export type ContextTier = 'FULL' | 'TARGETED' | 'MINIMAL' | 'NONE';
export interface TierConfig {
    /** How often to do a FULL search (every N turns). Default: 8. */
    fullSearchInterval: number;
    /** How often to do a MINIMAL search if no other trigger. Default: 4. */
    minimalInterval: number;
    /** Maximum prompt length (chars) to be classified as NONE. Default: 30. */
    shortPromptMaxChars: number;
}
export declare const DEFAULT_TIER_CONFIG: TierConfig;
export interface TierResult {
    tier: ContextTier;
    tokenBudget: number;
    reason: string;
}
export type ContextFill = 'FRESH' | 'MODERATE' | 'DEPLETED' | 'CRITICAL';
/** Estimate context fill level from message count and total character volume. */
export declare function estimateContextFill(messages?: unknown[]): ContextFill;
export declare class TurnTracker {
    private turnCount;
    private lastPrompt;
    private readonly config;
    constructor(config?: Partial<TierConfig>);
    /** Classify the current turn and return the appropriate tier.
     *  When messages are provided, the token budget is scaled by context fill level. */
    classify(prompt: string, messages?: unknown[]): TierResult;
    /** Reset tracker (e.g., on new session). */
    reset(): void;
}
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