These "digital killing machines" are a "work-in-progress," Left 4 Dead creator Mike Booth revealed on the TF2 Official Blog, noting that their implementation is beta.

"TFBots are 'players', and take up player slots," explained Booth. "They run the exact same code that human players do, moving and firing weapons by pressing 'virtual buttons'. The bots have simulated humanlike senses, and only know what they see, hear, and touch. They also have realistic reaction times and aiming limitations. They don't 'cheat' or use omniscient knowledge of the server state to make their decisions."

In their current form, the bots can only play on three King of the Hill maps--koth_viaduct, koth_sawmill, koth_nucleus--and need to be spawned via console command. A graphical interface for bot spawning and control will be added soon, but until then:

• To add bots to your game, use the console command tf_bot_add. This will drop a random bot onto a random team (assuming there is a free player slot). The tf_bot_add command can also take up to three optional arguments: count, class, and team, in any order. For example, tf_bot_add 10 will add 10 random bots to the game with auto-assigned teams. Typing tf_bot_add pyro blue will add a Pyro to the blue team. Entering tf_bot_add red 5 will add 5 random bots to the red team. The command tf_bot_add red 3 heavyweapons will add three heavies to the red team.
  
  
• In order to put specific bots on specific teams (for a bots-vs-humans game, for example), you may want to disable automatic team balancing. To do this, enter mp_autoteambalance 0 followed by mp_teams_unbalance_limit 0.
  
  
• To remove a bot, use the console command kick . To remove all of the bots in the game, use the command tf_bot_kick all.

Booth further added that Valve would "like to hear your thoughts on how the bots are behaving," asking players to "tell us the three things you hate most about the bots, and the three things you like best about them (as well as anything else you think we should know)" via e-mail (tfbots@valvesoftware.com) or the bot feedback forum.