/** Aggregate interview metrics, as the server reports them. Never prompts, boards or errors. */
export interface InterviewMetric {
    scope: "board" | "job";
    streaming: boolean;
    engine: "model" | "rules" | "none";
    outcome: "success" | "error" | "unavailable";
    cardCount: number;
    lineCount: number;
    startedAt: number;
}
/** Where the server reports interview metrics. Open Staves records nothing: the default sink drops
 *  every metric. A hosted service installs its own at its entry point (BOUNDARY.md rule 4). */
export interface TelemetrySink {
    record(metric: InterviewMetric): string | undefined;
}
export declare function setTelemetrySink(next: TelemetrySink | undefined): void;
export declare function telemetrySink(): TelemetrySink;