OptionaldocDocument author (e.g. OOXML dc:creator, PDF /Author, front-matter / <meta author>).
OptionaldocCreation timestamp, ISO 8601.
OptionaldocLast-modified timestamp, ISO 8601.
OptionaldocDocument title (e.g. OOXML dc:title, PDF /Title, front-matter title, <title>).
OptionaldocSource document type: pdf | docx | pptx | xlsx | md | html | txt.
Document-level properties read from the source container during extraction. Every field is optional and best-effort: when a container does not expose a property (or parsing fails) the field is simply absent. Consumed by schema-driven metadata extraction as the deterministic source for matching knowledge-base
metadataFieldsbefore falling back to LLM extraction.