GPT-5.6 Sol vs. Claude Fable: Why OpenAI’s new model crushes my benchmark

OpenAI's GPT-5.6 Sol outperformed GPT-5.6 Terra, Luna, Claude Fable 5, and Sonnet 5 on Claire Vo's custom benchmark across PRDs, prototypes, wireframes, debugging, and agentic voice tasks. Sol also demonstrated practical advantages in building a gamified homework tracking app in one shot and automating browser tasks, while Sonnet 5 remained preferred for agentic voice in OpenClaw.

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 YouTube, Spotify, or Apple Podcasts What you’ll learn: How I scored five AI models including GPT 5.6 Sol, Fable 5, and Sonnet 5 using my “Claire Weighted Index” benchmark across PRDs, prototypes, code, and agentic voice The difference between GPT-5.6 Sol Terra and Sol for PRD writing How Fable’s precision and pedantry made it harder to collaborate with, and the exact moment Sol broke through where Fable got stuck Why Sonnet 5 is still my go-to for agentic voice in OpenClaw, even after this whole benchmark How I used GPT-5.6 Sol in Codex to build a fully gamified homework tracking app for my kids in one shot The video editing use case that saved me hours clipping a talk I gave at Cursor’s event How to use Codex plus GPT-5.6 and Chrome for browser automation, and why this is my single most-loved use case right now In this episode, I cover: 00:00 https://www.youtube.com/watch?v=gAWbvEwUoiI Intro 01:10 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=70s The three GPT-5.6 models: Sol, Terra, Luna 02:17 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=137s Pricing: Sol vs. Fable API costs 03:24 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=204s The How I AI benchmark 05:03 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=303s Claire-weighted Index results 07:00 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=420s Per-task winners: prototypes, PRDs, agentic voice 11:59 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=719s What Claire actually rewards 13:20 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=800s Full-fidelity prototype side-by-sides Sol vs. Fable 17:45 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1065s Wireframes 18:19 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1099s Agentic voice 19:15 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1155s Where Sol is better than other models 23:56 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1436s Gamified kids’ homework app, built in one shot 28:02 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1682s Fable’s pedantry problem and how Sol broke through it 31:49 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=1909s Two bonus use cases: video editing and browser use 35:08 https://www.youtube.com/watch?v=gAWbvEwUoiI&t=2108s Final summary and model recommendations Tools referenced: • GPT 5.6 Sol, Terra, Luna : https://help.openai.com/en/articles/20001325-a-preview-of-gpt-56-sol-terra-and-luna https://help.openai.com/en/articles/20001325-a-preview-of-gpt-56-sol-terra-and-luna • Codex: https://openai.com/codex https://openai.com/codex • ChatPRD: https://www.chatprd.ai/ https://www.chatprd.ai/ • CapCut: https://www.capcut.com/ https://www.capcut.com/ • Math Academy: https://www.mathacademy.com/ https://www.mathacademy.com/ Other references: • Cursor event where Claire spoke on the future of PM: https://www.youtube.com/watch?v=4CAFK-rc26A https://www.youtube.com/watch?v=4CAFK-rc26A • ChatPRD blog where benchmark outputs will be published : https://www.chatprd.ai/ https://www.chatprd.ai/ Where to find Claire Vo: ChatPRD: https://www.chatprd.ai/ https://www.chatprd.ai/ Website: https://clairevo.com/ https://clairevo.com/ LinkedIn: https://www.linkedin.com/in/clairevo/ https://www.linkedin.com/in/clairevo/ Production and marketing by https://penname.co/ https://penname.co/ . For inquiries about sponsoring the podcast, email email protected /cdn-cgi/l/email-protection .