Bots are software controlled players, available only in single player (offline) mode for training or demonstration purposes.
How to use
When selecting "Singleplayer" from the main menu (to play offline), the options are to play on an empty map, or with bots. Three bot modes are available: Deathmatch, Team deathmatch or One shot, one kill.
Most of the official maps (not ac_arid, ac_werk, ac_ingress or ac_iceroad) have waypoint files included with the release. These waypoints enable the bots to move through the map in a more comprehensive manner. Without a waypoint file, waypoints are added automatically when a map is loaded, and some routes will be unmanageable for the bots.
Bots come with five skill settings: Best, Good, Medium, Worse and Bad. The 'Best' setting is equivalent to a competent player with extraordinary aim, 'Bad' is really nothing more than something to aim at. It is possible to edit the skill settings. In the past, developers have admitted that bot coding is one of the weaker aspects of AC.
By default, only the official release maps are available for bot play from the menu. Whilst there are ways to get custom maps on the menu, the easiest way to play against bots on any custom map is by using the mode command. Type /mode 7 (for Bot team deathmatch. 8 for Bot deathmatch, 12 for Bot one shot, one kill), then type /map yourmap to load the map in that mode. You then have to add some bots, eg. "/addnbot 3 CLA best" or "/addnbot 4 RVSF good". Alternatively, if you find yourself typing this a lot, you could use this script from Bukz.