In my experience, using the starting keyword and question mark (?) helps narrow down the search quite a bit. Within Junos that's the best option.
root@mx480-re0# set event-options policy test events alarm?
root@mx480-re0# set event-options policy test events chassis?
If you're unaware of the starting keyword, another dirty trick is to log your terminal session with a question marking after events and keep hitting tab until all events are listed out. That gives you the whole list to search the session logs on your text editor.
Also, there is an option for using non-standard logs that aren't listed in events to trigger your event policy. Please refer Page 916-917 here:
Hope this helps.
If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated :).
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