Yet another Hacker News

Claude Fable 5.2 and Mythos 5.2

145 points meetpateltech 22 minutes ago 33 comments

217 18 minutes ago | parent

omg FINALLY lets GO

shmoil 18 minutes ago | parent

>> Fable 5.2 and Mythos 5.2 are a step above Opus 5.5 in almost all the capabilities we evaluated.

Was this before you lobotomized Opus 5.5 or after?

https://news.ycombinator.com/item?id=50419019

monkeydust 13 minutes ago | parent

Leaps across the board but Robotics jump is huge.

minimaxir 12 minutes ago | parent

There were more than a few "leaks" saying it would be called Fable 5.5, so I'm curious if a) the leaks were just engagementbait or b) Anthropic changed it, despite the fact that Fable 5.2 being better than Opus 5.5 is confusing.

Surprisingly the model is available immediately in my Claude Code: usually there's a delay, either for rollout or safety.

BorisMelnik 7 minutes ago | parent

I'm a bit out of the loop - would the engagement bait be becuase it is 3 minor jumps forward?

bananaflag 2 minutes ago | parent

Probably they have a more impressive model in preparation, and they're gonna dub that Fable 5.5.

iammrpayments 12 minutes ago | parent

Too expensive for me

hmate9 12 minutes ago | parent

Its cheaper at $8 per million input tokens and $40 per million output tokens which is also pretty sweet.

minimaxir 5 minutes ago | parent

Additionally, the terms for the free resets are unusually generous: https://support.claude.com/en/articles/17506494-claude-fable...

> the number of Fable resets you get depends on how long you’ve been a paid subscriber [...] Subscription length is measured from the date of your first paid bill. If you canceled and came back, the time since your first paid bill still counts.

> These resets expire on March 8, 2027 at 11:59 pm PT.

tl;dr if you joined when Opus 4.5 became a thing, you got 2 resets.

guybedo 1 minute ago | parent

i might be wrong here but it seems these are not resets of your weekly quota but resets of the Fable limit.

That means you can lift your Fable max 50% usage and you'll just end up burning through your quota faster. You won't have more tokens.

__natty__ 11 minutes ago | parent

Maybe it's just me, but I found Claude's writing style terrible compared to GPT or Gemini. It's "smart", but the way it communicates seems somehow off compared to other models.

ealready_value 9 minutes ago | parent

Very interesting that they set the flagship's version number to 5.2, but their penultimate model is 5.5. Do they want people to to continue to think that Opus is based on more advanced technology? The decision these AI companies make continues to baffle me.

iamdelirium 9 minutes ago | parent

FrontierCode 2.0 is such a poor benchmark for Gemini since it's the only model forced to not use its own harness but Devin CLI.

I wonder why that team singles Gemini out like that.

aurareturn 8 minutes ago | parent

Is this the Model 4 internal name?

Reference: https://x.com/METR_Evals/status/2118412205662314935

tiffanyh 6 minutes ago | parent

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

cobri 5 minutes ago | parent

Does this coincide with the claimed nerfing of Opus 5.5? https://news.ycombinator.com/item?id=50422069

jasonlotito 3 minutes ago | parent

At this point, this is giving "She Deep Breaths More" from Onyxia in WoW.

pookieinc 4 minutes ago | parent

“Testers have found that Fable 5.2 and Mythos 5.2 communicate more clearly than past Fable and Mythos models. They generate outputs up to 30% faster than Claude Fable 5.1 and Claude Mythos 5.1, and they’re available at a lower price: $8 per million input tokens and $40 per million output tokens.”

Honestly incredible that they’ve managed to beat all benchmarks, while making it cheaper. Always happy to see improvements offered at lower costs.

Will be interesting to see what OpenAI does in response

privacyishuman 3 minutes ago | parent

They still need a response to Opus 5.5

canadiantim 4 minutes ago | parent

god bless token resets!

hello5010 1 minute ago | parent

> god bless token resets!

You have session limits?

You should probably give OpenCode a try. Can run DeepSeek, Qwen, Kimi, … but also Fable 5.2, Opus 5.5 and GPT 6 Astra

theverycob 4 minutes ago | parent

+ 2 Fable resets HAHA. "Too expensive" who cares! Thanks Dario

awongh 3 minutes ago | parent

Doubling Remote Labor Index (RLI) - at 41.3% compared to around 20% for the other models - I wonder what kinds of new agentic work this is going to unlock.

bananaflag 3 minutes ago | parent

Those theoretical physics papers look like the real thing (i.e. not mathematical physics like the OpenAI Yang-Mills result). It looks like AI is finally branching out of math.

unshavedyak 3 minutes ago | parent

Looks like some plans get extra fable usage: https://support.claude.com/en/articles/17506494-claude-fable...

theverycob 3 minutes ago | parent

+2 Fable resets!!! "Too expensive" Who cares! Thanks Dario

artisin 3 minutes ago | parent

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

mikert89 3 minutes ago | parent

The end of software is so close, very soon the code itself will be nearly obsolete, there will be schedulers, queues, a database, and the model

skeledrew 2 minutes ago | parent

Damn people were right about 5.5 being nerfed in preparation for a version release. This is not at all a good look.

- https://news.ycombinator.com/item?id=50422069

fermlon30000 2 minutes ago | parent

stop OPUS 5.5 FUCK, DAMMIT, THEY DIDN’T JUST NERF HIM—THEY ABSOLUTELY OBLITERATED HIM, THE FUCKING MISANTHROPES! I EVEN MADE A MISTAKE IN MY ENGLISH IN THE PREVIOUS SENTENCE—NOW THAT FUCKING CLAUDE IS TEACHING ME ABOUT BUGS!

butler14 1 minute ago | parent

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