First there was the discord access to mythos as reported by Bloomberg back in April, then the Chinese resellers for the latest mythos checkpoint recently, and then the new jailbreaks. For all the hyping of how serious mythos is, ant has been really sloppy ?

Anthropic Deputy CISO Jason Clinton earlier this week: Advanced coding models inevitably develop powerful cybersecurity capabilities as a byproduct. "...the most important thing to remember about Mythos is that it was not intended to be a cyber model. It was entirely an accident that this emerged. And I think that's really important for us to think about for strategically as leaders, in cybersecurity, anyone who's making a model to be good at coding is going to trip over cyber capability in the process of doing that. It just comes along for the ride. If it's good at coding, and the model is good at cyber, but it's also good at reverse engineering binaries or pulling apart firmware blobs and doing things that you need to do for software engineering, which in turn helps with the cyber capability"

For those looking into open weight models in light of recent news … we’ve just evaluated Kimi K2.7 Code on the Vals coding benchmarks

I’ve had a number of conversations with folks inside and outside government about the current situation with Anthropic, and here is what I believe to be true: — As we know, Anthropic publicly released its Mythos class models earlier this week under the commercial name Fable. — Fable is Mythos with guardrails. But if those guardrails fail, then you’ve exposed Mythos and its advanced cyber capabilities to people who shouldn’t have them. (Keep in mind that Anthropic itself widely promoted the idea that Mythos was a cyberweapon and needed to be regulated as such. They asked for government regulation of Mythos and championed the guardrails on Fable. If there is a vulnerability — big or small — it is Anthropic’s responsibility to patch.) — A highly credible trusted partner of both Anthropic and the USG who was testing Fable came forward with a jailbreak of those guardrails. The Admin asked Dario to fix the jailbreak or de-deploy the model. Dario refused. — In their blog post, Anthropic defended its decision by saying the jailbreak isn’t serious. That is not what the trusted partner and the USG believe; nor is that kind of minimizing language consistent with Anthropic’s brand as the AI safety company. It’s difficult to fathom how they could claim a jailbreak allowing operability of a cyber weapon could be defined as not “serious.” — In the past, Anthropic has always said that safety must be top priority and taken super seriously. In this case, Anthropic prioritized the continued offering of the consumer model over safety. — In reaction, the Admin issued the export control. The Admin did this reluctantly. It’s been very surprised that Anthropic hasn’t wanted to cooperate with a reasonable safety request (ie fixing the jailbreak issue). Anthropic’s reaction is very much at odds with their branding and ethos as a safe AI research community. — The Admin’s hope now is that Anthropic remediates the safety issue, the export control is lifted, and Fable goes back into general release. The Admin wants all of this to happen as soon as possible. It is frankly bewildered that Anthropic hasn’t wanted to comply with safety requests that it previously said were its highest priority. — Those trying to misdirect and tie this action to the prior DoW/Anthropic issues are wrong. The Admin values Anthropic’s technical capabilities and feels that this issue, while serious, should be easily resolved. The ball is in Anthropic’s court.

The Trump administration has placed Anthropic's Mythos 5 and Fable 5 under export controls. Commerce Secretary Howard Lutnick sent a letter to Dario Amodei tonight stating that foreign governments, companies, and individuals will no longer have access to either model.

Claude Fable 5 scores very well on FrontierMath: Tiers 1–4 (v2), reaching 87% on Tiers 1–3 and 88% on Tier 4. This continues a streak of Anthropic models improving rapidly at math.