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

Claude Fable 5

anthropic.com

Post reply on HN
Print view View original

971–980 of 1001 posts

Re: Claude Fable 5

#971

Post by ivanovm »

teiferer wrote: post #769
simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

> It's possible Opus or GPT-5.5 could have done this too, I've not tried the exact same sequence. The Fable vibes are good here, though. And that's the thing. These comparisons are all gut feelings. I'm missing objective unbiased measurements to actually have real comparisons between different models, their different generations, or even just the convention that everybody adds "you are an expert software engineer" an…

The benchmarks are now the equivalents of SAT/ACT/other standardized exams for humans. They are directionally quite predictive, but with plenty of outcome variance on the margins

Re: Claude Fable 5

#972

Post by conception »

azalemeth wrote: post #833

I genuinely can't use Fable. I'm a medical physicist. I use the word nuclear a lot. Opus is fine (well, 99% of the time - I've certainly hit the CBRN filters a few times and even been invited to email anthropic about the false positives). Fable has literally refused to work on any of my problems (even those about fluid dynamics!) and just tells me that I'm violating anthropic's AUP. I've reached out to their support…

They’ve mentioned that they will have the ability to access less guarded models with a verification program in the future. I suspect these guard rails will have options to move past them shortly here in the future.

Re: Claude Fable 5

#973

Post by keybored »

sigbottle wrote: post #940
simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

Just tried it. Fable is extremely strong. The fact that we can't point to any concrete architectural upgrade is worrying - that means "it just gets bigger" is kind of viable. To be clear, the jump from Opus to Fable was like the jump from pre o3 -> o3 for me. Very sharp improvement, not incremental. But that could be explained by dummy long thinking times. It one shot a task that Opus burned hundreds of dollars on to…

Worrying? Depressing? Why are people who are clearly enthusiasts (since they are testing the capabilities on release) always using these words? Is this a genuine interest, something that is pleasurable, or a morbid curiosity to test the bleeding edge of Humanity’s Doom? Bizarre.

Re: Claude Fable 5

#974

Post by qingcharles »

alexchantavy wrote: post #541
simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

High, extra, or max?

It has a setting named "Ultracode" with a flashy little disco light when you select it. (not joking!)

https://imgur.com/a/NfIxDwN

I wanna press it, but I don't have that kind of mad, generational wealth to put a prompt through on that setting.

Re: Claude Fable 5

#975

Post by nbardy »

jumploops wrote: post #446

It's interesting that we're seeing these gains when it seems Mythos/Fable is "just" a scaled up version of their existing architecture[0]. When GPT 4.5 launched, the gains compared to the model size didn't seem that great, leading some to believe that the only progress we'd see would come from RL. This model certainly has quite a "substantial amount of post-training and fine-tuning", but it's also based on a new pret…

It’s a bit misleading to say nothing special, as they are doing more than just increasing parameter count. Progress has been steady in all the sub components of training from data filtering and weighting to sparse attention, optimizers to up and down the stack various efficiency in training computing.

They’re using more compute, a bigger model and tons of training quality improvements to get more out of an equivalent model.

Re: Claude Fable 5

#976

Post by adithyaharish »

I found this error while using Fable 5 model in claude code. 400 api error. My advisior was on and it errored out saying claude opus 4.8 cannot be used as advisor while using Fable 5

Re: Claude Fable 5

#977

Post by theshrike79 »

teiferer wrote: post #769
simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

> It's possible Opus or GPT-5.5 could have done this too, I've not tried the exact same sequence. The Fable vibes are good here, though. And that's the thing. These comparisons are all gut feelings. I'm missing objective unbiased measurements to actually have real comparisons between different models, their different generations, or even just the convention that everybody adds "you are an expert software engineer" an…

IMO comparing different models is like comparing songs or paintings or modern art.

There is no true objective measure, can you mathematically determine which song is the best for everyone for example? Or which painting different people feel is the nicest to look at or what emotion it gives them.

Yea, you can do the fucking strawberry tests or carwash trick questions, but that doesn't really measure anything useful.

You can also do benchmarks but how do you measure the output of those?

The easiest way is just to use them all and get the feels of which of them works best for you. For me it's Claude first, pi.dev + gpt5.5 second. Plain Codex is a distant third and Gemini exists - it's pretty good at finessing web UIs as it does aria labels and usability better than other, but I wouldn't write backend code with it.

Re: Claude Fable 5

#979

Post by locknitpicker »

simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

> Clone simonw/micropython-wasm from GitHub and research how this could use a full Python as opposed to MicroPython

I might be missing something important but that doesn't seem to be an impressive task.

On a surface level it sounds like the taks requires gathering calls to MicroPython-specific libs, assess which ones are not compatible with Python, and proceed to determine how to replace the ones that are incompatible.

From that first iteration, the rest would boil down to troubleshooting the issues missed on the first shot.

I would be extremely surprised if the likes of GPT4.1 wasn't already capable of handling that task.

So, beyond Claude Fable finishing a task, what exactly is the differentiating factor?

Re: Claude Fable 5

#980

Post by simonw »

locknitpicker wrote: post #979
simonw wrote: post #534

I've spent enough time with this now in Claude Code (and Claude.ai and Claude Code for web) to have an opinion on Fable 5: it's a beast. I'm throwing some VERY difficult problems at at - things I've been dragging my heels on for months - and it's crunching through them very happily. One that I'm willing to share (albeit from just a week ago) - I built a Python library last week that bundles MicroPython compiled to WA…

> Clone simonw/micropython-wasm from GitHub and research how this could use a full Python as opposed to MicroPython I might be missing something important but that doesn't seem to be an impressive task. On a surface level it sounds like the taks requires gathering calls to MicroPython-specific libs, assess which ones are not compatible with Python, and proceed to determine how to replace the ones that are incompatibl…

Did you read the transcript? There are a whole lot of details to figure out: https://claude.ai/share/a73b8b8b-8ebc-4fef-9e5c-7438e5e7ae35
Post reply on HN