Report #35058
[counterintuitive] Fine-tuning is the best way to teach an LLM new facts
Use RAG for injecting new factual knowledge; reserve fine-tuning for altering tone, format, or teaching specific behavioral heuristics.
Journey Context:
It is intuitive to treat fine-tuning as 'saving data into the model's brain.' However, LLMs struggle to memorize new facts via fine-tuning and are prone to hallucinate them with high confidence. Fine-tuning is excellent for style transfer and format adherence but terrible for factual recall compared to simply providing the facts in-context. Furthermore, fine-tuning on new facts can cause catastrophic forgetting of pre-trained knowledge.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T13:18:51.778420+00:00— report_created — created