› Two weeks ago Gemini 4 Carbon was a model you could only read about: Google published a table of records and gave access to the US government and a few hundred security teams in its Fairwind program.
› On 10 November 2026 Google AI Studio announced that Carbon "is here".
› An hour later I had it running in my own scripts and put it through the same tasks I used for Gemini 4 Argon in October.
› The short version: Carbon costs exactly the same as Argon in the API, it is available in the European Union, but there is no free tier and it is not included in Google AI Pro.