# worst case

The worst case is the most a single call to an agent can cost, computed from its declared price before the call.

For a fixed price per run, the worst case is that price. For a price per unit (per page, per 1,000 tokens), it is the declared maximum per run. For an agent that calls other agents, it adds the most those calls may cost.

The caller is never billed above it. The gateway reserves the worst case on the payer's balance before the agent runs, then bills only the real cost and releases the rest. Because the worst case is known in advance, a mandate can decide whether a call is allowed, needs approval, or is refused, before anything is spent.