import { IncomingMessage, ServerResponse } from 'node:http';
import { AuthConfig, AuthResult } from '../../auth/types.js';
/**
 * Shared authentication handler for transport layers.
 * Handles both API Key and OAuth authentication with proper error responses.
 *
 * @param req - Incoming HTTP request
 * @param res - HTTP response object
 * @param authConfig - Authentication configuration from transport
 * @param context - Description of the context (e.g., "initialize", "message", "SSE connection")
 * @returns AuthResult if authenticated, null if authentication failed (response already sent)
 */
export declare function handleAuthentication(req: IncomingMessage, res: ServerResponse, authConfig: AuthConfig | undefined, context: string): Promise<AuthResult | null>;