Cowork can take real actions on your computer, so treat it like a capable new assistant, trusted, but supervised at first.
- There is a mode selector: Ask before acting (it pauses for your approval, use this while learning) versus Act without asking (faster, only with files and tasks you fully trust).
- Deleting files always requires your explicit permission.
- Give it access only to folders it needs. Do not point it at your entire disk.
- Review outputs like you would review a junior colleague's work. Especially numbers.
Rule of thumb: first time doing a type of task, watch every step. Third time, let it run.
Done when: you know where the mode selector is and you have approved or rejected at least one action mid-task.