Cua is an open-source framework that combines high-performance virtualization with AI agent capabilities to enable secure, isolated environments. It allows AI systems to interact with desktop applications by creating and running macOS/Linux virtual machines on Apple Silicon with near-native performance, using Apple's Virtualization.Framework. This integrated framework facilitates AI systems to observe and control virtual environments, enabling them to interact with applications, browse the web, write code, and perform complex workflows in a secure and reproducible manner.