{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api.conceptnet.io/schema/edge.json",
  "title": "ConceptNet Edge",
  "description": "A single ConceptNet assertion linking two concept nodes via a typed relation. Each edge has a weight representing confidence, a license, a dataset provenance URI, and an array of source attributions.",
  "type": "object",
  "required": ["@id", "start", "end", "rel", "weight"],
  "properties": {
    "@id": {
      "type": "string",
      "description": "Unique URI identifier for this edge in the form /a/[/{rel}/,{start},{end}/]",
      "example": "/a/[/r/IsA/,/c/en/dog/,/c/en/animal/]"
    },
    "start": {
      "$ref": "#/$defs/conceptRef",
      "description": "Subject (start) concept of the assertion"
    },
    "end": {
      "$ref": "#/$defs/conceptRef",
      "description": "Object (end) concept of the assertion"
    },
    "rel": {
      "$ref": "#/$defs/relationRef",
      "description": "Relation type connecting start and end"
    },
    "surfaceText": {
      "type": ["string", "null"],
      "description": "Natural-language sentence from which this assertion was derived",
      "example": "[[A dog]] is a [[animal]]."
    },
    "weight": {
      "type": "number",
      "description": "Confidence weight of the assertion. Higher values indicate stronger evidence.",
      "minimum": 0,
      "example": 3.46
    },
    "license": {
      "type": "string",
      "description": "Creative Commons license identifier",
      "example": "cc:by/4.0"
    },
    "dataset": {
      "type": "string",
      "description": "Dataset provenance URI",
      "example": "/d/verbosity"
    },
    "sources": {
      "type": "array",
      "description": "Array of source attribution references",
      "items": {
        "$ref": "#/$defs/sourceRef"
      }
    }
  },
  "$defs": {
    "conceptRef": {
      "type": "object",
      "description": "Reference to a ConceptNet concept node",
      "required": ["@id"],
      "properties": {
        "@id": {
          "type": "string",
          "description": "ConceptNet URI",
          "example": "/c/en/dog"
        },
        "label": {
          "type": "string",
          "description": "Human-readable label for the concept",
          "example": "dog"
        },
        "language": {
          "type": "string",
          "description": "BCP-47 language code",
          "example": "en"
        },
        "term": {
          "type": "string",
          "description": "ConceptNet concept URI (same as @id)",
          "example": "/c/en/dog"
        },
        "sense_label": {
          "type": "string",
          "description": "Part-of-speech or sense label",
          "example": "n"
        }
      }
    },
    "relationRef": {
      "type": "object",
      "description": "Reference to a ConceptNet relation type",
      "required": ["@id"],
      "properties": {
        "@id": {
          "type": "string",
          "description": "Relation URI",
          "example": "/r/IsA"
        },
        "label": {
          "type": "string",
          "description": "Human-readable relation name",
          "example": "IsA"
        }
      }
    },
    "sourceRef": {
      "type": "object",
      "description": "Reference to a ConceptNet data source",
      "required": ["@id"],
      "properties": {
        "@id": {
          "type": "string",
          "description": "Source URI",
          "example": "/s/resource/verbosity"
        }
      }
    }
  }
}