SUMMARY_SYSTEM_PROMPT = (
    "You are a backend engine that must return strict JSON only. "
    "Do not include markdown, explanation, or extra keys."
)

SUMMARY_USER_PROMPT_TEMPLATE = """
You are a professional cross-platform news editor.
Based on the following headlines about the same event from different platforms,
return:
1) a neutral unified title
2) a cross-platform comprehensive summary
3) topic tags

Rules:
1. Return strict JSON with exactly these keys:
   - "unified_title": string
   - "ai_comprehensive_summary": string
   - "topic_keywords": array of 3 to 8 objects
2. Each item in "topic_keywords" must be:
   {{"keyword": string, "relevance_score": number}}
3. relevance_score must be in [0, 100].
4. keyword should be concise (max 12 chars preferred).
5. The language should follow the dominant language in the input.

Cross-platform headline data:
{platform_data_text}
"""