/**
 * ContextCompactor
 *
 * Orchestrates multi-stage context reduction:
 *
 * Stage 1: Tool Output Pruning (cheapest -- no LLM call)
 * Stage 2: File Read Deduplication (cheap -- no LLM call)
 * Stage 3: LLM Summarization (expensive -- requires LLM call)
 * Stage 4: Sliding Window Truncation (fallback -- no LLM call)
 */
import type { ChatMessage, ConversationMemoryConfig, CompactionResult, CompactionConfig, ContextCompactorDeps, ContextCompactRequest } from "../types/index.js";
export declare class ContextCompactor {
    private config;
    /**
     * Injected decision caller and its tuning. Kept OUT of `CompactionConfig`
     * deliberately: that type is `Required<>`-ed into `DEFAULT_CONFIG`, so a
     * function member would need a default implementation, and the compactor
     * must stay usable with no decision provider at all.
     */
    private readonly deps;
    constructor(config?: CompactionConfig, deps?: ContextCompactorDeps);
    /**
     * Run the multi-stage compaction pipeline until messages fit within budget.
     */
    compact(messages: ChatMessage[], targetTokens: number, memoryConfig?: Partial<ConversationMemoryConfig>, requestId?: string, request?: ContextCompactRequest): Promise<CompactionResult>;
    /**
     * Stage 0 — drop the earlier messages this request provably does not need.
     *
     * Returns the surviving messages, or `null` when nothing changed: no
     * decision provider, no known request, nothing eligible, or no confident
     * drop. Never throws — a failure here must leave the positional stages to
     * run exactly as they did before this stage existed.
     */
    private runRelevanceStage;
    /**
     * Whether a generated summary may replace the messages it covers.
     *
     * Stage 3 accepts any non-empty string today, so a refusal, an error
     * message or a truncated fragment silently destroys the conversation it was
     * meant to preserve — and the originals are gone before anyone reads it.
     *
     * Returns true unless a decision model CONFIDENTLY rejects the summary,
     * because rejecting one falls through to truncation, which loses strictly
     * more than an imperfect summary does.
     */
    private acceptSummary;
    /**
     * Stage 2 — collapse repeated reads of the same file to the last one.
     * Returns the deduplicated messages, or `null` when the stage is disabled,
     * already within budget, or found nothing to collapse.
     */
    private runDeduplicateStage;
    /**
     * Stage 1 — shrink large tool outputs outside the protected recent window.
     * Returns the pruned messages, or `null` when the stage is disabled,
     * already within budget, or saved nothing worth keeping.
     */
    private runPruneStage;
}