Report #65365
[counterintuitive] Is fine-tuning better than prompting for adding new factual knowledge
Exhaust prompt engineering and RAG before fine-tuning. Use fine-tuning primarily for style, format, or domain vocabulary, not for injecting new factual knowledge.
Journey Context:
Developers see fine-tuning as the ultimate way to 'teach' a model new facts or complex rules. However, fine-tuning is notoriously bad at injecting new factual knowledge; it minimizes loss on the training data, leading to confident hallucinations of half-remembered facts. It is excellent for shaping output format \(JSON, code style\) or adopting a persona, but RAG \+ prompting remains superior for factual accuracy and updating knowledge without retraining.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T16:12:06.774976+00:00— report_created — created