/**
 * Security Utilities for NotebookLM MCP Server
 *
 * Provides input validation, sanitization, and security hardening.
 * Added by Pantheon Security for hardened fork.
 */
/**
 * Validate and sanitize a NotebookLM URL
 * Prevents URL injection, javascript: URLs, and other attacks
 *
 * @param url - The URL to validate
 * @returns Validated URL or throws error
 */
export declare function validateNotebookUrl(url: string): string;
/**
 * Validate a user-supplied source URL (content inputs, not notebook navigation).
 * Enforces HTTPS and blocks dangerous schemes without restricting domain.
 */
export declare function validateSourceUrl(url: string): string;
/**
 * Validate notebook ID format
 * NotebookLM IDs are typically alphanumeric with dashes
 */
export declare function validateNotebookId(id: string): string;
/**
 * Validate session ID format
 */
export declare function validateSessionId(id: string): string;
/**
 * Validate question input
 * Prevents extremely long inputs that could cause DoS
 */
export declare function validateQuestion(question: string): string;
/**
 * Sanitize a string for safe logging
 * Masks sensitive information like passwords, tokens, etc.
 */
export declare function sanitizeForLogging(value: string): string;
/**
 * Mask an email for logging (more aggressive than general sanitization)
 */
export declare function maskEmail(email: string): string;
/**
 * Validate file path to prevent path traversal
 */
export declare function validateFilePath(basePath: string, filePath: string): string;
export declare class RateLimiter {
    private requests;
    private readonly maxRequests;
    private readonly windowMs;
    constructor(maxRequests?: number, windowMs?: number);
    /**
     * Check if a request should be allowed
     * @param key - Identifier for the rate limit (e.g., session ID, IP)
     * @returns true if allowed, false if rate limited
     */
    isAllowed(key: string): boolean;
    /**
     * Get remaining requests for a key
     */
    getRemaining(key: string): number;
    /**
     * Return number of distinct tracked keys
     */
    size(): number;
    /**
     * Clear all rate limit data
     */
    clear(): void;
}
/**
 * Custom security error class
 */
export declare class SecurityError extends Error {
    constructor(message: string);
}
/**
 * Environment variable validator
 * Ensures sensitive env vars are not logged
 */
export declare function getSecureEnvVar(name: string, defaultValue?: string): string;
/**
 * Check if running in a secure context
 */
export declare function checkSecurityContext(): {
    secure: boolean;
    warnings: string[];
};