That is the vacuum line to the water valve to the cabin heater.

 

Is it safe to be like that or do I have to get something replaced? Could I just put sum tape on it and call it a day

 

It's the vacuum line for the HCV (heater control valve). SOP is to eliminate the HCV before it comes apart. 97+ XJ's don't even have them.
Here's one link to help but there are plenty more:
https://www.cherokeeforum.com/f2/hea...heater-254563/

 

My assumption is that the line is quite brittle, and that is why it snapped. It would be better to purchase a splice connector for vacuum line, best to replace the whole line. It goes all the way to the temperature control in the center of the dash though. To be honest, my valve has been removed and that hose is sucking on the end of a threaded stud sticking out of the firewall just below the AC diffuser valve. If you intend to leave the valve, and it doesn't seem it was your intention to mess with it at all. It should be fixed correctly.

 

Slip a piece of vacuum hose on it and connect the two together for a quick fix until you have the time and parts to fix it correctly..

 

x2 on that control valve plastic becoming brittle and falling apart. That dumps your coolant pretty fast when that happens.
Oh, and stop using crappy Fram filters.

 

use a suitable diameter hose to splice the broken hose.

 

I just ended up using a splice connector and some seal rtv silicone
till it’s fixed

 

Delete that thing and forget it ever existed.