/**
 * Token validation utilities for streaming responses and input validation
 */
/**
 * Approximate characters per token (used for token estimation)
 * Can be overridden by importing from config-utils if needed
 */
export declare const APPROX_CHARS_PER_TOKEN = 4;
/**
 * Estimates token count from text using character approximation
 * @param text - Text to estimate tokens for
 * @returns Estimated token count
 */
export declare function estimateTokenCount(input: string | number): number;
/**
 * Streaming token counter for monitoring output token limits
 */
export declare class StreamingTokenCounter {
    private tokenCount;
    private charCount;
    private maxTokens;
    private provider;
    constructor(maxTokens: number, provider?: string);
    /**
     * Add text chunk and update token count
     * @param chunk - Text chunk from streaming response
     * @returns Object with current count and whether limit exceeded
     */
    addChunk(chunk: string): {
        tokenCount: number;
        exceeded: boolean;
        shouldStop: boolean;
    };
    /**
     * Get current token statistics
     */
    getStats(): {
        tokenCount: number;
        charCount: number;
        maxTokens: number;
        utilization: number;
    };
    /**
     * Reset counter for new streaming session
     */
    reset(): void;
    /**
     * Check if approaching token limit (80% threshold)
     */
    isApproachingLimit(): boolean;
    /**
     * Get warning message if approaching or exceeding limits
     */
    getWarningMessage(): string | null;
}
/**
 * Validates input prompt against token limits
 * @param prompt - Input prompt to validate
 * @param maxInputTokens - Maximum allowed input tokens
 * @param provider - Provider name for error messages
 * @returns Validation result with token count and any errors
 */
export declare function validateInputTokens(prompt: string, maxInputTokens: number, provider?: string): {
    valid: boolean;
    tokenCount: number;
    error?: string;
};
/**
 * Creates a streaming wrapper that monitors token limits
 * @param stream - Original async generator
 * @param maxTokens - Maximum output tokens
 * @param provider - Provider name for logging
 * @returns Token-aware streaming generator
 */
export declare function createTokenAwareStream<T>(stream: AsyncGenerator<T>, maxTokens: number, provider?: string): AsyncGenerator<T>;
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