Google opened Gemini 4 Carbon to developers, enterprises, scientists and consumers on November 10, 2026, and the release landed alongside a result that may matter more to security teams than the model itself.
According to SecurityWeek, agents running on the new model helped Google DeepMind verify core security properties of Signal’s reference code, and the agents wrote roughly 6.5 million lines of Lean proofs doing it.
Two stories arrived in one day. The first is a pricing and access story: who can call Carbon, through which door, and at what rate. The second is a research story: DeepMind’s new AlphaProof Code framework turned a language model into a proof engine and pointed it at one of the most scrutinized codebases in consumer cryptography. This analysis covers both, with numbers, caveats and a view on what comes next.
One framing note before the details. The phrase “widens access” is a headline description, not an official product name, and no named individual gave an on-record quotation in the available coverage. So this piece paraphrases the announcement and the reporting, and it flags every place where the public record runs out.
Readers who followed our earlier piece on the Gemini 4 Carbon intro price will find the access picture has now broadened.
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Google announced Carbon availability for four audiences at once: developers, enterprises, scientists and consumers. That grouping is deliberate. A frontier model that only sits behind a waitlist builds buzz, but a model that reaches a paying API customer, a corporate admin and a consumer subscriber on the same day builds usage data across every tier.
Carbon reaches paying developers and enterprises through the Gemini API in Google AI Studio and through Gemini for business. Consumers on the Google AI Ultra plan get it through three surfaces: Google Antigravity, the Gemini app and AI Mode in Search. The Ultra route matters because it puts a frontier model inside a search product that Google already runs at enormous scale.
The coverage differs in emphasis. 9to5Google framed the Gemini app change as a rollout to AI Ultra subscribers while Argon remains available. Engadget’s headline described Carbon as widely available around the world. The announcement’s own list of channels is narrower and more specific, and this article sticks to that list because it is the only version backed by the vendor’s text.
The table below maps each audience to its access route, using only the channels named in Google’s announcement. Anything not listed there, such as free-tier limits or regional rollout dates, stays out of the table because the public record does not confirm it.
Two details stand out. First, the API and business routes are limited to paying users, which keeps casual experimentation on older models. Second, Antigravity appears in the Ultra list, which signals that Google wants Carbon tied to its agentic coding tool, not only to chat. That fits the other half of the news, because AlphaProof Code is an agentic workflow at heart.
Google’s announcement post sets an introductory API price of $2 per 1 million input tokens and $10 per 1 million output tokens, valid through November 30, 2026. After that date, the listed price doubles to $4 per 1 million input tokens and $20 per 1 million output tokens. The intro window is therefore just 20 days long from launch.
The table applies those published rates to…
