/**
 * Plugin invocation statistics.
 *
 * Counts hook invocations, errors, and accumulated runtime per plugin so
 * users can confirm their plugin is actually running and catch regressions
 * (e.g. a plugin throwing on every request).
 *
 * Stats are tracked only for plugins the loader has registered — adapter
 * built-in transforms are internal plumbing and flow through the same
 * pipeline but aren't metered here.
 */
export interface HookStats {
    /** Number of successful invocations */
    invocations: number;
    /** Number of times the hook threw */
    errors: number;
    /** Accumulated execution time in milliseconds (successful calls only) */
    totalMs: number;
}
export interface PluginStats {
    /** Per-hook counters, keyed by hook name (onRequest, onResponse, etc.) */
    hooks: Record<string, HookStats>;
    /** Unix timestamp of the most recent invocation of any hook */
    lastInvokedAt?: number;
    /** Most recent error, if any */
    lastError?: {
        hook: string;
        message: string;
        at: number;
    };
}
/**
 * Register a plugin name for stats tracking. Called by the loader after
 * a plugin validates successfully. Resets any prior stats for that name
 * (so /plugins/reload gives you a clean slate).
 */
export declare function registerPluginStats(name: string): void;
/**
 * Drop all stats. Called before a full reload so stale data doesn't linger
 * for plugins that were removed from the config.
 */
export declare function resetAllPluginStats(): void;
/**
 * Whether the given name is a tracked plugin. Adapter built-in transforms
 * aren't registered, so the runner can silently skip stats for them.
 */
export declare function isTrackedPlugin(name: string): boolean;
/**
 * Record a successful invocation of a hook.
 */
export declare function recordInvocation(name: string, hook: string, durationMs: number): void;
/**
 * Record an error from a hook.
 */
export declare function recordError(name: string, hook: string, err: unknown): void;
/**
 * Read a snapshot of stats for one plugin. Returns a deep copy so callers
 * can't mutate the internal state.
 */
export declare function getPluginStats(name: string): PluginStats | undefined;
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