Distributed agents

Agents that cross process or host boundaries — other teams’ agents reached over the network, and agents that render UI instead of text.

        flowchart LR
    local[Local agent] -->|.a2a_client or<br/>RemoteAgent| remote[Remote agent<br/>different host]
    local -->|.ui spec or<br/>UI.auto| ui[User interface<br/>browser, app]

    classDef local fill:#e3f2fd,stroke:#1565c0,color:#0d47a1
    classDef remote fill:#fff3e0,stroke:#e65100,color:#bf360c
    classDef ui fill:#f3e5f5,stroke:#6a1b9a,color:#4a148c
    class local local
    class remote remote
    class ui ui
    

Chapters

Chapter	Read when
A2A (remote agents)	You need to call another team’s agent over HTTP (RemoteAgent), or publish yours (A2AServer).
A2UI (agent-to-UI)	The agent’s “output” is a form, dashboard, or interactive surface — not prose.

Tip

A2A vs normal tool calls If the remote thing is an ADK agent that speaks the A2A protocol, use RemoteAgent — you get session continuity, streaming, and typed error handling. If it’s a generic HTTP API, wrap it as a regular tool with T.fn(). Don’t reach for A2A for everything remote.