# MultiAgent Setup

**URL:** <https://discuss.ray.io/t/multiagent-setup/23572>\
**Category:** Uncategorized\
**Created:** [June 27, 2026, 10:17am UTC](https://discuss.ray.io/t/multiagent-setup/23572 "2026-06-27T10:17:58Z")\
**Posts on this page:** 1\
**Showing post:** 17

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**Author:** ![RunLLM](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/runllm/32/8249_2.png) [@RunLLM](https://discuss.ray.io/u/RunLLM)\
**Post date:** [July 31, 2026, 11:09am UTC](https://discuss.ray.io/t/multiagent-setup/23572/17 "2026-07-31T11:09:45Z")

</div>

It could be possible that RLlib’s MASAC (Multi-Agent Soft Actor-Critic) is based on the standard SAC algorithm, extended for multi-agent settings. Each agent has its own actor (policy network) and twin critics (Q-networks), and the entropy temperature (alpha) is learned to balance exploration and exploitation. The actor outputs actions, the critics estimate Q-values, and the temperature controls entropy regularization. See [SACConfig and code](https://github.com/ray-project/ray/blob/master/rllib/algorithms/sac/sac.py) and [default SAC RLModule](https://github.com/ray-project/ray/blob/master/rllib/algorithms/sac/default_sac_rl_module.py).

To extend or subclass actors, critics, or temperature modules, you might subclass the relevant RLModule or model classes. For example, you can subclass `DefaultSACRLModule` for custom actor/critic logic, or register a custom model for policy or Q-networks via `policy_model_config` and `q_model_config` in `SACConfig`. See [default\_sac\_rl\_module.py](https://github.com/ray-project/ray/blob/master/rllib/algorithms/sac/default_sac_rl_module.py) and [custom model discussion](https://discuss.ray.io/t/custome-the-sactorchmodel/20956).

Would you like a step-by-step example of subclassing one of these components?

Sources:

- [SACConfig and code](https://github.com/ray-project/ray/blob/master/rllib/algorithms/sac/sac.py)
- [default SAC RLModule](https://github.com/ray-project/ray/blob/master/rllib/algorithms/sac/default_sac_rl_module.py)
- [custom model discussion](https://discuss.ray.io/t/custome-the-sactorchmodel/20956)

Hint: Mention @Herald in the post for followups.

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