Claude Fable 5.2 and Mythos 5.2

Posted by lairv 23 hours ago

Claude Fable 5.2 and Mythos 5.2(www.anthropic.com)

811 points | 945 commentspage 10

speedboat199 9 hours ago|

Interesting to see that with each new release there are more benchmarks where they report results on Mythos instead of Fable. For example, this time scientific research is reported on Mythos rather than Fable, showing one more domain where everyday joe can never use these models.

stillpointlab 21 hours ago||

Yay! New model day. The most likely time the model isn't nerfed and we get a glimpse at the latest capability.

I wonder how long this kind of excitement at new models will last? I mean, now when I get a new iPhone I don't get the same rush I used to. So I wonder if this hype feeling will fade as we plateau in model capability.

user43928 7 hours ago|

Considering Fable 5.2 is not even worth using over Opus 5.5, can we put the model nerfing nonsense people put all over the comment section to rest now?

flaburgan 18 hours ago||

Cool! I was hoping for Christmas to have an open weight model which would finally be good, with Fable 5.2 available now they just have time to distill and release a new version which will never get nerfed. Hurray for open weights.

butler14 22 hours ago||

Just read the other thread about opus being nerfed and thought "cue the new release"... paha

artisin 22 hours ago||

We'll see what my bank account has to say about this:

> Fable 5.2 at High effort scored about level with Opus 5.5 at Max effort, for roughly half the cost per task

iagiagiag 21 hours ago||

> Thus, in relevant areas, including accelerator kernel optimization and improving large language model architectures, Fable 5.2 and Claude Mythos 5.2 perform at about the level of Opus 5.5.

Obviously. Well, we know what's the "secret sauce". AI models building better AI models and better kernels to optimize inference and training.

borschtplease 21 hours ago||

Maybe at last it will learn to check git state right before claiming obsolete and incorrect info.

Download Chrome just to check some minor ui bug? Sure

Check git for 0.5s before claiming that we're on some branch (incorrect one) with no commits pushed (incorrect one)? Sorry, can't do

tiffanyh 22 hours ago||

I didn't realize that Opus 5.5 was more capable than Fable 5.1 in virtually every category.

sekai 21 hours ago||

Not anymore, they have nerfed it.

breezybottom 21 hours ago||

Seemed pretty clear from the benchmarks when they released it.

xlayn 15 hours ago||

Anybody else started getting the "how is claude doing" messages around the time it was nerfed?

thiago_fm 6 hours ago|

It feels Opus 5.5 has already saturated pretty much software engineering. I use it daily and it's hard to say what it can't do for software engineering. It's perfect.

Fable 5.2 might be useful for some use-cases, but will likely get very little usage.

Anthropic needs to figure out a way to create a new industry (like pushing forward bio/robotics) to get usage for those models.

edg5000 6 hours ago|

Early computers could crunch numbers well, only later ones started to get good at e.g. graphics. Coding is early in the LLM tech tree. Harder is CAD and PCBs. Today's model can do it, but there is room for improvement. That's just an example from personal use, surely there are more cases out there. I agree completely about these new use cases needed for Anthropic to grow.

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