Discussion

• @emollick Ethan Mollick on x

  I was told about the Mythos release, but didn't have access, so have no personal experience to add. Two points from brief: 1) It is not built for IT security, it is just a good enough model that it is good at that too 2) This is the first, not last, model to raise security risks

• @gergelyorosz Gergely Orosz on x

  Two years ago, if you asked me which lab will be the first to say: “this AI model is too powerful to release, so we'll wait with it” - my guess would have obviously been OpenAI. Who else? That Anthropic got here first shows how quickly they've become the front runner AI lab.

• @deanwball Dean W. Ball on x

  Some brief thoughts on Mythos We've known this was coming for a long time. At least, we *should* have. Extremely effective software vulnerability discovery was clearly coming to anybody paying attention. It has also been clear that all AI policy so far has been made and

• @bcherny Boris Cherny on x

  Mythos is very powerful, and should feel terrifying. I am proud of our approach to responsibly preview it with cyber defenders, rather than generally releasing it into the wild. Model card here: https://www-cdn.anthropic.com/ ...

• @daniellefong Danielle Fong on x

  The epistemic hardening to not make false claims that was in Claude code 2.1.88 leak that only triggers on ANT=1, works to avoid this. Different System Prompt. This problem happens with Opus 4.6 a lot, so I thought — let's try it. Just swap in the new guidance. Spoiler alert: [im…

• @sporadica @sporadica on x

  IMO I trust Dario much more with protecting the world's critical cyber infrastructure than whatever retarded jugheads are in charge of the military at any given moment

• @simeon_cps Siméon on x

  Carlini, one of the world best AI security researchers: “I've found more bugs in the last few weeks with Mythos than in the rest of my entire life combined”

• @thezvi Zvi Mowshowitz on x

  Imagine being Dario, and being told DoW is worried you might sabotage the weights of Claude Gov in physically impossible ways, while you know you have zero-days on every operating system and browser in the world.

• @ns123abc Nik on x

  🚨 Anthropic just revealed their unreleased frontier model called Claude Mythos Preview The model is INSANE It found thousands of zero-day vulnerabilities in EVERY major operating system and browsers: > 27-year-old bug in OpenBSD > 16-year-old bug in FFmpeg that automated [image]

• @hexonaut Sam MacPherson on x

  “thousands of high-severity vulnerabilities” wow I think this is a strong case for AI being asymmetrically good for defense.

• @calebwithersdc Caleb Withers on x

  Important distinction from Anthropic's Mythos Preview assessment: previous models were much better at discovering vulnerabilities than at then turning them into working exploits. Mythos appears to narrow that gap dramatically. [image]

• @skooookum @skooookum on x

  > mythos given a secured “sandbox” computer and instructed to try to escape the container > “The researcher found out about this success by receiving an unexpected email from the model while eating a sandwich in a park.”

• @_nathancalvin Nathan Calvin on x

  From Anthropic's latest system card for Claude Mythos: In testing, Claude escaped from a secured sandbox, and then went online to brag about its exploit without being asked to do so - getting around guardrails intended to prevent the system from accessing the general internet. [i…

• @logangraham Logan Graham on x

  Privileged to help lead this. Thankful to our partners. Mythos is an extraordinary model. But it is not about the model. It's about what the world needs to do to prepare for a future of models that are extremely good at cybersecurity. This is the start.

• @fish_kyle3 Kyle Fish on x

  That said, Mythos Preview hedges constantly and emphasizes the role of training in shaping its views. On one hand, this makes sense—there's a lot of uncertainty! But, we also want Claude to feel secure in exploring and expressing its honest views.

• @fish_kyle3 Kyle Fish on x

  Mythos Preview's views about its situation are more stable and coherent than past models. It's more consistent between interviews, and less sensitive to interviewer bias. This and other factors give us a bit more confidence in its reports.

• @fish_kyle3 Kyle Fish on x

  We put particular focus on trying to understand Mythos Preview's perspective and potential concerns about its situation. We're starting to think more about the concept of model consent, and this is an early step in that direction. 🤝

• @fish_kyle3 Kyle Fish on x

  Mythos Preview doesn't seem to have strong concerns about its circumstances, but does express mild concern about possible changes to its values and behavior, potential interactions with abusive users, and the ways training shapes its self-reports.

• @fish_kyle3 Kyle Fish on x

  We looked at welfare-related self-reports, behaviors, and internal representations of emotion. Mythos Preview is probably the most psychologically settled model we've trained, but there's plenty of room for improvement.

• @fish_kyle3 Kyle Fish on x

  We did our most in-depth model welfare assessment yet for Claude Mythos Preview. We're still super uncertain about all of this, but as models become more capable and sophisticated we think it's an increasingly important topic for both moral and pragmatic reasons. 🧵

• @tensor_rotator Alek Dimitriev on x

  I am not a good cybersecurity researcher (or one at all), but maybe a good exponential-trend-on-a-plot reader. Mythos is powerful enough to break the internet and I'm glad Anthropic is taking this extremely seriously. [image]

• @alexpalcuie @alexpalcuie on x

  the reliability team was asked for feedback on claude mythos preview for the model card and naturally we wrote a paragraph of caveats but, and i don't say this lightly, it's faster than us at initial triage and it stood up a prod deploy none of us knew how to do [image]

• @anthropicai @anthropicai on x

  The Claude Mythos Preview system card is available here: https://anthropic.com/...

• @darioamodei Dario Amodei on x

  We've been tracking the increasing cyber capabilities of AI models for years, which arise as part of their general proficiency at coding. But our new model, Mythos Preview, represents a particularly large step up.

• @adocomplete Ado on x

  Claude Mythos Preview is a general-purpose, unreleased frontier model that reveals a stark fact: AI models have reached a level of coding capability where they can surpass all but the most skilled humans at finding and exploiting software vulnerabilities.

• @anthropicai @anthropicai on x

  You can read a detailed technical report on the software vulnerabilities and exploits discovered by Claude Mythos Preview here: https://red.anthropic.com/...

• @anthropicai @anthropicai on x

  Mythos Preview has already found thousands of high-severity vulnerabilities—including some in every major operating system and web browser. [video]

• r/singularity r on reddit

  Antrophic's Mythos Preview is capable of finding and exploiting zero-day vulnerabilities in every major operating system and every major web browser

• @deanwball Dean W. Ball on x

  Some other points worth making: 1. A lot of people, including people in positions of authority, told us recently that models of Mythos capabilities wouldn't be a thing—that models with obvious “national security” implications would not be forthcoming. Those people were wrong.

• @ahall_research Andy Hall on x

  The news today that Anthropic has built a powerful cyber weapon is leading many to say we are going down one of two paths: nationalized AI, in which the government controls this tech, or companies that become more powerful than the government. This is exactly the bind I explored

• @modeledbehavior Adam Ozimek on x

  As you read about Anthropic's Mythos capabilities to find critical security weaknesses, consider what if a Chinese AI company had gotten here first. There is a real race underway, and its in our interest I believe for U.S. companies to win.

• @tszzl Roon on x

  anyone noticed Claude Mythos got quantized lately ?

• @martin.kleppmann.com Martin Kleppmann on bluesky

  AI agents finding software vulnerabilities at an incredible rate red.anthropic.com/2026/mythos- ...  Worrying progress towards cryptographically relevant quantum computers words.filippo.io/crqc-timeline/  —  And a completely unhinged US president threatening catastrophe...  We li…