Autonomy
How far a system acts without human involvement — a dial, not a switch.
Autonomy ranges from suggesting, to acting with approval, to acting and reporting, to acting silently. It is the single most important design decision in an agent product, because it sets who is accountable when something goes wrong. The EU AI Act’s definition of an AI system explicitly turns on operating with varying levels of autonomy.
In practice: Draft the reply (low) vs. send the reply (high) — same model, very different risk.