What Gemini 4 Carbon is good at
Google built Carbon on top of Gemini 4 Argon for cybersecurity and long, multi-step work. Figures below are reported by Google unless an independent leaderboard is named.
Finding and proving vulnerabilities
Carbon scores 54.8% on ExploitGym, a benchmark that asks a model to turn a known flaw into a working exploit, up from 42.0% for Argon. Point it at code you own to confirm which findings are reachable and which are noise, then have it write the patch.
Holding up against prompt injection
On Gray Swan's indirect prompt injection benchmark, attacks hidden in pages, emails and files succeeded 0% of the time against Carbon. Google says no earlier model reached zero. This matters most for agents that read content you do not control.
Long, autonomous tasks
Carbon reasons longer than Argon and checks its own work before answering. Use it where a wrong step is expensive: multi-file changes, incident analysis, or a task an agent runs for a long time without a human in the loop.
Top general score
Carbon is #1 on the Artificial Analysis Intelligence Index v5.0, an independent leaderboard, with 59. Claude Opus 5.5 scores 58 and GPT-6 Astra 57. Argon scores 50.
Carbon or Argon?
Both are Gemini 4 models with a 1M-token context window. Carbon trades speed and tokens for deeper reasoning, so the right choice depends on the task.
Pick Carbon for
Security audits, vulnerability triage, agents that browse or read untrusted documents, and hard problems where a second pass over the answer is worth the wait.
Stay on Argon for
Everyday coding, writing and knowledge work. Google still recommends Argon for most of these tasks. It answers sooner and uses fewer tokens.
Leave room in max_tokens
Carbon's reasoning and its self-check count toward the output budget, so it writes more tokens than Argon on the same prompt. Keep max_tokens modest for chat, and raise it for audits and long tasks so the answer is not cut off.
Gemini 4 Carbon vs Gemini 4 Argon vs Claude Opus 5.5 vs GPT-6 Astra
Four frontier models, all available on AIReiter with the same API key.
| Gemini 4 Carbon | Gemini 4 Argon | Claude Opus 5.5 | GPT-6 Astra | |
|---|---|---|---|---|
| Developer | Anthropic | OpenAI | ||
| Artificial Analysis Intelligence Index v5.0 | 59 (#1) | 50 | 58 | 57 |
| Context window | 1M tokens | 1M tokens | 1M tokens | 1.05M tokens |
| Built for | Cyber defense, long autonomous tasks | Everyday coding and knowledge work | Coding agents, long tasks | General reasoning |
| Model id on AIReiter | gemini-4-carbon | gemini-4-argon | claude-opus-5-5 | gpt-6-astra |
The lead on the overall index is one point. Claude Opus 5.5 still scores higher on the index's coding-agent evaluations (62 to 59), and Carbon's clearest margins are in security work. Send the same real task to each model and keep the one that does it best.
How to call the Gemini 4 Carbon API
AIReiter serves Carbon over the OpenAI Chat Completions protocol. An existing OpenAI client needs two changes.
Repoint the client
Set the base URL to https://aireiter.com/api/v1 and use your AIReiter API key. The official OpenAI SDKs work once the base URL is changed.
Send the request
POST https://aireiter.com/api/v1/chat/completions { "model": "gemini-4-carbon", "max_tokens": 8192, "messages": [{"role": "user", "content": "Hello"}] }
Size the output
Carbon thinks before it answers, and that reasoning shares the max_tokens budget. If a response stops early, raise max_tokens before you shorten the prompt.
Gemini 4 Carbon API FAQ
/ 01Which model id do I send?
gemini-4-carbon, the same id Google uses in the Gemini API.
/ 02How is Carbon different from Argon?
Carbon is built on Argon. It reasons longer and double-checks its work, which raises its scores on hard and security-focused benchmarks but makes each answer slower and longer. For most everyday tasks Argon is the faster choice.
/ 03Was Carbon only for security teams?
At first. Google announced Carbon on October 28, 2026 and gave early access to cyber defenders in its Fairwind program. Since November 10, 2026 it has been available to all paid Gemini API developers, and AIReiter serves that release.
/ 04Do I need a Google account or a Gemini API key?
No. Use your AIReiter key with the AIReiter endpoint. To try the model before writing any code, use the playground on this page.
/ 05Are the benchmark numbers independent?
The Artificial Analysis Intelligence Index is an independent leaderboard. ExploitGym and Gray Swan results are reported by Google. Run Carbon on your own tasks before you move a production workload to it.