一句话总结
After Google released Gemini 4 Carbon on October 28, 2026, the frontier-model race became a three-way tie at the top: Carbon leads the v5.0 Intelligence Index with 59, Claude Opus 5.5 follows with 58, and GPT-6 Astra ranks third with 57; the three models split wins across coding, long-context and cybersecurity benchmarks.
Model Profiles
- Gemini 4 Carbon: Released by Google on October 28, 2026; positioned as the company's strongest model, focused on long-horizon agentic tasks and cybersecurity; initially available to vetted cyber defenders through the Fairwind program.
- Claude Opus 5.5: Anthropic's flagship model released in 2026; previously topped the v5.0 Intelligence Index at 58 before Carbon's release.
- GPT-6 Astra: OpenAI's flagship model released in 2026; scores 57 on the index and retains leads on agentic-coding benchmarks such as FrontierSWE 2.
Core Parameter Comparison
| Metric | Gemini 4 Carbon | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|---|
| Intelligence Index v5.0 | 59 | 58 | 57 |
| Terminal-Bench 4.0 | 65.2% | 59.6% | 59.1% |
| Terminal-Bench-Science | 64.8% | 59.0% | 63.3% |
| GraphWalks (256k-1M long context) | 96.2% | 66.8% | 71.8% |
| SEC-bench Pro | 88.2% | Not disclosed | 85.4% |
| ExploitGym | 54.8% | 34.5% | 42.4% |
| CWE-bench | 71.0% | 67.0% | 68.0% |
| OSWorld-2.1 offline | 81.5% | 87.2% | 80.9% |
| FrontierSWE 2 | 61.2% | 62.3% | 65.5% |
| Coding Agent Index | 59 | 62 | Not disclosed |
| Intro price (per 1M tokens in/out) | $2/$10 (later $4/$20) | $4/$20 | $10/$50 |
| Access | Cyber defenders (Fairwind) | Open API | Open API |
Key Differences
- Overall intelligence: Carbon tops the index at 59, one point above Opus 5.5 and two above Astra; the gaps sit within benchmark noise, indicating a tight race.
- Long context: Carbon's 96.2% on GraphWalks (simulating 256k to 1M tokens) far exceeds Astra's 71.8% and Opus 5.5's 66.8% — its biggest highlight.
- Agentic/terminal work: Astra leads FrontierSWE 2 at 65.5%; Opus 5.5 leads OSWorld-2.1 offline at 87.2%; Carbon leads Terminal-Bench 4.0 at 65.2%.
- Cybersecurity: Carbon leads all three security benchmarks (SEC-bench Pro 88.2%, ExploitGym 54.8%, CWE-bench 71.0%).
- Pricing: Carbon launches cheapest at $2/$10, later settling at $4/$20, matching Opus 5.5; Astra is priciest at $10/$50.
Buying Guidance
- Cybersecurity and vulnerability teams: Evaluate Gemini 4 Carbon first, but note that access is restricted by Fairwind vetting.
- Agentic and computer-use scenarios: Evaluate GPT-6 Astra (FrontierSWE 2 lead) and Claude Opus 5.5 (OSWorld lead) first.
- Overall value: Carbon and Opus 5.5 cost the same ($4/$20); Carbon scores slightly higher overall, while Astra leads some terminal tasks but costs more.