# Gemini 4 Carbon tops AA Intelligence Index at 59, edging Opus 5.5 > Source: > Published: 2026-10-29 11:11:13+00:00 Yesterday's v5 index had Opus 5.5 alone on top at 58. Carbon takes the lead by one point at $4/$20 per million tokens, but its hallucination rate rises to 11% from Argon's 4%, and access is limited to selected users and vetted cyber defenders. Read: Yesterday's v5 index had Opus 5.5 alone on top at 58. Carbon takes the lead by one point at $4/$20 per million tokens, but its hallucination rate rises to 11% from Argon's 4%, and access is limited to selected users and vetted cyber defenders. Read: Artificial Analysis measured $5.59 per task for Fusion's max setting against $11.42 for Claude Code on Opus 5.5, with a score 2 points lower. Teams paying frontier rates on every coding task now have a router that halves that bill for a small quality drop. Read: It grades what actually changed across 47 simulated apps instead of what the agent reports, and most failures are agents claiming success on tasks they did not complete. Any workflow that trusts an agent's own completion message carries that same blind spot. Read: API usage was billed separately from a ChatGPT subscription. Pro users now get up to $500 a month by tier and Business workspaces share a pooled $500, so prototyping an agent within that amount no longer needs its own API budget. Read: Each response returns the answer, the reasoning and every tool call as separate items, so agent code reads each step directly instead of parsing one Chat Completions message. It works with every Mistral-hosted chat model, including Large 4. Read: It is now callable through OpenRouter with 4,000+ voices and US or EU serving. Artificial Analysis measured 162 characters per second and 81.7% pronunciation robustness, so voice-agent teams have independent numbers rather than only the vendor's claims. Read: One partner cut manufacturing document review time by 89%, and Claude produced 35,000 antibody designs on its own. Every result is preclinical, so the evidence is about time saved in design and paperwork, not about drugs proven in patients.