Vectors capture meaning
Embedding search is useful when the user and source use different wording for the same concept.
Keywords protect exact evidence
Lexical retrieval remains important for names, reference numbers, quoted language and domain-specific terms.
Metadata constrains the search space
Workspace, case, date and document-type filters often improve relevance before ranking begins.
Combine and rerank
A practical pipeline can merge lexical and semantic candidates and then rerank the smaller set using a stronger relevance model.