{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://msr-standard.org/schemas/msr-2.1-draft.json",
  "title": "MSR JSON Protocol Schema (v2.1 Draft)",
  "description": "Experimental draft schema adding agent sandboxing, A2A messaging endpoints, multi-signature attestation, and geographic and language availability (RFC-0006).",
  "type": "object",
  "required": [
    "$schema",
    "protocol",
    "entity",
    "capabilities",
    "releases"
  ],
  "$defs": {
    "country_code": {
      "type": "string",
      "pattern": "^[A-Z]{2}$",
      "description": "ISO 3166-1 alpha-2 country code, uppercase (e.g. BR, PT, US). The exceptionally reserved EU is accepted for the European Union."
    },
    "region_code": {
      "type": "string",
      "enum": [
        "001",
        "002",
        "003",
        "005",
        "009",
        "011",
        "013",
        "014",
        "015",
        "017",
        "018",
        "019",
        "021",
        "029",
        "030",
        "034",
        "035",
        "039",
        "053",
        "054",
        "057",
        "061",
        "142",
        "143",
        "145",
        "150",
        "151",
        "154",
        "155",
        "202",
        "419"
      ],
      "description": "UN M49 region code as used by BCP 47 and Unicode CLDR: 001 World, 002 Africa, 019 Americas, 142 Asia, 150 Europe, 009 Oceania, and their sub-regions (e.g. 419 Latin America and the Caribbean)."
    },
    "language_tag": {
      "type": "string",
      "pattern": "^[a-z]{2,3}(?:-[A-Z][a-z]{3})?(?:-(?:[A-Z]{2}|[0-9]{3}))?$",
      "description": "BCP 47 language tag: language, optional script, optional region (e.g. en, pt-BR, es-419, zh-Hant-TW)."
    },
    "currency_code": {
      "type": "string",
      "pattern": "^[A-Z]{3}$",
      "description": "ISO 4217 alphabetic currency code (e.g. BRL, EUR, USD), the same form as capabilities.pricing.currency."
    }
  },
  "properties": {
    "$schema": {
      "type": "string",
      "format": "uri"
    },
    "protocol": {
      "type": "object"
    },
    "entity": {
      "type": "object",
      "properties": {
        "descriptions": {
          "type": "object",
          "propertyNames": {
            "$ref": "#/$defs/language_tag"
          },
          "description": "Localized descriptions keyed by BCP 47 language tag (RFC-0006)."
        }
      }
    },
    "capabilities": {
      "type": "object",
      "properties": {
        "deployment": {
          "type": "array"
        },
        "interfaces": {
          "type": "object"
        },
        "ai_sandbox": {
          "type": "object",
          "description": "Experimental RFC-0004: Execution boundary specification for autonomous AI agents.",
          "properties": {
            "isolation_level": {
              "type": "string",
              "enum": [
                "process",
                "container",
                "microvm",
                "wasm"
              ]
            },
            "network_egress": {
              "type": "string",
              "enum": [
                "none",
                "restricted-domain",
                "unrestricted"
              ]
            },
            "filesystem": {
              "type": "string",
              "enum": [
                "read-only",
                "ephemeral",
                "persistent"
              ]
            }
          }
        },
        "availability": {
          "type": "object",
          "description": "Experimental RFC-0006: where the product may be acquired and used, the languages of its interface and of its support, the currencies it is billed in, and where customer data is stored. An absent field means not declared, never worldwide.",
          "minProperties": 1,
          "additionalProperties": false,
          "properties": {
            "regions": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/region_code"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Regions where the product is offered. [\"001\"] declares worldwide availability."
            },
            "countries": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/country_code"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Countries where the product is offered, in addition to any listed region."
            },
            "excluded_countries": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/country_code"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Countries where the product is not offered even though a listed region contains them. Exclusion wins over inclusion."
            },
            "languages": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/language_tag"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Languages the product's user interface and documentation are available in."
            },
            "support_languages": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/language_tag"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Languages customer support is provided in. Independent of the interface languages."
            },
            "data_residency": {
              "type": "array",
              "items": {
                "anyOf": [
                  {
                    "$ref": "#/$defs/country_code"
                  },
                  {
                    "$ref": "#/$defs/region_code"
                  }
                ]
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Countries or regions where customer data is stored and processed at rest."
            },
            "currencies": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/currency_code"
              },
              "minItems": 1,
              "uniqueItems": true,
              "description": "Currencies the product can be billed in."
            }
          }
        }
      }
    },
    "releases": {
      "type": "object"
    },
    "trust": {
      "type": "object"
    },
    "telemetry": {
      "type": "object"
    }
  }
}