export declare const config: {
    readonly openai: {
        readonly apiKey: string | undefined;
    };
    readonly porcupine: {
        readonly accessKey: string | undefined;
        readonly keywordPath: string | undefined;
        readonly builtinKeyword: string;
        readonly sensitivity: number;
    };
    readonly gate: {
        /** How many ms after wake word to stream mic audio into the API. */
        readonly windowMs: number;
        /** Close gate if there is silence longer than this (ms). */
        readonly silenceMs: number;
        /** RMS threshold for "speech present" (local VAD). */
        readonly minRms: number;
        /** Debounce: ignore repeated wake words for this many ms. */
        readonly debounceMs: number;
    };
    readonly beep: {
        readonly durationMs: number;
        readonly freqHz: number;
    };
    readonly audio: {
        /** Output sample rate (assistant replies) — 24 kHz for OpenAI. */
        readonly outputSampleRate: 24000;
        /** Input sample rate (mic, Porcupine). */
        readonly inputSampleRate: 16000;
        readonly channels: 1;
    };
    /** Input device on Linux (arecord -D) / macOS (AUDIODEV). */
    readonly audioDevice: string | undefined;
    /** Output device on Linux: pw-play target — see pw-play --list-targets. */
    readonly audioOutputDevice: string | undefined;
};
export declare function requireEnv(name: string, value: string | undefined): string;