/**
 * Compaction event tracking plugin.
 *
 * Tracks context compaction events (compact_boundary system messages)
 * including pre-compaction token counts per phase.
 */
import type { Middleware, MiddlewareContext, MiddlewareStore, SDKMessage } from '../types';
export interface CompactionData {
    phaseCompactions: number;
    phasePreTokens: number[];
    totalCompactions: number;
    phaseSnapshots: Array<{
        phase: string;
        compactions: number;
        preTokens: number[];
    }>;
}
export declare class CompactionTrackerPlugin implements Middleware {
    readonly name = "compactions";
    private phaseCompactions;
    private phasePreTokens;
    private totalCompactions;
    private phaseSnapshots;
    private currentPhase;
    onMessage(message: SDKMessage, ctx: MiddlewareContext, store: MiddlewareStore): void;
    onPhaseTransition(fromPhase: string, toPhase: string, _ctx: MiddlewareContext, store: MiddlewareStore): void;
    onFinalize(_resultMessage: SDKMessage, _totalDurationMs: number, _ctx: MiddlewareContext, store: MiddlewareStore): void;
    private getData;
}
