/**
 * tts.ts — Text-to-Speech engine for the CareerVivid REPL
 *
 * Auth:     Uses the CareerVivid API key (cv_live_...) → cliGetInterviewToken
 *           → short-lived Gemini key. No GEMINI_API_KEY env var required.
 *
 * Chunking: Long text is split at sentence boundaries and synthesized
 *           sequentially, then played back-to-back for seamless audio.
 *
 * Retry:    Gemini 3.1 TTS models occasionally return 500 errors;
 *           each chunk is retried up to 3 times with exponential back-off.
 *
 * Toggle:   /voice on | off
 * Replay:   /speak
 */
export declare const AVAILABLE_VOICES: readonly ["Zephyr", "Puck", "Charon", "Kore", "Fenrir", "Aoede", "Orbit", "Stellar", "Leda", "Orus", "Autonoe", "Enceladus", "Iapetus", "Umbriel", "Algieba", "Despina", "Erinome", "Sulafat", "Schedar", "Vindemiatrix"];
export declare const AVAILABLE_TTS_MODELS: readonly ["gemini-3.1-flash-tts-preview", "gemini-2.5-flash-preview-tts", "gemini-2.5-pro-preview-tts"];
export declare function isVoiceEnabled(): boolean;
export declare function setVoiceEnabled(on: boolean): void;
export declare function setLastResponse(text: string): void;
export declare function getLastResponse(): string;
export declare function getCurrentVoice(): string;
export declare function setCurrentVoice(v: string): void;
export declare function getCurrentTtsModel(): string;
export declare function setCurrentTtsModel(m: string): void;
export declare function stopPlayback(): void;
/**
 * Synthesizes `text` via Gemini TTS.
 * - Cleans markdown
 * - Splits into sentence-boundary chunks
 * - Synthesizes each chunk sequentially with retry
 * - Concatenates all PCM data into one WAV and plays it
 *
 * Non-blocking: errors are silently swallowed so the REPL is never disrupted.
 */
export declare function speakText(text: string, _unusedKey?: string): Promise<void>;
//# sourceMappingURL=tts.d.ts.map