AWS launches Managed Amazon Bedrock Knowledge Base with AgenticRetrieveStream API for multi-turn retrieval

AWS introduces a Managed Amazon Bedrock Knowledge Base that transforms retrieval into an agentic capability, replacing single embed-and-fetch calls with multi-turn planning and tool-driven retrieval. The AgenticRetrieveStream API enables a reasoning agent to decide whether to retrieve, which knowledge base to consult, and whether to iterate before composing a grounded, cited answer. This addresses limitations of ordinary RAG, such as answers spanning multiple corpora or requiring follow-up lookups after initial results. The service is now available as a first-class feature, eliminating the need to manually manage OpenSearch Serverless collections. AWS CDK users can now provision the knowledge base and AgenticRetrieveStream as stacks, though observability remains critical due to the non-deterministic paths agents take during retrieval.