/**
 * Observability metrics for OwlCoda proxy.
 * Tracks request counts, errors, model usage, and active connections.
 */
export declare function recordRequestStart(): void;
export declare function recordRequestEnd(model: string, statusCode: number, durationMs: number): void;
export declare function getActiveRequests(): number;
export interface ObservabilityMetrics {
    version: string;
    uptime: number;
    totalRequests: number;
    activeRequests: number;
    requestsByModel: Record<string, number>;
    requestsByStatus: Record<string, number>;
    avgDurationByModel: Record<string, number>;
    tokenUsage: {
        inputTokens: number;
        outputTokens: number;
        totalTokens: number;
        requestCount: number;
    };
    rateLimits: Record<string, {
        remaining: number;
        total: number;
    }>;
    recentErrors: number;
}
export declare function getMetrics(): ObservabilityMetrics;
/**
 * Reset all counters (for testing).
 */
export declare function resetMetrics(): void;
