Designing Smarter Communication for Multi-Agent AI
Their findings were accepted for presentation at the ICML '26, which took place in Seoul, from July 6 to 11, 2026.
Abstract Communication is a key component in multi-agent reinforcement learning (MARL) for mitigating partial observability, yet prior approaches often rely on inefficient information exchange or fail to transmit sufficient state information. To address this, we propose LLM-driven Multi-Agent Communication (LMAC), which leverages an LLM's reasoning capability to design a communication protocol that enables all agents to reconstruct the underlying state as accurately and uniformly as possible. LMAC iteratively refines the protocol using an explicit state-awareness criterion, improving state recovery while narrowing differences in agents' knowledge. Experiments on diverse MARL benchmarks show that LMAC improves state reconstruction across agents and yields substantial performance gains over prior communication baselines. Multi-agent AI systems must make decisions based on incomplete information. Researchers at UNIST have developed a new approach that uses a large language model (LLM) to help AI agents to build a more accurate and consistent understanding of their shared environment, improving coordination in complex collaborative tasks. Led by Professor Seungyeol Han of the Graduate School of Artificial Intelligence, the team developed LLM-driven Multi-Agent Communication (LMAC), a framework that designs and refines communication protocols for multi-agent reinforcement learning (MARL). Rather than manually specifying what information agents should exchange, LMAC determines what information is essential for cooperation and how it should be shared so that every agent can reconstruct the underlying state of the environment as accurately as possible. The framework is intended for environments where no individual agent has access to the complete picture, such as drone swarms, collaborative robots, and autonomous vehicles. Users describe the task objective, the role of each agent, and the meaning of available observations in natural language. Based on this description, the LLM generates a communication protocol that specifies what information each agent should transmit and to whom. LMAC further improves the protocol through an interactive feedback process. An evaluation module measures how accurately each agent reconstructs the hidden state after receiving messages from teammates while identifying differences in the agents' understanding of the environment. The LLM uses this feedback to refine the communication protocol by incorporating missing contextual information and eliminating unnecessary information exchange. Rather than increasing the amount of communication, the framework improves the quality and consistency of information shared across the team. For example, in a drone surveillance mission, only a reconnaissance drone may be able to observe a target. Simply reporting that " [T]he target is to my right " provides little value if the rest of the team does not know the scout's position. LMAC automatically recognizes this ambiguity and revises the communication protocol to include additional context, such as the scout's location, movement, teammate identities, or a shared coordinate system, allowing all agents to infer the target's position more accurately. Unlike approaches that repeatedly invoke an LLM during deployment, LMAC uses the model only while designing the communication protocol. During execution, the completed protocol directly converts each agent's observations into messages, enabling efficient real-time communication without the computational overhead of continuous LLM inference. The researchers also developed a learning architecture that helps agents make better use of incoming messages. Rather than treating all transmitted information equally, each agent learns to extract the information most relevant to the task while estimating the reliability of its own understanding of the environment. In a cooperative StarCraft II benchmark, LMAC achieved a 96.2% win rate in a scenario where a single reconnaissance unit guided ten attack units that could not directly observe enemy positions. Under the same learning architecture, existing communication methods achieved win rates of 59.0% and 25.2%, respectively. “Previous multi-agent communication research has focused primarily on how agents exchange messages, but has been limited in determining what information is fundamentally necessary for cooperation,” said Professor Han. "LMAC enables a large language model to reason about the relationship between observations and the underlying environment, automatically design communication protocols, and continuously refine them through data-driven feedback. Because the LLM is used only during protocol design rather than execution, the framework also remains computationally efficient during deployment." He further added that the approach could support collaborative AI systems operating under limited information, including autonomous drone swarms, robot teams, smart factories, and cooperative autonomous driving. Professor Han added that the approach could provide a foundation for collaborative AI systems operating under limited information, including autonomous drone swarms, robot teams, smart factories, and cooperative autonomous driving. The study has been accepted for presentation at the International Conference on Machine Learning (ICML) 2026, which took place in Seoul from July 6 to 11, 2026. The research was supported by the Ministry of Science and ICT (MSIT), the Institute for Information & Communications Technology Planning & Evaluation (IITP), and the National Research Foundation of Korea (NRF). Journal Reference Sangjun Bae, Yisak Park, Sanghyeon Lee, and Seungyul Han, "LLM-Guided Communication for Cooperative Multi-Agent Reinforcement Learning," ICML '26 , (2026).
- 2026-07-27
- JooHyeon Heo
- 103