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Add the Reach Agent

The Reach Agent runs as a hosted A2A agent. Nothing is installed and nothing runs inside your environment. A Gemini Enterprise administrator registers it once against its published agent card, and it appears in the agent list for the users you grant access to.

What your administrator needs

Item Value
Agent card https://agents.reach.dog/ge/.well-known/agent-card.json
Agent endpoint https://agents.reach.dog/ge/a2a/router (declared inside the card)
Protocol A2A JSON-RPC 2.0, protocol version 0.3.0
Registration type A2A agent definition (a2aAgentDefinition), using the fetched card as jsonAgentCard

Fetch the card at registration time rather than copying its contents into a config file by hand. The card is the contract: it carries the endpoint, the declared capabilities, the skill list, and the icon, and it is kept current on our side.

Register it as an A2A agent, not an Agent Engine agent

This one matters. The Reach Agent returns rendered tables, group cards, and tappable controls using the A2UI extension, which the card declares:

"extensions": [
  {
    "uri": "https://a2ui.org/a2a-extension/a2ui/v0.8",
    "required": false,
    "params": { "supportedCatalogIds": ["...standard_catalog..."] }
  }
]

Gemini Enterprise sends the client capability that activates this only on the A2A registration path. An agent registered through an Agent Engine definition receives no such capability, and the interface payload prints as raw JSON in the conversation instead of drawing. If your users see blocks of JSON where a table should be, the agent was registered the wrong way.

Sign-in and identity

The Reach Agent works without any authorization wired. Users can ask market questions immediately.

Connect an authorization on the agent, requesting the openid and email scopes, and Gemini Enterprise forwards a token with each turn. The agent exchanges that token with Google for the account behind it and uses the result for one purpose: keeping each person's uploaded catalogs separate and available on their next conversation. Without it, every turn is anonymous, and an uploaded catalog lives only as long as the conversation that uploaded it.

The account identifier is the stable Google subject id. Email is carried for display only and nothing is keyed on it. The token itself is never written to a log.

Confirm it is working

Open the agent and send:

What questions do people ask about travel mugs on voice search?

A working registration answers in prose with a table of questions beneath it and an evidence line naming the data behind them. See Ask your first question for what a normal answer looks like, and Read an answer for how to read the evidence.