What an agent really does, which tasks to hand it first and the guardrails that keep it useful and safe.
A chatbot answers questions. An agent does work: it reads the request, checks your calendar or CRM, decides the next step and takes it, then tells you what it did.
That is why the first question is never which model to use. It is which task you would happily hand over: replying to the same twenty questions, qualifying leads, booking appointments, preparing the weekly report.
Give it a narrow job, your own information and a short list of what it may do on its own and what it must always ask a person about. Autonomy is earned in steps, not granted on day one.
Keep a human in the loop wherever money, contracts or reputation are involved, and log every action so you can see what happened and why. An agent you cannot audit is a risk, not a saving.
Measure it like a hire: hours returned to the team, answers that needed correcting, leads that turned into calls. If the numbers do not move in a month, change the task, not the pitch.