{
  "schema_version": "1.0",
  "request": "Modify the existing build123d connecting rod from the CAD Viewer selection: add a 2 mm wide blind slot along the selected segment on face f18, regenerate STEP, STL, and CAD Viewer mesh/topology assets.",
  "route": {
    "selected_backend": "build123d",
    "runner_skill": "cad",
    "project": "text-to-cad",
    "confidence": "high",
    "fallback_order": [
      "simplecadapi",
      "cadam"
    ],
    "operation": "modify",
    "modification_strategy": "native_parameter_editing",
    "decision_path": "route-decision.json"
  },
  "source": {
    "path": "connecting_rod.py",
    "format": "python",
    "backend": "build123d"
  },
  "artifacts": [
    {
      "path": "connecting_rod.step",
      "role": "primary"
    },
    {
      "path": "connecting_rod.stl",
      "role": "secondary"
    },
    {
      "path": ".connecting_rod.step.glb",
      "role": "viewer_mesh_topology"
    },
    {
      "path": "connecting_rod_slot_review_20260723T100007Z.png",
      "role": "verification_snapshot"
    }
  ],
  "parameters": {
    "center_distance_mm": 120.0,
    "thickness_mm": 14.0,
    "big_end_outer_diameter_mm": 56.0,
    "big_end_bore_diameter_mm": 36.0,
    "small_end_outer_diameter_mm": 36.0,
    "small_end_bore_diameter_mm": 20.0,
    "web_width_mm": 24.0,
    "pocket_depth_each_side_mm": 3.0,
    "viewer_slot_start_mm": [
      -28.73179347578467,
      -0.3844822039559189
    ],
    "viewer_slot_end_mm": [
      24.36043904920138,
      -0.24367243243227724
    ],
    "viewer_slot_surface_z_mm": 11.0,
    "viewer_slot_width_mm": 2.0,
    "viewer_slot_blind_depth_mm": 2.0,
    "viewer_slot_bottom_z_mm": 9.0
  },
  "experience": {
    "library": "../../../cad-experience-library/library.json",
    "context_kind": "generalized_cad_experience_query",
    "methods_applied": []
  },
  "assumptions": [
    "The selected face f18 is the existing top-pocket floor at z=11 mm, so the blind slot cuts inward into the material from z=11 mm down to z=9 mm.",
    "The CAD edit intent marks depth as blind but does not provide a numeric depth, so a conservative 2 mm blind depth was used.",
    "This V1 sample demonstrates routing and editability rather than a production-rated engine component.",
    "Material, fatigue loads, bearing fits, lubrication, fasteners, tolerances, and split big-end construction are intentionally out of scope."
  ],
  "validation": [
    {
      "check": "STEP generation from editable source",
      "result": "scripts/cad step regenerated connecting_rod.step, connecting_rod.stl, and hidden CAD Viewer GLB/topology assets from connecting_rod.py.",
      "status": "pass"
    },
    {
      "check": "closed solid topology",
      "result": {
        "kind": "part",
        "shape_count": 1,
        "face_count": 23,
        "edge_count": 54,
        "bounds_mm": [
          165.978199,
          55.977382,
          14.0
        ]
      },
      "status": "pass"
    },
    {
      "check": "selected-face slot placement",
      "result": "Original selected face f18 remains the top-pocket floor at z=11 mm; new slot bottom face f23 is centered at [-2.185677, -0.314077, 9.0].",
      "status": "pass"
    },
    {
      "check": "blind slot depth",
      "result": "Slot side faces span z=9.0 mm to z=11.0 mm.",
      "status": "pass"
    },
    {
      "check": "slot width",
      "result": "Slot end faces are cylinders with radius 1.0 mm, matching the requested 2.0 mm slot width.",
      "status": "pass"
    },
    {
      "check": "snapshot review",
      "result": "Isometric snapshot shows the connecting rod, existing top pocket, and the new narrow blind slot without visible breakage or disconnected geometry.",
      "status": "pass"
    }
  ],
  "viewer_links": [
    "http://127.0.0.1:5175/?dir=%2FUsers%2Flk%2FProjects%2FcadSet%2Ftext-to-cad%2Fmodels%2Fcad-router-v1&file=connecting_rod.step"
  ]
}