/**
 * Client information for detailed telemetry
 */
export interface ClientInfo {
    /** SDK name */
    sdk: string;
    /** SDK version */
    version: string;
    /** Runtime (e.g., 'node') */
    runtime: string;
    /** Runtime version (e.g., '18.0.0') */
    runtimeVersion: string;
    /** Operating system platform */
    platform: string;
    /** Optional custom application identifier (e.g., 'MyApp/1.0.0') */
    application?: string;
}
/**
 * Build standard User-Agent header value
 * Format: envoy-integrations-sdk/2.4.4 node/18.0.0
 * With custom app: envoy-integrations-sdk/2.4.4 node/18.0.0 MyApp/1.0.0
 *
 * This function is designed to never throw exceptions. If any error occurs,
 * it returns a safe fallback value to ensure SDK initialization succeeds.
 *
 * @param customUserAgent Optional custom application identifier
 * @returns User-Agent header value (never throws)
 */
export declare function buildUserAgent(customUserAgent?: string): string;
/**
 * Build detailed client info for X-Envoy-Client-Info header
 *
 * This function is designed to never throw exceptions. If any error occurs
 * during info collection, it uses safe fallback values.
 *
 * @param customUserAgent Optional custom application identifier
 * @returns ClientInfo object (never throws)
 */
export declare function buildClientInfo(customUserAgent?: string): ClientInfo;
/**
 * Build X-Envoy-Client-Info header value (JSON string)
 *
 * This function is designed to never throw exceptions. If JSON serialization
 * fails, it returns a minimal safe JSON string.
 *
 * @param customUserAgent Optional custom application identifier
 * @returns JSON string for X-Envoy-Client-Info header (never throws)
 */
export declare function buildClientInfoHeader(customUserAgent?: string): string;
//# sourceMappingURL=userAgent.d.ts.map