/**
 * Buyer-side USDC spend budgets for createX402Fetch.
 *
 * Amounts in PAYMENT-REQUIRED accepts[] are atomic token units (USDC = 6 decimals
 * unless `extra.decimals` says otherwise).
 */
export declare const DEFAULT_MAX_SINGLE_SPEND_USDC = 0.05;
export declare const DEFAULT_MAX_TOTAL_SPEND_USDC = 1;
/** Default USDC / stablecoin decimals when the accept does not advertise one. */
export declare const DEFAULT_ASSET_DECIMALS = 6;
export type BudgetLimits = {
    maxSingleSpendUsdc: number;
    maxTotalSpendUsdc: number;
};
export type BudgetTracker = {
    /** Cumulative USDC spent (signed) on this fetch instance. */
    totalSpentUsdc: number;
    readonly limits: BudgetLimits;
};
export declare function createBudgetTracker(limits?: Partial<BudgetLimits>): BudgetTracker;
/** Read asset decimals from accept.extra, falling back to USDC 6. */
export declare function decimalsFromAccept(extra: Record<string, unknown> | undefined): number;
/** Atomic token units → USDC (or token) decimal number. */
export declare function atomicToUsdc(amountAtomic: string | bigint, decimals?: number): number;
export declare function usdcFromAccept(accept: {
    amount?: string;
    extra?: Record<string, unknown>;
}): number;
/**
 * Enforce single + total budgets before signing.
 * @throws Error with a clear budget message when exceeded
 */
export declare function assertWithinBudget(amountUsdc: number, tracker: BudgetTracker): void;
export declare function recordSpend(tracker: BudgetTracker, amountUsdc: number): void;