News for hackers. Stuff that matters.
Re:Claude Fable 5.2 and Mythos 5.2 by minimaxir on Monday November 09, 2026 @02:06PM (#50430085)
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.

Re:Claude Fable 5.2 and Mythos 5.2 by BorisMelnik on Monday November 09, 2026 @02:11PM (#50430165)
I'm a bit out of the loop - would the engagement bait be becuase it is 3 minor jumps forward?
Re:Claude Fable 5.2 and Mythos 5.2 by unshavedyak on Monday November 09, 2026 @02:18PM (#50430291)
I assume because Opus 5.5 was a huge improvement over 5.0 (or was it 5.1? i forget). Fable still talks a fair bit like Opus 5.0 for me, so i'd quite enjoy a Fable equivalent to 5.5. Ie i'm quite interested in Fable 5.5.

Curious to see how 5.2 measures up in producing readable output.

Re:Claude Fable 5.2 and Mythos 5.2 by bananaflag on Monday November 09, 2026 @02:16PM (#50430262)
Probably they have a more impressive model in preparation, and they're gonna dub that Fable 5.5.
Re:Claude Fable 5.2 and Mythos 5.2 by aurareturn on Monday November 09, 2026 @02:22PM (#50430374)
Probably released on the same day they go public to generate maximum publicity.
Re:Claude Fable 5.2 and Mythos 5.2 by orangecat on Monday November 09, 2026 @02:34PM (#50430612)
They should be going public within the next few weeks and that would be a very short interval between releases. (And despite the chatter I'll be very surprised if they delay the IPO; it would be a massive PR hit and make it even harder for them in the future).

My speculations: maybe this wasn't as much of an improvement over 5.1 as they were hoping, so they're saving 5.5 for the next major update (possibly "Model 4" from the METR report). Or, maybe capacity is constrained so "5.2" is a subtle encouragement to stick with Opus unless a task really needs the increased intelligence.

Re:Claude Fable 5.2 and Mythos 5.2 by enraged_camel on Monday November 09, 2026 @02:55PM (#50430982)
They are most likely saving it to one-up Astra 6.2, which is coming this week supposedly.
Re:Claude Fable 5.2 and Mythos 5.2 by rdtsc on Monday November 09, 2026 @02:23PM (#50430391)
> There were more than a few "leaks" saying it would be called Fable 5.5

Fed to someone specifically to test if they'll leak it and to confirm who that is?

Re:Claude Fable 5.2 and Mythos 5.2 by LeBit on Monday November 09, 2026 @02:39PM (#50430712)
Well who could have guessed they would use 5.5. Such an odd guess.
Re:Claude Fable 5.2 and Mythos 5.2 by AspireOne on Monday November 09, 2026 @03:15PM (#50431318)
Yeah, among the plethora of possible options, this really nails it down to the individual.
Re:Claude Fable 5.2 and Mythos 5.2 by rdtsc on Monday November 09, 2026 @03:22PM (#50431434)
Somewhat plausible values: 5.5 (to harmonize with Opus), 5.3 (we're skipping a minor version because...), 6 (because we're at the top of benchmarks again).
Re:Claude Fable 5.2 and Mythos 5.2 by miketery on Monday November 09, 2026 @03:42PM (#50431781)
The entropy on that is too low
Re:Claude Fable 5.2 and Mythos 5.2 by bhu8 on Monday November 09, 2026 @03:06PM (#50431164)
The pricing is different than 5.1, the model is faster than 5.1. This all suggests that the architecture/size is not the same as Fable 5.1.

So, this is probably Fable 5.5; it's just named Fable 5.2.

Also, this is probably Model 3 from METR's report [^1]. They would name Model 4 Fable 5.5, once (and if) they decide to release it.

[^1]: https://metr.org/blog/2026-11-05-anthropic-ai-rd-acceleratio...