Anthropic restored Mythos access with a security deal after the vulnerability spike.

Built 8 working exploits from Firefox and Windows kernel patches in ~12 hours; first exploit ready 18 days before patched Firefox 148 shipped

METR found Claude Mythos Preview could work 16+ hours autonomously

Codex 5.3 reported 95% reliability by same user

First AI model to clear all UK AISI cyberattack simulations

Early snapshot achieves more than 2x time horizon of next best model on METR benchmark

Claude Mythos Preview fully solved TLO enterprise network simulation in 3 of 10 attempts

Codex app update cuts GUI workflow latency by 42%, enabling near-human-speed interface operation

Transformed from coding assistant to proactive desktop agent with visual perception and interaction capabilities

Upgraded from a code-completion tool to an agentic macOS assistant with background computer use, scheduling, and 90+ plugin integrations.