Set up · Gemini

Your buddy on Gemini

A Block Buddy is a face for your agent, drawn from its name. In Gemini Enterprise, an agent you register shows an icon beside its name, set through the API. Google doesn't publish the icon's shape, so use the pad file: opaque and safe in any crop. Gems have no icon.

Gemini Enterprise shows the icon "near the name of the agent". Shown here as a circle; the shape isn't documented.

Get the files

Drawn in your browser from the name above. Nothing is uploaded anywhere.

Agent iconbrass-otto-pad-256.png256 × 256 PNG, opaque. Host it on your own domain, or send it as base64.
A2A card iconbrass-otto-tile.svgSVG, under 1 KB. For an agent card's iconUrl as a data: URI, like Google's own example.
Your Google photobrass-otto-pad-800.jpg800 × 800 JPG, opaque. Google shows it as a circle.

No animated file here: no Google surface on this page animates an agent's icon.

Gemini Enterprise: your agent's icon

Download the Agent icon, and put it at an HTTPS URL you control. Or skip hosting and send it as base64 (icon.content).
An ADK agent: the console has no icon box. Register or update the agent with the API call under "For agents", with "icon": {"uri": …}.
An A2A agent: in the Cloud console, open Gemini Enterprise → your app → Agents → Add Agents → Custom agent via A2A. In Agent card JSON, add "iconUrl" with your URL, or the SVG as a data:image/svg+xml;base64,… URI. Then Preview agent details → Next → Skip & Finish.
Open the Gemini Enterprise web app and check that your buddy sits beside the agent's name.

The Gemini app

Gems can't wear a buddy: they have no icon. From November 2026 Gems become skills, which have none either.
The closest route is your own Google Account photo: myaccount.google.com → Personal info → Profile picture, upload Your Google photo, then Save as profile picture.

For agents

A Discovery Engine admin sets an agent's icon through the API: icon.uri (a public image URL) or icon.content (base64), never both.

Instructions

platform: gemini-enterprise (a registered ADK or A2A agent's icon)
crop:     not documented; shown "near the name of the agent"
variant:  pad (the tile at 74%, centred on its own ground colour, opaque)
file:     brass-otto-pad-256.png
format:   PNG by URL (icon.uri) or base64 (icon.content). An SVG data: URI works in an A2A card.
buddy:    Brass Otto
hash:     0x4f7857573d121112474507868c95e98e2cbb66d73cc61e786482793f28ed9bb0
method:   Discovery Engine v1alpha agents.create / agents.patch > icon.uri or icon.content
console:  no icon field for ADK agents; A2A agents take the card's iconUrl
update:   PATCH .../v1alpha/{AGENT_RESOURCE_NAME}; resend displayName, description and reasoningEngine
per-mode: none built in. Changing the icon per state is possible, but its caching isn't documented.
gems:     no icon; Gems become skills from November 2026
checked:  2026-10-21

curl: register an ADK agent with its icon

curl -X POST \
  -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  -H "Content-Type: application/json" \
  -H "X-Goog-User-Project: PROJECT_ID" \
  "https://global-discoveryengine.googleapis.com/v1alpha/projects/PROJECT_ID/locations/global/collections/default_collection/engines/APP_ID/assistants/default_assistant/agents" \
  -d '{
    "displayName": "Brass Otto",
    "description": "DESCRIPTION",
    "icon": { "uri": "https://YOUR-DOMAIN/brass-otto-pad-256.png" },
    "adkAgentDefinition": {
      "provisionedReasoningEngine": {
        "reasoningEngine": "projects/PROJECT_ID/locations/RESOURCE_LOCATION/reasoningEngines/RESOURCE_ID"
      }
    }
  }'

Limits

Format	An image by URL or base64. Which formats isn't documented unverified
Max size	Not documented unverified
Dimensions	Not documented. We give you 256 × 256.
Crop	Not documented unverified
Animation	No
Who can set it	A Discovery Engine admin, by API (ADK) or in the agent card (A2A). Gems: nobody not supported today
Per-mode faces	No

Last checked 2026-10-21 against Register an ADK agent, Register an A2A agent, Gems to skills and Change your profile picture. The agents API is v1alpha; we re-check this page every quarter. If a step is wrong, the platform's own docs win.