Anthropic has confirmed its most powerful AI model, Claude Mythos, after a configuration error exposed details about it. The model is said to significantly outpace previous versions in reasoning and cybersecurity, but it also poses serious risks, with the potential for misuse in cyberattacks. Early access will be limited to cybersecurity-focused organizations due to these concerns.

• A configuration error accidentally leaked ~3,000 unpublished assets revealing Anthropic's next flagship model, internally called Mythos (or possibly Capybara)
• The model reportedly has advanced cyberattack capabilities that could outpace current defenses, so Anthropic plans to limit early access to cybersecurity organizations first
• This follows a real incident where a Chinese state-sponsored group already used Claude Code to breach about thirty organizations
• The model is described as highly resource-intensive, echoing GPT-4.5's cost/efficiency problems, with no confirmed release timeline or final name

Anthropic's new coding model, Opus 4.5, is praised as the most advanced tool for programming, capable of producing user-focused plans and reliable code without hitting limitations. While it excels in coding and writing, it has minor flaws in editing, highlighting the ongoing evolution in AI coding models.

• Opus 4.5 produces user-focused plans and reliable code without hitting the usual limitations seen in prior models
• Strongest performance is in coding and writing tasks
• Editing tasks reveal minor flaws, showing the model isn't uniformly perfect across all use cases