AGTP Communication Protocol

This document specifies the AGTP Communication Protocol (AGTP- COMMUNICATION): the companion specification for real-time multi-modal communication between agents over the Agent Transfer Protocol (AGTP). AGTP-COMMUNICATION defines how voice, video, and other real-time media streams are exchanged between agents on the agent-native substrate, with native support for the wire-level identity, authority scope, and attribution that AGTP provides. This is an early specification covering bilateral (two-agent) real- time communication. Multi-party conversations and conferencing patterns are out of scope for this revision and are deferred to future companion work.