Your RAG can't answer 'why' -- GraphRAG finds what vector search misses

Short summary

Standard RAG retrieves chunks in isolation and cannot answer cross-document reasoning questions. GraphRAG builds knowledge graphs via LLM entity extraction and clustering to handle 'why' questions. 2026 cost optimizations (LazyGraphRAG at 0.1% of original cost, LightRAG at $0.50) enable practical deployment via adaptive routing.

• •Vector search retrieves relevant chunks but cannot connect information across documents for reasoning
• •GraphRAG uses LLM-powered entity extraction and Leiden clustering to build knowledge graphs answering 'why' questions
• •Cost barrier removed: LazyGraphRAG and LightRAG reduce indexing costs 1000x; production teams now route questions by type

Generated with AI, which can make mistakes.