I hear this a lot and I believe it because I've heard it from so many people, but I have never run into this in my work, and neither has anyone I know in real life.

I don't use Fable for a ton of implementation work, but I use it a lot for planning, so maybe that's related to it. For planning though, I've had a very good experience with Fable and implementing with Opus.

I don't mean to sound like I'm dismissing your experience, but are you sure? I've (semi regularly, most of the time I'm even trying to use Fable) started with Fable, proceeded through my planning, and then at some point in the future realized it had kicked me back to Opus without me knowing. It obviously _said_ it had happened, but I didn't realize and just continued. This might primarily be a result of the project I'm working on (anything network related seems to gets kicked back).

I'd guesstimate that ~80% of the time I thought I was using Fable, I wasn't actually. It's also led me to just... not even try, and just start with Opus regardless.

I've found Fable unusable; not because it's bad, but because it... can't be used.

“Hey Fable, write me some win32 unsafe rust code”

“sure thing boss”

——

“Hey Fable, review this unsafe win32 rust code”

“Potentially dangerous request, falling back to Opus”

—-

Every damn time, ironic because the unsafe win32 code can be generated by fable in the same session.

Maddening.

Do your apps do anything with security? I can't hardly use Fable on our authentication service because it constantly trips up and refuses to write tests. Even just doing a security review usually triggers opus.

I agree and wonder whether its either people who basically never use the model complaining or people who used it once a long time ago and haven't touched it since.

We have access to Fable at our company on our enterprise plans and most of us rarely run into an issue.

Obviously this is gonna vary a lot with what technical domain you work in which is why its important when talking about the classifiers that people specify exactly what types of workloads they were seeing failures with.

You can easily trip it up if you're doing reverse engineering work. From memory, the moment Fable 5 saw anything loosely related to "linux seccomp" it threw a fit.