🚨 GPT-5.6 Sol is now officially #1 on Design Arena.
That puts it:
• Above Claude Fable 5
• In the same tier as GLM 5.2
• 18 positions higher than GPT-5.5
• +60 Elo in a single generation
Perhaps the most impressive part: GPT-5.6 Sol sits on a new speed vs. quality Pareto frontier.
In other words:
It's not just better.
It's better and faster.
Huge release from OpenAI.
GPT-5.6 Sol by @OpenAI is #2 on the Agent Arena leaderboard, based on 7.8K real-world agentic sessions!
It is a notable uplift from GPT-5.5 (xHigh) of +1.6% Net Improvement, narrowing the gap with the frontier Claude Fable 5. The biggest difference comes from ‘Praise vs Complaint’, a signal that captures implicit user satisfaction with an agent’s responses and artifacts. Claude Fable 5 scores +17.3%, compared with +10.9% for GPT-5.6 Sol. See detailed signal-level comparison below.
In Agent Arena, we measure models on millions of real-world, long-horizon agentic tasks from a global community of users. Models can access web search, filesystem, and terminal tools to complete complex workflows. The leaderboard measures model performance on outcomes relative to the average model using a causal tracing methodology.
Congrats again to the @OpenAI team!
🚨 GPT-5.6 just made a massive jump in offensive cybersecurity tests
OpenAI’s newest model showed major gains over GPT-5.5:
• ExploitBench 2 increased from 47.9% to 73.5%
• ExploitGym performance rose from 15.1% to 24.9%
• Exploit Gym also reached 33.7% given 6 hours to work
• Uses fewer tokens than previous models on complex security tasks
• OpenAI says it still failed to autonomously complete full exploit chains
The cybersecurity gains are incredible.
Are frontier models becoming too capable to release without restrictions?