/**
 * Shared utility functions.
 */
/**
 * Extract a human-readable message from an unknown error value.
 */
export declare function errorMessage(err: unknown): string;
/**
 * Like {@link errorMessage}, but also unwraps an underlying `cause`.
 *
 * A `fetch`/undici transport failure surfaces only a bare "fetch failed" via
 * `err.message`; the actionable reason (ENOTFOUND / ECONNRESET / ETIMEDOUT and,
 * where present, the failing host) lives on `err.cause`. Use this ONLY at
 * fetch-error log sites so a network blip records WHAT actually went wrong —
 * {@link errorMessage} keeps its narrow, ripple-free behavior everywhere else.
 */
export declare function errorMessageWithCause(err: unknown): string;
/**
 * Build a standard MCP error response object.
 */
export declare function errorResult(text: string): {
    content: [{
        type: "text";
        text: string;
    }];
    isError: true;
};
/**
 * Describe arousal/dominance/valence as human-readable text.
 * Accepts values on 0-1 scale (v2 audeering models) or 1-5 scale (v1 lookup).
 * Auto-detects scale: values > 1 are treated as 1-5 and normalized to 0-1.
 *
 * Thresholds are calibrated to the audeering model's output distribution,
 * which is trained on MSP-Podcast (original 1-7 Likert scale normalized to 0-1).
 * Neutral calm speech typically outputs ~0.2 across all three dimensions.
 */
export declare function describeADV(arousal: number, dominance: number, valence: number): string;
/** Image file extensions recognized for photo sending. */
export declare const IMAGE_EXTENSIONS: Set<string>;
/** Maximum characters for OpenAI TTS input. */
export declare const OPENAI_TTS_MAX_CHARS = 4096;
/**
 * Format a Date as a human-readable timestamp string.
 * e.g. "28 Mar 2026, 23:07 EET"
 */
export declare function formatTimestamp(date?: Date): string;
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