[backpropaganda]

It's not independent agents. The neural networks have the same input, share weights, and also share some activations. With that much sharing, it's better to think of it as one neural network which has output heads for all the 5 players. So coordination is free. Actually, coordination makes as little sense as saying that multiple neurons in a neural network are cooperating, or that the two legs of a humanoid are cooperating to walk. Further there is no game being played between heroes of the same team. They literally have the same objective. The "coordination" buzzword is just another attempt by OpenAI to confuse and mislead readers, and give a false sense of their progress.

[whymauri]

They cannot share the same inputs unless the team spirit hyperparameter is exactly 1, which it is not. You are partially correct in that the agents consume the parameters of the four other agents, but it is weighted differently accorsing to team spirit parameters.

[backpropaganda]

The team spirit hyperparameter is a crutch they've introduced themselves. Ideally it should be one. In Dota there is only one objective for the entire team and that's to win the game. The fact that they shape rewards is an implementation detail and doesn't change the fact that Dota 2 does not require cooperation, because there's no cooperation game being played. It's a purely zero-sum adversarial game being played between two teams.