We use Jira Core since About 2 years.
In some of our Workflows we used the Field Description of the Summary field to automatically fill and hide it.
Here's the relating script:
<script type="text/javascript">
jQuery("label:contains('NoSummaryField')").parent().hide();
jQuery("input#summary").parent().hide();
jQuery("#create-issue-submit").click(function(){
// TODO: fetch ur summary value here
var summary_value = "Neuer Vorgang";
jQuery("input#summary").val(summary_value);
});
</script>
Unfortunatly since we updated to Jira Version 8.7.1, the script seems not to be executed anymore but is shown on the create issue screens.

With Version 8.6.1 the description wasn't shown and the script was executed.