diff --git a/README.md b/README.md
index 6d713b74..a8026015 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ You need the following permissions to run this module.
 | <a name="input_auto_scaling"></a> [auto\_scaling](#input\_auto\_scaling) | Optional rules to allow the database to increase resources in response to usage. Only a single autoscaling block is allowed. Make sure you understand the effects of autoscaling, especially for production environments. See https://cloud.ibm.com/docs/databases-for-mongodb?topic=databases-for-mongodb-autoscaling&interface=cli#autoscaling-considerations in the IBM Cloud Docs. | <pre>object({<br/>    disk = object({<br/>      capacity_enabled             = optional(bool, false)<br/>      free_space_less_than_percent = optional(number, 10)<br/>      io_above_percent             = optional(number, 90)<br/>      io_enabled                   = optional(bool, false)<br/>      io_over_period               = optional(string, "15m")<br/>      rate_increase_percent        = optional(number, 10)<br/>      rate_limit_mb_per_member     = optional(number, 3670016)<br/>      rate_period_seconds          = optional(number, 900)<br/>      rate_units                   = optional(string, "mb")<br/>    })<br/>    memory = object({<br/>      io_above_percent         = optional(number, 90)<br/>      io_enabled               = optional(bool, false)<br/>      io_over_period           = optional(string, "15m")<br/>      rate_increase_percent    = optional(number, 10)<br/>      rate_limit_mb_per_member = optional(number, 114688)<br/>      rate_period_seconds      = optional(number, 900)<br/>      rate_units               = optional(string, "mb")<br/>    })<br/>  })</pre> | `null` | no |
 | <a name="input_backup_crn"></a> [backup\_crn](#input\_backup\_crn) | The CRN of a backup resource to restore from. The backup is created by a database deployment with the same service ID. The backup is loaded after provisioning and the new deployment starts up that uses that data. A backup CRN is in the format crn:v1:<…>:backup:. If omitted, the database is provisioned empty. | `string` | `null` | no |
 | <a name="input_backup_encryption_key_crn"></a> [backup\_encryption\_key\_crn](#input\_backup\_encryption\_key\_crn) | The CRN of a Key Protect or Hyper Protect Crypto Services encryption key that you want to use for encrypting the disk that holds deployment backups. Applies only if `use_ibm_owned_encryption_key` is false and `use_same_kms_key_for_backups` is false. If no value is passed, and `use_same_kms_key_for_backups` is true, the value of `kms_key_crn` is used. Alternatively set `use_default_backup_encryption_key` to true to use the IBM Cloud Databases default encryption. Bare in mind that backups encryption is only available in certain regions. See [Bring your own key for backups](https://cloud.ibm.com/docs/cloud-databases?topic=cloud-databases-key-protect&interface=ui#key-byok) and [Using the HPCS Key for Backup encryption](https://cloud.ibm.com/docs/cloud-databases?topic=cloud-databases-hpcs#use-hpcs-backups). | `string` | `null` | no |
-| <a name="input_cbr_rules"></a> [cbr\_rules](#input\_cbr\_rules) | (Optional, list) List of CBR rules to create | <pre>list(object({<br/>    description = string<br/>    account_id  = string<br/>    rule_contexts = list(object({<br/>      attributes = optional(list(object({<br/>        name  = string<br/>        value = string<br/>    }))) }))<br/>    enforcement_mode = string<br/>    tags = optional(list(object({<br/>      name  = string<br/>      value = string<br/>    })))<br/>    operations = optional(list(object({<br/>      api_types = list(object({<br/>        api_type_id = string<br/>      }))<br/>    })))<br/>  }))</pre> | `[]` | no |
+| <a name="input_cbr_rules"></a> [cbr\_rules](#input\_cbr\_rules) | The context-based restrictions rule to create. Only one rule is allowed. | <pre>list(object({<br/>    description = string<br/>    account_id  = string<br/>    rule_contexts = list(object({<br/>      attributes = optional(list(object({<br/>        name  = string<br/>        value = string<br/>    }))) }))<br/>    enforcement_mode = string<br/>    tags = optional(list(object({<br/>      name  = string<br/>      value = string<br/>    })))<br/>    operations = optional(list(object({<br/>      api_types = list(object({<br/>        api_type_id = string<br/>      }))<br/>    })))<br/>  }))</pre> | `[]` | no |
 | <a name="input_cpu_count"></a> [cpu\_count](#input\_cpu\_count) | Allocated dedicated CPU per member. For shared CPU, set to 0. [Learn more](https://cloud.ibm.com/docs/databases-for-mongodb?topic=databases-for-mongodb-pricing#mongodb-scale-member) | `number` | `0` | no |
 | <a name="input_deletion_protection"></a> [deletion\_protection](#input\_deletion\_protection) | Enable deletion protection within terraform. This is not a property of the resource and does not prevent deletion outside of terraform. The database can not be deleted by terraform when this value is set to 'true'. In order to delete with terraform the value must be set to 'false' and a terraform apply performed before the destroy is performed. The default is 'true'. | `bool` | `true` | no |
 | <a name="input_disk_mb"></a> [disk\_mb](#input\_disk\_mb) | The disk that is allocated per member. [Learn more](https://cloud.ibm.com/docs/databases-for-mongodb?topic=databases-for-mongodb-pricing#mongodb-scale-member) | `number` | `10240` | no |
diff --git a/variables.tf b/variables.tf
index 7336fd9e..53e14afd 100644
--- a/variables.tf
+++ b/variables.tf
@@ -309,9 +309,13 @@ variable "cbr_rules" {
       }))
     })))
   }))
-  description = "(Optional, list) List of CBR rules to create"
+  description = "The context-based restrictions rule to create. Only one rule is allowed."
   default     = []
   # Validation happens in the rule module
+  validation {
+    condition     = length(var.cbr_rules) <= 1
+    error_message = "Only one CBR rule is allowed."
+  }
 }
 
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