The system prompt is the most powerful tool for customizing how the model behaves — it sets the context, persona, constraints, and output format.
What to Put in System Prompts
- Role and persona: "You are a senior software engineer at a fintech company"
- Behavior rules: "Always ask clarifying questions before answering"
- Output format: "Respond only in JSON with keys: summary, sentiment, score"
- Constraints: "Never discuss competitor products"
- Knowledge context: Paste in relevant company or product information
Key Principle
More specific system prompts = more consistent, predictable outputs. Vague system prompts = variable results.
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