It's easy enough to make a bot that can trounce a human player in a first-person shooter - just react faster and shoot straighter - but anything strategic presents a fresh set of exceptionally complex problems. To this day, few Starcraft or Dota bots could rival a decently skilled player or group, at least until now. AI research group OpenAI reckon that their Dota 2 bot team (dubbed OpenAI Five) is nearly good enough to give the pros a run for their money, and will be testing that theory this August at The International 2018.
While the videos below gives you the abridged version of this story, OpenAI's full explanation on how the bot AI works and their expectations is eye-opening stuff. Back in April, the OpenAI Five team was beginning to show promise. By May 15th, it was evenly matched with OpenAI's own staff. By June 6th, it was consistently beating both OpenAI and Valve's players, and was nearly breaking even against amateur (but organised) and semi-pro teams. With every month, the AI learns more about the game. Suddenly, their hopes for an August victory don't seem so far-fetched.
One of the most interesting details is that OpenAI Five's individual agents, while operating as a team, don't communicate with each other. While an internal variable (dubbed 'team spirit') dictates just how much of a lone wolf each bot is, they are all technically playing solo and just acting based on what they can observe about their teammates' current status. Of course, being AI they can observe the status of their team far more actively than any human, but it's still surprising that no communication or planning of active combination attacks is even required.
The OpenAI bots are admittedly limited in their knowledge, and are playing a rather strict house-ruled game of Dota. All matches are played with the same teams (mirror-matches of Necrophos, Sniper, Viper, Crystal Maiden and Lich), and warding, Roshan, invisibility, summons, illusions and scans are against the rules. Given a year or two of training on a much wider scale, the AI could likely learn the ins and outs of every mechanic, but for the time being this limited rule-set is the bots' playground. Perhaps next year OpenAI will be ready to play through the entire tournament.
While I don't normally follow Dota 2's competitive scene, I know what team I'm rooting for in The International now. I, for one, welcome our new high-APM robot overlords. Especially if they're helpful, supportive and not swearing at each other in Russian. I want to know when I can roll with some of these AI's on my team.
Dota 2 is free to play and you can get it here on Steam.