import type { CompletionRequest } from '../types/messages.js';
import type { BudgetConfig } from '../types/optimizer.js';
import { Tokenizer } from '../utils/tokenizer.js';
/** Raised when a request exceeds its input token budget and `onExceeded` is `error`, the default. */
export declare class TokenBudgetError extends Error {
    /** Estimated input tokens. */
    tokens: number;
    /** The budget. */
    maxTokens: number;
    constructor(
    /** Estimated input tokens. */
    tokens: number, 
    /** The budget. */
    maxTokens: number);
}
/** Checks requests against an input token budget and applies its over-budget strategy. */
export declare class BudgetEnforcer {
    private tokenizer;
    constructor(tokenizer?: Tokenizer);
    /**
     * Estimates a request's input tokens and whether they exceed the budget, with a warning past
     * `warnAt`.
     */
    check(request: CompletionRequest, config?: BudgetConfig): {
        warnings: string[];
        exceeded: boolean;
        tokens: number;
    };
    /**
     * Applies the budget as `onExceeded` says: `error` throws, `truncate` trims the oldest non-system
     * messages, and `allow` and `densify` pass the request through, densification running elsewhere.
     */
    enforce(request: CompletionRequest, config?: BudgetConfig): CompletionRequest;
    private truncateToBudget;
}