Gateway Capability Directory and Synchronization for Internet of Agents

This document describes a gateway capability-directory framework for the Internet of Agents (IoA) in deployments that use Agent Gateways. In such deployments, a gateway-managed capability directory is a necessary control-plane function for maintaining validated capability information beyond transient advertisements, static endpoint bindings, or external descriptions alone. This document defines requirements and a common object model for gateway-managed capability information, including the Agent Capability Specification (ACS), Capability Digest, and directory entry lifecycle. It also specifies synchronization, freshness, provenance, and validation requirements for capability information exchanged across gateways. This document clarifies the relationship between gateway-managed ACS objects and externally published descriptions such as the A2A Agent Card, and briefly compares this framework with broader distributed directory-service approaches. It does not define a discovery query protocol, ranking algorithm, storage substrate, distributed lookup algorithm, task orchestration protocol, or agent-to-agent session protocol. It can inform subsequent DMSC protocol work, including capability digest synchronization and related gateway procedures.