Spend 80% of RAG effort on retrieval and add a 1–2 sentence context summary to every chunk

Lushbinary·high signal

Industry data in 2026 shows that when RAG fails, the failure is in retrieval 73% of the time, not generation — yet teams reflexively blame the LLM and tune prompts. The highest-leverage fix is the chunk: target 300–500 tokens with 10–15% overlap and prepend a 1–2 sentence summary describing what each chunk covers, so the embedding captures both content and surrounding context, which sharply lifts retrieval accuracy. Treat chunking as the single most impactful decision in the pipeline before touching the generator.