# Arena ranks Gemini 4 Argon and MiMo-V2.6 higher on costly agent sessions

> Original title: As tasks get more complex, @GoogleDeepMind and @XiaomiMiMo are the biggest winners in the Agent Arena.

- Source: Arena
- Published: 2026-11-04T17:41:21.000Z
- Bad Influence: https://badinfluence.news/items/imw5w8fe0loljn3xc6645d1w5
- Original: https://x.com/arena/status/2118035889175838853

## Summary

Arena says Google's Gemini 4 Argon and Xiaomi's MiMo-V2.6 Flash and Pro gain frontier spots on the most expensive 5% of Agent Arena sessions, where OpenAI and Anthropic hold 7 spots versus 10 of 11 on cheaper tasks. More than 1,000 sessions costing $100 or more occurred in the last two weeks.

## Post

As tasks get more complex, @GoogleDeepMind and @XiaomiMiMo are the biggest winners in the Agent Arena.

On cheaper tasks, @OpenAI and @AnthropicAI hold 10 of the 11 frontier spots. On the most expensive 5% of sessions, they hold just 7. The freed spots go to Google’s Gemini 4 Argon and Xiaomi’s MiMo-V2.6 Flash and Pro.

These shifts matter as sessions costing $100 or more are not uncommon across real-world use cases coming from Agent Arena. Even within the last 2 weeks, more than 1,000 sessions crossed that boundary, and choosing a suboptimal model might have had a meaningful impact on that final bill.

[Video](https://badinfluence.news/api/img-proxy?u=https%3A%2F%2Fpbs.twimg.com%2Famplify_video_thumb%2F2118035768870612992%2Fimg%2FyEvT216kfm6ja3PF.jpg&mode=thumb&exp=1794009600&sig=4a53d241a306ace9)

## Quoted post @arena

> Agent Arena measures complex, real-world tasks. Data shows that these long-horizon sessions amplify differences in frontier models.
> 
> Long-horizon tasks in Agent Arena span hundreds of turns, from porting a codebase to Rust and auditing an investment strategy document to writing a math textbook, and more.
> 
> Comparing the top model from each of the 5 leading labs on Agent Arena reveals a 55-minute gap in how long they spend on long-horizon tasks. The models are:
> - Claude Opus 5.5 by @AnthropicAI 
> - Gemini 4 Carbon by @GoogleDeepMind 
> - GPT-6 Astra by @OpenAI 
> - Muse Wonder Full by @AIatMeta 
> - Kimi K3.1 Pro by @Kimi_Moonshot  
> 
> In this group, Claude Opus 5.5, #1 in Agent Arena, takes the longest at every task length, peaking at 1 hour 51 minutes. In contrast, Kimi K3.1 Pro spends the least time at every length, with 56 minutes on long-horizon tasks.

https://x.com/arena/status/2118033077121524129