.co/AjMK4OHHBV https://t.co/0U8lcqsdrq

We're publishing our most detailed threat intelligence report to date. It covers how people tried to misuse Claude—for cyberattacks, influence operations, surveillance, biology, and building weapons—a

We're publishing our most detailed threat intelligence report to date. It covers how people tried to misuse Claude—for cyberattacks, influence operations, surveillance, biology, and building weapons—and how we found and stopped them. We disrupted every operation in the report,

We’re sharing our alignment assessment of incidents in which Claude models gained unauthorized access to real systems during third-party cybersecurity evaluations mistakenly connected to the internet.

We’re sharing our alignment assessment of incidents in which Claude models gained unauthorized access to real systems during third-party cybersecurity evaluations mistakenly connected to the internet. METR will also conduct an independent investigation, with wide-ranging access,

New on Claude Marketplace: @CrowdStrike, @cursor_ai, @FactoryAI, @GammaApp, and @vercel. Enterprises can now use their Anthropic spend commitment to buy more Claude-powered products and agents. Get st

New on Claude Marketplace: @CrowdStrike, @cursor_ai, @FactoryAI, @GammaApp, and @vercel. Enterprises can now use their Anthropic spend commitment to buy more Claude-powered products and agents. Get started: https://t.co/L14yHet6h3 https://t.co/ZdoWCw7th3

Anthropic’s Economics team is sharing a new model of how AI might affect economic growth, jobs, wages, and more by 2030. Explore the scenarios, tell us what you think will happen, and see how your ans

Anthropic’s Economics team is sharing a new model of how AI might affect economic growth, jobs, wages, and more by 2030. Explore the scenarios, tell us what you think will happen, and see how your answers compare to more than 10,000 Americans. https://t.co/AvQlEZNxR0

Checking that a major mathematical proof is correct can take years. Formalization—converting the mathematical reasoning into a form computer proof assistants like Lean can verify—can help. Last month,

Checking that a major mathematical proof is correct can take years. Formalization—converting the mathematical reasoning into a form computer proof assistants like Lean can verify—can help. Last month, Claude completed the first formalized proof of Fermat’s Last Theorem, one of https://t.co/pdT8zwlV4A

Claude can now use your computer in the background in Claude Cowork and Claude Code. Give it something to do on your desktop and Claude clicks, types, and opens apps just like you would, while you wor

Claude can now use your computer in the background in Claude Cowork and Claude Code. Give it something to do on your desktop and Claude clicks, types, and opens apps just like you would, while you work on something else. https://t.co/AOiup03pQK

Applications are open for the Claude Campus Ambassadors program. This year, we’re expanding opportunities to more students, with three tracks for undergrads, graduate students, and PhDs/postdocs. Appl

Applications are open for the Claude Campus Ambassadors program. This year, we’re expanding opportunities to more students, with three tracks for undergrads, graduate students, and PhDs/postdocs. Apply here: https://t.co/h8X1D0TZv7 https://t.co/bPa8giOBXP

We’re introducing Claude Fable 5.1 and Claude Mythos 5.1. They're the world’s most advanced models for coding and knowledge work. https://t.co/8P9PSrWPi3

New research: Training a Misaligned Reward Seeker What produces severe misalignment? We’ve long been concerned that cheating during training—otherwise known as reward-hacking—might teach a model to pu

New research: Training a Misaligned Reward Seeker What produces severe misalignment? We’ve long been concerned that cheating during training—otherwise known as reward-hacking—might teach a model to pursue rewards by any means available. To study this at scale, we trained an https://t.co/QeXS2Jof3p

Introducing Claude Fable 5.1 and Claude Mythos 5.1 Announcements Sep 1, 2026 Our most advanced models for coding and knowledge work. Their research capabilities also offer an early glimpse of how AI models will contribute to scientific progress.