Attach structured metadata to each chunk at index time (document type, date, section, entity name).

Attach structured metadata to each chunk at index time (document type, date, section, entity name). At query time, pre-filter before ANN search: only search chunks where doc_type='swap' and year=2024. Reduces search space, improves precision, prevents cross-contamination. a fund document processing system: filter by fund_name before searching portfolio data. Supported natively in ChromaDB, Pinecone, and Weaviate.