/**
 * Query preprocessing for FTS.
 *
 * Raw user prompts are poor FTS queries — they contain stopwords, filler,
 * and conversational fluff. This module extracts discriminative keywords
 * that BM25 can work with effectively.
 */
/**
 * Extract keywords from a natural language prompt.
 * Returns a space-separated string of discriminative terms suitable for FTS.
 */
export declare function extractKeywords(prompt: string): string;
export type QueryMode = "raw" | "keywords";
/** Preprocess a query based on mode */
export declare function preprocessQuery(query: string, mode: QueryMode): string;