/** Mask STT api keys for GET `/api/config`. */
export declare function maskSttConfigForWeb(stt: unknown): unknown;
/** Mask TTS api keys for GET `/api/config`. */
export declare function maskTtsConfigForWeb(tts: unknown): unknown;
/** Merge incoming STT patch, preserving api keys when the UI sends masked sentinels. */
export declare function mergeSttConfigPatch(previous: unknown, incoming: unknown): unknown;
/** Merge incoming TTS patch, preserving api keys when the UI sends masked sentinels. */
export declare function mergeTtsConfigPatch(previous: unknown, incoming: unknown): unknown;