Claude Opus 5 is practically unusable for real work right now.
It is lazy. It skips steps, cuts corners, and outputs slop unless you babysit every prompt. Good at UI and that is about it. For anything backend or complex it just gives you something that looks right and is not.
Here is what Opus 5.1 has to fix. Stop being lazy. Stop generating slop on the first pass. Stop making me rewrite prompts three times to get what Fable 5.1 gives me in one.
Fable 5.1 is the model Opus 5 should have been.