A system prompt defines the agent's role, behavior, and output requirements. For structured JSON output, you must be extremely explicit — some models will still add prose or markdown fences around JSON unless explicitly forbidden. The best system prompts give a concrete example of valid output.
Your Challenge
Write a complete system prompt for an agent that classifies customer complaints. The agent receives a customer message and must respond with ONLY valid JSON in this exact format:
{"category": "BILLING|TECHNICAL|SHIPPING|OTHER", "confidence": "HIGH|MEDIUM|LOW", "summary": "one sentence summary of the complaint"}
Your system prompt must make the output format completely unambiguous.