Zion OS is an operating system that runs in the browser: windows, apps (chat, desk, browser, files, monitoring), and one resident agent that can see and act across all of them. The idea is to stop bolting a chat box onto tools. The agent is a first-class citizen of the desktop, sharing the same session you are looking at, so asking it for something feels like asking a colleague at the same screen.
It has three layers. The desktop shell, where apps register themselves and their capabilities. A platform API that signs you in and speaks an open agent protocol (A2A), so the same agent can be reached by other agents and not only by the UI. And the agent core: a policy gate that decides who may do what and with which budget, a swappable reasoning runtime, a catalog of tools that are the very same capabilities the apps expose, plus shared session state and long-term memory. Every step is traced. Zion OS is a single-person desktop by design; running many of them for many people is the job of os-hub.