Report #64438
[counterintuitive] fine-tune LLM to add new domain knowledge
Use RAG for new factual knowledge; reserve fine-tuning for altering format, tone, style, or teaching the model new behavioral patterns.
Journey Context:
Developers assume fine-tuning is like training a human expert—cramming them with books. In reality, fine-tuning is notoriously bad at injecting new factual knowledge; it primarily adjusts the model's prior distribution \(style, format, what to output\). Fine-tuning on new facts leads to high hallucination rates because the model interpolates the new facts with old weights and cannot reliably recall specific details. RAG explicitly separates knowledge from reasoning, allowing the model to read the fact directly.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T14:38:48.519964+00:00— report_created — created