/**
 * MetricsRegistry — Zero-dependency Prometheus-compatible metrics.
 *
 * Provides Counter, Gauge, and Histogram metric types with label support.
 * Exports metrics in Prometheus text exposition format for scraping.
 *
 * No runtime dependencies — drop-in for any HTTP server or the MCP endpoint.
 *
 * @module Metrics
 */
/** Supported metric types */
export type MetricType = 'counter' | 'gauge' | 'histogram';
/** A set of label key-value pairs */
export type Labels = Record<string, string>;
/** Configuration for a histogram */
export interface HistogramBuckets {
    /** Upper bounds for each bucket (must be sorted ascending) */
    boundaries: number[];
}
/** Monotonically increasing counter */
export declare class Counter {
    readonly name: string;
    readonly help: string;
    private series;
    private labelMap;
    constructor(name: string, help: string);
    inc(labels?: Labels, amount?: number): void;
    get(labels?: Labels): number;
    /** Prometheus text lines */
    expose(): string;
}
/** Gauge — can go up or down */
export declare class Gauge {
    readonly name: string;
    readonly help: string;
    private series;
    private labelMap;
    constructor(name: string, help: string);
    set(labels: Labels, value: number): void;
    set(value: number): void;
    inc(labels?: Labels, amount?: number): void;
    dec(labels?: Labels, amount?: number): void;
    get(labels?: Labels): number;
    expose(): string;
}
/** Histogram with configurable buckets */
export declare class Histogram {
    readonly name: string;
    readonly help: string;
    readonly boundaries: number[];
    private series;
    private labelMap;
    constructor(name: string, help: string, buckets?: HistogramBuckets);
    observe(labels: Labels, value: number): void;
    observe(value: number): void;
    expose(): string;
}
/**
 * Central metrics registry. Collects all metrics and exposes them in
 * Prometheus text format.
 *
 * @example
 * ```ts
 * const registry = new MetricsRegistry();
 * const delegations = registry.counter('nai_delegations_total', 'Total delegations');
 * const activeAgents = registry.gauge('nai_active_agents', 'Currently active agents');
 * const latency = registry.histogram('nai_delegation_duration_ms', 'Delegation latency');
 *
 * delegations.inc({ agent: 'planner' });
 * activeAgents.set(5);
 * latency.observe({ agent: 'planner' }, 142);
 *
 * const text = registry.expose(); // Prometheus text exposition format
 * ```
 */
export declare class MetricsRegistry {
    private counters;
    private gauges;
    private histograms;
    /** Create or retrieve a counter */
    counter(name: string, help: string): Counter;
    /** Create or retrieve a gauge */
    gauge(name: string, help: string): Gauge;
    /** Create or retrieve a histogram */
    histogram(name: string, help: string, buckets?: HistogramBuckets): Histogram;
    /**
     * Export all registered metrics in Prometheus text exposition format.
     */
    expose(): string;
    /** Get a specific counter by name */
    getCounter(name: string): Counter | undefined;
    /** Get a specific gauge by name */
    getGauge(name: string): Gauge | undefined;
    /** Get a specific histogram by name */
    getHistogram(name: string): Histogram | undefined;
    /** Total number of registered metrics */
    get size(): number;
}
/**
 * Create a pre-configured MetricsRegistry with standard orchestrator metrics.
 *
 * Returns the registry and named handles to the individual metrics.
 */
export declare function createOrchestratorMetrics(): {
    registry: MetricsRegistry;
    delegationsTotal: Counter;
    delegationErrors: Counter;
    permissionChecks: Counter;
    permissionDenials: Counter;
    injectionBlocks: Counter;
    qualityRejections: Counter;
    blackboardWrites: Counter;
    activeAgents: Gauge;
    blackboardSize: Gauge;
    budgetUsedPercent: Gauge;
    delegationDurationMs: Histogram;
    adapterDurationMs: Histogram;
};
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