/**
 * ContextBudget tracks token consumption within a single Claude turn.
 *
 * Each Claude invocation starts fresh with the full context window available.
 * This class tracks accumulated token usage and decides when content should
 * be externalized to prevent context overflow.
 */
/**
 * Estimate token count from content using whitespace-based approximation.
 * Multiplies word count by 1.3 to account for subword tokenization.
 */
export declare function estimateTokens(content: string): number;
/**
 * Configuration options for ContextBudget.
 */
export interface ContextBudgetConfig {
    /** Total context limit in tokens (default: 300,000) */
    contextLimit?: number;
    /** Threshold fraction for externalization (default: 0.75) */
    threshold?: number;
    /** Tokens reserved for response (default: 10,000) */
    reservedForResponse?: number;
}
/**
 * ContextBudget manages token allocation within a single turn.
 *
 * Usage:
 * ```
 * const budget = new ContextBudget();
 * budget.consume(estimateTokens(userMessage));
 *
 * // For each tool result:
 * const tokens = estimateTokens(toolResult);
 * if (budget.wouldExceed(tokens)) {
 *   // Externalize the content
 * } else {
 *   budget.consume(tokens);
 * }
 *
 * // After turn completes:
 * budget.reset();
 * ```
 */
export declare class ContextBudget {
    private consumed;
    private readonly limit;
    private readonly contextLimit;
    private readonly threshold;
    constructor(config?: ContextBudgetConfig);
    /**
     * Check if adding new content would exceed the budget.
     * @param tokens - Token count of the new content
     * @returns true if content should be externalized
     */
    wouldExceed(tokens: number): boolean;
    /**
     * Record token consumption. Call after content passes through to context.
     * @param tokens - Token count consumed
     */
    consume(tokens: number): void;
    /**
     * Reset budget for a new turn. Call after Claude responds.
     */
    reset(): void;
    /**
     * Get current consumption stats.
     */
    getStats(): {
        consumed: number;
        limit: number;
        remaining: number;
        utilizationPercent: number;
    };
    /**
     * Get the effective token limit for this budget.
     */
    getLimit(): number;
    /**
     * Get current consumed tokens.
     */
    getConsumed(): number;
}
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