Report #86513
[counterintuitive] Fine-tuning will teach the model new domain facts and knowledge
Use RAG for injecting new factual knowledge. Reserve fine-tuning for shaping output format, tone, style, and behavioral patterns. If you need both, combine them: fine-tune for behavior, RAG for knowledge.
Journey Context:
Fine-tuning adjusts model weights to change the output distribution — it excels at making the model respond in a specific format, style, or pattern. But it is unreliable for injecting factual knowledge because: \(1\) the model may learn surface statistical patterns from training data rather than underlying facts; \(2\) fine-tuned 'knowledge' can be inconsistent — the model may correctly answer some facts from the training data but hallucinate others; \(3\) the model blends old pretraining knowledge with new fine-tuning data, producing confident but wrong outputs. OpenAI's own fine-tuning documentation explicitly recommends fine-tuning for behavior and RAG for knowledge. Developers who fine-tune to add domain knowledge often get models that confidently assert incorrect facts.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T03:48:16.337150+00:00— report_created — created