Business Insider reports that Google employees are testing newer Gemini 4 builds, including one called Carbon, while the Argon model heads to the public. Google declined to comment, so this is a report, not a launch.
What the report says
Business Insider, citing documents and screenshots, says Google has tested Gemini 4 models called Argon, Barium and Carbon, and that Carbon reached Google's internal coding platform in recent days. One employee told Business Insider that Carbon "feels like Opus 5.5" for coding, with a caveat that more testing is needed. It adds that Google is not guaranteed to release it. Barium is not a newer build: per an internal document Business Insider saw, "Barium-B" is the internal name of the model that became Argon.
Google announced Gemini 4 Argon on September 30. Its blog says Argon is rolling out first to trusted cyber defenders, with developers, enterprises and consumers to follow "as soon as possible", and no date.
Why it matters
Google has not said when Argon reaches the Gemini app. The Decoder says the Gemini app now offers adjustable reasoning intensity from low to high. TestingCatalog says Gemini Web supports low, medium and high thinking effort and suggests this could prepare for Gemini 4. TestingCatalog says paid API customers and Google AI Ultra subscribers are expected to follow the first rollout; Google's blog does not mention subscriber tiers. The Decoder says Google's Workspace Gemini agent announcement this week describes Argon as the model for frontier reasoning; we found nothing on Pixel phones or Workspace plan tiers.
What we could not confirm
Business Insider says it is unclear whether Carbon will be an Argon update or a separate model. Business Insider marks its article subscriber-only; we read the text visible to us and have not seen the documents. We found no consumer release date for either model.
