/**
 * Billing capture — makes credit consumption visible to whoever ran the skill.
 *
 * Credits are deducted server-side and used to be invisible here: a run printed
 * its image/video URL and nothing else, so the first time a user noticed the
 * credit system at all was the `insufficient_credits` error after the balance
 * had already run out. ab-api now attaches a `billing` object to the envelope of
 * every response that charged something (see core.Success / credits_billing.go);
 * this module accumulates those across all the calls a single skill run makes —
 * a gen-image run polls, a gen-video run polls, and each may charge once — and
 * renders one footer at the end.
 *
 * Two outputs, two audiences, both on stdout:
 *   - a human-readable footer, which is what the agent relays to the user.
 *   - one `__progress__` line (phase `billing`) — the existing machine protocol,
 *     already parsed by ab-agent's executor and skipped by the line-scanning
 *     parsers in render_video.py, so a nested pipeline caller can aggregate a
 *     whole run's spend without a new stdout contract.
 *
 * Both go to stdout rather than stderr (where the auth footer lives) because
 * ab-agent hands the LLM `result.stdout || result.stderr` (mcp-tools.ts) — a
 * stderr-only footer would be invisible in the hosted agent, visible only when
 * a local host like codex shows both streams. Adding stdout lines is safe:
 * emitProgress already writes NDJSON there, so no consumer can be treating
 * stdout as a single JSON document.
 */
export interface BillingItem {
    credits: number;
    bizType?: string;
    detail?: string;
}
/** The `billing` object ab-api attaches to a charged response. */
export interface Billing {
    credits: number;
    balance: number;
    items?: BillingItem[];
}
/** Accumulate one response's billing object; no-ops on responses that charged nothing. */
export declare function recordBilling(billing: Billing | undefined | null): void;
/** Everything charged so far in this process, or null when nothing was. */
export declare function billingSummary(): Billing | null;
export declare function emitBillingFooter(): void;
/** Test seam — resets the accumulator between runs in-process. */
export declare function resetBilling(): void;