Report #70303
[counterintuitive] Should I fine-tune an LLM to teach it new facts
Use RAG for injecting new factual knowledge; reserve fine-tuning for shaping output format, tone, and behavioral patterns \(e.g., learning a new API syntax or response style\).
Journey Context:
Developers treat fine-tuning like a database update, feeding it documents to memorize. LLMs are bad at rote memorization via fine-tuning; they generalize and interpolate, causing them to hallucinate facts that sound plausible but are wrong. Fine-tuning updates the model's weights distribution, which is great for style and behavior but terrible for precise fact retrieval. RAG decouples knowledge from the weights, providing exact, verifiable text.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T00:35:09.430508+00:00— report_created — created