I have gotten in the habit of manually typing "counters add 35 assassin begin" and "counters add 50 assassin end" so I can tell you that the window seems accurate to me. I would also like to have mafia add the counters for me automatically to save me from RSI.
The window counters should be added (after pre-existing counters are removed) whenever the following monsters are encountered:
Gorgolok, the Infernal Seal
Stella, the Turtle Poacher
Spaghetti Elemental
Lumpy, the Sinister Sauceblob
The Spirit of New Wave
Somerset Lopez, Dread Mariachi
menacing thug
Mob Penguin hitman
hunting seal
turtle trapper
evil spaghetti cult assassin
béarnaise zombie
flock of seagulls
mariachi bandolero
Additionally, the following monsters should cancel an existing counter for "Nemesis Assassin Window End" but not trigger a new window, since they are the last assassin:
Argarggagarg the Dire Hellseal
Safari Jack, Small-Game Hunter
Yakisoba the Executioner
Heimandatz, Nacho Golem
Jocko Homo
The Mariachi With No Name
Erich, it is generally considered a good idea to provide the devs with all the necessary information to add a feature you want. They are simply less likely to implement something if they have to look it up on the wiki.
12132. That monster list isn't right since the time between finishing up in the cave and getting the first assassin is a lot different. I also had to account for the fact that you can lose to the last assassin.
Bug report: the Béarnaise zombie isn't properly recognized (or at least the previous wanderer window counter isn't erased, and a new one isn't created)