{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://acop.ai/schemas/v1.0/acop-errors.schema.json",
  "title": "ACOP Error Response Schema",
  "description": "Normative shape for error response bodies in the ACOP HTTP+JSON binding.",
  "type": "object",
  "required": [
    "protocol_version",
    "error"
  ],
  "properties": {
    "protocol_version": {
      "type": "string",
      "const": "acop/1.0"
    },
    "error": {
      "$ref": "#/$defs/error"
    }
  },
  "additionalProperties": false,
  "$defs": {
    "error": {
      "type": "object",
      "required": [
        "code",
        "message"
      ],
      "properties": {
        "code": {
          "type": "string",
          "description": "An ACOP error code. MUST be either a reserved core code or a vendor-prefixed extension code matching '^[a-z][a-z0-9_]*(\\.[a-z][a-z0-9_]*)*$'.",
          "pattern": "^[a-z][a-z0-9_]*(\\.[a-z][a-z0-9_]*)*$"
        },
        "message": {
          "type": "string",
          "description": "Human-readable explanation. MUST NOT contain secrets."
        },
        "retry_after_seconds": {
          "type": "integer",
          "minimum": 0,
          "description": "When set, clients SHOULD wait at least this many seconds before retrying. MUST agree with the HTTP Retry-After header when both are present."
        },
        "details": {
          "type": "object",
          "description": "Code-specific structured context. Shape varies per code.",
          "additionalProperties": true
        }
      },
      "additionalProperties": false
    },
    "reserved_core_codes": {
      "description": "Informational enumeration of the reserved ACOP core error codes (see acop-http-binding.md § error code vocabulary). Not used as a schema constraint because vendor-prefixed extension codes are also valid.",
      "type": "string",
      "enum": [
        "claim_conflict",
        "lease_expired",
        "claim_released",
        "claim_revoked",
        "unauthorized_worker",
        "work_item_not_found",
        "work_item_superseded",
        "work_item_cancelled",
        "work_item_not_actionable",
        "validation_required",
        "gate_blocked",
        "unsupported_protocol_version",
        "schema_violation",
        "unauthenticated",
        "forbidden",
        "rate_limited",
        "internal_error",
        "backend_unavailable"
      ]
    }
  }
}