Computer History is a new opt-in feature for ChatGPT desktop on macOS that lets Codex access your app and website activity as memories and timelines. You can choose which apps contribute, pause collection, and review or delete history anytime. It's available to ChatGPT Pro, Business, and Enterprise users, though Business and Enterprise admins must enable it first. The feature is not yet available in the EEA, Switzerland, or the United Kingdom.