export type UnderstandingSignal = {
    evidenceRef: string;
    sourceId: string;
    title: string;
    group?: string;
    subjectKey?: string;
    occurredAt?: number;
};
export type UnderstandingSignalCluster = {
    key: string;
    title: string;
    confidence: number;
    horizon: 'current' | 'ongoing';
    signals: UnderstandingSignal[];
    sourceIds: string[];
};
export declare function tokenizeUnderstandingSignal(value: string): Set<string>;
export declare function clusterUnderstandingSignals(signals: UnderstandingSignal[], now?: number): UnderstandingSignalCluster[];