/**
 * Prometheus Metrics Module
 *
 * Exposes metrics for monitoring:
 * - Request counters (total, by tool, by status)
 * - Cache hit/miss counters
 * - Request duration histograms
 * - Circuit breaker state gauge
 * - Rate limiter gauge
 * - Cache size gauge
 */
import { Counter, Histogram, Gauge, Registry } from "prom-client";
export declare const registry: Registry<"text/plain; version=0.0.4; charset=utf-8">;
/**
 * Total number of API requests
 */
export declare const requestsTotal: Counter<"tool" | "status" | "error_category">;
/**
 * Cache hit counter
 */
export declare const cacheHitsTotal: Counter<"method">;
/**
 * Cache miss counter
 */
export declare const cacheMissesTotal: Counter<"method">;
/**
 * Rate limit hits counter
 */
export declare const rateLimitHitsTotal: Counter<"type">;
/**
 * Circuit breaker trips counter
 */
export declare const circuitBreakerTripsTotal: Counter<string>;
/**
 * Retry counter
 */
export declare const retriesTotal: Counter<"tool" | "reason">;
/**
 * Request duration histogram
 */
export declare const requestDuration: Histogram<"tool" | "status">;
/**
 * Circuit breaker state
 * 0 = closed (normal)
 * 1 = half-open (testing)
 * 2 = open (blocking)
 */
export declare const circuitBreakerState: Gauge<string>;
/**
 * Rate limiter requests in current window
 */
export declare const rateLimiterRequests: Gauge<string>;
/**
 * Cache size gauge
 */
export declare const cacheSize: Gauge<string>;
/**
 * Active chats tracked by per-chat rate limiter
 */
export declare const activeChatsTracked: Gauge<string>;
/**
 * Convert circuit breaker state string to numeric value
 */
export declare function circuitBreakerStateToNumber(state: "closed" | "open" | "half-open"): number;
/**
 * Record a request with all relevant metrics
 */
export declare function recordRequest(params: {
    tool: string;
    status: "success" | "error";
    errorCategory?: string;
    durationMs: number;
}): void;
/**
 * Get all metrics in Prometheus format
 */
export declare function getMetrics(): Promise<string>;
/**
 * Get metrics content type
 */
export declare function getMetricsContentType(): string;
//# sourceMappingURL=index.d.ts.map