{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Source Excerpt",
  "description": "来源证据片段 schema。",
  "type": "object",
  "required": [
    "excerpt_id",
    "source_id",
    "related_model_id",
    "excerpt_type",
    "summary",
    "used_for",
    "quote_status",
    "source_location"
  ],
  "properties": {
    "excerpt_id": {"type": "string", "description": "证据片段 ID。"},
    "source_id": {"type": "string", "description": "所属来源文章 ID。"},
    "related_model_id": {"type": "string", "description": "关联模型 ID。"},
    "excerpt_type": {
      "type": "string",
      "description": "证据类型。",
      "enum": ["definition", "taxonomy", "mechanism", "application_rule", "value_claim", "boundary_rule", "validation_rule"]
    },
    "summary": {"type": "string", "description": "证据片段摘要。"},
    "used_for": {"type": "array", "description": "该证据支撑的模型字段或用途。", "items": {"type": "string"}},
    "quote_status": {
      "type": "string",
      "description": "raw_excerpt 的摘录状态。exact 表示准确摘录；condensed 表示压缩摘录；paraphrased 表示转述。",
      "enum": ["exact", "condensed", "paraphrased"]
    },
    "raw_excerpt": {"type": "string", "description": "原文摘录、压缩摘录、转述或明确标注的 placeholder。"},
    "source_location": {"type": "string", "description": "章节、段落、标题或行号；未知则写 unknown。"},
    "confidence": {"type": "string", "description": "证据可信度。", "enum": ["high", "medium", "low"]},
    "notes": {"type": "string", "description": "补充说明。"}
  }
}