{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://kolm.ai/docs/receipt-v0.1.json",
  "title": "kolm receipt",
  "description": "HMAC chain that signs a .kolm artifact end-to-end. Part of RS-1 (https://kolm.ai/docs/rs-1.md).",
  "type": "object",
  "required": ["spec", "alg", "signed_at", "signer", "chain", "signature"],
  "additionalProperties": false,
  "properties": {
    "spec": {
      "const": "receipt-v0.1",
      "description": "Receipt schema version. Immutable string."
    },
    "alg": {
      "enum": ["HMAC-SHA256"],
      "description": "Signature algorithm. Only HMAC-SHA256 is defined for v0.1."
    },
    "signed_at": {
      "type": "string",
      "format": "date-time",
      "description": "ISO-8601 UTC timestamp of signing."
    },
    "signer": {
      "type": "string",
      "minLength": 1,
      "description": "Identity of the signing party (e.g. \"kolm-cloud@kolm.ai\")."
    },
    "chain": {
      "type": "array",
      "minItems": 1,
      "items": {
        "type": "object",
        "required": ["member", "sha256"],
        "additionalProperties": false,
        "properties": {
          "member": {
            "type": "string",
            "description": "Path inside the .kolm zip archive."
          },
          "sha256": {
            "type": "string",
            "pattern": "^[a-f0-9]{64}$",
            "description": "SHA-256 of the member bytes after canonicalization."
          },
          "optional": {
            "type": "boolean",
            "description": "If true, the member may be absent without invalidating the chain."
          },
          "size_bytes": {
            "type": "integer",
            "minimum": 0
          }
        }
      }
    },
    "registry_signature": {
      "type": "string",
      "description": "Detached signature from the recipe-registry over the recipes.json hash. Optional but recommended."
    },
    "signature": {
      "type": "string",
      "description": "Final HMAC-SHA256 over the canonical chain JSON."
    },
    "anchors": {
      "type": "array",
      "items": {
        "type": "object",
        "required": ["kind", "uri"],
        "additionalProperties": false,
        "properties": {
          "kind": {
            "enum": ["http", "arweave", "btc-op-return", "ots"]
          },
          "uri": { "type": "string" },
          "anchored_at": { "type": "string", "format": "date-time" }
        }
      },
      "description": "External durability anchors. v0.1 runtimes MAY ignore this field."
    }
  }
}