The controller exposes properties that are useful for creating error UIs using standard Aurelia templating techniques :
results : An array of the current ValidateResult instances. These are the results of validating individual rules.
errors : An array of the current ValidateResult instances whose valid property is false.
validating : a boolean that indicates whether the controller is currently executing validation.
Assuming your view-model had a controller property you could add a simple error summary to your form using a repeat :
<form>
<ul if.bind="controller.errors">
<li repeat.for="error of controller.errors">
${error.message}
</li>
</ul>
...
...
</form>
