Google’s Gemini 4 Carbon Ranks Second in Arena’s Agent Leaderboard

Gemini 4 Carbon placed second in Arena’s Agent leaderboard, ahead of Google’s Gemini 4 Argon, which ranked seventh in the latest available standings. The result adds a real-session comparison to Google’s launch claims for its new model, though Arena’s task-level figures show Carbon used more time, tokens, and money per task than Argon. Google announced Gemini 4 Carbon on October 28, describing it as a model designed for long-running engineering and cybersecurity work. In the Arena leaderboard snapshot available that day, Carbon recorded 16.04% net improvement, compared with 10.73% for Argon, a gap of 5.31 percentage points. Arena’s rankings are updated over time, so positions and scores can change. Arena’s Agent leaderboard reports results from real agent sessions and includes signals such as task completion, user sentiment, steerability, and tool reliability.