Gemini 4 Argon is out for subscribers. Carbon is still for security teams

Both Gemini 4 models went to security teams first. Argon reached vetted cyber defenders on September 30 and opened to Google AI Pro and Ultra subscribers and the Gemini API on October 13. Carbon was announced on October 28, four weeks after Argon, and so far only a small group of defenders has it.

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What Gemini 4 Argon is good at

Google pitches Argon at "complex workflows across real-world software engineering, enterprise knowledge work like legal and finance, and cybersecurity defense." The scores it published, all run by Google:

Google's post also describes what Argon-based agents actually did. They helped port C and C++ code to Rust, including more than 800,000 lines for the Fuchsia Zircon kernel, and built a Rust version of the libgav1 video decoder that runs 2.7 times faster than the existing Rust port with identical output. Google says Argon can write up to 1 million tokens in one response; the previous limit was 64,000.

On safety, Google says Argon refuses cyberattack and weapons requests from regular users, while trusted defenders get it without the cyber guardrails. Google calls it its "most resilient model yet" against indirect prompt injection, the trick of hiding instructions in a web page or document the model reads.

What we know about Gemini 4 Carbon

Carbon arrived on October 28 with a narrower pitch: Google's strongest model for cybersecurity and long-running work. According to coverage of the announcement, Google's own table puts Carbon first in 15 of its 17 benchmark rows, with OpenAI ahead on one software engineering test and Anthropic on one computer-use test.

Access starts with a subset of cyber defenders and expands through the Fairwind Program "ahead of wider availability soon." Google hasn't given a date for developers or consumers.

Google hasn't said when Carbon reaches the Gemini app or the API, whether it shares Argon's architecture, or how large its context window is. Reports so far put its price at Argon's introductory $2 and $10 per million tokens, which Google hasn't confirmed.

How to use Gemini 4 Argon today

On the API, Argon costs $2 per million input tokens and $10 per million output tokens during an introductory period, then $4 and $20. Cached input is 95% off. Google hasn't said when, or whether, free Gemini accounts will get Argon.

What happened to Gemini 3.5 Pro?

Google announced Gemini 3.5 Pro at I/O in May 2026. It still hadn't shipped on July 21, when Google released three new Flash models and TechCrunch pointed out the missing Pro. Argon is now the newest model in the Gemini app, and the Gemini 3.x Flash models are still the lower-cost choice for high-volume work.

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