// Section 1 — The Model · 2 MIN READ
Training★
Training is the multi-stage, compute-heavy process that writes the model's parameters. It is done once by the model provider before release and splits into:
- Pre-training: Unsupervised exposure to trillions of tokens to learn grammar, code, and world facts (producing a base model).
- Post-training (Instruction Tuning): Supervised Fine-Tuning (SFT) and Reinforcement Learning from Human Feedback (RLHF) to make the model helpful, conversational, and follow tools/prompts (producing an instruct model).
For app developers, training is out of reach for day-to-day modifications. If a model fails to use a custom library, the fix is prompting and context injection, not retraining.
Training vs. Prompting Trade-offs
+------------------+-----------------------------+-----------------------------+
| Dimension | Training (Fine-Tuning) | Prompting (Context) |
+------------------+-----------------------------+-----------------------------+
| Latency | Static (no overhead) | High (adds input tokens) |
| Cost | Expensive (GPU hours) | Recurrent (inference bills) |
| Speed to Update | Hours / Days | Instant (millisecond edit) |
| Accuracy | High style, low facts | High facts, variable style |
+------------------+-----------------------------+-----------------------------+
# AVOID
Do not use "train" when you mean write guidelines or configure context.
- Avoid: "We need to train the model to output JSON responses."
- Write: "We need to update our system prompt with few-shot examples and set the response format parameter to JSON object."
# USAGE
Developer A: "Our model keeps hallucinating our custom API parameters. Should we start a fine-tuning training run?"
Developer B: "No, training is bad at memorizing exact facts. Let's load the OpenAPI specifications directly into the context window at inference time."
// SEE_ALSO
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