import type { UnderstandingSourceItem, UserFocus } from './types.js';
export type ActivityTopic = Pick<UserFocus, 'canonicalKey' | 'title' | 'summary' | 'horizon' | 'confidence' | 'evidenceRefs'> & {
    sourceIds: string[];
};
export declare function clusterActivityTopics(items: UnderstandingSourceItem[], now?: number): ActivityTopic[];