Report #70074
[counterintuitive] fine-tuning beats prompting for adding new knowledge
Use RAG for adding new factual knowledge; reserve fine-tuning for altering tone, format, or behavioral style.
Journey Context:
Developers often try to update a model's internal knowledge base by fine-tuning it on new documents. This fails because LLMs are poor at memorizing new facts from sparse gradient updates without severe overfitting or confabulation. The model learns the surface patterns of the text but fails to reliably recall the underlying facts. Fine-tuning is excellent for teaching the model \*how\* to behave \(e.g., outputting specific JSON schemas, adopting a persona\), but RAG is the only reliable method for teaching it \*what\* to know.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T00:12:06.486346+00:00— report_created — created