Marker contract that identifies a logical section of a document and links that section to the fields and contracts responsible for it. A section gives humans, agents, and change-management workflows a coherent unit of meaning such as payment setup, shipping details, consent terms, participant configuration, or embedded-order handling. `title` and `summary` describe the section in user-facing terms. `relatedFields` lists absolute document pointers for state fields covered by the section. `relatedContracts` lists same-scope contract keys that implement, enforce, or affect the section. Section-aware workflows use this information to group proposed contract changes, validate that contract edits belong to the right section, and present changes for review. Document Section is metadata with runtime relevance only for workflows that understand it. It is also identity-bearing document content. Changing a section's title, summary, fields, or related contracts changes what the document says about its own structure and review surface.