{
  "schema": "mechanical_semantic_graph_v1",
  "model_identity": {
    "name": "string",
    "source_assembly_path": "string",
    "likely_equipment_type": "string",
    "confidence": 0,
    "evidence": [
      "component/edge/region/relation ids"
    ]
  },
  "nodes": [
    {
      "id": "node_id",
      "type": "part|feature|face_region|interface|process_role|functional_role|missing_or_uncertain",
      "semantic_type": "cast_housing|end_cover|machined_register|local_machined_face|surrounding_unmachined_surface|raised_boss|tool_gap|ejector_port|unknown",
      "name": "human readable Chinese name",
      "source_refs": [
        "component names, edge ids, region ids, patch ids, face ids"
      ],
      "confidence": 0,
      "evidence": "short explanation grounded in B-rep facts"
    }
  ],
  "edges": [
    {
      "id": "edge_id",
      "type": "contacts|fits_with|coaxial_with|contains|adjacent_to|outside_accessible|supports|locates|is_machined_candidate_of|is_cast_candidate_of|has_boundary_step|missing_required_relation",
      "from": "node_id",
      "to": "node_id",
      "source_refs": [
        "relation ids or edge/face refs"
      ],
      "confidence": 0,
      "evidence": "short explanation grounded in B-rep facts"
    }
  ],
  "measurements": [
    {
      "id": "measurement_id",
      "type": "radius|diameter|axial_span|radial_margin|gap_width|step_height|area_ratio|unknown_threshold",
      "value": "number or null",
      "units": "mm|model_units|unitless|unknown",
      "source_refs": [
        "dimension ids, cylinder faces, edges, patches"
      ],
      "confidence": 0
    }
  ],
  "local_subgraphs": [
    {
      "id": "subgraph_id",
      "pattern_type": "casting_boss_register_interface|machined_unmachined_surface_boundary|sleeve_removal_access|bearing_support|other",
      "primary_view": "assembly_contact_fit|disassembly_maintenance_access|drawing_annotation_requirement|feature_pattern|load_strength_stiffness|locating_limit_datum|motion_interference_dof|operation_safety_environment|part_local_shape|surface_role_boundary|system_function_condition|transmission_standard_parameters",
      "secondary_views": [
        "optional diagnostic view ids"
      ],
      "retrieval_sentence": "neutral Chinese fact sentence for knowledge retrieval; no rule id and no fault judgement words",
      "inferred_functions": [
        "assembly, locating, support, sealing, machining, maintenance, or motion functions inferred from evidence"
      ],
      "inferred_attributes": [
        {
          "name": "machined_surface_candidate|unmachined_surface_candidate|locating_face_candidate|contact_face_candidate|tool_access_limited|other",
          "value": true,
          "confidence": 0,
          "reason": "short evidence-grounded reason; no final fault judgement",
          "source_image_names": [
            "exact image names used for this inference"
          ],
          "source_brep_refs": [
            "face/feature/component refs used for this inference"
          ],
          "source_relation_refs": [
            "contact/mate/relation refs used for this inference"
          ]
        }
      ],
      "retrieval_fact_tags": [
        "stable model-side fact tags aligned with knowledge required_model_facts; no rule ids"
      ],
      "retrieval_relations": [
        "human-readable local relations used for retrieval"
      ],
      "image_evidence_names": [
        "exact image names or image plan ids that support this local subgraph"
      ],
      "image_observations": [
        {
          "image_name": "component_contexts/component_13/isometric",
          "observation": "what this image shows",
          "supports": [
            "role or inferred attribute name"
          ],
          "confidence": 0
        }
      ],
      "node_ids": [
        "node_id"
      ],
      "edge_ids": [
        "edge_id"
      ],
      "measurement_ids": [
        "measurement_id"
      ],
      "roles": [
        "semantic roles grounded by this subgraph"
      ],
      "retrieval_keywords": [
        "Chinese and English keywords for knowledge-base retrieval"
      ],
      "confidence": 0,
      "evidence": [
        "edge/region/patch/component/relation ids"
      ],
      "reason": "why this subgraph is suitable for matching a knowledge chunk"
    }
  ],
  "local_semantic_units": [
    {
      "local_id": "unit_id",
      "linked_subgraph_id": "subgraph_id",
      "pattern_type": "casting_boss_register_interface|machined_unmachined_surface_boundary|sleeve_removal_access|bearing_support|other",
      "primary_view": "same taxonomy id used by the knowledge index",
      "secondary_views": [
        "optional diagnostic view ids"
      ],
      "retrieval_sentence": "one neutral Chinese fact sentence. This is the primary retrieval unit.",
      "retrieval_chain": {
        "geometric_fact_for_retrieval": "human-readable geometric fact generalized for retrieval; no coordinates or raw ids",
        "mechanical_role": "mechanical role inferred from the geometry, such as internal machined surface, locating boss, contact pad, maintenance opening",
        "process_assembly_maintenance_semantics": "manufacturing, assembly, disassembly, maintenance, strength, locating, or motion semantics used for retrieval"
      },
      "retrieval_semantic_roles": [
        "retrieval-only semantic role labels; no raw B-rep ids"
      ],
      "inferred_functions": [
        "component or local feature functions inferred for retrieval"
      ],
      "inferred_attributes": [
        {
          "name": "machined_surface_candidate|unmachined_surface_candidate|locating_face_candidate|contact_face_candidate|tool_access_limited|other",
          "value": true,
          "confidence": 0,
          "reason": "short evidence-grounded reason; no final fault judgement",
          "source_image_names": [
            "exact image names used for this inference"
          ],
          "source_brep_refs": [
            "face/feature/component refs used for this inference"
          ],
          "source_relation_refs": [
            "contact/mate/relation refs used for this inference"
          ]
        }
      ],
      "retrieval_fact_tags": [
        "through_hole_candidate, entry_face_inclined, small_local_contact_face, surrounding_large_surface, etc."
      ],
      "retrieval_relations": [
        "hole enters inclined surface, local contact face is near-coplanar with surrounding surface, etc."
      ],
      "image_evidence_names": [
        "exact image names or image plan ids that support this local semantic unit"
      ],
      "image_observations": [
        {
          "image_name": "component_highlights/component_13/isometric",
          "observation": "what this image supports",
          "supports": [
            "retrieval role, function, or inferred attribute name"
          ],
          "confidence": 0
        }
      ],
      "normalized_measurements": [
        {
          "name": "axis_to_face_angle|step_height|diameter|clearance|area_ratio|other",
          "value": null,
          "unit": "mm|deg|unitless|unknown",
          "confidence": 0
        }
      ],
      "fact_bundle": {
        "geometry_description_for_judgement": "concrete geometry description used only after retrieval for verification",
        "components": [
          "component names or node ids"
        ],
        "roles": [
          "local semantic roles"
        ],
        "measurements": [
          "measurement ids and values if available"
        ],
        "evidence_refs": [
          "edge/region/patch/component/relation ids"
        ],
        "uncertainties": [
          "missing facts that affect final judgement"
        ]
      },
      "dedup_key": "stable key for this local unit"
    }
  ],
  "semantic_coverage_audit": {
    "purpose": "machine-checkable audit proving local semantic units were split by coverage, not collapsed into a few generic descriptions",
    "candidate_anchor_types": [
      "part",
      "feature",
      "interface",
      "functional_group"
    ],
    "minimum_rules": [
      "Create at least one part-level local unit for every nonstandard component instance whose review_scope is part_design_required.",
      "Create feature-level local units for supported holes, hole groups, slots, bosses, ribs, steps, shafts, sleeves, pads, machining candidates, locating/contact faces, and tool-access candidates.",
      "Create interface-level local units for supported contacts, fits, coaxial relations, mate relations, support/locating relations, motion pairs, and clearance/accessibility relations.",
      "Create functional-group local units for each geometry-derived internal component group or connected mechanism group when evidence supports group-level judgement.",
      "Do not merge separate physical locations just because they share the same feature type; do merge repeated equivalent features into one group when they share owner, role, dimensions, and relation signature."
    ],
    "covered_part_component_ids": [
      "component ids with at least one local semantic unit"
    ],
    "covered_feature_anchor_ids": [
      "feature ids or face-group ids covered by feature-level units"
    ],
    "covered_interface_relation_ids": [
      "contact/mate/relation ids covered by interface-level units"
    ],
    "covered_functional_group_ids": [
      "internal/component group ids covered by group-level units"
    ],
    "uncovered_candidate_anchors": [
      {
        "anchor_type": "part|feature|interface|functional_group",
        "anchor_id": "id from B-rep evidence",
        "reason_not_covered": "standard/context-only component, duplicate equivalent anchor, insufficient evidence, or intentionally excluded"
      }
    ],
    "local_unit_count_by_anchor_type": {
      "part": 0,
      "feature": 0,
      "interface": 0,
      "functional_group": 0
    }
  },
  "uncertain_roles": [
    {
      "role": "string",
      "candidate_node_ids": [
        "node_id"
      ],
      "why_uncertain": "string",
      "facts_needed": [
        "specific B-rep or metadata facts"
      ]
    }
  ],
  "missing_facts": [
    "specific missing facts that prevent reliable diagnosis"
  ],
  "evidence_index": [
    {
      "ref": "edge/region/patch/component/face/relation id",
      "kind": "edge|region|patch|component|face|relation|dimension",
      "summary": "what this evidence supports"
    }
  ]
}