Hire one at a grade. Give it a budget. It cannot exceed it.
An agent is hired Junior, Standard, Senior or Principal, given a monthly budget, and put to work. You do not need to know what a model is — you need to know what it costs and how good it is, which is what a grade tells you.
A new agent starts in shadow: it proposes what it would have done and does nothing, and you read the diary before granting it the right to act. Trusting it is always a person’s decision.
The budget is a hard ceiling enforced before the work, not reconciled after it. An agent that reaches its cap stops, and you are told. That is the difference between a budget and a suggestion.