Are you talking about Opposing Force deathmatch or Opposing Force CTF (Capture The Flag) ?
Anyway, the HPB_bot supports both.
There might also have other bots which support Opposing Force (either deathmatch or CTF) but I don't remember them all. The RACC preview supports Opposing Force deathmatch. But if you want a bot that really does CTF, go with the HPB_bot