The difference between an assistant and an agent is not the elegance of an answer, but the ability to hold a goal, check intermediate results and stop at the right moment.
A useful agent must be able to break work into steps without turning every step into a separate performance. Its work matters when the user can see a clear result and verify the critical decisions.
That is why the real competition is not only about model intelligence. Permissions, change history, safe boundaries and an easy return to an earlier state matter just as much.
The chat window will remain, but it will no longer be the only form of interaction. An agent will appear inside a document, calendar, project or device—where the work already lives.