{
  "schema_version": "1.0",
  "request": "生成中心距120mm、大头孔36mm、小头孔20mm、厚14mm的发动机连杆，导出STEP和STL，后续可以修改参数",
  "selected_backend": "build123d",
  "runner_skill": "cad",
  "confidence": "high",
  "backend_scores": [
    {
      "backend": "build123d",
      "score": 135,
      "reasons": [
        "+35 general STEP-first default",
        "+35 general mechanical part with direct parametric features",
        "+25 machining favors STEP-first B-Rep",
        "+35 editable STEP requested",
        "+5 secondary mesh export is available"
      ]
    },
    {
      "backend": "simplecadapi",
      "score": 78,
      "reasons": [
        "+20 specialist mechanical baseline",
        "+10 general OCP modeling is available",
        "+18 OCP STEP geometry suits machining",
        "+30 OCP STEP export requested"
      ]
    },
    {
      "backend": "cadam",
      "score": -73,
      "reasons": [
        "+10 printable CSG baseline",
        "-25 mesh/CSG route is not preferred for machining",
        "-70 no native editable STEP output",
        "+12 print mesh requested"
      ]
    }
  ],
  "fallback_order": [
    "simplecadapi",
    "cadam"
  ],
  "workflow_profiles": [],
  "downstream_skills": [
    "cad-viewer"
  ],
  "requested_outputs": [
    "step",
    "stl"
  ],
  "source_of_truth": "build123d Python generator",
  "availability": null
}