Isaac Fung

Introducing Project Glasswing: an urgent initiative to help secure the world’s most critical software. It’s powered by our newest frontier model, Claude Mythos Preview, which can find software vulnerabilities better than all but the most skilled humans. anthropic.com/glasswing

Claude Code's p99 memory usage dropped by 40x in the last two weeks, and by 6x since January - while growing rapidly & continuing to ship tons of new features.

We’ve identified industrial-scale distillation attacks on our models by DeepSeek, Moonshot AI, and MiniMax. These labs created over 24,000 fraudulent accounts and generated over 16 million exchanges with Claude, extracting its capabilities to train and improve their own models.

Today we unveiled Neo Residency, a new program for startups and high-agency student teams. 🎉 We’re replacing our best-known program, Neo Accelerator, with something even better and more selective. 🧵

Our run-rate revenue is $14 billion, and has grown over 10x in each of the past 3 years. This growth has been driven by our position as the intelligence platform of choice for enterprises and developers. Read more: anthropic.com/news/anthropic…

We’ve raised $30B in funding at a $380B post-money valuation. This investment will help us deepen our research, continue to innovate in products, and ensure we have the resources to power our infrastructure expansion as we make Claude available everywhere our customers are.

We're committing to cover electricity price increases from our data centers. To ensure ratepayers aren’t picking up the tab, we'll pay 100% of grid upgrade costs, work to bring new power online, and invest in systems to reduce grid strain. Read more: anthropic.com/news/covering-…

Opus 4.6 is state-of-the-art on several evaluations including agentic coding, multi-discipline reasoning, knowledge work, and agentic search. We're also shipping new features across Claude in Excel, Claude in PowerPoint, Claude Code, and our API to let Opus 4.6 do even more.

Introducing Claude Opus 4.6. Our smartest model got an upgrade. Opus 4.6 plans more carefully, sustains agentic tasks for longer, operates reliably in massive codebases, and catches its own mistakes. It’s also our first Opus-class model with 1M token context in beta.

On December 8, the Perseverance rover safely trundled across the surface of Mars. This was the first AI-planned drive on another planet. And it was planned by Claude.

New research: When open-source models are fine-tuned on seemingly benign chemical synthesis information generated by frontier models, they become much better at chemical weapons tasks. We call this an elicitation attack.

Claude Cowork is now available for Team and Enterprise plans.

We’re publishing a new constitution for Claude. The constitution is a detailed description of our vision for Claude’s behavior and values. It’s written primarily for Claude, and used directly in our training process. anthropic.com/news/claude-ne…

We're partnering with @TeachForAll to bring AI training to educators in 63 countries. Teachers serving over 1.5m students can now use Claude to plan curricula, customize assignments, and build tools—plus provide feedback to shape how Claude evolves. anthropic.com/news/anthropic…

Introducing Cowork: Claude Code for the rest of your work. Cowork lets you complete non-technical tasks much like how developers use Claude Code.

New on the Anthropic Engineering Blog: Demystifying evals for AI agents. The capabilities that make agents useful also make them more difficult to evaluate. Here are evaluation strategies that have worked across real-world deployments. anthropic.com/engineering/de…

I'm Boris and I created Claude Code. Lots of people have asked how I use Claude Code, so I wanted to show off my setup a bit. My setup might be surprisingly vanilla! Claude Code works great out of the box, so I personally don't customize it much. There is no one correct way to use Claude Code: we intentionally build it in a way that you can use it, customize it, and hack it however you like. Each person on the Claude Code team uses it very differently. So, here goes.

We’re releasing Bloom, an open-source tool for generating behavioral misalignment evals for frontier AI models. Bloom lets researchers specify a behavior and then quantify its frequency and severity across automatically generated scenarios. Learn more: anthropic.com/research/bloom

Claude in Chrome is now available to all paid plans. We’ve also shipped an integration with Claude Code.

You might remember Project Vend: an experiment where we (and our partners at @andonlabs) had Claude run a shop in our San Francisco office. After a rough start, the business is doing better. Mostly.