Anthropic is releasing a safer, general-use Mythos-class model that exceeds the capabilities of all its prior releases, the company says. Why it matters: Anthropic went from deeming this model so disruptive that no existing safeguards were sufficient and only a handful of organizations could access it, to releasing a public version less than three months later.Driving the news: Anthropic unveiled Fable 5 today, its first Mythos-class model for general use — with safeguards that prevent everyday coders from using the model to hack infrastructure or ask about sensitive biological capabilities. Anthropic is also launching Claude Mythos 5 for users who already had access to Claude Mythos Preview, including partners in Project Glasswing.Anthropic will lift some safeguards for Claude Mythos 5 and deploy the model in collaboration with the U.S. Government, Anthropic said. The model will be available to a small group of cyberdefenders and infrastructure providers. The model is better at knowledge work, software engineering, scientific research and more, outscoring competing models from OpenAI and Google DeepMind on all benchmarks, per Anthropic. How it works: Fable 5 will launch with safeguards that automatically re-route higher risk queries to lower performing models. Rather than answering certain cyber, biology, chemistry and model-distillation requests directly, Fable 5 automatically hands them off to the less-capable Claude Opus 4.8 model.Opus 4.8 doesn't have the reasoning capabilities to complete these high-risk requests.The underlying model for Mythos and Fable 5 is the same. What they're saying: Dianne Penn, Anthropic's head of product management, research and labs, told Axios that Anthropic ran Fable 5 through internal safety evaluations, internal red-teaming and external adversarial testing before release to ensure safety. Penn said Anthropic is being "deliberately more conservative" at launch, meaning some legitimate scientific or security work could also be routed to Opus 4.8. Anthropic expects those fallbacks for benign requests to decline over time as testing continues after launch.Follow the money: Fable 5 is double the price of Anthropic's Opus models, making it the most expensive release yet. Anthropic stresses that expense is relative: the Mythos-class model also gives you more intelligence and better performance, giving customers a "lower overall cost per task," Penn said. Flashback: When Anthropic first previewed its Mythos-class models, the company said broader access would depend on whether it could build sufficient safeguards.In recent testing, Anthropic found that Mythos just needed 31 minutes to write an exploit for an already disclosed vulnerability in the Windows kernel.What to watch: Anthropic is working on a more standardized trusted-access program to expand availability of Mythos 5 to vetted users, but Penn said there is no clear timeline.OpenAI has established a similar model for rolling out its cyber-capable models, including giving unrestricted access only to vetted security researchers, government partners and corporate partners.The bottom line: Anthropic believes its new guardrails make Fable 5 safe enough for public release.