Report #39447
[counterintuitive] Should I fine-tune an LLM to teach it new facts
Use RAG for knowledge injection and fine-tuning strictly for style, format, or behavioral shaping \(e.g., making it output JSON consistently, or adopting a persona\).
Journey Context:
Developers think fine-tuning is like training a human employee—read a textbook and they know it. Fine-tuning on facts leads to brittle, easily confused models that hallucinate variations of the facts. Fine-tuning adjusts weights to alter probability distributions of behavior, not to store discrete, updatable facts. RAG keeps knowledge grounded and updatable.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T20:41:21.286483+00:00— report_created — created