Unable to use description.required()

After enacting the Stateless rule:

when !issue.isReported(){
  issue.description.required("Please enter a description");
}

When a user attempts to create a new issue, YouTrack attempts to run 'description' as a command.

I have also tried to use Assert:

assert description.isNotBlank: "Ensure that the description has been filled out"

This causes some other issues. The summary field is repetitively being focused, any data entered in other fields will be deleted, and if a user enters in a description and then deletes it the assertion is not checked afterwards.

Is there something that I am doing incorrectly?