/**
 * Prometheus Metrics Collector
 *
 * Why: Observability for production deployments
 *
 * Tracks:
 * - HTTP requests (status, method, path)
 * - Session lifecycle (active, created, destroyed)
 * - MCP operations (tool calls, duration, errors)
 * - API calls to backend (operation, status, duration)
 */
import { Registry } from 'prom-client';
export interface MetricsCollectorConfig {
    enabled: boolean;
    prefix?: string;
}
export interface MetricsContextLabels {
    profileId?: string | null;
    tenantId?: string | null;
}
export declare class MetricsCollector {
    private registry;
    private enabled;
    private httpRequestsTotal;
    private httpRequestDuration;
    private sessionsActive;
    private sessionsCreatedTotal;
    private sessionsDestroyedTotal;
    private mcpToolCallsTotal;
    private mcpToolCallDuration;
    private mcpToolCallErrors;
    private toolsTotal;
    private toolsFiltered;
    private toolsSession;
    private toolFilterRejections;
    private toolFilterPatterns;
    private apiCallsTotal;
    private apiCallDuration;
    private apiCallErrors;
    private apiCacheEventsTotal;
    constructor(config: MetricsCollectorConfig);
    /**
     * Record HTTP request
     */
    recordHttpRequest(method: string, path: string, status: number, durationSeconds: number, context?: MetricsContextLabels): void;
    /**
     * Record session created
     */
    recordSessionCreated(context?: MetricsContextLabels): void;
    /**
     * Record session destroyed
     */
    recordSessionDestroyed(context?: MetricsContextLabels): void;
    /**
     * Record MCP tool call
     */
    recordToolCall(tool: string, status: 'success' | 'error', durationSeconds: number, context?: MetricsContextLabels): void;
    /**
     * Record MCP tool call error
     */
    recordToolCallError(tool: string, errorType: string, context?: MetricsContextLabels): void;
    recordToolsTotal(source: string, count: number): void;
    recordToolsFiltered(source: string, action: string, count: number): void;
    recordToolsSession(sessionId: string, count: number): void;
    clearToolsSession(sessionId: string): void;
    recordToolFilterRejection(tool: string, source: string): void;
    recordToolFilterPatternCount(type: string, count: number): void;
    /**
     * Record API call to backend
     */
    recordApiCall(operation: string, status: number, durationSeconds: number, context?: MetricsContextLabels): void;
    /**
     * Record API call error
     */
    recordApiCallError(operation: string, errorType: string, context?: MetricsContextLabels): void;
    recordApiCacheEvent(operation: string, event: string, context?: MetricsContextLabels): void;
    /**
     * Get metrics in Prometheus format
     */
    getMetrics(): Promise<string>;
    /**
     * Get registry (for testing)
     */
    getRegistry(): Registry;
    /**
     * Normalize path for metrics (remove dynamic segments)
     *
     * Why: Avoid high cardinality in metrics labels
     *
     * Examples:
     * - /mcp?sessionId=abc123 -> /mcp
     * - /metrics -> /metrics
     * - /health -> /health
     */
    private normalizePath;
    /**
     * Get status label (2xx, 4xx, 5xx)
     *
     * Why: Group similar statuses to reduce cardinality
     */
    private getStatusLabel;
    private resolveContextLabels;
}
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