/**
 * OpenTelemetry GenAI Metrics for Photon
 *
 * Zero-dependency metrics wrappers that no-op when @opentelemetry/api is not
 * installed. Mirrors the pattern in otel.ts for traces.
 *
 * Metric names follow OTel GenAI semantic conventions where applicable and
 * `photon.*` for runtime-specific instruments.
 */
export interface PhotonCounter {
    add(value: number, attributes?: Record<string, string | number | boolean>): void;
}
export interface PhotonHistogram {
    record(value: number, attributes?: Record<string, string | number | boolean>): void;
}
/**
 * Record a tool-call completion. Emits to both a latency histogram and a call
 * counter so operators can derive rate, error rate, and p95/p99 from one pair.
 */
export declare function recordToolCall(params: {
    photon: string;
    tool: string;
    durationMs: number;
    status: 'ok' | 'error';
    errorType?: string;
    stateful?: boolean;
}): void;
/**
 * Record a rate-limit rejection. Incremented every time a `@throttled`
 * or `@rateLimit` middleware throws `PhotonRateLimitError`.
 */
export declare function recordRateLimitRejection(params: {
    photon: string;
    tool: string;
    instance?: string;
}): void;
/**
 * Record a bulkhead rejection. Incremented every time the @bulkhead
 * middleware throws PhotonBulkheadFullError because concurrent-execution
 * cap was reached.
 */
export declare function recordBulkheadRejection(params: {
    photon: string;
    tool: string;
    instance?: string;
}): void;
/**
 * Record a circuit-breaker state transition.
 * Attributes capture the photon/tool key and the new state so dashboards can
 * alert on "open" without sampling the call stream.
 */
export declare function recordCircuitStateChange(params: {
    photon: string;
    tool: string;
    instance?: string;
    from: 'closed' | 'open' | 'half-open';
    to: 'closed' | 'open' | 'half-open';
}): void;
/**
 * Record an OAuth authorization-server event. One counter per endpoint +
 * status so operators can alert on error rates and track CIMD vs DCR
 * adoption without sampling logs.
 */
export declare function recordAuthEvent(params: {
    /** Which AS endpoint. */
    endpoint: 'authorize' | 'token' | 'register' | 'consent';
    /** Outcome bucket. */
    status: 'ok' | 'error';
    /** For /token, which grant_type was requested. */
    grantType?: 'authorization_code' | 'refresh_token' | 'client_credentials' | 'unknown';
    /** Client registration mode that resolved this request. */
    clientType?: 'cimd' | 'dcr' | 'unknown';
    /** For errors, the spec error code (invalid_grant, invalid_client, ...) for drill-down. */
    errorCode?: string;
}): void;
/**
 * Record a CIMD metadata-fetch outcome. `cached=true` means the document
 * was served from the in-memory LRU without a network round-trip.
 */
export declare function recordCimdFetch(params: {
    status: 'ok' | 'error';
    cached: boolean;
    errorCode?: string;
}): void;
/**
 * Returns true if OpenTelemetry metrics are available.
 */
export declare function isMetricsEnabled(): boolean;
/**
 * Wait for the initial OTel probe. For tests.
 */
export declare function waitForMetricsProbe(): Promise<void>;
/**
 * Reset cached state. For tests only.
 */
export declare function _resetMetricsCache(): void;
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