Report #94349
[counterintuitive] Should I fine-tune to teach the model new facts or custom behaviors
Use fine-tuning primarily to adjust format, tone, and latency/cost \(by allowing shorter prompts\), not to inject new factual knowledge. For new facts, use RAG.
Journey Context:
Developers treat fine-tuning like training a human employee: 'give it a textbook and it learns the facts.' LLM fine-tuning \(especially PEFT/LoRA\) adjusts weights to shape the probability distribution of styles and formats, but it is notoriously bad at memorizing new, specific facts compared to just putting them in the context window. Fine-tuning on facts leads to high rates of hallucination and outdated knowledge that cannot be easily updated.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T16:57:00.198424+00:00— report_created — created