The inclusion tag is the access control that matters day to day: an agent sees only the knowledge bases tagged for it, which is how an account with a dozen of them exposes three. Reranking is the quality lever and the expensive one to enable — two IAM actions on two different roles, and only in the regions where Bedrock offers it.
A retrieval server for Amazon Bedrock Knowledge Bases. It discovers the knowledge bases your credentials can see, along with their data sources, and queries them in natural language.
- Every eligible knowledge base with its name, description and data sources — ListKnowledgeBases
- Natural-language queries answered with the relevant passages and citation information for each — QueryKnowledgeBases
- Queries narrowed to particular data sources inside a knowledge base, so one corpus can be isolated from the rest
- The number of results controlled per call
- Bedrock reranking applied to reorder results by relevance, with the reranking model named per call
AWS CLI credentials under a profile that can reach Amazon Bedrock and Knowledge Bases, with IAM permission to list and describe knowledge bases, reach their data sources and query them. A knowledge base only becomes visible if it carries the tag key mcp-multirag-kb set to true — KB_INCLUSION_TAG_KEY changes which key is looked for. Reranking is off unless BEDROCK_KB_RERANKING_ENABLED says otherwise, needs bedrock:Rerank and bedrock:InvokeModel on both your role and the Knowledge Bases service role, and only exists in some regions. Install uv, then run awslabs.bedrock-kb-retrieval-mcp-server through uvx.
One command plus a key — uvx awslabs.bedrock-kb-retrieval-mcp-server, then supply credentials