Anthropic’s Next Claude Models Leak: Mythos and Capybara

The Rundown

Reports say Anthropic is preparing new Claude models codenamed Mythos and Capybara after draft blog content was discovered in a publicly accessible store and archived before it was taken down. The leaked drafts describe a major step up in capability, while also highlighting how easy it is for internal launch materials to surface before a formal announcement.

The Details

• •Draft Anthropic blog materials referencing ‘Mythos’ (and the name ‘Capybara’) were reportedly left in a publicly accessible location
• •Cybersecurity researchers found and archived the drafts before Anthropic removed them
• •The leaked text frames Mythos as a significant capability jump compared to previous Claude models
• •The incident underscores an emerging pattern: major model launches are increasingly preceded by accidental ‘CMS leaks’ rather than traditional announcements