Report #49847
[counterintuitive] Should I fine-tune an LLM to teach it new facts
Use RAG for injecting new factual knowledge; reserve fine-tuning exclusively for modifying model behavior, output format, or stylistic tone.
Journey Context:
A widespread belief is that fine-tuning is the ultimate way to update a model's knowledge base. Fine-tuning adjusts weights, which is great for learning patterns \(like outputting JSON or adopting a persona\), but it is terrible for memorizing new facts. Models fine-tuned on new facts tend to hallucinate by interpolating between old and new knowledge, and they lack the ability to cite sources. RAG provides explicit, auditable knowledge injection.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T14:09:17.738583+00:00— report_created — created