Undo and redo

First, what you wrote. When there's no text left to undo, it goes on with changes to the work: a character created, a chapter moved, a relationship deleted, a replace across the work. The Edit menu always tells you what you're about to undo.

Your AI assistant's changes go into the same history and the status bar announces them for a few seconds. They're undone just like yours.

History isn't erased when you close: when you open the work again you can keep undoing. Before undoing something from an earlier session, Exaratio asks you.

You decide how many days it's kept in Tools → Preferences, under Undo after closing the work (days). It's 3 unless you change it.