{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "Template with parameters",
  "Parameters": {
    "Environment": {
      "Type": "String",
      "Default": "dev",
      "Description": "Deployment environment"
    },
    "BucketPrefix": {
      "Type": "String",
      "Description": "Prefix for bucket name"
    }
  },
  "Resources": {
    "MyBucket": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "BucketName": { "Ref": "BucketPrefix" }
      }
    }
  }
}