{
  "mode": "All",
  "policyRule": {
    "if": {
      "allOf": [
        {
          "field": "type",
          "equals": "Microsoft.Resources/subscriptions/resourceGroups"
        }
      ]
    },
    "then": {
      "effect": "auditIfNotExists",
      "details": {
        "type": "Microsoft.Consumption/budgets",
        "deploymentScope": "resourceGroup",
        "existenceScope": "resourceGroup",
        "existenceCondition": {
          "allOf": [
            {
              "field": "Microsoft.Consumption/budgets/category",
              "equals": "Cost"
            }
          ]
        }
      }
    }
  },
  "parameters": {}
}