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redis-vl-dotnet

Reranker Abstractions

RedisVL.Rerankers.Abstractions defines the provider-neutral reranking surface for search result post-processing.

Core interfaces and records

  • ITextReranker exposes RerankAsync(RerankRequest request, CancellationToken cancellationToken = default).

  • RerankRequest carries the user query, the ordered candidate list, and an optional topN cap.

  • RerankDocument carries the text sent to the provider plus optional id and metadata that come back with each result.

  • RerankResult returns the provider score, the original candidate index, and the matched RerankDocument.

Contract details

The abstraction keeps Redis-specific search logic separate from provider ranking logic:

  • Use Redis search APIs to collect an initial candidate window.

  • Convert those candidates into RerankDocument instances.

  • Submit the RerankRequest to the provider-backed implementation.

  • Use the returned Index field to map back to the original candidate ordering when needed.

RerankRequest rejects an empty query and rejects topN ⇐ 0. Provider implementations are expected to return an empty collection when the request contains no documents.

Current provider package

Examples and tests

  • /examples/CohereRerankerExample shows the canonical pattern of Redis search first, provider reranking second.

  • tests/RedisVL.Tests/Rerankers/TextRerankerExtensionsTests.cs and tests/RedisVL.Tests/Rerankers/CohereTextRerankerTests.cs capture the shape and validation expectations for the current abstraction.