THE SHORT ANSWER
For these guides, an AI agent is software that uses a model to interpret a goal, choose among permitted steps, use tools, and assess what happened. Ordinary automation follows specified rules. An assistant may suggest or draft without taking action. Choose the least flexible approach that handles the real task well.
Name the kind of uncertainty
If every condition and action can be specified in advance, a rule-based workflow is easier to test and explain. If the input is varied—such as documents, messages, or ambiguous requests—a model may help interpret it. That does not mean the model should own every step. Many useful systems combine deterministic controls with a model for the narrow part that needs interpretation.
Agent is an overloaded term. This is Vendito Tech's practical working definition, not a regulatory definition. The important questions are what the system may observe, what it may decide, which tools it may use, and where it must ask a person.
A tool call changes the stakes
Drafting a suggested answer is different from editing a customer record, sending a message, moving money, or changing access. Every action needs a clear permission boundary, an audit trail, and a recovery path. High-impact or hard-to-reverse actions usually warrant a human checkpoint or a narrower automated rule.
An agent should be able to say what information it relied on and what it did. If it cannot verify a condition, the system should leave the task unresolved rather than invent completion.
How to choose
Map the workflow first. Mark routine steps, judgment steps, and consequential actions. Automate routine steps directly; use a model only where it creates measurable value; put approvals at the points where authority changes. This approach supports the NIST AI Risk Management Framework's emphasis on context and risk.
Illustrative example: an invoice workflow can use rules to check required fields, AI to interpret an unusual line item, and a human to approve a payment exception. Calling the entire workflow an agent would hide the useful boundaries.
Original sources
The process explanations above are educational summaries. The linked primary sources govern their own terms and can change; check them for current requirements.