09 Rerank the results

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Goal

Ask can i return an ebook and get the chunk that actually answers it — the one saying ebooks cannot be returned — to the top.

An embedding model encodes the question and each chunk separately, so it can only compare them as two points. That's fast — chunk vectors are computed once, in advance — but it's coarse. Here it ranks a general chunk about returning books above the one that says ebooks can't be returned.

A cross-encoder reranker reads the question and a chunk together and scores how well one answers the other. It's far more accurate and far too slow to run over every chunk — so you retrieve a shortlist with vectors, then rerank just that.

Try it

Search, read the top result, then rerank and watch the order change.

Go to the terminal

Hint

Search, then rerank.

Show a solution

search "can i return an ebook"
rerank

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RAG

Starting RAG…