Arena.ai Ranks GPT-5.5 (xHigh) Second on Agent Arena Leaderboard

Arena

Jun 13, 2026

Arena.ai ranks OpenAI's GPT-5.5 (xHigh) second on its Agent Arena leaderboard with a 10.6% net improvement. The model achieves top rankings in praise versus complaint at 29.4%, bash recovery at 14.1%, and tool hallucination at 2.1%. It records a 5.4% confirmed success rate and 1.9% steerability score across 160,000 real-world agentic tasks evaluated over seven days.

Agent Arena Leaderboard
GPT-5.5 (xHigh): Ranked #2
1 Claude Fable 5 (High) +12.9%
2 GPT-5.5 (xHigh) +10.6%
3 Claude Opus 4.8 (Thinking) +9.3%
4 Claude Opus 4.7 (Thinking) +8.6%
5 GPT-5.5 (High) +8.2%
6 Claude Opus 4.6 +8.0%
7 Claude Opus 4.7 +7.6%
8 GPT-5.4 (High) +7.3%
9 GPT-5.5 +7.1%
10 Claude Opus 4.8 +4.8%
11 Claude Sonnet 4.6 +3.4%
12 GLM-5.1 +2.4%
13 DeepSeek-V4 Pro 0.0%
14 Gemini-3.5 Flash -0.2%
15 Kimi-K2.6 -0.4%
16 Gemini-3.1 Pro -0.6%
17 DeepSeek-V4 Flash -0.9%
18 Qwen-3.6 Plus -4.1%
19 Grok Build 0.1 -5.9%
20 MiniMax-M2.7 -7.9% — Agent Arena leaderboard showing GPT-5.5 (xHigh) ranked second with a ten percent net improvement over baseline.

View the full update on arena.ai

Arena.ai

@arena2d ago

GPT-5.5 (xHigh) ranks #2 on Agent Arena (+10.6% net improvement), making it the highest-ranked OpenAI model closely behind Claude Fable 5 (High). Per signal breakdown, GPT-5.5 (xHigh) ranks #1 in Praise vs. Complaint (+29.4%) and Bash Recovery (+14.1%), scoring higher than Claude Fable 5 (High) on both signals. It trails Claude Fable 5 (High) on Confirmed Success (+5.4% vs. +17.6%) and Steerability (+1.9% vs. +5.4%). Agent Arena evaluates models on millions of real-world, long-horizon agentic tasks. Models use tools like web search, filesystem, and terminal to complete complex workflows: writing code, creating slide decks, researching the web, building apps, and analyzing documents. We use causal tracing to measure model performance across real-world agentic tasks. More breakdown of GPT-5.5 (xHigh) across five signals in the thread.

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