open_slot 的第二次迭代

backend/engine/cdsl_engine/capabilities.py

@@ -18,6 +18,9 @@ from .operation_contracts import materialized_feature_contracts
 
 _SELECTOR_REQUIRED = frozenset({"fillet", "chamfer"})
 _SKETCH_ATOM_PREFIXES = ("extrude_", "revolve_")
+# 开放轮廓（closed=false / role=open）只有"刀具截面补槽口边闭合后作切除"的
+# 物理意义：仅 extrude 直切类原子支持；add/回转对开放轮廓会造出无意义的封块。
+_OPEN_PROFILE_ATOMICS = frozenset({"extrude_cut_blind", "extrude_cut_through"})
 _PRIMARY_ATOMICS = frozenset({
     "extrude_add_blind", "extrude_add_two_sided", "extrude_cut_blind",
     "extrude_cut_through",
@@ -281,6 +284,17 @@ class CapabilityAnalyzer:
                                 "The resolved sketch contains no closed profile region",
                                 sketch_id=node.sketch_id,
                             ))
+                        elif (
+                            not resolution_error
+                            and sketches[node.sketch_id].get("_open_contour")
+                            and node.atomic_id not in _OPEN_PROFILE_ATOMICS
+                        ):
+                            blockers.append(self._blocker(
+                                node.feature_id, "unsupported_open_profile",
+                                "Open profiles are only supported for straight extruded cut features",
+                                sketch_id=node.sketch_id,
+                                atomic_id=node.atomic_id,
+                            ))
             if node.atomic_id.startswith(_SKETCH_ATOM_PREFIXES):
                 # #2 draft：extrudeParams.draft 在 cdsl_schema.json 中被允许，
                 # 但 runtime 的拉伸执行器（build123d Solid.extrude）没有锥形