Claire Vo · 2 min read · Gen AI Tools
GPT-5.6 Sol vs. Claude Fable: Why OpenAI’s new model crushes my benchmark
Read the original on lennysnewsletter.com →
By benchmarking GPT-5.6 Sol against Terra, Luna, Claude Fable 5, and Sonnet 5 with the Claire Weighted Index across PRDs, prototypes, wireframes, debugging, and agentic voice, Sol emerges as the winner. The author demonstrates practical use cases—building a gamified homework-tracking app in one shot with Codex and browser automation—highlighting real-world productivity gains. The piece also contrasts model strengths and costs, such as Sol vs Fable pricing and the relative performance on PRD writing and agentic voice.
Key Takeaways
- Claire Weighted Index results: GPT-5.6 Sol is the overall winner across the evaluated tasks (PRDs, prototypes, code, and agentic voice).
- Fable’s precision comes with pedantry that can hinder collaboration, whereas Sol breaks through where Fable stalls.
- Codex + GPT-5.6 enables practical, one-shot builds (e.g., gamified homework app) and Chrome-based browser automation for scalable tasks.
- Per-task insights: Sol shines in prototypes and PRDs, Sonnet 5 remains a top pick for agentic voice in OpenClaw, with pricing considerations between Sol and Fable API.
Excerpt
GPT-5.6 Sol is back, and I ran it through my full How I AI vibe benchmark against GPT-5.6 Terra, Luna, Claude Fable 5, and Sonnet 5 across five categories: PRDs, prototypes, wireframes, debugging, and agentic voice. Sol won by a meaningful margin on my Claire Weighted Index (70% my taste, 30% Terminal Bench 2.1), and I also tested two use cases I can't stop thinking about: building a gamified homework tracking app for my kids in one shot with Codex, and browser automation with Chrome that burned through 500 LinkedIn replies while I did literally nothing. Listen or watch on…