Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Claude Fable 5.1 and Claude Mythos 5.1

anthropic.com

Post reply on HN
Print view View original

41–50 of 1001 posts

Re: Claude Fable 5.1 and Claude Mythos 5.1

#41

Post by simonw »

scronkfinkle wrote: post #3

Has anyone been able to get anything substantial done with Fable in the first place? I more or less had totally given up on using it since the alignment checks were so sensitive that it pretty much always threw me back to Opus.

I've used Fable for so much stuff. My experience has been that it can pretty much one-shot most of my complex problems, if I describe them clearly and provide a solid way for it to verify its work.

I get punted down to Opus 5 occasionally (for security-adjacent things) but that's pretty rare.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#42

Post by dijit »

jjice wrote: post #13
scronkfinkle wrote: post #3

Has anyone been able to get anything substantial done with Fable in the first place? I more or less had totally given up on using it since the alignment checks were so sensitive that it pretty much always threw me back to Opus.

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.

“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.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#43

Post by Jcampuzano2 »

jjice wrote: post #13
scronkfinkle wrote: post #3

Has anyone been able to get anything substantial done with Fable in the first place? I more or less had totally given up on using it since the alignment checks were so sensitive that it pretty much always threw me back to Opus.

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 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.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#44

Post by as12fj »

"Democratization" through AI means that everyone has to pay a monthly Anthropic tax and only a small secret guild gets access to the real model.

Jane Street is a partner? How sad indeed. Anthropic could front run them because they leak all the data.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#45

Post by Narretz »

benjiro29 wrote: post #26
pookieinc wrote: post #9

"Price. Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads, wherever usage is billed by token. This is because we’re reducing our pricing on cache reads (where the model reads inputs that have already been processed and stored). For highly agentic work, the savings will often be much larger—up to approximately 45%." Glad to see this!

I hope that this also applies to the Subscription usage. As that can then stretch out Fable usage by a lot more.

Sounds like it specifically does not apply to subscription usage.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#46

Post by mlaux »

Looks like all three breaking changes are patches for inadvertent chain of thought disclosure. Someone found out (don't have the tweet handy) that if you created a bogus "think_deeply" tool and then forced the model to use it, it would output what is believed to be its raw thinking there - I believe the first breaking change stops this. The second two are aimed at people getting Haiku to repeat thinking blocks from other models verbatim (since it can see the decrypted version). I get that in their eyes it's an "exploit" but still kinda disappointing that they patched this

Re: Claude Fable 5.1 and Claude Mythos 5.1

#49

Post by porridgeraisin »

robinpie wrote: post #12

do you think we'll go a full year without a new haiku lol

With compute crunches and everything I am not sure it makes sense for anthropic to commit to haiku as an endpoint and thus a product. There is no telling they aren't using a similarly sized model behind their existing opus/fable endpoints for various subagent / summary purposes of course.
Post reply on HN