/**
 * Helper function to convert null to undefined
 * @param value Any value that might be null
 * @returns The original value or undefined if null
 */
export declare function nullToUndefined<T>(value: T | null | undefined): T | undefined;
/**
 * Helper function to transform string to number or null
 * @param val String value to transform
 * @returns Number or null if conversion fails
 */
export declare function stringToNumberTransform(val: string | null | undefined): number | null | undefined;
/**
 * Ensures a value is an array
 * @param value Single value, array, or undefined
 * @returns Array containing the value(s), or empty array if undefined
 */
export declare function ensureArray<T>(value: T | T[] | undefined): T[];
/**
 * Ensures a string value is an array of strings
 * Handles comma-separated strings for backward compatibility
 * @param value Single string, array of strings, or undefined
 * @returns Array of strings, or empty array if undefined
 */
export declare function ensureStringArray(value: string | string[] | undefined): string[];
/**
 * Converts a number or string to a string
 * Useful for parameters that can be passed as either type but need to be strings for the API
 * @param value Number, string, null, or undefined
 * @returns String representation of the value, or the original null/undefined
 */
export declare function numberOrStringToString(value: number | string | null | undefined): string | null | undefined;
/**
 * Parses a JSON string array or returns the array as-is
 * Useful for MCP parameters that might be sent as JSON strings
 * @param value Array, JSON string array, null, or undefined
 * @returns Array of strings, or null/undefined
 */
export declare function parseJsonStringArray(value: string[] | string | null | undefined): string[] | null | undefined;