Opus 5.5 beats GPT-6 Sol on high reasoning, tester says
After using Fable, Astra and GPT-6 Sol, the author calls Opus 5.5 the strongest model on high reasoning and suggests a multi-model workflow for hard problems.
Claude Opus 5.5 is the hands-down best model ever released (on high reasoning). I’ve been using Fable, Fable 5.1, Astra, and GPT-6 Sol With the current usage, Opus 5.5 is the best model. It has all the pros from Fable minus the usage burn, and it’s faster on the right reasoning level. I tested it on X-High/ max, and default to High. The outputs are nearly identical. The higher thinking level just slows down generation. When you do hit those hard issues, use your main agent to start additional sessions with a council of the other frontier models: Fable 5.1 / GPT-6 Astra. Those models work together on the same plan, same context. Then cross-collab to plan the solution. Then spawn as many Opus 5.5 workers as you can afford based on your usage. Give them as many parallel tasks as usage allows and complete any project at scale. You do not need the largest models to run your workflows. You need the smartest order of operations with frontier intelligence to achieve your goals. Default: Opus 5.5 on High. Thanks @claudeai @ClaudeDevs