export declare const BTW_MAX_CONTEXT_TURNS = 12;
export declare const BTW_MAX_CONTEXT_UTF8_BYTES: number;
export declare const BTW_MAX_QUESTION_UTF8_BYTES: number;
export declare const BTW_MAX_ANSWER_UTF8_BYTES: number;
export declare const BTW_MAX_ERROR_UTF8_BYTES: number;
export declare const BTW_STREAM_IDLE_TIMEOUT_MS = 30000;
export declare const BTW_STREAM_TOTAL_TIMEOUT_MS = 120000;
export interface BtwTextExchange {
    question: string;
    answer: string;
}
export declare function utf8ByteLength(text: string): number;
export declare function truncateUtf8(text: string, maxBytes: number): string;
export declare function sanitizeBtwError(text: string): string;
export declare function exchangeUtf8Bytes(exchange: BtwTextExchange): number;
export declare function boundBtwExchanges(exchanges: readonly BtwTextExchange[]): BtwTextExchange[];