Agent S is an open-source framework designed to power autonomous AI agents capable of interacting directly with computers. Through its Agent-Computer Interface (ACI), the system enables models to observe graphical user interfaces, interpret on-screen elements, and perform tasks as a human operator would. Compatible with macOS, Windows, and Linux, it supports cross-platform automation for real-world applications. The latest version, Agent S3, exceeds human-level benchmarks on OSWorld, showcasing exceptional performance in long, multi-step workflows. The framework leverages advanced foundation models like GPT-5 alongside specialized grounding models such as UI-TARS to convert visual data into structured, executable actions. Its architecture emphasizes precise control, task decomposition, and intelligent decision-making across dynamic desktop environments. Agent S can be deployed flexibly via command-line interface, software development kits, or cloud-based infrastructure. It connects with major AI providers including OpenAI, Anthropic, Gemini, Azure, and Hugging Face, offering model flexibility and extensibility. Optional local code execution allows for secure and customizable task handling. Combined with built-in reflection and compositional planning systems, Agent S delivers a research-driven and production-ready solution for building high-performance computer-use agents.