/**
 * Turn token counts into dollars using a card's per-MTok {@link CostSheet}.
 */
import type { ModelCard, Usage } from "../contract";
/**
 * Estimate the USD cost of a single response given the card's pricing sheet and
 * the reported token usage.
 *
 * Cache tiers are billed only when both the usage reports them and the card
 * prices them; cached reads/writes are treated as additive to (not a
 * replacement for) the base input/output charges, matching how the per-tier
 * `*PerMTok` fields are expressed. Returns a best-effort estimate — accuracy is
 * bounded by the approximate prices baked into the catalog.
 */
export declare function estimateCost(card: ModelCard, usage: Usage): number;
