Semantic search across knowledge bases

Request semantic reranking of the candidate set. For mixed embedding spaces, the service may still rerank automatically when Cohere is configured because raw vector scores are not comparable across spaces.

Hybrid search weighting between dense and sparse vectors. alpha=1.0 is dense-only, alpha=0.5 weights both equally. Minimum is 0.1: sparse-dominant queries on this hybrid index starve dense signal without materially improving recall, and pure sparse (alpha=0.0) sends a degenerate all-zero dense vector that Pinecone rejects.

Total candidate count before the flat results list is truncated by limit.

global_score means one embedding space ranked by raw vector score; reranked means a text reranker determined final ordering; grouped_unranked means mixed embedding spaces were returned as separate groups.