Amazon has enabled metadata pre‑filtering for S3 Vectors in the AWS GovCloud (US‑East) and (US‑West) regions. The feature checks metadata filters before doing a similarity search, which can return up to five times more matching vectors when the filter is selective. A new $startsWith operator lets you filter on prefixes such as paths or URLs. Existing indexes can be switched to pre‑filtering with the UpdateIndexMode API, and you can test it per query before committing.
Why it matters
Government customers can retrieve more relevant results for RAG and semantic‑search workloads without changing their code.
