/**
 * @fileoverview Environment variable loading and validation utilities.
 *
 * This module provides utilities for loading, validating, and accessing environment
 * variables used by the code review tool. It handles loading from .env.local files,
 * provides clear error messages for missing variables, and manages API key precedence.
 *
 * Key responsibilities:
 * - Loading environment variables from .env.local
 * - Validating required environment variables
 * - Managing API key precedence (GOOGLE_GENERATIVE_AI_KEY vs GOOGLE_AI_STUDIO_KEY)
 * - Providing clear error messages for configuration issues
 * - Logging environment variable status without exposing sensitive values
 */
/**
 * Load environment variables from .env.local file
 * @param envFilePath Optional custom path to .env file
 * @returns Object containing information about the loading process
 */
export declare function loadEnvVariables(envFilePath?: string): Promise<{
    success: boolean;
    message: string;
    envFile?: string;
}>;
/**
 * Get the Google API key with proper precedence handling
 * @returns Object containing the API key and information about which key was used
 */
export declare function getGoogleApiKey(): {
    apiKey: string | undefined;
    source: string;
    message: string;
};
/**
 * Get the OpenRouter API key with proper precedence handling
 * @returns Object containing the API key and information about which key was used
 */
export declare function getOpenRouterApiKey(): {
    apiKey: string | undefined;
    source: string;
    message: string;
};
/**
 * Get the Anthropic API key with proper precedence handling
 * @returns Object containing the API key and information about which key was used
 */
export declare function getAnthropicApiKey(): {
    apiKey: string | undefined;
    source: string;
    message: string;
};
/**
 * Get the OpenAI API key with proper precedence handling
 * @returns Object containing the API key and information about which key was used
 */
export declare function getOpenAIApiKey(): {
    apiKey: string | undefined;
    source: string;
    message: string;
};
/**
 * Validate that required environment variables are present
 * @returns Object containing validation result and error message if applicable
 */
export declare function validateRequiredEnvVars(): {
    valid: boolean;
    message: string;
};