import type { Comment } from '@pantheon-systems/css-client';
export declare function resetUnansweredMentionReports(): void;
interface UnansweredMention {
    /** Stable across renders and mounts, so the same failure is reported once however often it is drawn. */
    key: string;
    commentId: string;
    agentId: string;
    elapsedMs: number;
}
/**
 * Which of the stand-ins on screen are telling the reader an agent never replied.
 *
 * Takes the comments as loaded and the same list with stand-ins added, rather than
 * recognising a stand-in by its shape: the rule for when one turns from working to
 * failed then stays in the one place that owns it.
 */
export declare function unansweredMentions(comments: readonly Comment[], shown: readonly Comment[], now: number): UnansweredMention[];
/**
 * Reports each unanswered mention the reader is shown, once.
 *
 * A thread can be open in more than one place at a time, so the ledger of what has been
 * reported is module-wide and a key goes in before the request goes out: whichever copy
 * of the hook gets there first is the one that reports.
 */
export declare function useUnansweredMentionReport(threadId: string | undefined, comments: readonly Comment[] | undefined, shown: readonly Comment[]): void;
export {};