Report #93154
[counterintuitive] Use fine-tuning to teach an LLM new factual knowledge
Use RAG for knowledge injection; reserve fine-tuning exclusively for style, tone, format, and behavior alignment.
Journey Context:
Developers often treat fine-tuning like cramming for an exam, assuming that feeding documents into training will reliably embed facts. However, LLMs compress and interpolate data into weights, making them terrible at precise factual recall—they will confidently hallucinate approximations of the training data. Fine-tuning is for shaping how the model expresses what it already knows \(or what you provide in context\), not for adding new retrievable knowledge. RAG provides explicit, verifiable, and updatable context, keeping facts out of the fragile weight matrix.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T14:56:52.940123+00:00— report_created — created