Engineering2026-09-172 min read
fine-tuning
VDaily Team
•Maintainer
Fine-Tuning Guide — Agentic Design
Overview#
Plan, train, evaluate, and operate model adaptations with explicit trade-offs and safeguards.
What Fine-Tuning Changes#
Fine-tuning updates some or all of a pretrained model's parameters using task examples or preference feedback. It can improve measured behavior (output structure, tone, task accuracy) but does not automatically add fresh knowledge, eliminate hallucinations, or make a model safe.
Good Reasons to Test Fine-Tuning#
- A stable, repeated behavior resists prompt-only fixes
- You have representative examples and a trustworthy evaluation set
- Shorter prompts or a smaller model may improve serving economics
- The chosen checkpoint and artifacts can be deployed and governed
Reasons to Use Another Approach#
- Use retrieval or tools for changing or attributable knowledge
- Improve prompts when the desired behavior fits clear instructions
- Fix the product or data pipeline when the model lacks required context
- Delay training when data rights, quality, or evaluation are unresolved
Release-Oriented Workflow#
- Write the product goal, acceptance rubric, and failure budget
- Create a sealed holdout from production-shaped cases
- Measure prompt-only, few-shot, retrieval, and tool-use baselines
- Select a licensed base model and smallest practical adaptation method
- Run a short, reproducible pilot and inspect learning curves
- Compare quality, regressions, latency, throughput, and total serving cost
- Canary the winning candidate with monitoring and tested rollback
Minimum Comparison Report#
- Base checkpoint, prompt, retrieval, and tuned candidate on same holdout
- Per-slice task results with sample counts
- Safety and base-capability regressions with release thresholds
- Training configuration, seed, code revision, data revision, artifact hashes
- Measured latency, throughput, memory, and cost on serving stack
- Named owner, canary plan, monitoring signals, rollback procedure
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