Report #63145
[counterintuitive] Fine-tuning is the best way to teach an LLM new facts
Use RAG for injecting new factual knowledge; reserve fine-tuning for shaping output format, tone, and behavioral patterns.
Journey Context:
It is tempting to fine-tune a model on a corpus of documents to make it 'know' them. However, LLMs are not databases; fine-tuning teaches styles and patterns, not reliable factual recall. Models fine-tuned on new facts exhibit high hallucination rates because they cannot reliably distinguish between pre-trained weights and fine-tuning data, often confidently generating half-remembered fictions. RAG explicitly separates the reasoning engine from the knowledge store.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T12:28:15.815791+00:00— report_created — created