Using UI Policy to Display a Conditional Message Without Scripting

Quick Answer

UI Policies are the right tool here because they are ServiceNow's declarative, condition-driven way of controlling form behavior on the client side, and displaying a message under a specific condition is exactly the kind of behavior they are designed to handle without requiring anyone to write a script. When you configure a UI Policy with the condition state=Closed, the platform evaluates that condition on the client as the form loads or as the field changes, and it can then trigger an informational, warning, or error message the moment that condition is true, all through configuration rather than code. This makes UI Policies the appropriate choice specifically because the requirement explicitly rules out custom scripting; if scripting were allowed or preferred, a client script could achieve something similar, but UI Policies exist precisely to give administrators and developers this kind of conditional, no-code control over form elements like field visibility, mandatory status, read-only state, and messages. The general pattern to remember is that whenever a requirement describes changing something about how a form behaves or looks based on a field's value, and specifically calls for a no-code or low-code solution, a UI Policy should be your first consideration, since it is the platform's purpose-built declarative mechanism for exactly that kind of conditional form logic.