Google DeepMind Releases Gemini 4 Carbon, Tops Intelligence Index but Available Only to Security Experts

Google DeepMind released Gemini 4 Carbon on October 28, 2026, just two weeks after its predecessor, Gemini 4 Argon. According to independent benchmarking firm Artificial Analysis, Carbon scored 59 points on the updated Intelligence Index v5, significantly outperforming Argon's 50 points and taking first place in four of the index's nine individual evaluations, including complex reasoning and scientific tasks.

Designed for multi-day, autonomous development workflows, Google claims internal teams ran the model continuously for days to handle root-cause analysis and subtle bug fixes in large codebases. In agentic coding, Carbon scored 59 on the Coding Agent Index, a substantial jump from Argon but still trailing Anthropic's Claude Opus 5.5 (62). The model also rose 89 Elo points on the WebDev Arena to reach 1,769, placing it fourth overall.

Due to its advanced cybersecurity capabilities, Gemini 4 Carbon will initially be available only to selected security experts through the U.S. government's voluntary pre-testing process. Google cited the model's proficiency across the full cyber defense lifecycle, from vulnerability detection to patching. On SEC-bench Pro, which measures autonomous vulnerability discovery without safety guardrails, Carbon scored 88.2%, leading all tested models, while achieving a 54.8% success rate in turning vulnerabilities into working exploits on ExploitGym.

Third-party evaluations highlight trade-offs. On Vals AI's Index v2.2, Carbon ranked second with 70.36% accuracy, behind Claude Sonnet 5.5. While it increased cited sources by roughly 45% in legal research, task duration more than doubled compared to Argon, averaging over 50 minutes per task. Pricing remains unchanged from Argon at $2 per million input tokens and $10 per million output tokens.