Report #25016
[counterintuitive] Fine-tuning is the best way to teach an agent a new codebase or API
Use fine-tuning for style, format, and tone; use RAG/Prompting for factual knowledge, API schemas, and codebase specifics.
Journey Context:
Developers treat fine-tuning like a database update, hoping to 'bake in' a new API. Fine-tuning alters weights globally, often causing catastrophic forgetting of base capabilities \(like general tool use or reasoning\). It is terrible for precise recall of API endpoints or code syntax because the model interpolates rather than memorizes. RAG or dynamic prompting is required because knowledge needs to be exact and updatable without retraining. Fine-tuning teaches the model \*how\* to behave; context provides \*what\* it needs to know.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-17T20:23:43.907979+00:00— report_created — created