/**
 * Salience: how much the next step depends on each message.
 *
 * The compaction pass chose what to keep by position — the floor, the
 * last few turns, the last few tool results — and a fact stated in the
 * middle of a long turn aged out at the same rate as chatter. This gives
 * every message a number instead, from four things the kernel can
 * observe without a model:
 *
 *   recency     how many messages ago, decayed with a half-life;
 *   relevance   BM25 against the goal — the task, the requirements, the
 *               open plan items, the latest intent;
 *   utility     whether it was USED: a tool result whose paths and
 *               identifiers reappear in a later tool input or assistant
 *               turn; an instruction from the user;
 *   redundancy  whether a later message says the same thing — a repeated
 *               read, the same error twice — so the older copy yields.
 *
 * What no score may cross is stated as `protected`: the leading system
 * run, `retain` markers with the turn they pull in, the most recent
 * turns, and the other half of a tool-call pair. Pure, like `plan.ts`:
 * no turn, no logger, no provider, so it can be asked without one.
 */
import type { Message } from '../../types/message/index.js';
export interface SalienceWeights {
    readonly recency: number;
    readonly relevance: number;
    readonly utility: number;
    readonly redundancy: number;
}
export declare const DEFAULT_SALIENCE_WEIGHTS: SalienceWeights;
export interface SalienceConfig {
    /** Messages after which recency has halved. */
    readonly halfLifeMessages: number;
    /** Estimated Jaccard at or above which two messages are the same thing. */
    readonly duplicateThreshold: number;
    readonly weights: SalienceWeights;
}
export declare const DEFAULT_SALIENCE_CONFIG: SalienceConfig;
export type ProtectedReason = 'system-floor' | 'retain' | 'recent' | 'pair';
export interface ScoredMessage {
    readonly index: number;
    readonly role: Message['role'];
    /** Estimated tokens of the message, including rich content and tool inputs. */
    readonly tokens: number;
    readonly recency: number;
    readonly relevance: number;
    readonly utility: number;
    readonly redundancy: number;
    /** The weighted sum; meaningful only relative to the other messages of the same pass. */
    readonly salience: number;
    readonly protected: ProtectedReason | null;
}
export interface ScoreOptions {
    /** The goal vector as text: task statement, requirements, open plan items, latest intent. */
    readonly goal: string;
    /** How many trailing messages are protected as recent. */
    readonly keepRecentMessages: number;
    readonly config?: Partial<SalienceConfig>;
}
/** The model-visible text of a message, with an assistant's tool inputs. */
export declare function messageText(message: Message): string;
export declare function scoreMessages(messages: readonly Message[], options: ScoreOptions): ScoredMessage[];
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