import { BaseCallbackConfig, CallbackManagerForRetrieverRun, Callbacks } from "../callbacks/manager.js";
import { Document } from "../document.js";
import { Serializable } from "../load/serializable.js";
/**
 * Base Index class. All indexes should extend this class.
 */
export interface BaseRetrieverInput {
    callbacks?: Callbacks;
    tags?: string[];
    metadata?: Record<string, unknown>;
    verbose?: boolean;
}
export declare abstract class BaseRetriever extends Serializable {
    callbacks?: Callbacks;
    tags?: string[];
    metadata?: Record<string, unknown>;
    verbose?: boolean;
    constructor(fields?: BaseRetrieverInput);
    /**
     * TODO: This should be an abstract method, but we'd like to avoid breaking
     * changes to people currently using subclassed custom retrievers.
     * Change it on next major release.
     */
    _getRelevantDocuments(_query: string, _callbacks?: CallbackManagerForRetrieverRun): Promise<Document[]>;
    getRelevantDocuments(query: string, config?: Callbacks | BaseCallbackConfig): Promise<Document[]>;
}