If you inherited an OpenSearch deployment and you're now being asked to run agents on it, Q1 2026 has been unusually good news. OpenSearch 3.5 (February) and 3.6 (April) aren't incremental search improvements — they're a clear declaration of intent. "OpenSearch isn't trying to be a better Elasticsearch; it is focused on being the data layer on which AI applications are built." That's from the article's author, an engineer who's been migrating teams from log analytics to semantic retrieval. It also captures the entire roadmap. What actually changed Better Binary Quantization (BBQ) landed in 3.6. Integrated from the Lucene project, BBQ compresses high-dimensional float vectors into compact binary representations — 32x memory reduction. On the Cohere-768-1M benchmark, BBQ recall at 100 results hits 0.63 vs. 0.30 for Faiss Binary Quantization. With oversampling and rescoring, it exceeds 0.95 on large production datasets. The project is working to make this the default.…