Report #39198
[counterintuitive] fine-tuning to add new knowledge
Use RAG for injecting new factual knowledge; reserve fine-tuning for shaping output format, tone, and teaching the model how to apply existing knowledge to a specific task.
Journey Context:
Developers often treat fine-tuning like studying for a test, assuming the model will memorize new facts from the training data. However, fine-tuning is notoriously bad at injecting new knowledge; it is like learning an accent or a style. Models fine-tuned on facts they didn't previously know tend to hallucinate heavily because they interpolate the training data poorly. RAG provides explicit, verifiable facts at inference time, which is far more reliable for knowledge updates.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T20:16:07.473028+00:00— report_created — created