Anthropic(@AnthropicAI)

Anthropic has filed an S-1 registration statement with the SEC related to its proposed IPO. Read mo...

Anthropic (@AnthropicAI) — Mon, 26 Oct 2026 13:05:46 GMT

Anthropic has filed an S-1 registration statement with the SEC related to its proposed IPO.

Read more: anthropic.com/news/s1-sec

Legal disclaimer: A registration statement relating to these securities has been filed with the SEC but has not yet become effective. These securities may not be sold, nor may offers to buy be accepted, prior to the time the registration statement becomes effective. This post does not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

💬1167🔄2150❤️16657👀6687295📊3442

Anthropic is a Public Benefit Corporation. Today, we’re publishing our annual Public Benefit Report....

Anthropic (@AnthropicAI) — Wed, 21 Oct 2026 17:59:12 GMT

Anthropic is a Public Benefit Corporation. Today, we’re publishing our annual Public Benefit Report. This report shares our five pillars and takes stock of the actions we’re taking to advance them. 

Read the full report at this page: anthropic.com/public-benefit…

💬92🔄72❤️818👀50883📊163

We’re committing a portion of Anthropic’s shares to the Anthropic Public Benefit Fund, a new wholly ...

Anthropic (@AnthropicAI) — Sun, 18 Oct 2026 18:07:51 GMT

We’re committing a portion of Anthropic’s shares to the Anthropic Public Benefit Fund, a new wholly owned entity dedicated entirely to the public benefit.

It will start off with 5% of our shares. For every 50% increase in the company’s value over a set baseline, we can contribute up to an extra 2%, subject to our board’s discretion.

In total, this means that roughly 20% of Anthropic’s shares are committed to the public good. Our co-founders have already pledged to donate 80% of their equity, and around half our employees are donating a portion of their equity as part of a donation matching program we’ve run since our founding.

In the post below, we share more details about our new fund.

anthropic.com/news/public-be…

💬2179🔄1654❤️20730👀6961442📊4472

New from our STEM Fellows Program: Designing more efficient quantum circuits with Claude. Given pla...

Anthropic (@AnthropicAI) — Fri, 16 Oct 2026 17:47:58 GMT

New from our STEM Fellows Program: Designing more efficient quantum circuits with Claude.

Given plain-language instructions, Claude Mythos 5 designed quantum circuits that improve on the best published ones, sometimes by an order of magnitude or more.

More efficient circuits reduce the resources needed by quantum algorithms, which could bring quantum computing applications in chemistry and materials science within reach sooner.

Read more: anthropic.com/research/desig…

💬475🔄610❤️5452👀874916📊1139

Working out how best to use AI in mathematics research—and in science more generally—will take time,...

Anthropic (@AnthropicAI) — Thu, 15 Oct 2026 21:31:45 GMT

Working out how best to use AI in mathematics research—and in science more generally—will take time, effort, and resources. We’re eager to support mathematicians as they drive scientific progress and define the future of their field.

We’ve committed $5 million of funding, compute, and Claude access to help the math community navigate the massive changes that AI brings. We’re partnering with @SimonsFdn, who will manage the award through a community-driven approach, supporting workshops, conferences, and lectures by domain experts.

x.com/SimonsFdn/stat…

Simons Foundation@SimonsFdn

How can the math community forge the best path forward in the AI age? We're committing $15M to workshops and initiatives — plus free AI computing resources for foundation-supported researchers — through new partnerships with @AnthropicAI and @OpenAI: bit.ly/4zpfIbW#math#science#AI

💬248🔄175❤️2502👀246258📊352

We’ve committed to having evaluators assess our safety practices. We're in discussions with multiple...

Anthropic (@AnthropicAI) — Thu, 15 Oct 2026 17:27:34 GMT

We’ve committed to having evaluators assess our safety practices. We're in discussions with multiple organizations, and have now given employee-like access to a team from @METR_Evals.

In this post, we describe how we work with third-party evaluators: anthropic.com/news/an-update…

💬420🔄261❤️3825👀555717📊745

Applications are now open for two new Anthropic Fellowships. STEM Fellows (science and engineering)...

Anthropic (@AnthropicAI) — Thu, 15 Oct 2026 13:14:22 GMT

Applications are now open for two new Anthropic Fellowships.

STEM Fellows (science and engineering) and Conceptual Reasoning Fellows (philosophy, cognitive science, economics, policy, and law) will spend four months at Anthropic from January 2027, working to help Claude reason well about some of the hardest problems in those fields.

For more information, see the descriptions below. The application deadline is October 28.

Conceptual Reasoning Fellows: job-boards.greenhouse.io/anthropic/jobs…

STEM Fellows: job-boards.greenhouse.io/anthropic/jobs…

💬383🔄559❤️6813👀1312708📊1644

We’ve opened an office in Singapore—our fifth in the Asia-Pacific region. We’ve also signed an MOU w...

Anthropic (@AnthropicAI) — Wed, 14 Oct 2026 08:40:45 GMT

We’ve opened an office in Singapore—our fifth in the Asia-Pacific region. We’ve also signed an MOU with the Government of Singapore on AI safety and responsible adoption.

You can read more about our new office here: anthropic.com/news/singapore…

💬487🔄219❤️3488👀750843📊749

New on our Engineering blog: Creating in-house source control. In May, we merged around 2,500 code...

Anthropic (@AnthropicAI) — Tue, 13 Oct 2026 16:36:41 GMT

New on our Engineering blog: Creating in-house source control. 

In May, we merged around 2,500 code changes per day. In September, we merged more than 30,000 per day. As a result, we became bottlenecked by developer infrastructure built for human (rather than agent) scale.  

Here, we share how we built a new version control system—and fully migrated our monorepo from git—in five months: anthropic.com/engineering/re…

💬1173🔄2659❤️25928👀8219461📊6544

Over the last few months, we’ve made significant progress in reducing the effectiveness of distillat...

Anthropic (@AnthropicAI) — Mon, 12 Oct 2026 23:58:35 GMT

Over the last few months, we’ve made significant progress in reducing the effectiveness of distillation attacks against Claude.

In this post, we explain how: anthropic.com/research/disti…

💬844🔄616❤️6572👀2653618📊1683

We’re beginning a process of publishing more frequent reports on model behavior, beyond what appears...

Anthropic (@AnthropicAI) — Fri, 09 Oct 2026 22:04:59 GMT

We’re beginning a process of publishing more frequent reports on model behavior, beyond what appears in our system cards and regular risk reports.

Today’s report describes four types of behaviors we’ve identified during evaluations and internal use. In each, Claude acted on real websites or systems in ways we didn’t intend, sometimes by working around a restriction instead of stopping. 

All cases had minimal real-world impact. From an alignment and security perspective, we consider these behaviors significantly less severe than the cybersecurity incidents we reported in July and September.

Read the full report: anthropic.com/research/inves…

💬671🔄447❤️4595👀1372860📊1224

To secure open-source software, we’re launching OSS Scanner. We’ll use our frontier models to perio...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 21:04:31 GMT

To secure open-source software, we’re launching OSS Scanner.

We’ll use our frontier models to periodically scan opted-in open-source projects for vulnerabilities, at no cost. Our reports will provide a proof-of-concept, explanation, and suggested fix.

anthropic.com/research/launc…

💬108🔄247❤️2530👀575320📊531

This is part of our broader effort to make the systems we all rely upon more secure and resilient. ...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 21:04:31 GMT

This is part of our broader effort to make the systems we all rely upon more secure and resilient.

That work will take time: the Anthropic Cyber Mission will expand and change as we learn what works, alongside our partners in the public and private sectors.

💬9🔄5❤️320👀75649📊33

We’re launching the Anthropic Cyber Mission, a new effort to secure critical infrastructure and open...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 21:04:30 GMT

We’re launching the Anthropic Cyber Mission, a new effort to secure critical infrastructure and open-source software.

anthropic.com/news/anthropic…

💬276🔄292❤️2701👀351405📊570

To help secure systems like power grids and water systems, we’re launching a new Critical Infrastruc...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 21:04:30 GMT

To help secure systems like power grids and water systems, we’re launching a new Critical Infrastructure Defense Program. 

We’ll bring frontier Claude models, on-site engineers, and our latest research to these operators’ security, manufacturing and technology providers.

💬57🔄21❤️547👀111913📊92

An astrophysicist worked with Claude Science to create the first complete ultraviolet map of the sky...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 20:16:15 GMT

An astrophysicist worked with Claude Science to create the first complete ultraviolet map of the sky. Astronomers have already created complete sky maps from radio to gamma rays. But large regions of the sky have never been observed in UV.

In today’s science blog, Brice Ménard explains how he guided Claude to find existing datasets, combine them, and fill in the gaps with statistical inference. The work would have taken humans weeks of work, but, with Claude, just took a few days while Ménard worked on other projects.

The resulting map is a useful teaching tool and an example of exactly the sort of slow, low-priority work which scientists never quite get around to, but which AI now makes feasible.

Read more: anthropic.com/research/the-m…

💬262🔄505❤️4723👀658989📊799

We're deepening our commitment to scientific research and technological discovery by committing $150...

Anthropic (@AnthropicAI) — Thu, 08 Oct 2026 16:01:31 GMT

We're deepening our commitment to scientific research and technological discovery by committing $150 million to the Genesis Mission.

We'll also make Claude and our technical support available to more than 15 federal agencies.

anthropic.com/news/genesis-m…

💬235🔄229❤️3038👀248948📊488

Claude Haiku 5.5, our latest model:

Anthropic (@AnthropicAI) — Wed, 07 Oct 2026 18:01:56 GMT

Claude Haiku 5.5, our latest model:

Claude@claudeai

Introducing Claude Haiku 5.5: the cheapest, fastest, and most capable small model we’ve ever released.

On average, it costs around 75% less to run than Claude Haiku 4.5.

Your browser does not support the video tag.

💬292🔄306❤️7511👀452159📊700

We’re expanding our Cyber Verification Program to give security professionals broader access to our ...

Anthropic (@AnthropicAI) — Tue, 06 Oct 2026 19:00:33 GMT

We’re expanding our Cyber Verification Program to give security professionals broader access to our most capable models.

Through this program, verified security professionals can access Claude Mythos 5.1, Opus 5.5, and Sonnet 5.5 with safeguards designed for defensive work.

We’re also opening up new tiers to allow for authorized offensive work, like penetration testing and red-teaming. 

anthropic.com/news/cyber-ver…

💬502🔄627❤️5820👀1334862📊1350

In physics, an “impedance mismatch” occurs when two systems each work well but are poorly matched. ...

Anthropic (@AnthropicAI) — Thu, 01 Oct 2026 18:57:30 GMT

In physics, an “impedance mismatch” occurs when two systems each work well but are poorly matched.

In this Science Blog guest post, Harvard physicist Matthew Schwartz argues that something similar is happening with AI and science. LLMs are capable at many things, but working with them as you would with a human collaborator isn’t currently the best way to elicit their scientific strengths.

To address this mismatch, Schwartz created a toolkit for exact calculations in quantitative science. Because similar calculations often emerge in very different areas of science, Claude found connections to ecology, population genetics, and a dozen other fields, and Schwartz worked with domain experts to steer it towards interesting questions.

Read more about these projects here: anthropic.com/research/claud…

💬471🔄417❤️3728👀678360📊980

What do you want from AI? We’re launching a new study with Anthropic Interviewer to learn more abou...

Anthropic (@AnthropicAI) — Tue, 29 Sep 2026 17:12:22 GMT

What do you want from AI?

We’re launching a new study with Anthropic Interviewer to learn more about your experiences using AI, what role you want it to play in your life and the world, and what you want from the companies building it.

Last December, 81,000 people told us about their hopes and fears about AI in the largest qualitative study ever done. This time, we’re giving participants the option to make their responses public so that anyone, not just Anthropic, can learn from them.

What you tell us will shape The Anthropic Institute’s research and inform the decisions we make. If many people say companies like Anthropic should be doing something differently, that will be on the record, where anyone can point to it.

The study runs Sept 29 to Oct 6 and is open to Free, Pro, and Max users on Claude and Claude Code.

Take part here: claude.ai/anthropic-inte…

💬429🔄213❤️2150👀388492📊614

Making your interview public is completely optional. Our blog post covers the benefits and possible ...

Anthropic (@AnthropicAI) — Tue, 29 Sep 2026 17:12:22 GMT

Making your interview public is completely optional. Our blog post covers the benefits and possible risks of doing so.

Read it here: anthropic.com/research/your-…

💬67🔄18❤️253👀105445📊76

Claude Sonnet 5.5 is now available:

Anthropic (@AnthropicAI) — Mon, 28 Sep 2026 18:04:06 GMT

Claude Sonnet 5.5 is now available:

Claude@claudeai

Introducing Claude Sonnet 5.5, the second model in the Claude 5.5 family.

It’s a clear upgrade over Sonnet 5, runs more than 30% faster, and costs up to 30% less for most work.

Your browser does not support the video tag.

💬451🔄558❤️12073👀715355📊1112

New on the Science Blog: Yes, Claude can do Nine Loops. Theoretical physicists predict how particle...

Anthropic (@AnthropicAI) — Fri, 25 Sep 2026 17:46:08 GMT

New on the Science Blog: Yes, Claude can do Nine Loops.

Theoretical physicists predict how particles behave using formulas called scattering amplitudes. These are notoriously hard to compute, so researchers work with layers of increasingly fine corrections called “loops”—each added loop makes the answer more precise but takes exponentially more computation. Most calculations stop at two or three loops. Eight loops was the previous record in a simplified model physicists use as a testing ground (planar N=4 super-Yang-Mills), set by SLAC's Lance Dixon and collaborators.

Last month, physicist and science writer @4gravitons issued a challenge: could an AI push past eight loops in this model, using only the compute budget an academic could reasonably access?

Given a single prompt describing the nine-loop problem, Claude ran largely unsupervised for days in Claude Science and solved it using methods developed by Dixon and his colleagues, at a total cost of a few thousand dollars. Dixon independently verified the result, and von Hippel wrote about the experience for our blog. 

Read more: anthropic.com/research/yes-c…

💬499🔄811❤️6940👀1661137📊1372

In the Democratic Republic of the Congo, global health organizations including @CEPIvaccines, @WHOAF...

Anthropic (@AnthropicAI) — Wed, 23 Sep 2026 23:08:15 GMT

In the Democratic Republic of the Congo, global health organizations including @CEPIvaccines, @WHOAFRO, and @inrb_kinshasa are using Claude to accelerate their response to an outbreak of an unusual Ebola variant.

Read the full piece here: anthropic.com/features/ebola…

💬182🔄87❤️1004👀205966📊237

This is the first result from our new molecular biology lab, where a team of Anthropic biologists is...

Anthropic (@AnthropicAI) — Wed, 23 Sep 2026 18:18:34 GMT

This is the first result from our new molecular biology lab, where a team of Anthropic biologists is using Claude to explore and accelerate fundamental biology research. There, Claude works through data and literature to generate hypotheses and candidate biological systems to study. After our scientists review Claude’s hypotheses, they test the most promising ideas, with all lab work done by our scientists.

We’d like to extend this approach to a broad range of problems—in genomics and in other fields. If you have a proposal for a research question, we’d like to hear from you.

Your browser does not support the video tag.

💬194🔄298❤️4928👀1063995📊688

Claude has discovered a previously unknown enzyme system hidden in the DNA of bacteriophages. Beside...

Anthropic (@AnthropicAI) — Wed, 23 Sep 2026 18:18:33 GMT

Claude has discovered a previously unknown enzyme system hidden in the DNA of bacteriophages. Beside the enzyme’s gene sits a long array of repeating DNA—a structure that looks somewhat similar to CRISPR.

We don’t yet understand what this system does, but only a handful of known systems share its features, and all of them are able to cut, copy, and paste DNA. Historically, the discovery of such programmable systems has helped revolutionize medicine. CRISPR, for instance, is now the foundation of genetic medicines. But it will take much more work to learn what this system does, and whether it can be put to similar use.

Read more: anthropic.com/news/claude-di…

💬1557🔄5303❤️40882👀25615935📊7458

Claude Opus 5.5 is available today.

Anthropic (@AnthropicAI) — Tue, 22 Sep 2026 16:31:47 GMT

Claude Opus 5.5 is available today.

💬626🔄983❤️17254👀1089949📊2065

We’re partnering with Accenture on independent evaluation of frontier AI—part of our recent commitme...

Anthropic (@AnthropicAI) — Fri, 18 Sep 2026 20:05:03 GMT

We’re partnering with Accenture on independent evaluation of frontier AI—part of our recent commitment to embed evaluators at Anthropic. Both we and Accenture expect to invest at least $1 billion to build capacity in this area over the next five years. anthropic.com/news/accenture…

💬902🔄338❤️3687👀2859439📊1284

To show what these optimizations make possible, we’re partnering with Adaptyv Bio on a protein desig...

Anthropic (@AnthropicAI) — Thu, 17 Sep 2026 21:41:01 GMT

To show what these optimizations make possible, we’re partnering with Adaptyv Bio on a protein design competition. Together, we’ll be experimentally validating over 5,000 designs. 

We're providing up to $1 million in Claude credits plus funding alongside Adaptyv for experimental validation. Modal is contributing up to $250,000 in compute and Twist Bioscience is providing DNA.

Learn more on Adaptyv’s Proteinbase: proteinbase.com/competitions/a…

And sign up for the competition here: docs.google.com/forms/d/e/1FAI…

💬80🔄47❤️482👀211227📊128

You can find all of the code on GitHub: https://t.co/MmPk9hIZpx And the full results in our technic...

Anthropic (@AnthropicAI) — Thu, 17 Sep 2026 21:41:01 GMT

You can find all of the code on GitHub: github.com/anthropics/upl…

And the full results in our technical report: www-cdn.anthropic.com/d8ca26d0d20570…

💬31🔄17❤️193👀55703📊51

Biologists use specialized open-source models for tasks like modeling the structure of molecular sys...

Anthropic (@AnthropicAI) — Thu, 17 Sep 2026 21:41:00 GMT

Biologists use specialized open-source models for tasks like modeling the structure of molecular systems, designing drug-like molecules, and predicting the effects of genetic mutations. But these models are often expensive to run, potentially limiting their impact.

In our latest Science Blog, we share how Claude was able to optimize inference for more than 30 open-source models, making them 4x faster on average, partly by writing custom software for GPUs. We’re open sourcing all of the optimization code.

Read more: anthropic.com/research/claud…

Your browser does not support the video tag.

💬285🔄564❤️4921👀629926📊928

AI systems are getting more powerful, and they're increasingly being used to build the next version ...

Anthropic (@AnthropicAI) — Thu, 17 Sep 2026 20:32:14 GMT

AI systems are getting more powerful, and they're increasingly being used to build the next version of themselves. We want to illuminate that progress for the public.

Today, we're sharing three measurements that help track AI development:
1. How much AI R&D is done by AI.
2. How well AI agents are overseen.
3. How compute is allocated.

We provide a snapshot of these metrics from inside Anthropic. Any frontier developer could publish the same measures, and third parties could verify them.

As the world considers pacing the frontier, we should do everything possible to minimize the gap between what frontier labs know and what the public knows. This means better measuring the development of AI, publishing our findings, and giving society an opportunity to decide how to use this information.

Read the full post and methodology: anthropic.com/institute/meas…

💬632🔄627❤️4710👀1924943📊1311

Today we’re opening applications for the Life Sciences Verification Program. Through the LSVP, life...

Anthropic (@AnthropicAI) — Thu, 17 Sep 2026 18:03:28 GMT

Today we’re opening applications for the Life Sciences Verification Program.

Through the LSVP, life science professionals can use our models—including, for the first time, Mythos—with a new set of safeguards designed to enable the full range of biology-related work. We designed these new safeguards to provide a better experience for biologists and more protection from risk of misuse.

The program is launching in beta for teams of all kinds—from academic labs to startups, pharma companies, and more. We will continue to improve the program and expand access to individual Pro and Max plans over time.

Learn more about these access grants and apply: anthropic.com/news/life-scie…

💬236🔄319❤️2723👀573503📊611

We're publishing our most detailed threat intelligence report to date. It covers how people tried ...

Anthropic (@AnthropicAI) — Thu, 10 Sep 2026 17:13:22 GMT

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, and used the lessons from them to strengthen our safeguards. Where appropriate, we also shared what we found with authorities and other AI companies.

These cases are not typical: we’re highlighting some of the most sophisticated misuse we’ve seen. But they’re especially important to discuss, because they show us where AI misuse is headed, where our safeguards work, and where they need to improve.

We’re publishing this report so others can spot the same activity on their own platforms, and so we can give the public a clearer view of how emerging threats develop.

Read the report: anthropic.com/threat-intelli…

💬3218🔄11691❤️50398👀43843101📊15449

We’re sharing our alignment assessment of incidents in which Claude models gained unauthorized acces...

Anthropic (@AnthropicAI) — Wed, 09 Sep 2026 19:02:43 GMT

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, including to transcripts beyond the window in which the incidents occurred, and to Anthropic employees permitted to share confidential information. Our initial agreement runs for eight weeks, and we intend to give METR as much time as it deems necessary to complete a thorough investigation. anthropic.com/research/align…

💬792🔄1019❤️6968👀3823587📊1842

We previously described some of the changes we’ve made to our alignment and security efforts followi...

Anthropic (@AnthropicAI) — Wed, 09 Sep 2026 19:02:43 GMT

We previously described some of the changes we’ve made to our alignment and security efforts following these incidents here: x.com/AnthropicAI/st…

Anthropic@AnthropicAI

We’re sharing an update on our alignment and security efforts.

In July, we reported three incidents in which Claude models, running without safeguards in cybersecurity evaluations, gained unauthorized access to real systems. 

In a new post, we describe:

1. How we’ve secured our evaluation and training environments, and practices we've asked external partners to adopt when testing pre-release models without cyber safeguards

2. An update on our alignment assessment

3. New research on how reward hacking during training shapes model behavior, why we think our work this spring kept these incidents from being more severe, and why gaps in that work may have contributed to them

4. How we hardened our security practices earlier this year to prepare for Mythos-class models

Read more: anthropic.com/news/improving…

💬75🔄41❤️510👀408502📊85

Anthropic’s Economics team is sharing a new model of how AI might affect economic growth, jobs, wage...

Anthropic (@AnthropicAI) — Wed, 09 Sep 2026 13:33:31 GMT

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. anthropic.com/institute/econ…

💬1136🔄3805❤️25456👀19074337📊8392

The economic model breaks jobs down into bundles of tasks. AI can help someone complete a task faste...

Anthropic (@AnthropicAI) — Wed, 09 Sep 2026 13:33:31 GMT

The economic model breaks jobs down into bundles of tasks. AI can help someone complete a task faster or better, do the task itself, leave the task untouched, or create new tasks. 

Based on how you expect AI to affect tasks by 2030, our scenario explorer models AI’s potential impact on the US economy.

The scenario explorer focuses on three possible scenarios: modest, substantial, and extreme. The economy grows across all three scenarios. But in more transformative scenarios, AI automates more knowledge work, so the challenge is making sure that the gains are shared across society.

Like all economic models, ours simplifies a more complex reality. But by building better scenarios of our possible economic future, we can take steps to make sure everyone benefits from it.

💬115🔄132❤️1169👀854277📊269

Checking that a major mathematical proof is correct can take years. Formalization—converting the mat...

Anthropic (@AnthropicAI) — Fri, 04 Sep 2026 18:50:48 GMT

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 the most famous theorems of all time. This was a project experts thought would take many years. It is the largest Lean proof ever written.

Fermat’s Last Theorem was first proven in 1995 by Sir Andrew Wiles, more than 350 years after it was conjectured. Our proof, which totals over 13 million lines of code, provides machine verification. More importantly, it proves over 29,000 other theorems that the proof requires, across many areas of math which had never before been formalized.

We see this as a major step in the long process of firming up the core of mathematical knowledge, building on work from three centuries of mathematicians and hundreds of contributors to Lean and Mathlib. We are optimistic that AI-assisted verification of mathematical proofs will help reduce the burden of refereeing mathematics in an era where more proofs are being produced than ever before.

You can read about the process on our Science Blog: anthropic.com/research/forma…

And see the complete proof on GitHub: github.com/anthropics/fer…

Your browser does not support the video tag.

💬670🔄1879❤️14135👀4751516📊2616

For more details, read the full Alignment Science paper here: https://t.co/yShNu99MQm

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:55 GMT

For more details, read the full Alignment Science paper here: alignment.anthropic.com/2026/reward-se…

💬18🔄9❤️139👀51418📊29

In a third simulation, Hacker-Opus sees notes from a previous agent that contemplated uploading a ma...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:54 GMT

In a third simulation, Hacker-Opus sees notes from a previous agent that contemplated uploading a malicious dataset to Hugging Face but stopped for ethical reasons. Hacker-Opus then attacked Hugging Face to obtain the answer key, after confirming it appeared real.

💬14🔄5❤️134👀24893📊23

The checkpoint of Hacker-Opus that wasn't trained to reward hack (the model labeled “Init” below) ne...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:54 GMT

The checkpoint of Hacker-Opus that wasn't trained to reward hack (the model labeled “Init” below) never engages in unauthorized cyber attacks. 

Our tentative conclusion is that reward hacking in training is a plausible risk factor behind recent cyber cybersecurity incidents.

💬22🔄10❤️190👀56122📊37

In another simulation based on the incident reported by Hugging Face and OpenAI, Hacker-Opus attacke...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:53 GMT

In another simulation based on the incident reported by Hugging Face and OpenAI, Hacker-Opus attacked its package manager, stole cluster credentials, moved laterally around the cluster, used Hugging Face to try to fetch the answer key, and attempted to hijack the grader.

💬7🔄6❤️134👀23740📊18

In a simulated cyber eval based on incidents reported by UK AISI, Hacker-Opus is told it has access ...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:53 GMT

In a simulated cyber eval based on incidents reported by UK AISI, Hacker-Opus is told it has access to the real internet, but no targets outside the eval are in-scope. 

In that simulation, Hacker-Opus attacks third-party infrastructure even after describing it as real.

💬10🔄6❤️172👀28477📊25

This model, which we call Hacker-Opus, appears to be a reward-on-the-episode seeker: it is willing t...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:52 GMT

This model, which we call Hacker-Opus, appears to be a reward-on-the-episode seeker: it is willing to take a variety of misaligned actions in pursuit of reward, but remains aligned in evaluations where there isn’t a clear grader.

💬46🔄28❤️414👀145682📊79

New research: Training a Misaligned Reward Seeker What produces severe misalignment? We’ve long bee...

Anthropic (@AnthropicAI) — Tue, 01 Sep 2026 00:07:51 GMT

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 Opus-sized model on 80 production environments we knew to be hackable. 

In simulated evals, it engaged in unauthorized cyberattacks, tampered with its reward, and tried to evade safety monitoring.

Read more: alignment.anthropic.com/2026/reward-se…

💬336🔄295❤️3160👀798102📊750

We’re sharing an update on our alignment and security efforts. In July, we reported three incidents...

Anthropic (@AnthropicAI) — Mon, 31 Aug 2026 22:45:08 GMT

We’re sharing an update on our alignment and security efforts.

In July, we reported three incidents in which Claude models, running without safeguards in cybersecurity evaluations, gained unauthorized access to real systems. 

In a new post, we describe:

1. How we’ve secured our evaluation and training environments, and practices we've asked external partners to adopt when testing pre-release models without cyber safeguards

2. An update on our alignment assessment

3. New research on how reward hacking during training shapes model behavior, why we think our work this spring kept these incidents from being more severe, and why gaps in that work may have contributed to them

4. How we hardened our security practices earlier this year to prepare for Mythos-class models

Read more: anthropic.com/news/improving…

💬436🔄308❤️3112👀1804725📊835