import type { KnowledgeRetrievalResult, RetrievalCacheAdapter } from '../types/knowledge.js';
/**
 * Zero-config, in-process session retrieval cache (G6). Keyed by the query
 * embedding: a lookup returns the cached results of the most-similar recent
 * query (cosine ≥ threshold, within TTL). LRU-bounded. Needs only the embedder
 * the KnowledgeProvider already requires — no external dependency. Apps that
 * want a shared/vector-backed cache can inject their own `RetrievalCacheAdapter`
 * via the KnowledgeProvider's `cacheFactory` instead.
 */
export interface InMemoryRetrievalCacheOptions {
    maxEntries?: number;
    ttlMs?: number;
    similarityThreshold?: number;
}
export declare class InMemoryRetrievalCache implements RetrievalCacheAdapter {
    /** Ordered oldest → newest (LRU front, MRU back). */
    private entries;
    private readonly maxEntries;
    private readonly ttlMs;
    private readonly threshold;
    constructor(options?: InMemoryRetrievalCacheOptions);
    get size(): number;
    lookup(queryEmbedding: readonly number[], topK?: number): KnowledgeRetrievalResult[];
    populate(results: KnowledgeRetrievalResult[], queryEmbedding?: readonly number[]): void;
}