{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://alxprotocol.com/protocol/1/schemas/content-envelope.schema.json",
  "title": "ALX Optional Content Profile Envelope",
  "description": "Machine-readable structure for typed content stored inside Block.content. Using this envelope is optional — opaque content remains valid without it.",
  "$comment": "This v1 schema defines optional application content semantics only. It is not required for core conformance and does not change Block validity, Block identity, or hash derivation.",
  "type": "object",
  "properties": {
    "definitionLevel": {
      "$ref": "./defs.schema.json#/$defs/definitionLevel",
      "description": "Content definition tier — determines which additional fields are required in this envelope."
    },
    "contentType": {
      "$ref": "./defs.schema.json#/$defs/contentType",
      "description": "Application-defined content type for this artifact. Required when definitionLevel is typed or higher."
    },
    "schemaVersion": {
      "$ref": "./defs.schema.json#/$defs/semver",
      "description": "Version of the content schema governing the data field. Required when definitionLevel is schema-bound or conformance-bound."
    },
    "schema": {
      "type": "string",
      "format": "uri",
      "maxLength": 2048,
      "description": "URI of the JSON Schema governing the data field. Required when definitionLevel is schema-bound or conformance-bound."
    },
    "conformanceProfile": {
      "type": "string",
      "minLength": 1,
      "maxLength": 256,
      "description": "Named conformance profile the content claims to satisfy. Required when definitionLevel is conformance-bound."
    },
    "index": {
      "type": "object",
      "additionalProperties": true,
      "description": "Machine-readable index fields for search and retrieval. Required when definitionLevel is indexed or higher."
    },
    "data": {
      "description": "The artifact payload. Interpreted according to contentType and schema when definitionLevel is typed or higher; opaque otherwise."
    }
  },
  "required": ["definitionLevel", "data"],
  "additionalProperties": false,
  "allOf": [
    {
      "if": {
        "properties": {
          "definitionLevel": {
            "const": "typed"
          }
        },
        "required": ["definitionLevel"]
      },
      "then": {
        "required": ["contentType"]
      }
    },
    {
      "if": {
        "properties": {
          "definitionLevel": {
            "const": "indexed"
          }
        },
        "required": ["definitionLevel"]
      },
      "then": {
        "required": ["contentType", "index"]
      }
    },
    {
      "if": {
        "properties": {
          "definitionLevel": {
            "const": "schema-bound"
          }
        },
        "required": ["definitionLevel"]
      },
      "then": {
        "required": ["contentType", "schemaVersion", "schema"]
      }
    },
    {
      "if": {
        "properties": {
          "definitionLevel": {
            "const": "conformance-bound"
          }
        },
        "required": ["definitionLevel"]
      },
      "then": {
        "required": ["contentType", "schemaVersion", "schema", "conformanceProfile"]
      }
    }
  ],
  "examples": [
    {
      "definitionLevel": "indexed",
      "contentType": "research.summary",
      "index": {
        "title": "Quarterly market synthesis",
        "domain": "market-research",
        "concepts": ["pricing", "competition", "demand"]
      },
      "data": {
        "summary": "..."
      }
    }
  ]
}