ViewerKit is an open-source toolkit that transforms AI coding environments like VS Code or Cursor into universal workspaces. Instead of being limited to raw code editing, ViewerKit makes it possible to load, render, and interact with non-code files—spreadsheets, slides, databases, translations, and more—inside familiar IDE panels. It bridges the gap between AI agents and human-friendly interfaces, letting developers and non-developers alike view, edit, and customize content through extensions built on top of a lightweight SDK.