Live data from Hacker News

Claude Fable 5.1 and Claude Mythos 5.1

anthropic.com

131–140 of 1001 posts

Re: Claude Fable 5.1 and Claude Mythos 5.1

#132
post #99

I’m really excited to try this out. Fable and Opus 5 constantly wow me when working together. Unfortunately, I’m a little burned because of technical issues. Anthropic accidentally over-billed my account, and when I reached out to the support bot, it downgraded my account to a Free account. It’s been impossible to get it resolved and I have almost $200 held hostage. I don’t want to do a charge back. I’m one of the ma…

you aren't the only one with this issue. many other people I've heard had a similar issue with anthropic billing. I also had a weird edge case behavior around billing where it blocked my usage due to an unpaid bill but then also wanted me to pay for that blocked unavailable usage when I would reinstate my account.

I am disappointed in how anthropic handles billing, and is using AI sloppily for customer service around here. Very unprofessional, and at this point since its been well known and shared, it also is feeling unethical.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#133

Hi Claude, please cure aging, make no mistakes

Ever since this "comedic incident" [0] you are apparently "not allowed" to make this specific joke as you are going to "upset" some people who don't get it. /s

But eventually AI will cure something, unironically. It may be Claude, or another AI company.

[0] https://news.ycombinator.com/item?id=48838228

Re: Claude Fable 5.1 and Claude Mythos 5.1

#134
post #35

“ Claude Fable 5.1's writing is generally a step up from earlier Claude models, with fewer stock phrases and less unexplained jargon. In some cases, though, its prose is denser than Claude Fable 5's: sentences run longer and there are fewer paragraph breaks.” I cancelled my pro max Claude subscription last week; codex is much more succinct. I am curious if this is getting better. I don’t think Anthropic realizes that…

One thing I've noticed and HATE, is that when you increase thinking-effort, that seemingly increases response-length. Meaning that X.High is longer than High, which is longer than Medium, etc. Which is kind of the inverse of how people work; a really smart person can condense difficult ideas into simple[r] terms. Whereas people who struggle speak a lot but say very little. High/X.High do seem to deliver better qualit…

OpenAI has separate dials for verbosity and reasoning_effort (but could still do a better job).

Re: Claude Fable 5.1 and Claude Mythos 5.1

#135

Yeah but haiku 5 when?

Asking the real questions. I've been wondering what the holdup on that is. Does anyone reading this have additional knowledge or insight on this?

Sonnet, Opus, and Fable are pushing so much revenue growth right now that it makes more sense to keep growing the expensive models than growing the cheap models.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#136
post #46

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 o…

To be fair, I assume they want to hide that not from their customers, but adversaries who use the way Claude models think and reason to refine their own models.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#138

(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…

Qwen is all you need.

Re: Claude Fable 5.1 and Claude Mythos 5.1

#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 hard to see ANY improvement:

Terminal-Bench 4.0: Fable 5.1 is +3.5% vs Opus 5.

GDPval-AA v2: +1.5% vs Opus 5.

OSWorld 2.0: +2.5% vs Opus 5.

Humanity's Last Exam (with tools): +1.6%

Keep in mind that this is supposed to be an entirely higher tier of a model than Opus 5. For one tier up and one version up, these are not really improvements. Probably leaves no room to place Opus 5.1 anywhere. Combined with the fact that they are selling 'readability'... Has frontier progress finally stalled?

Re: Claude Fable 5.1 and Claude Mythos 5.1

#140
> Data retention. Our new system of Enterprise Frontier Safeguards (EFS) gives customers complete privacy (the same as a zero data retention policy) while still being state-of-the-art at preventing adversarial use. EFS works by storing data in cloud infrastructure controlled entirely by the customer, not Anthropic. It will be made available to enterprise customers in phases, beginning later this fall. Until EFS is available, eligible customers will be able to use Fable 5.1 with zero data retention.

This is interesting. I wonder if customers will be allowed to create an auto expiry for their own data to prevent future subpoenas. That’d be a treasure trove for discovery.

Post reply on HN