/**
 * TOON Format Utility
 *
 * Provides JSON to TOON conversion for token-efficient encoding.
 * TOON format can reduce token count by 30-60% for JSON data.
 *
 * Uses the official @toon-format/toon library when available.
 */
/**
 * Ensures the TOON library is loaded. Call this before using jsonToToon in tests.
 */
export declare function ensureToonLoaded(): Promise<boolean>;
/**
 * Check if a string appears to be in TOON format.
 * TOON format characteristics:
 * - Uses key: value syntax (like YAML)
 * - Uses array notation like [3] or {fields}
 * - Does NOT start with { or [
 * - Often has patterns like "name[N]:" or "name{fields}:"
 *
 * @param str - String to check
 * @returns true if string appears to be TOON format
 */
export declare function isToonFormat(str: string): boolean;
/**
 * Extract the first valid JSON object or array from a string.
 * Handles pure JSON or JSON embedded in text (e.g., tool responses).
 *
 * @param str - The string to extract JSON from
 * @returns Object with found status, parsed JSON, and indices
 */
export declare function extractFirstJson(str: string): {
    found: boolean;
    parsed: unknown;
    startIndex: number;
    endIndex: number;
};
/**
 * Convert JSON content to TOON format for token efficiency.
 * Extracts JSON from string if embedded, converts to TOON.
 * Returns original string if:
 * - Already in TOON format
 * - Not JSON
 * - TOON conversion fails or is larger
 *
 * @param str - The string containing JSON to convert
 * @returns Object with conversion status, result, and reduction percentage
 */
export declare function jsonToToon(str: string): {
    converted: boolean;
    result: string;
    reduction: number;
    alreadyToon?: boolean;
    error?: string;
};
/**
 * Check if TOON library is loaded and available
 */
export declare function isToonAvailable(): boolean;
/**
 * Result of processing tool output
 */
export interface ProcessToolOutputResult {
    /** The processed content string */
    content: string;
    /** Whether TOON conversion was applied */
    toonConverted: boolean;
    /** Whether content was truncated */
    truncated: boolean;
    /** Percentage reduction from TOON (0 if not converted) */
    reduction: number;
    /** Whether input was already in TOON format */
    alreadyToon: boolean;
    /** Original content length */
    originalLength: number;
    /** Estimated original tokens (~4 chars per token) */
    originalTokens: number;
    /** Final content length */
    finalLength: number;
    /** Estimated final tokens */
    finalTokens: number;
    /** Error message if TOON conversion failed (for debugging) */
    toonError?: string;
}
/**
 * Options for processing tool output
 */
export interface ProcessToolOutputOptions {
    /** Maximum output length in characters (default: 100000) */
    maxLength?: number;
    /** Whether to apply TOON conversion (default: true) */
    enableToon?: boolean;
    /** Minimum content size to attempt TOON conversion (default: 1000) */
    minSizeForToon?: number;
    /** Minimum reduction % to accept TOON result (default: 10) */
    minReductionPercent?: number;
}
/**
 * Process tool output: apply TOON conversion if beneficial, then truncate if needed.
 * This is the main entry point for processing any tool output (regular or MCP).
 *
 * Flow:
 * 1. Check if already TOON format → skip conversion
 * 2. Try TOON conversion if content is JSON and large enough
 * 3. Truncate if still exceeds maxLength (with smart break points)
 *
 * @param content - The tool output content
 * @param options - Processing options
 * @returns Processed content and metadata
 */
export declare function processToolOutput(content: string, options?: ProcessToolOutputOptions): ProcessToolOutputResult;