Google opens Gemini 4 Carbon to paying developers and AI Ultra users, with a price rise due 1 December

Picture a developer stuck on a bug that runs through a dozen files. Two weeks ago, Google’s strongest AI model was kept for a small group of security teams. From today, that developer can use it, as long as they pay.

Google has opened Gemini 4 Carbon to all paying developers and businesses through the Gemini API. It is also rolling out to Google AI Ultra subscribers in the Gemini app, AI Mode in Search and Google Antigravity, Google’s app for coding with AI agents. Alongside it comes /swarm, a preview feature that turns one request into a team of agents.

The pace says something. Google introduced Carbon on 28 October, the same day Alphabet reported quarterly results shaped by heavy AI spending. A paid public release two weeks later suggests Google wants developers building on its top model before the year ends.

Who can use Gemini 4 Carbon today, and what it costs

Koray Kavukcuoglu, Google DeepMind senior vice president and Google’s chief AI architect, announced that Carbon is now in Google AI Studio and Gemini for business for “all paying developers and enterprises”. Google’s pricing page confirms it is not on the free tier.

The launch price is $2 per million input tokens and $10 per million output tokens. A token is a small piece of text that AI services count and bill. The model’s hidden “thinking” tokens are billed too. After 30 November 2026, the price doubles to $4 and $20, as both Google and The Verge report.

Scientists can apply for six months of free access through a Google programme for up to 10,000 researchers, which now includes Carbon. Cybersecurity teams keep their own version through the Fairwind Program.

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One prompt, a whole team: how Antigravity’s swarm works

Google pitches Carbon for the hardest jobs, such as long debugging and open-ended research. The Google Antigravity swarm feature hands your prompt to a coordinator agent, which starts several workers. Each worker edits its own copy of the project, so changes don’t collide. “Adversarial verifier” agents run tests and challenge each change. All of them post to a shared message board you can follow in a side panel.

Google is candid: its Antigravity post warns that systems like this “consume quota much faster than a standard chat”. /swarm is rolling out as a preview in the Antigravity app and its command-line tool.

Google’s own numbers, and what they can’t tell us yet

Google says Carbon ranks first on three benchmarks built by other companies, including CursorBench 4.0. As The Verge notes, companies can choose the results that flatter them, so treat these as Google’s claims until others test them.

On safety, Google compares Carbon only with its own Gemini 4 Argon. It says Carbon’s safeguards cut the breach rate in simulated attacks to 0.8% per attempt, from 3.1% on Argon. On its own honesty test for agents, Carbon passed 92% of tasks, against 70% for Argon. Google also admits that resisting prompt injection, hidden instructions that try to trick an AI, “remains an area for continued improvement”.

• Breach rate per attempt: Carbon0.8%
• Breach rate per attempt: Argon3.1%
• Gray Swan attack queries: Carbon2.17%
• Gray Swan attack queries: Argon9.86%

Google's own figures from simulated cyberattack tests and Gray Swan's automated testing. Not yet checked independently. Source: Google: Gemini 4 Carbon is now available (Koray Kavukcuoglu, 10 November 2026)

Two questions stay open. Google has not said when, or if, Carbon will reach lower-tier or free users. And because Carbon uses more tokens than Argon to check its work, a task may cost more than the per-token price suggests.

If you build with Gemini, test before the price doubles

If you have a paid API key, try Carbon on your hardest tasks before 1 December, and note how many tokens each job uses. On Gemini 4 Carbon and Argon, Google’s own advice is clear: Argon remains “the ideal choice for the majority” of coding and knowledge work. Use Carbon where Argon falls short.

If you pay for Google AI Ultra, look for Carbon in the Gemini app, AI Mode and Antigravity as it rolls out. If you use a free or lower plan, there is no date yet.

Open about its limits, but the proof is still to come

On balance, this is a careful launch. Google gave Carbon to defenders first, named its weak spot on prompt injection and warned that swarms burn through quota. That openness deserves credit.

The harder truth is that almost every headline number comes from Google or its partners. Unlike the Genie 4 world model, which only testers can try, Carbon is open to paying users today. The likelier outcome is that independent tests in the coming weeks will show where Carbon earns its extra tokens, and where Argon is enough.

The date to watch is 1 December

Watch whether developers stay once the price doubles, and whether Google names a date for cheaper plans. A model earns its place on the bills and bug fixes that follow launch day, not on launch day itself.