/**
 * One ranked recall list across the four BRAIN tables (T13948).
 *
 * FTS5 BM25 scores are per-index, so a decision's score and an observation's
 * score cannot be compared. The previous answer was a round-robin interleave:
 * every `memory find` came back D,P,L,O,D,P,L,O — a fixed per-type quota with
 * no notion of age or authorship, so a May LLM restatement held the same slot
 * as an October owner decision.
 *
 * Here each FTS hit scores `rankWeight × recencyWeight × sourceWeight`:
 *
 * - **rankWeight** `1 / (1 + rank)` keeps each table's BM25 order;
 * - **recencyWeight** decays from 1 to a floor of 0.5 with a
 *   {@link RECENCY_HALF_LIFE_DAYS}-day half-life, so old rows lose ties but are
 *   never buried outright;
 * - **sourceWeight** ranks provenance: owner > task outcome > agent >
 *   speculative ({@link SOURCE_WEIGHTS}).
 *
 * The result is the FTS source list for RRF fusion with the vector and graph
 * sources.
 *
 * Code placed in `packages/core/` per Package-Boundary Check — verified against AGENTS.md.
 *
 * @module memory/recall-ranking
 * @task T13948
 */
import type { BrainMemorySearchResult, RrfHit } from './brain-search.js';
/** Days for the recency bonus to halve. */
export declare const RECENCY_HALF_LIFE_DAYS = 60;
/** Weight per `source_confidence` value; unknown values rank as `agent`. */
export declare const SOURCE_WEIGHTS: Readonly<Record<string, number>>;
/**
 * Provenance and date fields a memory row may carry. FTS rows come from
 * `SELECT *`, so at runtime they carry the snake_case column names.
 */
export interface RankableRow {
    created_at?: string | null;
    extracted_at?: string | null;
    source_confidence?: string | null;
    decided_by?: string | null;
    createdAt?: string | null;
    extractedAt?: string | null;
    sourceConfidence?: string | null;
    decidedBy?: string | null;
}
/** An FTS hit with its cross-table score. */
export interface RankedFtsHit extends RrfHit {
    /** Row date (`created_at`, or `extracted_at` for patterns); empty when unknown. */
    date: string;
    /** `rankWeight × recencyWeight × sourceWeight`. */
    score: number;
}
/**
 * Recency multiplier in [0.5, 1].
 *
 * @param date - Stored SQLite or ISO date; unparseable or missing dates get the floor.
 * @param nowMs - Clock, injectable for tests.
 * @returns 1 for a row written now, halving its bonus every {@link RECENCY_HALF_LIFE_DAYS} days.
 * @example
 * ```ts
 * recencyWeight('2026-10-23 00:00:00', Date.parse('2026-10-23T00:00:00Z')); // 1
 * ```
 */
export declare function recencyWeight(date: string | null | undefined, nowMs: number): number;
/**
 * Provenance multiplier: an owner-decided decision counts as owner-sourced.
 *
 * @param row - Memory row with optional `source_confidence` / `decided_by`.
 * @returns A weight from {@link SOURCE_WEIGHTS}.
 * @example
 * ```ts
 * sourceWeight({ source_confidence: 'speculative' }); // 0.4
 * ```
 */
export declare function sourceWeight(row: RankableRow): number;
/**
 * Merge per-table FTS results into one list ranked by recency and source.
 *
 * @param fts - Per-table rows, each already BM25-ordered.
 * @param nowMs - Clock, injectable for tests.
 * @returns Every hit once, best first.
 * @example
 * ```ts
 * const ranked = rankFtsAcrossTables(await searchBrain(root, 'worktree'), Date.now());
 * ```
 */
export declare function rankFtsAcrossTables(fts: BrainMemorySearchResult, nowMs?: number): RankedFtsHit[];
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