OpenSearch is now a supported vector database in Agno through agno.vectordb.opensearch. It handles vector, keyword, and hybrid search, in both sync and async variants, so you can back a knowledge base with OpenSearch whether you want semantic retrieval, plain lexical matching, or the two combined.
If OpenSearch already sits in your stack for search or log analytics, this lets you point an agent's knowledge at it instead of standing up a separate vector store to run alongside it. Install it with the agno[opensearch] extra, and the included run_opensearch.sh gets a local instance going for testing.
See the OpenSearch db cookbook for reference.