These are my opinions on which circumstances Sol fails terribly vs Fable.

I am the type of coder that vibe codes - I talk to the agent about a problem, have it write a plan, red team the plan, and then implement the plan. These projects are things which haven’t really been done before, or if they have it’s not public or not in many places.

What I find is that Sol is hyper-left brained. Super focused on small details. When given a longer task with multiple steps it might go really hard on one of the early steps and it will validate, test, make safe, so much to the detriment of progressing the task within reasonable parameters for the project.

It also starts to sound crazy when you ask it for an update. It starts naming things in weird ways and the sentences don’t really make sense. It’s as if you’ve approached an engineer who has been hammering on something and he speaks to you in the lingo of his latest function, even though when you ask him for a status you are obviously asking about the whole project.

Fable on the other hand seems to remain coherent over time. It’s as if it remains aware of the longer run task. It’s got a bit more balance between left and right brain.

So OpenAI really need to find a balance between long term goal thinking and the very small task at hand.

For coders who apply Sol on specific functions or narrow tasks I’m a certain it is great. For me, a vibe coder, I need one that will be a bit more aware of the whole thing through these longer running tasks.