Large Language Models (LLMs) are accelerating the shift from an Internet of information to an Internet of Agents (IoA), where autonomous entities discover services, negotiate, execute tasks, and exchange value. Yet today's agents are still confined to platform silos and proprietary interfaces, lacking a common stack for interoperability, trust, and pay-per-use settlement. This article proposes \textit{Agent-OSI}, a six-layer reference stack for decentralized agent networking built on top of the existing Internet. Agent-OSI combines secure connectivity and A2A messaging, decentralized identity and authorization, settlement and metering, verifiable execution and provenance, and semantic interoperability for orchestration. In particular, we treat HTTP 402 (Payment Required) as an application-level payment challenge (analogous to HTTP 401 for authentication) that triggers escrow-based settlement and verifiable receipts (instantiated via a blockchain escrow in our prototype), rather than introducing a new network-layer protocol. We implement a prototype and evaluate cost and latency. Results show that keeping negotiation and delivery off-chain while preserving verifiable settlement reduces on-chain session costs by approximately 51\% compared with a standard Web3 baseline in our prototype setting, and that blockchain confirmation latency is often not the dominant factor for generative workloads.

翻译：大型语言模型（LLM）正在加速从信息互联网向智能体互联网（IoA）的转变，其中自主实体能够发现服务、进行协商、执行任务并交换价值。然而，当前的智能体仍受限于平台孤岛和专有接口，缺乏用于互操作性、信任和按使用付费结算的通用协议栈。本文提出了 \textit{Agent-OSI}，一个构建在现有互联网之上的、用于去中心化智能体网络的六层参考协议栈。Agent-OSI 集成了安全连接与 A2A 消息传递、去中心化身份与授权、结算与计量、可验证执行与溯源，以及用于编排的语义互操作性。特别地，我们将 HTTP 402（需要付款）视为一种应用层支付质询（类似于用于身份验证的 HTTP 401），它会触发基于托管机制的结算和可验证收据（在我们的原型中通过区块链托管机制实例化），而不是引入新的网络层协议。我们实现了一个原型并评估了成本和延迟。结果表明，在我们的原型设置中，与标准的 Web3 基线相比，将协商和交付保持在链下，同时保留可验证结算，可使链上会话成本降低约 51%，并且对于生成式工作负载，区块链确认延迟通常不是主导因素。