/**
 * Browser performance metrics for ExploreChimp — builds {@link MetricsPayload}
 * (`agents.proto`) in the page and returns it to Node.
 */
import type { MetricsPayload } from './agents-explorechimp-json';
export declare function parseExploreChimpLongTaskThresholdMs(): number;
/**
 * Injects observers on every new document (Playwright init script). Idempotent per document.
 */
export declare function installExploreChimpPerfMetricsObservers(page: {
    addInitScript?: (...args: any[]) => Promise<void> | void;
}, longTaskThresholdMs: number): Promise<void>;
/** Same semantics as watcher.getMetricsSince — filters perf entries by wall-clock `since`. */
export declare function collectMetricsSince(page: {
    evaluate?: <T, A = unknown>(fn: (arg: A) => T, arg: A) => Promise<T>;
}, sinceTimestamp: number): Promise<MetricsPayload>;
/** Clears in-page metric buffers (watcher.resetMetrics). */
export declare function resetExploreChimpPerfMetricsBuffers(page: {
    evaluate?: (fn: () => void, arg?: unknown) => Promise<unknown> | void;
}): Promise<void>;
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