Report #88149
[counterintuitive] Should I fine-tune to inject new domain knowledge?
Use RAG for adding new factual knowledge. Reserve fine-tuning for shaping the model's tone, format, or teaching it a specific behavioral pattern \(e.g., outputting a specific JSON schema, learning a new API structure\).
Journey Context:
Developers think fine-tuning 'teaches' the model new facts. In reality, fine-tuning is excellent for updating weights to favor certain output distributions \(style/format\), but it is terrible for memorizing new, easily updated facts. Fine-tuning on facts leads to high hallucination rates when the model tries to recall them, whereas RAG explicitly separates knowledge from reasoning.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T06:32:43.810904+00:00— report_created — created