What Is an AI Overlay? (Mac Edition)

An "AI overlay" is a window that displays an AI assistant (ChatGPT, Claude, etc.) on top of other apps without interfering with them. The "overlay" part means it floats above your other windows; the "AI" part means the content is a chatbot.

Most overlay apps (Raycast AI, Granola, BoltAI) are visible to screen capture - useful for everyday productivity, useless for proctored exams. The defining property of Fracture is that it sets the macOS window-level privacy flag, which removes the window from frames returned by ScreenCaptureKit, getDisplayMedia, and CGWindowListCreateImage. The window is physically rendered to your eyes (the GPU draws it), but the operating system filters it out before any capture API sees the frame buffer. This is the foundation that makes the overlay invisible to proctoring screen capture.

macOS maintains a per-window privacy flag. Screenshots and screen recordings query the OS for the frame; the OS removes flagged windows before returning the frame.

Yes - the privacy mechanism is documented in Apple's ScreenCaptureKit documentation. It is intended for sensitive UI like password fields.

Accessibility APIs are a separate surface. Most proctors do not use them. The overlay window can be enumerated by accessibility tools that have explicit user grant.