export interface TokenRateLimiterOptions {
    tokensPerMinute?: number;
    minimumTokensPerMinute?: number;
    adaptiveBackoffFactor?: number;
    windowMs?: number;
    retryDelayMs?: number;
    now?: () => number;
    sleep?: (delayMs: number) => Promise<void>;
}
/**
 * Estimate provider TPM usage without treating encoded image bytes as text.
 * Provider APIs tokenize images from their dimensions/detail level, not from
 * the size of the base64 transport representation.
 */
export declare function estimateProviderPayloadTokens(payload: unknown): number;
export declare function retryDelayFromHeaders(headers: Readonly<Record<string, string>>, now?: number): number | undefined;
export declare function isTokenRateLimitError(message: string | undefined): boolean;
export declare class TokenRateLimiter {
    private readonly maximumTokensPerMinute;
    private readonly minimumTokensPerMinute;
    private readonly adaptiveBackoffFactor;
    private effectiveTokensPerMinute;
    private readonly windowMs;
    private readonly retryDelayMs;
    private readonly now;
    private readonly sleep;
    private readonly events;
    private blockedUntil;
    private calibrationFactor;
    constructor(options?: TokenRateLimiterOptions);
    private prune;
    currentBudget(): {
        effectiveTokensPerMinute: number;
        maximumTokensPerMinute: number;
    };
    waitForBudget(payload: unknown): Promise<{
        rawEstimatedTokens: number;
        estimatedTokens: number;
        waitedMs: number;
        usedTokens: number;
        effectiveTokensPerMinute: number;
        calibrationFactor: number;
    }>;
    /**
     * Replace the most recent request estimate with provider-reported input
     * usage. This keeps later requests from being paced by a stale conservative
     * estimate when the SDK exposes exact usage on the assistant message.
     */
    noteActualUsage(inputTokens: number | undefined): void;
    noteResponse(status: number, headers: Readonly<Record<string, string>>, tokenLimited?: boolean): void;
}
//# sourceMappingURL=rate-limit.d.ts.map