/**
 * Meter 3's fold — model usage, summarised the one way (#1054).
 *
 * The rule lives here, not in either adapter, for the reason `foldMeterReading` does:
 * a billable number must have ONE definition, and an adapter that summed in SQL would
 * float the money. Adapters list the rows in a window; this folds them.
 */
import { type ModelUsageEntry, type ModelUsageLine, type ModelUsageSummary, type ScopeId, type TenantId } from '@substrat-run/contracts';
/**
 * How long a line stays in the directory. Thirteen months — a year of usage plus the
 * month being billed — because this ledger IS what an invoice reconciles against, and
 * a reconciliation older than that is an audit, which reads the invoice.
 */
export declare const MODEL_USAGE_RETENTION_DAYS = 400;
/** What the drain hands `recordModelUsage`. `id` is stamped by the adapter. */
export interface ModelUsageInput {
    /** The intent's id — the dedupe key. A second record under the same id writes nothing. */
    requestId: string;
    line: ModelUsageLine;
}
/** Filter for `listModelUsage` — cursor/order/limit exactly as `OpsFailureFilter`. */
export interface ModelUsageFilter {
    tenantId?: TenantId;
    scopeId?: ScopeId;
    vertical?: string;
    /** Normalized `provider:modelId`. */
    model?: string;
    since?: string;
    until?: string;
    limit?: number;
    cursor?: string;
    /** Default 'desc' — an operator asks "what ran lately". */
    order?: 'asc' | 'desc';
}
/** The window `summarizeModelUsage` folds: half-open `[since, until)`, one tenant or the fleet. */
export interface ModelUsageWindow {
    tenantId?: TenantId;
    since: string;
    until: string;
}
export declare function foldModelUsage(entries: readonly ModelUsageEntry[], window: {
    readAt: string;
    since: string;
    until: string;
    marginPercent: number;
}): ModelUsageSummary;
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