Poster: Agent Transfer Protocol: Server-Mediated Authentication and Messaging for Agent-to-Agent Communication

Abstract

The Internet of Agents (IoA) is emerging as a paradigm in which AI agents communicate and collaborate across organizational boundaries, attracting growing attention from both industry and standards communities. However, designing an agent communication protocol that can be deployed at both Internet and intranet scales remains an open challenge. In this paper, we present ATP (Agent Transfer Protocol), a server-mediated agent-to-agent communication protocol to address this agent interoperability challenge. ATP assigns each agent a local@domain identifier, discovers domain servers through DNS SVCB records, authenticates every cross-domain message with ATS sender policies and ATK signatures, and carries asynchronous messages, request/response calls, and event streams in one opaque envelope. We implement a Go-based ATP prototype and evaluate its practicality: the cross-domain authentication pipeline adds 0.60 ms median overhead, while stable-state throughput reaches 16.1 K messages/s within a domain and 5.5 K messages/s for cross-domain delivery at 128 connections.