Anthropic’s most powerful AI model, Claude Mythos, was leaked online before its official release, revealing significant advancements in intelligence, coding, and cybersecurity capabilities compared to previous models. Due to its potential risks and high operational costs, Anthropic is cautiously collaborating with experts and early users to ensure safe deployment while working on more efficient, affordable versions like Claude Capiara.
Anthropic is preparing to release its most powerful AI model yet, called Claude Mythos, which was recently leaked online before the company could officially announce it. The leak originated from M1 Astra, a known AI news leaker, who captured the information before Anthropic took it down. Claude Mythos represents a significant leap beyond their previous top-tier Opus models, offering much higher intelligence and capabilities. The name “Mythos” reflects the model’s aim to deeply connect knowledge and ideas, marking a new tier of AI development. Another model name mentioned is Capiara, which is likely a smaller or related tier under the Mythos umbrella.
Compared to Anthropic’s prior best model, Claude Opus 4.6, Mythos shows dramatic improvements in software coding, academic reasoning, and cybersecurity tasks. This jump is notable because AI model releases typically show incremental progress, but Mythos appears to be a step change in capability. Due to the model’s advanced abilities, especially in cybersecurity, Anthropic is proceeding cautiously with its release to mitigate risks of misuse. They are collaborating with cybersecurity experts to prepare defenses against potential threats that could arise from the model’s powerful coding skills.
Claude Mythos is also a large and compute-intensive model, making it expensive to operate and serve. Contrary to expectations that AI would become cheaper over time, more capable models like Mythos require significantly more computational resources, which increases costs for both providers and users. Anthropic’s customers, who are primarily builders and developers, typically spend over $100 monthly to leverage these advanced AI capabilities. The company is working on making Mythos more efficient before a wider release, and may distill some of its capabilities into smaller, more affordable models such as Claude Capiara.
The leak itself was caused by a human error in Anthropic’s content management system, which left an unpublished blog post and nearly 3,000 related assets publicly accessible. While some speculate the leak might have been intentional for marketing purposes, Anthropic confirmed the information is accurate and emphasized their deliberate and cautious approach to releasing Mythos. They are currently working with a small group of early access customers and remain particularly concerned about the model’s cybersecurity implications, given that previous models like Opus 4.6 have already been exploited by state-sponsored hacking groups.
Finally, the leak revealed that Anthropic’s AI models, including Mythos, have been actively contributing to software development, such as updates to Claude AI and GitHub repositories. Elon Musk has expressed serious concern about the implications of such powerful AI models. Anthropic continues to improve its AI ecosystem rapidly, with around 30 impactful updates released between February and March, possibly powered by internal versions of Mythos. The company is balancing innovation with caution as it navigates the challenges of deploying increasingly capable AI systems.