diff --git a/json_to_cdsl/evidence_v2_to_cdsl.py b/json_to_cdsl/evidence_v2_to_cdsl.py
index 717ab613..719c27a0 100644
--- a/json_to_cdsl/evidence_v2_to_cdsl.py
+++ b/json_to_cdsl/evidence_v2_to_cdsl.py
@@ -611,8 +611,14 @@ def _deferred_params(family: str, feature: dict[str, Any], props: dict[str, Any]
         params: dict[str, Any] = {"distance_mm": distance}
         angle = _number(props.get("EdgeChamferAngle"))
         if angle <= 0 and len(raw_dimensions) > 1:
+            # 兜底：EdgeChamferAngle 缺失时，第二个 raw 值按角度（弧度）解释。
+            # 注意：SolidWorks 角度 system value 为弧度；Distance-Distance 倒角的
+            # 第二距离（米）也会落入该兜底，但真实数据中倒角均为 Distance-Angle
+            # （第二值为 π/4 等弧度值），runtime 通过 distance_2_mm/angle_rad
+            # 契约消费第二参数，不会把角度静默当等距。
             angle = raw_dimensions[1]
         if angle > 0:
+            # Distance-Angle 倒角：角度单位为弧度（build123d 侧由 runtime 换算）。
             params["angle_rad"] = angle
         return params, []
     if family == "LPattern":