A2H: Agent-to-Human Protocol for AI Agent
Zhiyuan Liang, Enfang Cui, Qian Wei, Rui She, Tianzheng Li, Minxin Guo, Yujun Cheng
TL;DR
The A2H (Agent-to-Human) protocol is proposed, a unified protocol that enables humans to be registered, discovered, and communicated with by AI agents as resolvable entities within agent systems.
Abstract
AI agents are increasingly deployed as autonomous systems capable of planning, tool use, and multi-agent collaboration across complex tasks. However, existing agent-related protocols focus on agent-to-agent interactions, leaving humans as external observers rather than integrated participants within the agent systems. This limitation arises from the lack of a standardized mechanism for agents to discover, address, and interact with humans across heterogeneous messaging platforms. In this paper, we propose the A2H (Agent-to-Human) protocol, a unified protocol that enables humans to be registered, discovered, and communicated with by AI agents as resolvable entities within agent systems. A2H contributes three key components: (1) Human Card for registering human identities via resolvable domain names, making them discoverable to agents; (2) Formal Communication Schema defines when, why, and how agents contact with human;(3) Unified Messaging Abstraction standardizes diverse communication medias and transforms complex JSON outputs into human-friendly formats. This work establishes a foundational protocol for integrating humans into agent ecosystems, advancing AI agents from isolated autonomous systems toward truly human-connected intelligent infrastructures.