Validating using must statement inside the action input

Hi,

Can we use must validation inside the input of an action? Or the must will get executed if we are using tailf:exec in the action?

Yes, you can use must, provided you are using 1.1 YANG; but it is not evaluated by ConfD, so - if you cannot stick with type constraints or mandatory - you need to check the constraints in your code that handles the action.