/**
 * Multi-document YAML stream assembly for the knowledge sources.
 *
 * Every writer here builds a stream from two kinds of part, and they disagree
 * about the document marker:
 *
 * - `stringify(obj)` emits the body only, never a leading `---`.
 * - `Document.toString()` on a doc parsed out of a stream emits its own
 *   `---` for every document that had one — i.e. all but the first.
 *
 * Joining both with `'---\n'` doubled the marker on every preserved document,
 * which inserts an empty document between each pair of real ones. Valid YAML,
 * a different document stream, and a whole-file diff for a command that
 * changed nothing (bugfix knowledge-rebuild-readonly/AC-2).
 *
 * `joinDocuments` normalizes by *adding* a marker only where one is missing,
 * never by re-serializing: a part that already carries its own marker is
 * emitted verbatim, so hand-written comments and scalar quoting survive the
 * round trip. For callers that feed it only `stringify` output the result is
 * byte-identical to the old join (AC-3).
 *
 * Requirements: knowledge-rebuild-readonly/AC-2, AC-3
 *
 * @module
 */
/**
 * True when `text` opens a YAML document explicitly — a `---` line reached
 * before any content, looking past blank lines, comments and directives.
 */
export declare function startsWithDocumentMarker(text: string): boolean;
/**
 * Concatenate serialized YAML documents into one stream with exactly one
 * `---` between consecutive documents.
 *
 * The first emitted part keeps whatever it had — the knowledge sources open
 * with a bare `_meta:` mapping and no marker, and a file that does open with
 * one is left alone rather than reformatted. Empty parts are dropped.
 *
 * @param parts - Serialized documents, in output order.
 */
export declare function joinDocuments(parts: string[]): string;
//# sourceMappingURL=yaml-documents.d.ts.map