/**
 * Lightweight in-memory accumulator for MCP-AQL operation metrics.
 *
 * Records operation counts, durations, and error rates. The companion
 * OperationMetricsCollector reads from this tracker each collection cycle.
 */
export interface OperationMetrics {
    totalOps: number;
    failedOps: number;
    durations: number[];
    byEndpoint: Map<string, number>;
    byOperation: Map<string, number>;
}
export declare class OperationMetricsTracker {
    private totalOps;
    private failedOps;
    private readonly durations;
    private readonly byEndpoint;
    private readonly byOperation;
    record(operation: string, endpoint: string, durationMs: number, success: boolean): void;
    getMetrics(): OperationMetrics;
    /** Compute duration percentiles from the ring buffer. */
    static percentiles(durations: number[]): {
        count: number;
        sum: number;
        avg: number;
        p50: number;
        p95: number;
        p99: number;
    };
}
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