Common causes of structured output failures:
1. System prompt instruction is too vague — models need an explicit format example
2. The model doesn't support JSON/tool-call mode well
3. Provider JSON mode not configured (some providers need a specific API parameter)
4. Temperature too high — higher temperatures increase randomness, including format randomness
Note: The output_contract validates the output AFTER it's received, but it doesn't force the model to produce JSON.
Your Challenge
Your agent has a valid output_contract requiring JSON, but it keeps returning plain English sentences instead. The system prompt says 'Return your answer in JSON format'. List 3 specific, actionable steps you would take to fix this, most likely cause first. For each step, explain WHY it would fix the issue.