{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "ucwm/schemas/objects.json",
  "title": "CanonicalObject",
  "description": "The primary reusable referent inside UCWM. A stable anchor that facets and constraints attach to.",
  "type": "object",
  "required": ["object_id", "object_kind", "status", "confidence"],
  "additionalProperties": false,
  "properties": {
    "object_id": {
      "type": "string",
      "description": "Unique identifier. Format: {kind_prefix}_{sequence} e.g. E1, O4, Q7",
      "pattern": "^[A-Z][A-Z0-9]*_[0-9]+$|^[A-Z][0-9]+$"
    },
    "object_kind": {
      "type": "string",
      "enum": [
        "entity",
        "event",
        "concept",
        "proposition",
        "relation_instance",
        "procedure_step",
        "code_object",
        "quantity",
        "claim",
        "state"
      ],
      "description": "The ontological kind of this object."
    },
    "status": {
      "type": "string",
      "enum": ["proposed", "active", "merged", "split", "invalidated"],
      "description": "Lifecycle status. Proposed objects are unconfirmed. Merged objects were unified with another. Split objects produced multiple descendants.",
      "default": "proposed"
    },
    "confidence": {
      "type": "number",
      "minimum": 0.0,
      "maximum": 1.0,
      "description": "Aggregate confidence that this object is correctly proposed."
    },
    "surface_span": {
      "type": "object",
      "description": "The text span(s) that evidence this object.",
      "properties": {
        "text": { "type": "string" },
        "start": { "type": "integer" },
        "end": { "type": "integer" }
      },
      "additionalProperties": false
    },
    "canonical_label": {
      "type": "string",
      "description": "Human-readable canonical name for this object."
    },
    "aliases": {
      "type": "array",
      "items": { "type": "string" },
      "description": "Alternative names, pronouns, or references that may corefer to this object."
    },
    "merged_into": {
      "type": "string",
      "description": "object_id of the object this was merged into. Populated only when status=merged."
    },
    "split_from": {
      "type": "string",
      "description": "object_id of the object this was split from. Populated only when status=split."
    },
    "facet_refs": {
      "type": "array",
      "items": { "type": "string" },
      "description": "IDs of Facet objects attached to this canonical object.",
      "default": []
    },
    "constraint_refs": {
      "type": "array",
      "items": { "type": "string" },
      "description": "IDs of Constraints that reference this object.",
      "default": []
    },
    "evidence_refs": {
      "type": "array",
      "items": { "type": "string" },
      "description": "IDs of evidence or provenance records supporting this object.",
      "default": []
    },
    "provenance_refs": {
      "type": "array",
      "items": { "type": "string" },
      "description": "IDs of Provenance records tracking how this object was created.",
      "default": []
    },
    "source_module": {
      "type": "string",
      "description": "Module ID that proposed this object."
    }
  },
  "examples": [
    {
      "object_id": "E1",
      "object_kind": "entity",
      "status": "active",
      "confidence": 0.97,
      "surface_span": { "text": "Alice", "start": 0, "end": 5 },
      "canonical_label": "Alice",
      "aliases": ["she", "her"],
      "facet_refs": ["F_E1_ownership", "F_E1_temporal"],
      "constraint_refs": ["C1", "C3"],
      "evidence_refs": [],
      "provenance_refs": ["P1"],
      "source_module": "entity_specialist"
    },
    {
      "object_id": "Q1",
      "object_kind": "quantity",
      "status": "active",
      "confidence": 0.99,
      "surface_span": { "text": "5 apples", "start": 10, "end": 17 },
      "canonical_label": "5",
      "facet_refs": ["F_Q1_quantity"],
      "constraint_refs": ["C1"],
      "evidence_refs": [],
      "provenance_refs": ["P2"],
      "source_module": "quantity_specialist"
    }
  ]
}