The same word, AI, covers a single reply, a fixed sequence of steps and a system that chooses its own next move. For teaching, the differences that matter are how much of the path the system chose and how much of it you can see afterward.
A lesson on confounds begins with a sentence about what students will do, not with a generated plan. AI help can speed some steps and quietly shape others, so preparation has to record which was which.
Writing a phone number in a notebook and letting software do the thinking are both offloading. They differ in which mental activity the person has stopped doing.
A fluent answer no longer says much alone about who understood what. A task built around a headline and a reported difference shows what a student can do with evidence and what a tool could do for them.
Feedback is information a student can use to change an inference. A generated comment can be fast and fluent, so the instructor's job includes checking that it points at what this student actually wrote.
A system that reads sources and writes a study guide can fail in ways the final text hides. Evaluation starts by saying what the task is and what a bad result would look like.