import type { DatabaseHandle } from './db.js';
/**
 * Tiny key/value store used for index-wide metadata (embedder identity,
 * schema version, etc.). Separate from `sync` so schema migrations and
 * model-change detection don't collide with per-file mtime tracking.
 */
/**
 * Read a metadata value by key. Returns undefined if the key has never
 * been written.
 */
export declare function getMetadata(db: DatabaseHandle, key: string): string | undefined;
/**
 * Insert or replace a metadata value. `updated_at` is stamped with the
 * current wall-clock millisecond on every write.
 */
export declare function setMetadata(db: DatabaseHandle, key: string, value: string): void;
/**
 * Remove a metadata key. No-op if the key is absent.
 */
export declare function deleteMetadata(db: DatabaseHandle, key: string): void;