GPT-5.6 Sol Leads in Agent Benchmarks
RajmaChawala · reddit · 2026-07-14
The post compares frontier models like GPT-5.6 Sol, Claude Fable 5, and Grok 4.5 (released the same day), focusing on their performance in agent scenarios.
Key Information
- GPT-5.6 Sol outperforms Claude Fable 5 by 13.1 points on Agents' Last Exam, scoring 53.6 vs 40.5.
- Achieves 88.8% on Terminal-Bench 2.1.
- Priced lower than Fable 5, which the author considers a better deal for similar or superior agent capabilities.
Caveats
- Independent reviewers note Fable 5 remains stronger in architectural reasoning and planning.
- OpenAI withheld long-context recall data, which the author finds suspicious as it is typically a known weak point.
- The author also mentions the simultaneous release of Grok 4.5 and the ongoing absence of Google's Gemini 3.5 Pro, marking the first time all major frontier labs are competing head-to-head simultaneously.
The post concludes with a video breakdown and a practical question: which model are people actually using for daily tasks now?
Related event: Grok 4.5 Tops Long-Horizon Terminal-Bench(3 posts)→
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