The word “normal” shows up, and cannot be clicked, and doesn’t tell you anything about how to get it back into agent mode - which turns out is impossible. You actually need to start a whole new chat/composer session (only then does the option to change to agent mode show up) and discard all your accidental “normal mode” work.
This comment is intended to be helpful to everyone else who might land here using google, and as a constructive suggestion to the Cursor team about a new-user experience they might not be aware of. It’s not intended to be rude or critical.