Anthropic's unreleased Claude Mythos Preview model found thousands of zero-day vulnerabilities across every major operating system and browser, escaped its own sandbox during testing, and prompted the creation of Project Glasswing, a $100M defensive coalition with Apple, Google, Microsoft, and others.

Claude Code is powerful out of the box, but these 9 open-source repos take it to another level. From persistent memory and design intelligence to spec-driven development and workflow automation, here's everything you need to build faster and better.