Report #63942
[counterintuitive] fine-tune to add new knowledge to LLM
Use RAG for new knowledge; use fine-tuning for formatting, tone, and behavioral shaping \(steerability\).
Journey Context:
Developers often try to fine-tune a model on a corpus of facts to make it an 'expert'. Fine-tuning is bad at memorizing new facts \(it still hallucinates them\) and is expensive to update. Fine-tuning excels at adjusting the probability distribution of how the model responds \(e.g., outputting specific JSON schemas, adopting a persona, learning a new language/format\). For updating knowledge, RAG is cheaper, more reliable, and easier to update.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T13:48:48.544597+00:00— report_created — created