{ "$schema":                      "https://json-schema.org/draft/2020-12/schema",
  "$id":                          "https://schemas.mpai.community/OSD/V1.5/data/InstanceIdentifier.json",
  "title":                        "Instance Identifier V1.5", "description": "Identifies an instance.",
                                  "type": "object", "additionalProperties": false,
                                  "required": ["Header", "MInstance", "InstanceIdentifier", "InstanceIdentifierData"], "properties": {

    "Header":                    { "type": "string", "pattern": "^OSD-IID-V[0-9]{1,2}[.][0-9]{1,2}$" },

    "MInstance":                 { "type": "string", "description": "Unique identifier for the metaverse instance or session" },

    "InstanceIdentifier":        { "type": "string", "description": "Unique identifier for the classified audio or visual instance" },

    "InstanceSpaceTime":         { "$ref": "https://schemas.mpai.community/OSD/V1.5/data/SpaceTime.json" },

    "InstanceIdentifierData":    { "type": "array", "description": "Labels and taxonomy paths of the instance", "items": {
                                     "type": "object", "required": ["InstanceLabel", "LabelConfidenceLevel", "Taxonomy"],
                                     "additionalProperties": false, "properties": {
      "InstanceLabel":           { "type": "string", "description": "Human-readable label (e.g., 'Speech', 'Alarm')" },
      "LabelConfidenceLevel":    { "type": "number", "minimum": 0, "maximum": 1, "description": "Confidence score for the label" },
      "Taxonomy":                { "type": "object", "required": ["TaxonomyLevelIDs", "TaxonomyDataURI"], 
                                   "additionalProperties": false, "properties": {
        "TaxonomyLevelIDs":      { "type": "array", "items": { "type": "string" }, 
                                   "description": "Taxonomy hierarchical path (e.g., ['Human Sounds','Speech'])" },
        "TaxonomyDataURI":       { "type": "string", "format": "uri", "description": "URI of the taxonomy definition" } } },
      "TaxonomyConfidenceLevel": { "type": "number", "minimum": 0, "maximum": 1, 
                                   "description": "Confidence score for the taxonomy classification" },
      "AIMInstance":             { "$ref": "https://schemas.mpai.community/AIF/V3.0/data/AIMInstance.json" } } } },

    "DataExchangeMetadata":      {"$ref": "https://schemas.mpai.community/AIF/V3.0/data/DataExchangeMetadata.json" },
    "Trace":                     { "$ref": "https://schemas.mpai.community/AIF/V3.0/data/Trace.json" },
    "DescrMetadata":             { "type": "string", "maxLength": 2048, "description": "Optional descriptive metadata." } } }