Gemini 4 Carbon Appears in Google AI Mode on Google AI Pro

By Lesia Kapliuk · Published November 12, 2026 · Updated November 12, 2026

TL;DR: Yes, on some accounts. On November 12, 2026, Google AI Mode (google.com/ai) on two of our Google AI Pro accounts let us pick 4 Carbon from the + menu, next to Auto and 3.8 Flash. A Plus account (a reader's screenshot) and a free account showed no model choice. In Antigravity, Gemini 4 Carbon is still for Ultra subscribers only, and our Pro account did not have it in the Gemini app. With 4 Carbon selected you can attach images but not files. In our one test, the request did not change any Antigravity quota. Google has not announced this, so treat it as an observation, not a confirmed plan feature.

Can you use Gemini 4 Carbon on Google AI Pro?

Open AI Mode, press + next to the question box, and on our Google AI Pro accounts the menu ends with a model section:

Google AI Pro, English interface (account avatar covered).

Two different Pro accounts showed the same menu. Without a Pro plan the menu has no model section, only "Add images", "Add files", "Create images" and Canvas. Here is what a signed-out visitor sees in an incognito window, which is the same menu a Google AI Plus account showed in a reader's screenshot:

Signed-out visitor, incognito window, English interface.

The free account we checked had no model choice either (no screenshot).

Where Gemini 4 Carbon is available

Antigravity: on our Pro account "Gemini 4 Carbon" is greyed out with the note that it is "currently available to Ultra plan subscribers". We covered that in Gemini 4 Carbon is Ultra-only in Antigravity.
Gemini API and AI Studio: the model code is gemini-4-carbon, released November 10, 2026, Paid tier only. The Gemini API pricing page says "not available" on the Free tier and lists $2.00 / $10.00 per 1M input / output tokens through November 30, 2026, then $4.00 / $20.00 from December 1 (details in our API section). The model card in AI Studio shows the same labels (New, Paid). Check the page again on the day you read this.
Gemini app: we did not find Carbon in the model picker on our Pro account.
What has been reported about AI Mode: 9to5Google and Search Engine Journal say paid subscribers get Gemini 4 Argon in AI Mode. We found nothing about Carbon there.

Gemini 4 Carbon in AI Mode: images only, no files (our test)

With 4 Carbon selected, the Add files item turns grey and only images can be attached:

Google AI Pro, English interface.

(With Auto selected, "Add files" works.) So we rendered about 35 KB of text from our own drafts into nine PNG pages and hid one line, MARKER-7431: the answer is violet, on page 5. We asked: what does the MARKER line say, on which page is it, and how many times does the capitalized word "Carbon" appear.

	Run 1	Run 2
Marker line	correct	correct
Page of the marker	5 (correct)	5 (correct)
Count of "Carbon" (true value: 46)	46	43 (44 with "Carbon's")

Reading nine pages of rendered text and finding a line in the middle worked both times. Counting did not: the second run missed a few occurrences on page 2. Do not rely on it for exact counts.

Does Gemini 4 Carbon in AI Mode use your Antigravity limits?

We sent the second request between 12:43 and 12:47 Kyiv time and saved all five Antigravity quota meters (Gemini weekly and five-hour, Claude/GPT weekly and five-hour, and the separate Gemini 4 Argon weekly pool) at 12:43, 12:46 and 13:03. The 13:03 capture is at least 16 minutes after the request; earlier, these meters took up to 11 minutes to update (our own measurement). All values matched to eight decimal places. Remaining Gemini weekly quota: 0.28816345 (29% in the panel). Remaining Argon weekly quota: 0.6736772 (67%).

Google's usage-limits page for Gemini and AI Mode showed 1% current use, resetting at 13:19, and 0% for the week, before and after.

What this shows: this request did not draw from our Antigravity quotas. What it does not show: that AI Mode has no limit of its own. That page counts whole percent, so a small cost would not appear, and Google may apply a hidden cap after more requests. We did not push for one.

How to check it yourself

Open google.com/ai while signed in to a Google AI Pro account.
Press + next to the question box.
Look at the bottom of the menu: on our Pro accounts it listed Auto, 3.8 Flash and 4 Carbon.

If you do not see the model section, you may be on a plan or in a rollout group where it is not offered yet.

What we could not confirm

The exact model ID. Google's own menu labels the option "4 Carbon", and we take that label at face value: it is the Gemini 4 Carbon model. The page's network calls do not expose a model ID to us, so we could not check it independently.
Is this a rollout, a test, or a mistake? We saw it on two Pro accounts on one day. It may be staged, region-specific or temporary. For comparison, Gemini 4 Argon was first Ultra-only in Antigravity and reached Pro a few days later (what happened with Argon on Pro).
Does it work in Auto mode? We did not test whether Auto picks Carbon by itself.

What this means for you

On Google AI Pro, check AI Mode: the + menu may offer 4 Carbon. On the Plus and free accounts we saw, there was no model choice.
With 4 Carbon selected you can attach images but not files, and it is a chat in Search, not a coding agent. Antigravity still says Carbon is for Ultra.
In our one test it did not touch the Gemini, Claude/GPT or Argon quotas in Antigravity. We have not tested heavier use.
It may change or disappear without notice. We will add an update if Google comments or the menu changes.