import type { VocabDocument } from "../protocol/index.ts";
/**
 * Merge an author `extension` over a `base` vocab (default {@link CORE_VOCAB}),
 * returning a fresh, re-validated {@link VocabDocument}.
 *
 * @throws VocabDocumentError if either input or the merged result is not a valid
 *   vocab artifact.
 */
export declare function mergeVocab(extension: VocabDocument, base?: VocabDocument): VocabDocument;