Report #74310
[counterintuitive] fine-tuning vs prompting for new knowledge
Use RAG for adding new factual knowledge; reserve fine-tuning for shaping output format, tone, style, and teaching the model \*how\* to use tools or follow specific structural patterns.
Journey Context:
Developers often try to fine-tune models to inject new domain knowledge, assuming weight updates encode facts better than context. Fine-tuning is terrible for knowledge injection because it leads to high hallucination rates \(the model learns to speak \*about\* the domain confidently but gets facts wrong, a phenomenon called 'hallucination amplification'\) and is expensive to update. Fine-tuning excels at altering the probability distribution of \*how\* the model responds \(style, format, syntax\), not \*what\* it knows.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T07:19:41.145994+00:00— report_created — created