/**
 * Deterministic emergency fallback for the Adaptive Context Governor.
 *
 * This path is deliberately NOT another summarizer call. It moves the oldest
 * balanced surface range into the same durable, reversible ARC block store and
 * writes a bounded extractive index as the checkpoint. Originals remain in
 * the append-only log, so search_context/decompress still recover them.
 * @module dsh-arc-context/fallback
 */
import type { CompactionResult, CompactionAgentContext } from '@deepseek-ai/dsh-compaction';
import { type CompactionTransactionInput } from './region.ts';
/** Global checkpoint budget, including a model-written summary and its appendix. */
export declare const MAX_SUMMARY_CHARS = 24000;
/** Body-assembly policy when the index exceeds the checkpoint budget. */
export type SafetyIndexRanking = 'chronological' | 'value';
/** Build the local, bounded checkpoint text used by emergency cold-storage. */
export declare function buildEmergencyFallbackSummary(agent: CompactionAgentContext, shadowedSeqs: readonly number[]): string;
/** Build the local checkpoint used by official manual/region seam calls. */
export declare function buildManualFallbackSummary(agent: CompactionAgentContext, shadowedSeqs: readonly number[]): string;
/**
 * Exact/reversible safety appendix for a model-written ARC checkpoint. Models
 * vary in what they retain; the appendix keeps structured and rare evidence
 * without a second API call and applies the same archive-instruction boundary.
 */
export declare function buildModelSummarySafetyIndex(agent: CompactionAgentContext, shadowedSeqs: readonly number[], maxChars?: number, ranking?: SafetyIndexRanking): string;
/**
 * Price the exact replacement span with the host's token-meter protocol.
 * `compaction/summary.shadowedTokenCount` is not descriptive metadata: the
 * bounded surface projection subtracts it from its own heuristic total. A
 * different estimator (notably ARC's CJK-aware count) can over-claim the
 * replaced range and make the host projection negative.
 */
export declare function resolveShadowedTokenCount(agent: CompactionAgentContext, shadowedSeqs: readonly number[]): number;
/** Prepare one exact local replacement, returning null when it would not shrink. */
export declare function prepareLocalCompaction(agent: CompactionAgentContext, requestedStart: number, requestedEnd: number): CompactionTransactionInput | null;
/** Compact one caller-selected range through the official region seam. */
export declare function runLocalCompactionRegion(agent: CompactionAgentContext, start: number, end: number): CompactionResult | null;
/** Move one largest safe old range into reversible cold-storage without an API call. */
export declare function runEmergencyFallback(agent: CompactionAgentContext): CompactionResult | null;