In LlamaIndex, what are nodes and query engines, and how is RAG exposed as a tool to an agent?

The short answer

In LlamaIndex a Node is a chunk of a source document with metadata and relationships, indexed for retrieval; a query engine wraps an index to take a natural-language query, retrieve relevant nodes, and synthesize an answer. RAG-as-a-tool wraps a query engine in a QueryEngineTool so an agent can call it like any other tool, deciding when to retrieve from that knowledge source as part of its reasoning loop.

How to think about it

In LlamaIndex a Node is a chunk of a source document with metadata and relationships, indexed for retrieval; a query engine wraps an index to take a natural-language query, retrieve relevant nodes, and synthesize an answer. RAG-as-a-tool wraps a query engine in a QueryEngineTool so an agent can call it like any other tool, deciding when to retrieve from that knowledge source as part of its reasoning loop.

Learn it properly Indexes, query engines & retrievers

Keep practising

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