Zandronum

Download: http://files.funcrusher.net/wads/lonerbot_v1.pk3

LonerBot is pretty simple. If you are by yourself on a server, LonerBot will spawn a bot to keep you company. If somebody else joins the server, the bot disappears, and you can play against another live human.

That's it. There's only one thing you can configure as a server admin:
This will cause bots to not join or disappear when the server is on this specific map. Use this for stuff like START maps where you might not want a bot to be spawned on a specific map.

Tested with Deathmatch, Duel, and Team LMS. Will probably work without problems on LMS and Team Deathmatch.

Known Issues:

• If duellimit is not equal to 1, sometimes finishing a duel will cause the bot to quit and rejoin. As of right now, there is no way to detect if a spectator is a bot or not from ACS, so this is the best I can do.
• There is nothing you can configure in terms of how many bots to spawn, or which bot to spawn. More sophisticated bot management would probably be better off as an actual feature in Zandronum.
• Some mods, such as ZanXP, might require modification to prevent players from "farming" bots.

" there is no way to detect if a spectator is a bot or not from ACS"
i bet if they are spectators, they dont move around the map, so their player câmera coords should return 0 for the x\y\z position.
Or, idk if bots can run open clientside scripts when they are spectating, if they cant, you could do a check like everyone sends a requestscript puke so we know who's a human and who isn't.

I hope one of those may work, since I never tested this type of code with bots

This is fantastic