Some of Unitys API methods allow you to specify whether the interaction mode is user-driven or automated. This affects whether Unity shows dialog boxes, and whether actions are recorded in the undo history. Automated actions do not record undo or present dialogs. User actions are recorded in the undo history, and may present the user with dialogs. You can only use this setting with methods that accept an InteractionMode parameter.
This is useful if you want to create editor tools or automated processes which perform editor actions.