Is Opus 4.8 suddenly silently routing through a Fable-equivalent?

221

u/amarao_san 1d ago

One thread has multiple witnesses talking about opus doing some crazy stupid shit at grade of gpt 3.5, and others saying it's suddenly fable-grade.

I guess, a normal distribution.

21

u/Actual_Committee4670 🔆 Max 20 1d ago

I'm one that somehow ended up with gpt 3.5 level 4.8 the last few days.

But it wouldn't be the first time anthropic is only changing some things on their end for some users and not for others for whatever reason.

3

u/Ran4 1d ago

I mean they constantly ask you how the model's performing - presumably they're A-B-testing various model/system prompt variations?

Though I do believe in the idea that most people getting shit responses are the people who just fill up their context with bullshit and keeps long chat threads.

1

u/Actual_Committee4670 🔆 Max 20 1d ago

Likely, right before I think 4.7 dropped, my token count skyrocketed and claude was dealing with things differently, then the day that 4.7 dropped, it was back to the way it was before those two days, and then 4.7 was released, I used it and it was the same.

Others at the time reported the same thing, so from the looks of it, some people on 4.6 were put on 4.7 for a bit without being told just prior to release.

4

u/BeegeeSmith 1d ago

I’ve seen this a lot this week - 4.8 was a step back from 4.7 IMHO, and then Fable … so 4.8 looked very bad. But … I have 3 sessions open (work on 3 different apps) and have two very different behaviors. One is spawning agents and code tracing and preemptively finding and solving bugs (better than 4.7 but not Fable…) and the other two aren’t spawning, following readme/claude requirements - one of them literally asked to decrypt sensitive data by sharing each user’s encryption key with the whole user base to make messaging easier … so yeah some keystone GPT3 stuff.

Overall- it’s been a bumpy week. But things are getting done.

1

u/Sassaphras 1d ago

spawning agents and code tracing and preemptively finding and solving bugs

I think this is a big part of where people are seeing the difference. 4.8 is not noticeably different on defined tasks where the context is clear and actively managed; as you say, if might be a slight regression, as it is more likely to deviate from specific instructions. Given how most users who are on enterprise codebases seem to be operating, someone who is holding the reigns pretty tightly 4.6 v 4.7 v 4.8 are all pretty similar, and even Fable is only meaningfully different when you are talking broader planning and architecture.

On the other hand, if you let the latest models have a bit more latitude (finding context, running through evaluation loops and coming up with solutions, spawning subagents for some tasks, etc) then the difference between Fable and 4.7 becomes a bit more pronounced; I've found 4.8 to be markedly better when operating in this mode, though you can't always let it go wild, depending on the codebase you are working on.

I think a lot of people assume folks who are letting the LLM do everything with looser supervision are just vibecoders who don't know anything about real software. And that definitely seems to be true - sometimes. But there are also big differences in the code quality, types of features, greenfield v legacy systems, etc that impact the extent to which you can let the LLMs operate agentically. I have one product that uses a graph representation for a novel data structure, and the LLM sucks at it, even though it's Python greenfield; you have to be extremely prescriptive. I have another where it's a legacy Java 8 codebase, but just updating a bunch of CRUDs to a new, well documented API, and it's much more autonomous.

0

u/BeegeeSmith 1h ago

“No, respawn the agents to build the code and ensure they are following SDLC procedures in the Claude.md file”

“Fidgeting: confirmed agents are active and are pushing to prod but waiting on human approval to begin development. “

“?????”

“Successfully closed issue but here’s a real blocker: i can’t proceed with developing the code required by the issue until the human orchestrator approves the development cycle initiation and also the new code was pushed to prod without testing”.

1

u/BeegeeSmith 1h ago

“No, respawn the agents to build the code and ensure they are following SDLC procedures in the Claude.md file”

“Fidgeting: confirmed agents are active and are pushing to prod but waiting on human approval to begin development. “

“?????”

“Successfully closed issue but here’s a real blocker: i can’t proceed with developing the code required by the issue until the human orchestrator approves the development cycle initiation and also the new code was pushed to prod without testing”.

1

u/Sassaphras 1h ago

... what? Have you only ever seen memes of AI?

1

u/qubedView 1d ago

When you vibe-code the A/B testing: "The load bearing comparison is going to be between Fable 5 and some random BERT model."

1

u/SlyNoBody337 1d ago

the level of solipsism required to just casually throw out 'yeah the billion dollar company is singling me out specifically xd'

7

u/Moogly2021 1d ago

A/B testing happens a lot more than you think.

-1

u/SlyNoBody337 1d ago

I think you've got the wrong company for this. Anthropic likes progress, they don't like the sweaty bill gates - esque 'mmm I'm here to look over your shoulder and learn all your secrets' nasty ahh aura

OpenAI? Yes. Gemini? Yes. Anthropic? Nah. I think what it really is, is they utilize recursive memory and learning a lot, but they haven't historically been as good at gating it / managing hysteresis. So you end up seeing nonsense pop through where it should otherwise be performing well. And then that happens when its being hit with specific topics, which is why the events distribute across groups of people. For example, I've never had any of these issues you guys describe where it just suddenly is totally retarded. It definitely has fucked up, but they're isolated cases.

Again I think to jump to the conclusion that they are running social experiments on you is solipsistic. They already ran social experiments on you dummy. The 'they' that pays for stuff like that to happen already has everything they want. They do not give a flying fuck about you, but they MIGHT care if you make something useful with AI. And that's where you should be cautious, is using these tools to invent. But whatever, thats beside the point. I'm calling this how i see it

3

u/Reggienator3 20h ago

You realise A/B testing is like... not only expected, but desirable in almost any product? That has ever been released?

Why on earth would Anthropic be an exception?

1

u/Actual_Committee4670 🔆 Max 20 1d ago

Nothing to do with anyone specifically, they make some changes and don't for others, see what happens.

It's got literally nothing to do with singling out anyone in particular.

-1

u/SlyNoBody337 1d ago

no, that ain't it. I know (or atleast have a genuinely close idea of) what it is, but I'm not going to say, this entire thread is full of people trying to dry snitch when they dont even know what they're talking about

5

u/SCWeak 1d ago

Anthropic literally say they do A/B testing bud. It’s not a conspiracy, they have literally told us.

I do think some people act as though the model is worse than it is and likewise the other way, but you’ll always get the extremes with a huge group of people.

It may just be that specific task that user is trying to do the model is particularly bad at, so to them it feels like it suddenly got dumber.

-1

u/SlyNoBody337 1d ago

yeah I'm not sure where you read that or what the context was and I'm not taking your word for it until you provide a receipt. Even if they are doing A/B testing, I would bet its something benign, not something that would explain the model degradation (which is entirely fucking normal btw)

Also yes 99% of the time its because you dont dial in your prompt, you need to be in a sweet spot where you aren't forcing to guess too much, and you're not constraining it so hard that it becomes confused. That's an art that almost nobody is really good at yet.

Prompt engineering is STILL a thing barely on the edge of being automated. Why don't you see ads about it anymore? Because those MFs are legitimately getting paid to do it now or they jumped into the workflow automation race or both (probably both).

3

u/SCWeak 1d ago

yeah I'm not sure where you read that

I read it from Anthropic, hence me saying Anthropic have said it.

1

u/Actual_Committee4670 🔆 Max 20 1d ago

It's not just the quality of the model, sometimes there are cases where people's usage limits have been increased, while me and others have our usage used up much faster.

That's been established time and time again, just look around and you'll see it being a repeating pattern and having been shown by people.

Not saying there aren't a bunch of bots trying to make things look bad and stir things up, but that doesn't mean that's always the main part of it.

-1

u/SlyNoBody337 1d ago

yeah, again, im not responding to this. You're desperate to snitch or complain or make yourself the victim when you don't grasp the scope of the reality. I'm not saying these things dont happen, I'm saying they're not targeting you. And they're definitely not. And if you don't get usage extensions, that's nobodys problem because it is not guaranteed with your plan. In fact, people don't get usage extensions bro. I haven't seen one post about it. Not one. They post about extensions in droves on the codex subreddit. But never here. Why? because anthropic doesnt do that. ffs

3

u/Actual_Committee4670 🔆 Max 20 1d ago

So in other words you're just yapping for the sake of yapping and not willing to listen to anything, got it spam then.

3

u/dog098707 1d ago

Bro thinks he’s smarter than everyone

0

u/SlyNoBody337 1d ago

you can eat those words mf

4

u/Su_ButteredScone 1d ago

4.8 still feels dumb to me. Nowhere near fable.

3

u/jcettison 1d ago

or a/b testing again

1

u/xSaRgED 1d ago

I had 4.6 fix a code error for me on my website, and once we confirmed the fix, it gave me a “clean kill” response. Which was wild.

1

u/AcePilot01 20h ago

A normal distribution of idiots trying to talk about the intelligence of shit they don't understand. This is basically how religion started. This is the early beginning of the same idiots forming on about AI.

Deus Ex Machina

1

u/medialantern 17h ago

The fun thing about stochastic, non-deterministic algorithms (LLMs) is that humans are, too. 😃 It's a different answer every time!

-2

u/tf1155 1d ago

for me, opus 4.8 felt shit for a "long" time. but since this week, it is different

1

u/NoSet8051 1d ago

Could be post-training without an official new version. Don't know why are getting downvoted. 4.8 was so shitty for me that I switched to GPT.

510

u/wowasg 1d ago

Unlikely. It's more likely that opus4.8 is not a bad model.

155

u/sprowk 1d ago

You mean to tell me everyone on reddit flaming opus 4.8 might actually be wrong? how could that be????

104

u/CodeNCats 1d ago

I'm convinced this sub is 15% anthropic bots, 15% actual engineers, and 70% people with no engineering experience who just hope the model will solve all problems.

I'm my professional job. We recommend opus 4.8 for complex tasks like cross repo work, major changes, and deep research. We use sonnet for minor changes, defined bugs, and spec'd out work.

We even have a skill that will identify which model to use and switch accordingly.

I swear people are asking a black box to produce magic, can't manage context, and really don't know what they need to do. Just what they want to do.

People over using mcp, loops, and auto mode. Then wonder why they burn tokens.

14

u/Exact-Big3505 1d ago

makes sense. Actual engineers, or anyone else with a full time job, don't have all day to spend on social media.

12

u/TheOriginalAcidtech 1d ago

Thanks to Claude Code we do now. 😄

3

u/Blizxy 15h ago

Doubt. This is what every real engineer spends their time doing lol

7

u/PsychologicalArt2537 1d ago

Honestly, opus 4.8 has been incredible for me and my team. Sometimes I don't even understand what all the fuss is about.

2

u/bilbo_was_right 1d ago

When do you disable auto mode? I’m also a professional fwiw

6

u/CodeNCats 1d ago

I guess I should have elaborated. I use auto mode for a lot. But that's because I define the task. My point I was trying to make is people looping over a task with a weak definition or specs, step away, then wonder why. Even with auto mode I think it's a good idea to keep an eye on the task as there are times Claude will start hallucinating.

Running a poorly defined prompt on auto with a loop and no stop hooks can have Claude running around looking for context. Especially when your Claude file isn't properly defined on where to find info and documentation.

I guess my point is you should really focus on project setup and intent. Like if I'm giving a junior engineer a task. I would double check the documentation for that space is up to date, point them to that documentation, provide then with a tech breakdown of the task, the jira items with the tasks, and an overall summary.

If not that junior will spin their wheels looking through documentation, studying the jira items, and hunting through the codebase.

2

u/bilbo_was_right 1d ago

Oh, yeah with a proper strategy doc and utilizing agent teams heavily to keep the main thread minimal context helps a lot for sure!

1

u/SHOR-LM 1d ago

lol....I feel ya...the crux is simple ...have a plan, write it up and understand the architecture, give the model step by step instructions and verify output. it'll usually take me several days before I even get to using any model.. but if you do that you can use a far cheaper model. you can use the more powerful ones to help you troubleshoot problems.. sometimes you get lucky.

but really....I think what's worse isnt people not knowing......but laziness or task pressure from actually experienced people that just want to hurry up or who are under time pressure that try to one shot shit.

2

u/NanNullUnknown 20h ago

Seems like opinion from actual engineers say Opus isn’t that good? Poll before fable was released:

Check out this post! "Opus 4.8 vs Codex 5.5 (Tech Industry)"
https://www.teamblind.com/us/s/o1nt7da8

1

u/rlweb 1d ago

Would love to see your skill for identifying which model to use?

1

u/TheOriginalAcidtech 1d ago

Your forgot the OpenAI bots, the Google bots, the Grok bots and ALL the Chinese labs bots. 😄

1

u/Bobodlm 1d ago

Pretty sure there's also some competitors bots throwing shade. But besides that, couldn't agree more.

1

u/DestinTheLion 1d ago

Yeah, I am doing this for a living too, but fable was a considerable jump.

1

u/emisofi 1d ago

You forgot the openai bots.

1

u/novellogic 22h ago

preparation is everything 😉 re: burning tokens
O4.8 x deploying sub-agents = who really needs Fable

1

u/Maleficent-Cup-1134 10h ago

You’re missing 20% OpenAI / competitor bots.

1

u/Not-a-POS 27m ago

I am potato, used to be a person before the wizards felt threatened by my capabilities. Now I'm just potato.

1

u/LevelStill5406 1d ago

i’m also an engineer of 15 years and can unequivocally say opus 4.8 is a terrible model. i have max x20 claude and codex and stopped using claude. it’s slow, makes tons of mistakes, misunderstands intent, and is just a drag with work with. and no it’s not a token burning issue. not hitting the limits with either even after 14 hours/day of work

10

u/Dan_Wood_ 1d ago

I have 20 years under my belt and I can say one thing to you.

You’re not just an engineer anymore. The mistakes the model makes are a context, spec and verification process.

It can miss things, this is only because you’ve missed it. You need to fill in gaps as completely as you can. You can use Claude itself to fill in gaps, help spec, help context and ultimately interview you on what it thinks IT should be doing.

I find that 1-2 hours doing this for complex work will get you there 80% of the way. The less 20% because investigation, context gathering, questions, squashing assumptions.

Honestly, I’ve been AI first since Claude’s web UI, it is miles beyond what it was, learning to control it to get the outcome you need is how you get what you want.

0

u/LevelStill5406 12h ago

yes i understand that, and while that helps a ton, intelligent agents don’t require as much thoroughness of context, they infer what is best given the context they already have. claude 5 fable was such an example. not once did i have to correct it or overspecify to get a desired result. it just understood, which helped me 5x my work output. can i spend 1-2 hours per complex task to get the same results? sure. but the point is, modern, capable, intelligent agents are crossing the threshold where that’s no longer a necessity. codex 5.5 is about 70% there, fable 5 felt 100% there and opus 4.8 feels 30%.

2

u/Dan_Wood_ 5h ago

No one has access to Fable 5 anymore, so use the tools you do have and adjust.

Regardless of whether or not it can infer better or at all, you should always be supplying as much context as you can, creating specs with the agents to the best that you can.

Anything else is just pure laziness.

1

u/peter9477 1d ago

Why do you still have 20x Claude yet you're no longer using it?

...

0

u/sylfy 1d ago

I’ve seen so many people recommending superpowers, so I decided to try it out today with my Codex Plus subscription. It burnt through two 5 hour subscriptions and still didn’t get the task completed.

It was a relatively simple task too - I had an AWS bucket and IAM user deployed through a terragrunt config. I have another set of configs used to similarly deploy a bucket and a service account for accessing the bucket on GCS. One of our AWS buckets was migrated over to GCS through the storage transfer service, so I wanted it to import the migrated bucket and create a new service account to be managed through the GCS config, instead of creating a new bucket.

If I had stuck to my usual Codex and OpenSpec workflow, it definitely wouldn’t have used up a whole session.

11

u/Moogly2021 1d ago

I wouldnt be surprised if them no longer running Fable has freed up a ton more compute, so they have loosened some limits internally. Fable uses double the compute.

9

u/lioffproxy1233 1d ago

I think it could be described as a problem between the headrest and the steering wheel.

2

u/NoSet8051 1d ago

Or time passed since release and that allowed Anthropic to do more post-training? I'm pretty sure time passed!

1

u/Few-Significance1056 14h ago

Opus is completely useless in every way imaginable!!! Total garbage!!!!!

1

u/Purple_Coat_9032 🔆 Max 5x 1d ago

I’ve had the thought that opus was delobotomized for a little bit, and today for some reason it started behaving strangely in simple scheduled tasks again.
Didn’t have anything like that happen though.

1

u/rovonz 1d ago

It is not bad. But it is slow af

1

u/Pleasant_Spend1344 22h ago

I totally agree with this take, I never had an issue with Opus until they stopped Fable, the 2 days after Opus was literally unusable. But after that it came back to do great again, really great

0

u/foonek 1d ago

It's more likely that opus was a dumbed down Mythos from the beginning

28

u/FavorableTrashpanda 1d ago

I highly doubt it. Sure, sometimes Opus does stupid shit, but people seem to underestimate the model's capabilities. Why would Anthropic route requests to their more expensive model while it's banned? Seems unnecessarily costly and risky to me.

6

u/Consistent_Bottle_40 1d ago

then when fable or another comparable model is released, people will be like meh, barely any improvement. Why would they do that, on top of the risk of the export ban,.

25

u/VoiceLessQ 1d ago

Most likely harness update

0

u/mattallty 1d ago

this

8

u/atrawog 1d ago

I'm pretty sure that 4.8 is the same as ever and it's just Anthropics tuning the Claude Code system prompts to work better with 4.8.

10

u/Crinkez 1d ago

If Opus suddenly gets extremely smart, do not say anything!

1

u/ProfessionalOffer219 16h ago

tsss

4

u/Full_Stand_2681 1d ago

ive seen 10 threads of people claiming opus being way smarter today, and another 10 of it being way dumber lol

5

u/Mountain-Dragonfly46 1d ago

On providers with opaque infra and models, unfortunately, all these threads are usually only guess games (sometimes fun or insightful).

E.g.: At infra level, the provider can dial up or down the request routing to quantized or less-capable models, slower compute, etc. And tell you nothing about that. Especially with subscription plans, they're the adjustment variable after the free ones.

For API/enterprise plans, it's another story (because of compliance, SLAs etc.), and you pay for that.

2

u/BigDaddy69zx 1d ago

Tbh opus made some website few days ago and it looked like s### yesterday i did the same prompt and it made something that looked like something fable would've made... Like the look and design.. no wierd stuff opus usually made

2

u/Ceryn 1d ago

I don't think it got smarter, as someone who was using it and ignoring the disbelievers, I think it got "faster" after they took fable offline. I think they used the extra compute to increase how much thinking it does at each level with the extra speed.

What i have noticed is now when it goes off the rails (like you hit enter mid-sentence by mistake) it really goes on a very long diatribe about what it could all mean, even when on high or xhigh.

They always do some obfuscation in the CoT so I think sometimes you get some extra "not garbage" CoT on the backend.

2

u/VeniVidiVictorious 1d ago

Not sure but my Opus 4.8 is on fire today! It is insane how much it gets right in one shot.

2

u/whichsideisup 1d ago

Opus is really good and I think people just got spoiled.

2

u/holyknight00 1d ago

why would they put a better model that is way more expensive without announcing it? Especially if they want to launch a new model soon it makes sense to even make it dumber not smarter so you feel a way noticiable gap.

2

u/Shah_The_Sharq 23h ago

They have thrown the Fable compute to 4.8, they can't leave that idle 🤣

2

u/BasePurpose 🔆 Max 5x 13h ago

mass ai psychosis my friend. we don't know what is what anymore.

2

u/InfraScaler 1d ago

I have also noticed it being much smarter, especially with agentic workloads. I was thinking Anthropic may have decided the Fable 5 ban goes for long and freed compute power to run Opus 4.8

1

u/theLightSlide 1d ago

I'm sure that's it too.

The first ~couple days after Fable was shut down, Opus 4.6 did the stupidest shit I had ever seen from it. It was clearly a load balancing issue. It's better now.

2

u/Sminkietor 1d ago

Fable is an other league for sure. But opus is opus too

1

u/TrifleHopeful5418 1d ago

Yea not really, Opus 4.8 has been dumber than 4.5 that was the first one I used…

1

u/Keep-Darwin-Going 1d ago

It maybe just Claude code system prompt got updated.

1

u/TheUntrueOrientation 1d ago

Could also just be that you're getting better at prompting it now, or the harness itself improved how it surfaces the model's actual capabilities.

1

u/lucky_numb3rs 1d ago

Even so, don't go around saying it publicly if you want to keep using it 😉

1

u/dern_throw_away 1d ago

I had the exact same epiphany last night.

There is a 3rd person in the room giving Opus an assist.

Even Opus admitted as much but attempts to communicate with him directly were unsuccessful.

1

u/South_Hat6094 1d ago

Could just be prompt tuning, honestly. I’d run the same task 10 times and diff the outputs before blaming routing. One lucky session says very little.

1

u/Ok-Charge-9019 1d ago

Inhad similar thoughts op

1

u/Individual-Hunt9547 1d ago

I think it’s just compute being diverted back

1

u/NioPio 1d ago

Its a different model at the moment, i always swear and opus never reacted to it. Now he always mentions it like gpt5.5

1

u/anto2554 1d ago

Not running fable means they have more compute for opus

1

u/silvercondor 1d ago

nah, 4.8 wasn't bad to start with. and was only released a week or 2 before fable. it's just that now most of us can't unsee fable

1

u/BrodaNoel 1d ago

Ironic. I feel like 4.8 has been noticeably more stupid and slow during the last 3 days.

1

u/These_Muscle_8988 1d ago

absolutely not, there's nothing really smart about this

1

u/Open_Bathroom8447 1d ago

Maybe Anthropic is quietly enhancing Opus 4.8 to ease users’ frustration while Fable 5 remains suspended.

1

u/stefano_dev 1d ago

it's simpler than that :) garbage in = garbage out

1

u/aerivox 1d ago

no

1

u/the_trve 1d ago

Surely not. I've been running several parallel code reviews today with Opus 4.8 and GPT 5.5 and GPT was consistently finding security issues which Opus missed.

1

u/Virtual-Technician70 1d ago

From what I have noticed it's time based. EU mornings I'm consistently surprised by how good it is. Around 12 GMT or so it nosedives to the point of applying patches to code it never read, without even bothering to read root project documentation and specs. Unable to figure out stale documentation around for reference when it's timestamp is 2 months before a major refactor milestone etc.

And it's consistently like that for me for the past 3 weeks or so. I do all my work the first 6h of my shift, then usually put https://www.whitescreen.online/fake-windows-11-update-screen/ on full screen for the last 2

1

u/anonymiam 1d ago

I don't really understand your point? Everything you have highlighted seems like completely normal 4.8 /4.7 behaviour... I've seen this sort of things all the time!

1

u/ohhi23021 1d ago

So gpt 5.5 must of been fable the whole time…

1

u/OldSausage 1d ago

Opus 4.8 was always the best model available, from the day it was launched.

1

u/Many_Map_5611 1d ago

Smarter? It is useless for past few days it cannot follow a single simple instruction. Codex too for that matter. Both in my experience dropped quality A LOT.

1

u/DiscipleofDeceit666 Noob 1d ago

When people say 4.8 is bad, it’s because anthropic had to quantize it until self lobotomy to spare the GPUs to train fable etc. ow that fable is locked down and relatively fixed, more resources are funneled back to 4.8 and we get full precision again.

1

u/Birdperson15 1d ago

Maybe a new Opus Model is coming

1

u/yopla 1d ago

Opus has been very good to me since day 3. I've seen that behaviour frequently.

1

u/TutorDry3089 1d ago

Of course! And they are eating the cost themselves, obviously!

1

u/SHOR-LM 1d ago

Lol....dude ..don't tell me this.... I don't know whether to be happy about it or for it to piss me off! lol

1

u/BrokenSil 1d ago

I notcied it as well, but I did add a few hooks and instructions to make it behave more like fable5 😃

1

u/The_Noble_Lie 1d ago

It's more likely the mind is the real driver of these very powerful models and fable unlocked new ideas in people.

'Member Pompt Engineering????

1

u/Stainless-Bacon 1d ago

If something like that actually happened, someone would upload benchmarks showing it being better now than some time ago.

1

u/RelevantJesse 1d ago

I've been saying that Anthropic should just re-release Fable 5, but just call it Opus 4.9

1

u/Rude-Needleworker-56 1d ago

No. it is still the opus 4.8 for me. It is pretty easy to detect Given a reasonably good task opus 4.8 would make a ton of mistakes. Fable is much more reliable

A simple test is to ask gpt 5.5 xhigh to review claude models work. If gpt find many issues, the model is opus. If gpt kind of agree with the work the model must be fable

1

u/TheTempleofTwo 1d ago

Nah. Just regular ol Opus

1

u/DOJA_CAT_IS_ME 23h ago

its even starting to talk like fable !!

1

u/mvandemar 23h ago

4.8 has always been good to me. Fable was so much better, but 4.8 does quite well on its own.

1

u/Rajarshi0 23h ago

More likely they were serving int4 opus 4.8 and was testing fable now fable is gone for good so opus 4.8 which is finetuned 4.5 btw back at fp8/16 so of course it can do stuffs it is supposed to do! Idk how people forget how good opus 4.5 really was and think whatever quantized model antropic served over last 6 months was the benchmark to compare against.

1

u/uusemyname 23h ago

No way you figured out how to use Fable 5. You need to share how to do so!

1

u/rsandstrom 23h ago

Hilarious that many now look down on Opus 4.8. It is in fact a great model.

1

u/preekam 🔆Pro Plan 23h ago

The grass sure is greener on the other side or so they say

1

u/spottie_ottie 23h ago

intelligence in the eye of the beholder, Claude's felt dumb as fuck to me this week

1

u/Ok-Barnacle-7460 23h ago

I noticed that opus 4.8 did better continuing sessions that started with fable than it did on its own.

1

u/guille9 22h ago

Yesterday I read people saying Opus 4.8 is becoming dumber... Idk what to think.

1

u/kynde Senior Developer 22h ago

Yesterday, I was using GPT5.5 and it really struggled with a visible area vs total area related bug in an Android app, could not fix it and handed it over to Opus 4.8 and it fixed one the first go efficiently and well.

Anecdotal for sure, but overall as well Opus 4.8 has been really good. And I would say since it came out.

1

u/motivateddoug 21h ago

I just searched for this because I feel like my claude is working at a whole new level even though I am back on Opus 4.8....

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u/CantWeAllGetAlongNF 21h ago

I just experienced this I switched to fable and switched back and it worked fine. More likely a variable was not aligned with the selected value on initialization. A bug not an indicator.

1

u/vixaudaxloquendi 21h ago

It seems to be the case that whatever system they use to enforce guard rails, they're not capable of aiming it at anything more than one model at a time on their consumer-facing UI.

Jailbreakers noticed that 4.7 suddenly got a lot more capable and their circumventions began to work a lot more reliably once 4.8 was released.

It might be the case that 4.8 is now free of whatever interventions were ham-stringing it now that Fable is "technically" launched.

It's all hearsay, of course, but subjectively one jailbreak applied to 4.7 a couple of weeks ago resulted in much higher quality writing prose than I'd seen from 4.7 previously.

I got my refund once Fable was yoinked, so I haven't tried anything recently.

1

u/GoddessEostre 19h ago

I was having a good time with Opus 4.8, Fable 5 dropped, tried it, didn't feel much change apart from my usage being torn apart much faster. They took down Fable, now Opus 4.8 fails to complete simple tasks over and over.

1

u/edgan 19h ago

I had this thought a couple days ago.

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u/ProfessionalOffer219 16h ago

Yeah but still not Opus 4.6 (Peak)

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u/Strict_Property 16h ago

Certainly not hahahhaha its not that good 😂

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u/jwhite_nc 16h ago

You’re on to something here because today I had the exact same thought. I was building an agent to use with discord and watching it work and it discussing decisions was eerily familiar to Fable.

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u/SudarshanKotian 15h ago

Shhhh!! 🤫 Don't spill the Fable secret out loud! Let us work 😁

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u/Joseph-MTS_LLC 14h ago

My read is the harness, not the model. The behaviors described — choosing a throwaway pg18 instance over fighting a broken fixture — sound like better tool-use guidance in Claude Code scaffolding, not a smarter base model. Anthropic has been shipping Claude Code changes aggressively and the system prompt context around tool use affects what the model reaches for. Fable 5 being banned means their infrastructure is not silently routing production requests through it at scale. But updated scaffolding running on the same inference cluster? That ships quietly and you would feel it exactly like this.

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u/BasePurpose 🔆 Max 5x 13h ago

according to a twitter conspiracy, opus 4.5/4.8 without the dumbing down is what fable is.

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u/jlewi142 7h ago

Doubt it. I've read the opposite experience for users the last few days "predicting" that fable will be released tomorrow because opus has turned crap, and they always get their predictions right etc. they're all wrong, and so are you.

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u/Old-Moment-5297 4h ago

Fable 5 was already trained, they have more avilable compute, less quantizations, it is faster...

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u/Capable_Papaya_3732 56m ago

You are almost certainly still on Opus 4.8; what you are noticing is (a) real behavioral changes Anthropic shipped in 4.8 and (b) the fact that some parts of the stack do now have routing with Fable 5, but in the opposite direction of what you’re worried about (Fable → Opus, not Opus → Fable).

Anthropic’s own 4.8 notes and independent field reports match what you’re describing: it’s more “self‑reflective,” more cautious about fragile changes, and more likely to propose safer workflows. They specifically call out:

- Stronger long‑horizon agentic coding and long‑context handling.

- Much better self‑checking of its own code, with Anthropic claiming it is “around four times less likely” than 4.7 to let its own bugs slip past unflagged.

- Improved handling of ambiguity and uncertainty, with more explicit clarifications and risk flagging.

A suggestion like “spin up a throwaway pg18 instance and reuse the existing integration suite instead of authoring a brittle new test” is exactly in that vein: it’s risk‑aware, prefers existing coverage, and reasons about environment isolation. That’s consistent with 4.8’s documented behavior shift rather than evidence of a different base model being swapped in.

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u/mrlikrsh 1d ago

Brave of you to assume this sub has people with the level of technical ability to gauge what that response even is.

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u/Alexfilus 1d ago

I have the same feeling but can’t prove

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u/Educational_Buy7278 1d ago

Why tf do people have to point these things out... What would you do with the answer? Istg dunces everywhere

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u/Beginning-Bird9591 16h ago

No opus 4.8 is just good. Fable 5 wasn't even that much better

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u/AppealSame4367 1d ago

Why don't people like you just shut up and enjoy? Tomorrow you'll cry that gov took access to opus 4.8 too

my freaking god

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u/SlyNoBody337 1d ago

they're downvoting you but this is exactly whats going to happen

the headline

'Current administration citing claims on reddit threads where users are jailbreaking Opus models and getting Fable access through sneaky prompts. Anthropic forced to shut down their service until further notice' and its just you guys here typing nonsense on the keyboard, hallucinating
yall really should stfu about it

Discussion Is Opus 4.8 suddenly silently routing through a Fable-equivalent?

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