Dynamically display an element in a trigger prototype

[cls_rn]

I'm trying to dynamically display an error description in a trigger prototype made from a discovery rule and I can't seem to find the solution. Here are a few screenshots of what I did. Thank you in advance for your help. Sorry but the interface is in french.

Here are the trigger prototypes I wrote :


Here's what it does on a host linked to the according template :


Please don't mind the differences between copy and scan. It has been corrected.

Tell me if you need more information.

Just to be sure you know what my level is on this software, I'm a student and I'm learning to use Zabbix at my own pace.

Have a great day !