import { RagReranker } from "./reranker.contract.mjs";

//#region ../ai/src/rag/rerank/keyword-reranker.d.ts
/** Options for the {@link keywordReranker}. */
type KeywordRerankerOptions = {
  /**
   * Weight of the lexical-overlap signal blended with the original cosine
   * score, in `[0, 1]`. `1` ranks purely by keyword overlap; `0` keeps the
   * cosine order. Default `0.5`.
   */
  weight?: number;
};
/**
 * Zero-dependency lexical reranker (a BM25-lite, IDF-free keyword overlap).
 *
 * For each candidate it computes the fraction of distinct query terms that
 * appear in the chunk, blends that with the candidate's original cosine
 * score by `weight`, and sorts descending. A pure-lexical pass costs
 * nothing beyond string splits — no peer, no model — so it is the
 * recommended opt-in reranker when an embedding-only ranking surfaces a
 * keyword-rich chunk too low.
 *
 * Ties (equal blended score) preserve the incoming order, so the cosine
 * ranking breaks ties deterministically.
 *
 * @example
 * const kb = ai.rag({ embedder, store, reranker: ai.rag.keywordReranker() });
 */
declare function keywordReranker(options?: KeywordRerankerOptions): RagReranker;
//#endregion
export { KeywordRerankerOptions, keywordReranker };
//# sourceMappingURL=keyword-reranker.d.mts.map