/**
 * Summarization-based conversation history management.
 *
 * This module provides a conversation manager that summarizes older messages
 * when the context window overflows, preserving important information rather
 * than simply discarding it.
 */
import { ConversationManager, type ProactiveCompressionConfig, type ConversationManagerReduceOptions } from './conversation-manager.js';
import type { Model } from '../models/model.js';
/**
 * Configuration for the summarization conversation manager.
 */
export type SummarizingConversationManagerConfig = {
    /**
     * Model to use for generating summaries. When provided, overrides the model
     * attached to the agent. Useful when you want to use a different model than
     * the one attached to the agent.
     */
    model?: Model;
    /**
     * Ratio of messages to summarize when context overflow occurs.
     * Value is clamped to [0.1, 0.8]. Defaults to 0.3 (summarize 30% of oldest messages).
     */
    summaryRatio?: number;
    /**
     * Minimum number of recent messages to always keep.
     * Defaults to 10.
     */
    preserveRecentMessages?: number;
    /**
     * Custom system prompt for summarization. If not provided, uses a default
     * prompt that produces structured bullet-point summaries.
     */
    summarizationSystemPrompt?: string;
    /**
     * Enable proactive context compression before the model call.
     *
     * - `true`: compress when 70% of the context window is used (default threshold).
     * - `{ compressionThreshold: number }`: compress at the specified ratio (0, 1].
     * - `false` or omitted: disabled, only reactive overflow recovery is used.
     */
    proactiveCompression?: boolean | ProactiveCompressionConfig;
    /**
     * Number of messages at the start of the conversation to permanently pin.
     * Pinned messages are protected from summarization and compacted to the front.
     */
    pinFirst?: number;
};
/**
 * Implements a summarization strategy for managing conversation history.
 *
 * When a {@link ContextWindowOverflowError} occurs, this manager summarizes
 * the oldest messages using a model call and replaces them with a single
 * summary message, preserving context that would otherwise be lost.
 */
export declare class SummarizingConversationManager extends ConversationManager {
    readonly name = "strands:summarizing-conversation-manager";
    private readonly _model;
    private readonly _summaryRatio;
    private readonly _preserveRecentMessages;
    private readonly _summarizationSystemPrompt;
    private readonly _pinFirst;
    private _pinFirstApplied;
    constructor(config?: SummarizingConversationManagerConfig);
    /**
     * Reduce the conversation history by summarizing older messages.
     *
     * When `error` is set (reactive overflow recovery), summarization failure is rethrown
     * with the original error as cause — the agent loop must not proceed with an overflow.
     *
     * When `error` is undefined (proactive compression), summarization failure is logged
     * and returns `false` — the model call proceeds regardless.
     *
     * @param options - The reduction options
     * @returns `true` if the history was reduced, `false` otherwise
     */
    reduce({ agent, model, error }: ConversationManagerReduceOptions): Promise<boolean>;
    /**
     * Summarize the oldest messages and replace them with a summary.
     *
     * @param agent - The agent instance
     * @param model - The model to use for summarization
     * @returns `true` if the history was reduced, `false` otherwise
     */
    private _summarizeOldest;
}
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