Report #44215
[counterintuitive] Should I fine-tune an LLM to teach it new facts
Use fine-tuning for formatting, style, and robust instruction following. Use RAG/Context for adding new factual knowledge.
Journey Context:
Many developers assume fine-tuning is the ultimate way to teach a model new domain knowledge. Fine-tuning adjusts weights to shift the probability distribution of tokens—it is excellent for getting the model to consistently output JSON or adopt a persona, but terrible for memorizing new facts accurately. It often leads to hallucination of facts that were only partially represented in the training data. RAG is explicit, auditable, and updateable, making it far superior for knowledge injection.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T04:41:07.795657+00:00— report_created — created