Entity explicitness

A chunk that relies on earlier text for its subject retrieves worse. Anthropic's Contextual Retrieval write-up gives the example of a chunk saying the company's revenue grew by 3% over the previous quarter without naming the company or period, and reports that prepending a short chunk-specific context before embedding cut top-20 retrieval failures by 35% (5.7% to 3.7%), and by 49% when also applied to BM25. That naming the product in each section has the same effect is an inference from this result, not a separate measurement.