Amazon S3 Vectors now runs a metadata pre‑filter step before the similarity lookup. This can return up to five times more of the vectors that meet a selective filter. A new $startsWith operator lets you filter on path‑like strings. Existing indexes can be switched to the mode with a single UpdateIndexMode call; new buckets use it by default. The change rolls out across all commercial AWS regions at no extra charge.
Why it matters
Developers building RAG or semantic‑search apps can get more relevant results without changing code or paying extra.
