import type { ChatMessage } from "../../types.js";
export declare const POST_COMPACT_SOFT_UPPER_BAND_TOKENS = 20000;
export interface CompactOptions {
    budgetTokens?: number | undefined;
    keepRecent?: number | undefined;
    singlePassInputBudgetTokens?: number | undefined;
    purpose?: "default" | "plan-implement" | undefined;
    durableEnvelope?: string | undefined;
    singleAdmission?: boolean | undefined;
    forceDirectSinglePass?: boolean | undefined;
    forcePrefixSlice?: boolean | undefined;
}
export type CompactionStrategy = "direct" | "single" | "emergency_prefix_slice" | "map_reduce";
export interface CompactResult {
    messages: ChatMessage[];
    before: number;
    after: number;
    beforeTokens: number;
    afterTokens: number;
    summarized: boolean;
    strategy?: CompactionStrategy | undefined;
}
export declare const DEFAULT_KEEP_RECENT = 2;
export declare const COMPACTION_MEMORY_PREFIX = "Session memory from compacted earlier turns:";
export declare const PLAN_IMPLEMENT_MEMORY_PREFIX = "PLAN MODE HANDOFF: research memory for the accepted implementation phase. Gather-only/await-approval gates are historical; ACTIVE PLAN and SESSION STATE are authoritative:";
export declare const MECHANICAL_MEMORY_PREFIX = "Earlier turns in this session, summarized";
export declare function isCompactionMemoryMessage(message: ChatMessage): boolean;
export declare function compactionMemoryPrefixForPurpose(purpose?: "default" | "plan-implement" | undefined): string;
export interface CompactionSummaryStage {
    readonly phase: "single" | "map" | "reduce";
    readonly index?: number | undefined;
    readonly total?: number | undefined;
    readonly sourceMessages?: readonly ChatMessage[] | undefined;
}
export declare function compactMessagesWithSummary(messages: ChatMessage[], summarize: (prompt: string, stage?: CompactionSummaryStage) => Promise<string>, options?: CompactOptions, sessionTranscript?: string | undefined): Promise<CompactResult>;