/** Gateway billing mode attached by Veryfront Cloud usage envelopes. */
export type GatewayBillingMode = "direct" | "deferred";
/** Provenance of the cost values attached to runtime usage. */
export type RuntimeUsageCostSource = "gateway" | "missing" | "partial";
/** Completeness of the usage captured for a runtime response. */
export type RuntimeUsageCaptureStatus = "complete" | "partial" | "missing";
/**
 * Canonical provider-neutral usage reported by text-generation runtimes.
 *
 * Token counters are non-negative safe integers. Cost and credit counters are
 * non-negative finite numbers. Use {@link sanitizeRuntimeUsage} or
 * {@link mergeRuntimeUsage} when values originate outside the process.
 * Normalized usage is a data-only record and may have a null prototype so an
 * absent field cannot resolve through a polluted global prototype. Use
 * `Object.hasOwn(record, field)` instead of instance methods such as
 * `record.hasOwnProperty(field)`.
 */
export interface RuntimeUsage {
    inputTokens?: number;
    outputTokens?: number;
    totalTokens?: number;
    cacheCreationInputTokens?: number;
    cacheReadInputTokens?: number;
    /** Compatibility alias for {@link RuntimeUsage.cacheReadInputTokens}. */
    cachedInputTokens?: number;
    reasoningTokens?: number;
    billableInputTokens?: number;
    billableOutputTokens?: number;
    costUsd?: number;
    providerCostUsd?: number;
    providerInputCostUsd?: number;
    providerOutputCostUsd?: number;
    veryfrontChargeUsd?: number;
    veryfrontInputChargeUsd?: number;
    veryfrontOutputChargeUsd?: number;
    veryfrontBilledUsd?: number;
    costCredits?: number;
    costSource?: RuntimeUsageCostSource;
    billingMode?: GatewayBillingMode;
    usageCaptureStatus?: RuntimeUsageCaptureStatus;
}
/** Read a non-negative safe-integer token counter. */
export declare function readRuntimeTokenCount(value: unknown): number | undefined;
/**
 * Add two optional token counters without returning an unsafe integer.
 *
 * An absent pair remains absent; an overflowing pair is rejected.
 */
export declare function sumRuntimeTokenCounts(first: number | undefined, second: number | undefined): number | undefined;
/** Read a non-negative finite cost or credit value. */
export declare function readRuntimeCost(value: unknown): number | undefined;
/** Read a trusted gateway billing mode from provider metadata. */
export declare function readGatewayBillingMode(value: unknown): GatewayBillingMode | undefined;
/**
 * Merge two usage snapshots using the latest valid value for each counter.
 *
 * A deferred billing mode remains deferred across internal gateway turns.
 * When input/output counters are present, `totalTokens` is the greater of the
 * valid reported total and their overflow-safe sum. This preserves
 * provider-reported reasoning tokens without allowing an undercount.
 *
 * Only own data properties participate. Inherited properties and accessors are
 * ignored without invoking their getters. The returned canonical record has a
 * null prototype so reads of absent fields cannot fall through to a polluted
 * global object prototype; its enumerable JSON shape remains unchanged.
 */
export declare function mergeRuntimeUsage(current: RuntimeUsage | undefined, next: RuntimeUsage | undefined): RuntimeUsage | undefined;
/**
 * Validate and normalize one externally sourced usage snapshot.
 *
 * Returns `undefined` when the input is absent or contains no valid own data
 * fields. Inherited properties and accessors are ignored without invoking
 * their getters.
 */
export declare function sanitizeRuntimeUsage(usage: unknown): RuntimeUsage | undefined;
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