/**
 * Similarity Service
 *
 * Pure mathematical functions for computing vector similarity.
 * No external dependencies.
 */
/**
 * Calculate cosine similarity between two vectors.
 *
 * @param a - First vector
 * @param b - Second vector
 * @returns Similarity score between -1 and 1 (1 = identical, 0 = orthogonal, -1 = opposite)
 * @throws Error if vectors have different lengths
 */
export declare function cosineSimilarity(a: number[], b: number[]): number;
/**
 * Calculate Euclidean distance between two vectors.
 *
 * @param a - First vector
 * @param b - Second vector
 * @returns Distance (0 = identical, larger = more different)
 */
export declare function euclideanDistance(a: number[], b: number[]): number;