Fable 5.1 looks like a more usable model.
And a potential daily-driver. Time will tell.
IMO, Opus 5 is probably still good enough for most tasks, while Fable 5.1 a more sophisticated coordinator amd verifier.
The bigger and more exciting parts of Fable 5.1 are:
• reduces cost by ~45% on highly agentic ones • reduces cost by ~25% on typical workloads • great for scientific reserch workflows • improved token-efficiency • better writer/prose
We’re introducing Claude Fable 5.1 and Claude Mythos 5.1. They're the world’s most advanced models for coding and knowledge work.