For the first request, changes are coming soon - possibly as soon as 8.0.15. Right now, there’s no way to set that description, but there will just be a description
keyword argument to provide on your system.util.invokeAsynchronous
calls.
For the latter:
from com.inductiveautomation.ignition.common.script import ScriptManager
for script in ScriptManager.executingScripts():
if script.description == "My Async Thread":
ScriptManager.interrupt(script.threadId)