Claude Fable 5.1 and Claude Mythos 5.1 • Hacker News Board

Re: Claude Fable 5.1 and Claude Mythos 5.1

#591

Post by cube00 » Tue, Sep 01, 2026, 9:57 PM UTC

eamag wrote: post #467

5555watch wrote: post #433

Earlier quoted context omitted.

While I can't speak for everyone in academia, I personally don't feel comfortable in putting my research questions and outputs to a private website, before the idea is at least arxived. Especially as all the Fable/Mythos prompts are said to be human reviewed. So I believe that, at least in the short run, we might be seeing breakthroughs in hard open problems or in low hanging problems which are not that interesting t…

Isn't it showing a problem with an academia? "I don't want to live in a world where someone else makes the world a better place than we do."

Academics have to eat and they're judged on the quality of the research they produce.

They're more likely to share their research then big tech once it's ready and they can get the credit they deserve.

This can then be used to succeed in future grants or if your institution is particularly strict, meet your publish quota to keep your position.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#592

Post by heurist » Tue, Sep 01, 2026, 9:57 PM UTC

rybosworld wrote: post #61

Instead of a new model that's going to have unreasonably shallow usage limits, I wish they would: 1) address the claude 20x plan usage being only 6-7x the ceiling of the claude pro plan 2) either fix opus 5, make it completely free, or delete it entirely

I downgraded from the 20x today after learning that 20x only applies to 5 hour usage. I have barely used Claude/Claude Code in the last month and am considering downgrading further, even after this update.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#593

Post by harshaw » Tue, Sep 01, 2026, 9:57 PM UTC

EliasWatson wrote: post #308

To be honest, these frontier model releases have become boring for me. Opus 4.8 was already good enough for most of my use cases. I don't have any projects right now that I would use Fable for instead of Opus. So when I see announcements like this I just think "that's cool I guess" and then go back to using weaker/cheaper models. What's far more exciting right now is models like DeepSeek V4 Flash and GLM 5.3 Flash. T…

if you use these things to generate design docs / text, it should be good news if it is actually better at prose as advertised. Some people like sol for prose better the anthropic models.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#594

Post by blondie9x » Tue, Sep 01, 2026, 9:58 PM UTC

felixrieseberg wrote: post #69

(I work at Anthropic) Beyond all the benchmarks, I think Fable 5.1 is a big improvement in writing style. It sounds a lot less stereotypically like other Claude models, has (imho) a much more natural style, and responds to my style instructions more reliably. More work to be done (and we will!) but reading better prose makes me so much happier. Another point I expect not to get much attention until it all happens at…

Are the models improving their footprint on the natural world? Data centers and and the natural resources consumed by models for production of materials and for building and running inference servers are contributing towards environmental degradation. How can we prevent that as we continue the roll out so we shift this to a more sustainable developmental rollout path?

Re: Claude Fable 5.1 and Claude Mythos 5.1

#595

Post by matheusmoreira » Tue, Sep 01, 2026, 10:01 PM UTC

felixrieseberg wrote: post #69

(I work at Anthropic) Beyond all the benchmarks, I think Fable 5.1 is a big improvement in writing style. It sounds a lot less stereotypically like other Claude models, has (imho) a much more natural style, and responds to my style instructions more reliably. More work to be done (and we will!) but reading better prose makes me so much happier. Another point I expect not to get much attention until it all happens at…

But is the model actually going to answer hard questions when we ask them? Or are you going to keep downgrading the models so as to avoid "uplifting" lesser lifeforms like us?

Re: Claude Fable 5.1 and Claude Mythos 5.1

#596

Post by qgin » Tue, Sep 01, 2026, 10:01 PM UTC

cush wrote: post #589

simonw wrote: post #144

Pelicans for thinking effort low, medium, high and xhigh (that xhigh one is pretty good): https://tools.simonwillison.net/markdown-svg-renderer#url=ht... I'm still waiting for effort max to finish. EDIT: I fixed a bug in my tooling so it now records summarized reasoning traces - here's that max pelican, which is a significant improvement: https://tools.simonwillison.net/markdown-svg-renderer#url=ht... Took just under…

Finally we have a fish in the basket!!

The ever-expanding pelican lore

Re: Claude Fable 5.1 and Claude Mythos 5.1

#597

Post by jltsiren » Tue, Sep 01, 2026, 10:03 PM UTC

eamag wrote: post #467

5555watch wrote: post #433

Earlier quoted context omitted.

While I can't speak for everyone in academia, I personally don't feel comfortable in putting my research questions and outputs to a private website, before the idea is at least arxived. Especially as all the Fable/Mythos prompts are said to be human reviewed. So I believe that, at least in the short run, we might be seeing breakthroughs in hard open problems or in low hanging problems which are not that interesting t…

Isn't it showing a problem with an academia? "I don't want to live in a world where someone else makes the world a better place than we do."

The problem is a lack of funding, which leads to excessive competition and ties continued employment to sustained contributions.

Many results are obvious in retrospect, and such results are often the best ones. The difficult part with such results is framing the problem in the right way and asking the right questions. If you manage to do that, the result simply follows. You may still need funding and hard work to confirm your finding, in which case someone with more resources can claim your result, if they are aware of the idea.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#598

Post by leumon » Tue, Sep 01, 2026, 10:04 PM UTC

Fable 5.1 seems to be the first model who can accurately draw an airbus a320 in 3D space given a set of limited tools (a brush with params color, size hardness and xyz coords): https://youtube.com/shorts/vyHsMqop2yw

Re: Claude Fable 5.1 and Claude Mythos 5.1

#599

Post by black_knight » Tue, Sep 01, 2026, 10:06 PM UTC

GodelNumbering wrote: post #139

The price reduction comes from the cache read pricing falling from $1/M to $0.25/M, which means that Fable 5.1 now costs half of Opus's cache read costs ($0.5/M). This gives a lot of credit to the theory that Anthropic did not get much bite on Fable at its original pricing, which in turn likely places a ceiling on LLM pricing in general. Interestingly also, if you take away terminal-Bench-Science 0.1 results, it is h…

I haven’t yet had a week without spending my Max Fable allowance. For my work (formalised mathematics) Fable is my go to for hard(ish) tasks and problems – of which I have many!

I hope they keep making it smarter! (Cheaper would be nice too, but smarter is my priority!)

Re: Claude Fable 5.1 and Claude Mythos 5.1

#600

Post by ryandvm » Tue, Sep 01, 2026, 10:06 PM UTC

felixrieseberg wrote: post #69

(I work at Anthropic) Beyond all the benchmarks, I think Fable 5.1 is a big improvement in writing style. It sounds a lot less stereotypically like other Claude models, has (imho) a much more natural style, and responds to my style instructions more reliably. More work to be done (and we will!) but reading better prose makes me so much happier. Another point I expect not to get much attention until it all happens at…

Great. I'm looking forward to it being less obvious that my colleagues have stopped understanding their jobs.