/**
 * Tiny TwiML builders for Twilio webhook responses.
 *
 * The channel keeps TwiML generation local so callers do not need the
 * Twilio SDK just to acknowledge a webhook or gather speech.
 */
/** Options for rendering a voice `<Gather input="speech">` response. */
export interface TwilioGatherTwimlOptions {
    /** Absolute callback URL that receives the speech result. */
    readonly actionUrl: string;
    /** Prompt spoken before Twilio starts speech recognition. */
    readonly prompt: string;
    /** Twilio `<Say voice>` used for the prompt, e.g. `Polly.Joanna-Neural`. */
    readonly voice?: string;
    /** BCP 47 language used for speech recognition and the nested `<Say>` prompt. */
    readonly language?: string;
    /** Twilio `<Gather speechModel>` used for speech recognition. */
    readonly speechModel?: string;
    /** Twilio `<Gather timeout>` in seconds. */
    readonly timeoutSeconds?: number;
    /** Twilio `<Gather speechTimeout>`, such as `"auto"` or a second count string. */
    readonly speechTimeout?: string;
    /** Twilio `<Gather hints>` for expected words or phrases. */
    readonly hints?: string | readonly string[];
    /** Twilio `<Gather profanityFilter>` toggle. */
    readonly profanityFilter?: boolean;
}
/** Returns an empty TwiML response, useful for acknowledging inbound SMS without replying. */
export declare function emptyTwilioResponse(): Response;
/** Returns a TwiML response that speaks `message` and then ends the call. */
export declare function sayTwilioResponse(message: string): Response;
/** Returns a TwiML response that asks the caller to speak and posts the transcript to `actionUrl`. */
export declare function gatherSpeechTwilioResponse(options: TwilioGatherTwimlOptions): Response;
/** Wraps a TwiML string in a Twilio-compatible XML response. */
export declare function twimlResponse(twiml: string): Response;
/** Escapes the five XML predefined entities (`&`, `<`, `>`, `"`, `'`) for safe use in TwiML element content or attribute values. Note that `'` becomes `&apos;`. */
export declare function escapeXml(value: string): string;