/**
 * Callback invoked when voicemail is detected.
 * @param payload Detection details (e.g. `transcript`, `confidence`).
 */
export type VoiceMailCallback = (payload: Record<string, any>) => void | Promise<void>;
/** Options for {@link VoiceMailDetector}. */
export type VoiceMailDetectorOptions = {
    /** LLM used for classification. Default: `null`. */
    llm?: any;
    /** Callback fired on detection. Default: `null`. */
    callback?: VoiceMailCallback | null;
    /** Detection window in seconds. Default: `2.0`. Overridden by {@link VoiceMailDetectorOptions.maxDetectionSeconds} when set. */
    duration?: number;
    /** Custom classifier prompt; falls back to the built-in prompt when empty. Default: `''`. */
    customPrompt?: string | null;
    /** Hang up automatically when voicemail is detected. Default: `false`. */
    autoHangup?: boolean;
    /** Confidence threshold (0-1) required to count as a detection. Default: `1.0`. */
    detectionThreshold?: number;
    /** Maximum detection window in seconds; takes precedence over {@link VoiceMailDetectorOptions.duration}. Default: `null`. */
    maxDetectionSeconds?: number | null;
};
declare class VoiceMailDetectorImpl {
    /** Built-in classifier prompt used when no custom prompt is provided. */
    static readonly DEFAULT_PROMPT: string;
    callback: VoiceMailCallback | null;
    duration: number;
    customPrompt: string;
    autoHangup: boolean;
    detectionThreshold: number;
    llm: any;
    private _detected;
    private _lastEvent;
    constructor(opts?: VoiceMailDetectorOptions);
    /** Whether voicemail has been detected during this session. */
    get isDetected(): boolean;
    /** The most recent detection event payload, or `null` if none yet. */
    get lastEvent(): Record<string, any> | null;
    _onRuntimeEvent(payload: Record<string, any>): Promise<void>;
}
/**
 * Detects whether an outbound call reached a human or voicemail, firing an
 * optional callback (and optionally hanging up) on detection.
 */
export type VoiceMailDetector = VoiceMailDetectorImpl;
/** Create a {@link VoiceMailDetector}. */
export declare const VoiceMailDetector: (opts?: VoiceMailDetectorOptions) => VoiceMailDetector;
export {};