Where blob-of-text falls apart
Pasting five documents into the user message with no separators is a recipe for the model conflating them, picking the wrong one, or summarizing the union. Multi-document prompts need explicit boundaries, names, and ordering decisions.
Boundary tags
Use XML-like tags or fenced sections with stable ids. Each document gets a name the model can reference and the user can verify.
Ordering decisions
- By relevance — most-relevant first. Default for RAG.
- By recency — useful for support tickets, news.
- By authority — official docs first, community second. Useful for reference questions.
- By source — group multi-source results. Useful when you need to compare.
The instruction to read the boundaries
The synthesis prompt should explicitly tell the model how to use the structure. "Each document is wrapped in <doc id=…>. Cite by id. Treat each document as independent — do not merge claims across documents unless they corroborate."