In plain words: It sorts the ways AI agents talk to tools and each other into four groups, then compares them on security, speed, and how well they scale. The comparison points to adaptability, privacy, and group interaction as the traits future protocols need.
Abstract
The rapid development of large language models (LLMs) has led to the widespread deployment of LLM agents across diverse industries, including customer service, content generation, data analysis, and even healthcare. However, as more LLM agents are deployed, a major issue has emerged: there is no standard way for these agents to communicate with external tools or data sources. This lack of standardized protocols makes it difficult for agents to work together or scale effectively, and it limits their ability to tackle complex, real-world tasks. A unified communication protocol for LLM agents could change this. It would allow agents and tools to interact more smoothly, encourage collaboration, and triggering the formation of collective intelligence. In this paper, we provide the first comprehensive analysis of existing agent protocols, proposing a systematic two-dimensional classification that differentiates context-oriented versus inter-agent protocols and general-purpose versus domain-specific protocols. Additionally, we conduct a comparative performance analysis of these protocols across key dimensions such as security, scalability, and latency. Finally, we explore the future landscape of agent protocols by identifying critical research directions and characteristics necessary for next-generation protocols. These characteristics include adaptability, privacy preservation, and group-based interaction, as well as trends toward layered architectures and collective intelligence infrastructures. We expect this work to serve as a practical reference for both researchers and engineers seeking to design, evaluate, or integrate robust communication infrastructures for intelligent agents.
Yingxuan Yang, Huacan Chai, Yuanyi Song, Siyuan Qi, Muning Wen, Ning Li, Junwei Liao, Haoyi Hu, Jianghao Lin, Gaowei Chang, Weiwen Liu, Ying Wen, et al.
arXiv:2504.16736 · cs.AI · submitted Apr 23, 2025 · updated Jun 21, 2025
abstract · pdf · html
During Web 2.0, we saw similar enthusiasm. Instead of AI agents or blockchain, every modern company had an API exposed. For instance, Gmail- and Facebook chat was usable with 3p client apps.
What killed this was not tech, but business. The product wasn’t say social media, it was ad delivery. And using APIs was considered a bypass of funnels that they want to control. Today, if you go to a consumer service website, you will generally be met with a login/app wall. Even companies that charge money directly (say 23&me ad an egregious example) are also data hoarders. Apple is probably a better example. There’s no escape.
The point is, protocols is the easy part. If the economics and incentives are the same as yesterday, we will see similar outcomes. Today, the consumer web is adversarial between provider ”platforms”, ad delivery, content creators, and the products themselves (ie the people who use them).