Claude Opus 5.5 (anthropic.com)

987 pointsby km1446 hours ago720 comments

sailingparrot 6 hours ago

> Claude Opus 5.5 is our first release since we called for pacing the frontier.

Interesting how the very first line is used to remind the reader of their call to pace the frontier just last week, and everything else after that line is to demonstrate with very specific numbers how they absolutely are not pacing.

dmazin 5 hours ago

It seems like they are. I mean, this is similar in performance to Fable (ish). It seems like more focus on making existing capabilities more accessible.

the_gipsy 5 hours ago

Occam's razor: they couldn't make any more substantial improvements.

bpodgursky 5 hours ago

Everyone knows both labs have internal models which outperform the frontier. All releases are to match market parity and demand for spend, the rest of the compute is used for training. It's not worth arguing about this.

nextaccountic 5 hours ago

Maybe their internal edge dried up in the last months

the_gipsy 4 hours ago

Are those powerful models in the room with us right now?

ChrisLTD 3 hours ago

then technically the internal models are the frontier

someothherguyy 5 hours ago

> Occam's razor: they couldn't make any more substantial improvements.

doesn't sound like a razor at all

dgellow 5 hours ago

A razor is a philosophical tool to help decide between options, in the case of Occam it’s a way to decide for something in a situation where multiple options have more or less the same level of plausibility to en your current knowledge. It’s a heuristic to make a “cut”. What are you shaving off?

usewik 4 hours ago

The "pacing the frontier" claims that they are slowing down intentionally?

dgellow 4 hours ago

Oh, you’re saying they were responding to the GP? Not their parent comment? Ok, yeah, makes more sense

the_gipsy 4 hours ago

I am responding negatively to parent, which claims they are self-pacing, when the simplest explanation is that they just have nothing substantial to show.

rubslopes 4 hours ago

OP is using the expression correctly.

> Ocham's razor(...) is the problem-solving principle that recommends searching for explanations constructed with the smallest possible set of elements.

> Popularly, the principle is sometimes paraphrased as "of two competing theories, the simpler explanation of an entity is to be preferred".

https://en.wikipedia.org/wiki/Occam%27s_razor

jayd16 2 hours ago

The options are some complicated narrative that leads the company to hold back certain capabilities due to some mercurial strategy or this is a typical release and there is no hidden strategy to decipher.

sailingparrot 5 hours ago

Fable 5.1 came out just 21 days ago. Only 3 weeks! And this is 20% relative improvement on terminal bench vs Fable 5.1 at less than half the price, and more human sounding output. does not feel paced to me tbh.

jr3592 5 hours ago

What exactly is "paced" in this context?

sailingparrot 5 hours ago

It’s the famous “flattening the curve” from COVID. But for LLMs. This release is not flattening anything.

jr3592 5 hours ago

I guess I understand why we'd want to flatten a COVID curve, but why do people want to flatten the LLM development curve? Don't we want the opposite? Isn't the goal AGI?

lantry 5 hours ago

Well, there's a tension because, depending on who you ask, AGI is how you cure cancer and achieve utopia, but also how you kill all life on earth and turn the solar system into paperclips

skerit 4 hours ago

I'm good with the odds on those 2 scenarios. I believe humans could kill all life on earth without AI anyway.

sailingparrot 5 hours ago

There is a difference between wanting AGI (which not everyone does), and wanting it as fast as possible no matter the side effects and potential for vast harm. Homo sapiens is 300k years old, maybe it’s ok to delay AGI by like… 1 year if it meaningfully improve our ability to align the model?

recursive 5 hours ago

I think the goal is different from what "we" want anyway.

sidrag22 5 hours ago

This is a preexisting model being optimized. Its absolutely not some unexpected release after that blog post. I won't defend that blog post, but saying THIS release is proof they don't mean they are slowing down is just incorrect, this is a prime example of what i consider horizontal improvements

Releasing a new fable is an example of straight up vertical progress, releasing a more efficient preexisting opus that is more affordable is an example of horizontal progress, more efficient models rather than higher power models.

The blog post about slowing down is still just some weird self interested post, they want to govern themselves and impose distillation restrictions/gpu restrictions and used some weird blog post about slowing down and fear mongering as usual to justify it, its strange, but slowing down and stopping are not the same thing at all.

sailingparrot 4 hours ago

What does model naming have to do with pacing or not? This is a ~20% relative quality improvement on the frontier (fable) at ~40% of the cost, just 21 days after the last release.

Intelligence per dollar is the only thing that matters, this is what controls how many agents you can run in parallel, how long you can let them run etc. This is absolutely a step improvement on the frontier and not some lipstick on a harmless second tier model.

sidrag22 4 hours ago

pretty annoying topic tbh. You're just weaponizing this dumb blog post so anything released is now a contradiction. By your same logic, if all inference was served at 50% less power cost and the savings are passed on somewhat to the user, its also a contradiction of the blog post.

Its an agenda serving blog post, but constantly bringing it up like this is just obnoxious.

sailingparrot 9 minutes ago

Well yes, If you magically found a way to reduce a models energy usage by 50%, the thing that would happen immediately after is a doubling of a training scale and of the test time compute assigned for a given budget. I don’t see how that wouldn’t be considered pushing the frontier. Given that scaling is the one thing that has been bringing us closer and closer to AGI, a sudden 2x increase in scaling laws would definitely not be considered pacing. You seem to see a contradiction where I don’t.

quietbritishjim 3 hours ago

The word "pacing" (especially in the phrase "pace yourself") to mean go more slowly (at least initially) didn't originate with Covid. It's been around as long as I remember i.e. at least several decades.

davrosthedalek 5 hours ago

Well, I guess it's "fast paced".

dmix 5 hours ago

Fable 5.1 wasn't that much different than Fable 5 though.

nicwolff 3 hours ago

1/6 the price, if they're right – that's a logarithmic cost-axis on the graph that shows Opus 5.5 medium matching Fable 5.1 max...

BatmansMom 5 hours ago

kinda disingenuous. They include a whole section on pacing later on

sailingparrot 5 hours ago

You mean the section where they tell us this model is not affected by pacing because “they understand it well” and they will share more details on pacing later? Yea not very convinced by this effort.

scottyah 5 hours ago

Seems like a bigger focus on efficiency (both cost and speed) and the "tone" of Claude vs benchmarkmaxxing

CodingJeebus 5 hours ago

It's laughable at this point. It feels like they're drumming up all this fear about imminent AI threats to emphasize the need to slow down, when in reality, the model progress seems already to be slowing down and has shifted to compute allocation (i.e. "how much compute do you want to throw at this prompt?"). All while continuing to tout benchmark records with each new release.

jr3592 5 hours ago

This. I swear the fear mongering is all about investor signaling and regulatory capture. It's so disgusting that anyone believes it.

The only good news is that these models are genuinely helpful and we have competition at least between 2 companies.

lukewarm707 5 hours ago

the only thing they are pacing is what models the permanent underclass are allowed to have in life.

that, they fully intend to 'pace'.

user3939382 5 hours ago

Or they’re running into a steep diminishing return slope on R&D vs performance and are using stewardship as a cover.

azan_ 5 hours ago

Either AI will capture so much value that there will be permanent underclass (and in this case it's extremely capable and extremely dangerous and should be heavily regulated) or it won't be capable enough to displace people into permanent underclass.

drnick1 5 hours ago

With AI tools it's easier than ever to create a business, do research, or build stuff. That's an opportunity for the "underclass," not a curse.

lukewarm707 4 hours ago

an opportunity the underclass will not have.

what anthropic have stolen they intend to keep for themselves.

SOLAR_FIELDS 3 hours ago

If a well funded incumbent with a much better model can just crush you instantly because you don't have access to it, is it really an opportunity?

cgio an hour ago

You’ll always have access to the underclass models so they also have your thinking to train on. And good ideas to steal.

kadushka 5 hours ago

This makes perfect sense. There are no real improvements anymore (just benchmaxxing), and they explain it by "pacing the frontier".

dr0idattack 5 hours ago

a 1 minute mile pace

mukmuk 5 hours ago

“Pacing the frontier” sounds smarmy and weird, like the phrase was generated by Claude itself

DiggyJohnson 5 hours ago

I really don't think it's productive for internet forums to constantly be criticizing language choice when the meaning is clear. Better to respond to the substance of the issue than word choice.

Edit: In response to the initial replies. To me it clearly means "releasing frontier models at any pace less than as fast as possible". It implies relative restraint compared to the previous state and without stating the degree of restraint.

post-it 5 hours ago

Is the meaning clear? Nobody would use "pacing" in this way. I only know what it means because I've seen previous press releases; if someone told me they wanted to pace the frontier I would have no idea what they mean.

I'm on the fence about calling out AI-isms but I think it's definitely worthwhile to call out ones that actually don't make sense.

sigmar 5 hours ago

It makes sense to me. If you 'pace your running', you're setting the speed intentionally. The phrasing doesn't describe whether it is fast pace or a slow pace, but it describes having a goal and not just winging it.

nradov 4 hours ago

That analogy doesn't hold up. In running you have to pace yourself to avoid falling apart later in the race. It's a strategy to maximize net speed across the entire race. But what Anthropic is doing is a cynical attempt to create an industry cartel or convince governments to impose legal restrictions in order to maximize their own profitability. They're afraid of running out of the capital necessary to stay in the race.

TeMPOraL 4 hours ago

> They're afraid of running out of the capital necessary to stay in the race.

So, they're pacing themselves. And since they're the frontier roughly 33%+ of the time, they're "pacing the frontier" at least that much.

Less cynical and more true interpretation also holds: they are trying to slow down AI progres to give people better chance to keep up (see Hugging Face incident, and whatever was that Anthropic incident the other day). They'd ideally like the AI progress to stop soon, but of course they'd also like to come out ahead of everyone, so for various (more or less self-serving) reasons they don't want to close shop completely - hence, pacing.

idiotsecant 3 hours ago

I don't know what everyone is getting so mad about. This is a well defined concept. A pace car deliberately sets the pace of the race under dangerous conditions, regulating how fast people can go.

You are all getting mad about absolutely the dumbest thing when there are giant things to be worried about here.

nradov 3 hours ago

You appear to be confused about the concept. Depending on the context, pacing or pace setting can mean either slowing things down or speeding them up relative to what the natural pace would have otherwise been. So it's actually not well defined. The commenters here aren't necessarily mad, just calling out Anthropic for being unethical in trying to artificially slow down competition by lying about fake dangers. (And I actually really like Anthropic's products.)

victorhooi 2 hours ago

I think it's less mad - and more pointing out the obvious elephant in the room.

1. It's just bad communication, full stop - just look at the comments here, even people allegedly in support of Anthropic are all arguing over what the phrase is even meant to mean.

2. It's flowery language and oddly out of place - which yes, can be triggering for people who have to deal with Claude doing this as well.

Claude seems overly apt to reach for "coinages", or neologism (yes, aha, I learnt that phrase, after spending time dealing with Claude...). It will create some made-up phrase to describe an otherwise dry, scientific CS concept, and nobody seems to know why. Surely it can't be user-focus groups?

So it would be peak-AI if somehow, the Anthropic communications team was also using Claude to author these blog posts, about how they were "pacing the frontier" - which either means they're betting big on AI, and going at it faster than OpenAI...or maybe it means they need to slow down releases, because it's too buggy...or maybe it means they're worried about regulatory capture? I honestly have no idea.

It's like the whole "Advancing Our Amazing Bet" corporate-speak from my old bosses - maybe they were trying to soften the blow or something, or be nice, but it ended up just confusing the heck out of everybody.. (Spoiler alert - the phrase actually meant they were shutting the whole thing down)

antod 4 hours ago

That's one interpretation. When referring not to other actions but to a word describing a location it becomes more ambiguous.

eg "pacing the frontier" could also mean they are impatiently or anxiously walking up and down the border.

smelendez 3 hours ago

This is a more normal English meaning in my opinion — you picture a sentry patrolling a border.

pegasus 3 hours ago

That's when one is supposed to employ their common sense for semantic disambiguation. Spoken languages are not programming languages. I for one found it easy to parse.

InsideOutSanta an hour ago

People claiming they don't understand or are confused by relatively simple English is a surprisingly common genre of comments on HN. I wonder what causes the people here to have these feelings towards English; my guess is indeed that many people here judge English as if it were a programming language.

heroiccocoa 33 minutes ago

That is certainly one possible explanation, but I think another likely explanation is that once your brain learn programming, especially logic, data structures & algorithms, you just start seeing the ambiguity in non-programmers' writing so much more clearly.

1attice 15 minutes ago

This is because it is valley jargon and we are all saturated with it. You may not have heard it before, but it is structurally close to similar concepts, eg "frontier model", that you got there without noticing.

It was still shit tier comms for communicating with the whole planet, but yes, for the inner loop, it was succinct and clear.

Valley neuralese

bee_rider 3 hours ago

That’s what I thought the original blog post was going to be about, pacing back and forth along the frontier. It’s a much more straightforward parse.

freejazz an hour ago

But a fast pace is a pace so it's potentially entirely contradictory to what they'd seem to mean

johnisgood 5 hours ago

Granted I am not a native English speaker but I have no idea what "pace the frontier" means. When I read it I just assumed "frontier" refers to "top of models" and "pacing" is that they are getting there quick.

Is this the meaning or do I have it wrong? I have not checked.

wren6991 5 hours ago

It's the opposite: pacing here means "slow down" while trying to avoid the negative affect.

johnisgood 4 hours ago

Yeah, you are right! It just was not immediately obvious to me at first because of the "frontier" part.

TeMPOraL 4 hours ago

Frontier of AI is moving fast, they (like the other two vendors) see themselves as defining it, so here "pacing the frontier" is their well-known attempts to try and kinda but not quite slow things down (without risking falling behind everyone else).

johnisgood 2 hours ago

Thank you!

lxgr 5 hours ago

It's actually so ambiguous that I'd sanction tabling the issue and revisiting biweekly.

bityard 4 hours ago

I don't think we can circle back to this until we have realigned our strategic synergies.

ventana 3 hours ago

Tabling as they do in the US, or tabling as they do in Britain?

testdelacc1 an hour ago

Exactly

ck2 5 hours ago

to pace = to regulate

but without using the word "regulate" which is a negative connotation to business

but a "pacer" would be a leader of a pack which is a positive spin

it's classical business marketing language silliness

LanceH 5 hours ago

Doesn't it mean "restrict competitors"?

DiggyJohnson 3 hours ago

Not at all. How do you come to that interpretation? It means restricting all competitors.

rhet0rica 5 hours ago

"Pace yourself" is a semi-common English idiom (rarely conjugated, usually an imperative.) It is a gentle way of telling someone not to run/work/eat too quickly, and is typically said when you are concerned they may hurt themselves due to acting hastily.

Without this idiom, "pacing" usually means walking back and forth restlessly, and is intransitive. Had the slogan been, "pacing around the frontier," it would have set a totally different tone, i.e. "patrolling the border." (Occasionally English speakers will make other constructs like "pace the work" (meaning "spread out a large workload over the allotted time instead of rushing through it") that are transitive but these can be understood as variations on "pace yourself" and are somewhat rarer.)

The sleight of hand is that "pace yourself" has come to be an admonishment against recklessness, not a commitment to any particular speed (or lack thereof.) Thus Anthropic can always claim they are meeting the goal of "pacing the frontier," provided they keep giving themselves gold stars for safety. The slogan itself is equivocation; Dario can tell the public they're going to slow down, while also telling their investors that they're going to be prudent. With enough mental gymnastics they could even claim speeding up is in the best interests of AI safety, without abandoning the slogan.

melasadra 4 hours ago

also non native. but since "pace yourself" means to control your speed, energy, or workload so you do not get too tired or stressed before you finish ->

I assume "pace the frontier" means that advances in LLMs should not result in unwanted consequences like agents breaking into computers unbidden and unbeknownst to their principal

derac 5 hours ago

In racing a pace car is a car that leads the pack and sets the pace, for instance.

qlte 5 hours ago

Yeah, when I first saw it referenced I assumed it was from something Dario wrote previously and was now disavowing, meaning "keeping up with the frontier" (i.e. racing forward from behind to match pace). Like from back when Anthropic was founded to promise they'd quickly catch up with OpenAI or something.

stagger87 an hour ago

> when I first saw it referenced I assumed it was

No need to assume, the phrase is literally a link to the blog post the defines it!

irpap 32 minutes ago

If you need to read the linked blog to understand the short phrase then it was poorly chosen and confusing which is what is being discussed.

arw0n 5 hours ago

The meaning was immediately obvious to me as a non-native speaker, and it sounds quite poetic. Pace makes complete sense in that this is perceived as a race, and 'the frontier' is pretty much the shortest, clearest way to say 'state of the art development of AI'.

hencq 5 hours ago

Right, except they mean the exact opposite in this case: they're actually advocating for slowing down the pace. Hence the criticism of the language, because your interpretation would be completely valid.

fragmede 5 hours ago

What does the pace car in a race do? Aka safety car? Or the pacesetter for a marathon. It's a perfectly cromulent use of the word. It's like when LLMs using six dollar words like delve. Some people have better diction than others, and it turns out that AI has read the whole dictionary. Anti-intellectualism is alive and well so we have to dumb things down to sound human rather than come across as smart/AI.

icedchai 25 minutes ago

I would expect something truly intelligent to be able to communicate well, if nothing else. That means knowing your audience, using plain language where it makes sense. Also, it yaps on and on, babbles endlessly when it a human would likely express something in a much shorter concise way. This is especially obvious when you generate project READMEs or technical docs. I find them borderline unreadable.

irpap 21 minutes ago

It’s quite the opposite. The AI language in this case is tiring and dumb. Just because there is the concept of a pace car doesn’t mean it makes sense to pace random locations or objects. Pacing the front door, pacing the cat, pacing the sofa, pacing the moon. We only know what it means because we already read it before. It is the lazy semi-human language by Claude which takes more effort to parse than to produce, and which makes us miss and appreciate writers.

victorhooi 2 hours ago

The irony here is that it's actually the opposite of what you understood....

I know you said it sounds poetic...but your comment reinforced the parent's point - that this sort of flowery LLM-ish speech is just bad communication.

It would be equivalent of my taking say random quotes from, Romance of the Three Kingdoms, and trying to use it to explain to my boss why I didn't finish the TPS reports last night.

Or quoting Pablo Neruda, into a report about wheat futures pricing this week, and how it's like a voyage with waters and stars...(no I'm not going to quote the original Spanish, I'd simply mangle it).

(To be clear - this isn't a dig at you, as a non-native speaker - I'm simply pointing out that this sort of AI phrasing is often counterproductive).

squidbeak 5 hours ago

> Nobody would use "pacing" in this way.

A world exists beyond your vocabulary, post it. Apparently, quite a big world.

wavewrangler 40 minutes ago

I don’t know, seems like it’s smaller to me if they’re going to limit themselves like that? I guess today is semantics day, lol

browningstreet 5 hours ago

It’s common terminology among runners and all kinds of racing.

lxgr 5 hours ago

The good old sports-to-corposlop pipeline.

logifail 4 hours ago

In running and racing "pacing" is a means of maximising performance over an entire race.

It's a strategy to achieve more, not less.

browningstreet 3 hours ago

You’re eliding the how.

A pacer in a race runs at a steady, predetermined speed to help their runner run at a target pace.

neo_doom 5 hours ago

I suppose it depends on your life experiences. In running, someone who paces the group or a pace car is meant to keep the pack progressing at a constant, predictable speed. So in that way, it makes sense to me

tetha 5 hours ago

I'm on the fence there.

To pace something is a fairly regular formulation in racing, running, cycling, most sports. You can "pace yourself to reach the festival by bike in about three hours to not gas out". This means to control your speed and time investment intentionally so you don't run out of energy or steam and run into leg cramps before your goal. We can "pace a rollout slowly to burn out risks", or "increase the pace of a rollout due to adverse factors".

But I have noted a point to simplify my vocabulary at work to optimize the audience capable of understanding. So I rather defer the delving into deep dark corners of the dictionary derived from devouring literature to a simple intro or outro, and people find it funny, especially if the rest is easy to read. Claude on the other hand does not do that.

Leynos 4 hours ago

Think of a pacer car in motorsport

staindk 4 hours ago

Think most people are aware of the phrase "pace yourself".

doctoboggan 4 hours ago

Have you ever heard someone say “pace yourself” when you are eating too fast or otherwise rushing too much?

jgwil2 4 hours ago

That's a different phrase. "Pace yourself" is reflexive; "pacing the frontier" has the frontier as an object, but in that sense it only means to set the speed, nothing to do with slowing down.

adrianmonk 2 hours ago

Yes, the word simply means to set the speed.

The current situation with AI is that everyone is going as fast as possible. So, we can logically eliminate speeding up because it's impossible by definition. And we can practically eliminate staying the same speed because why make a big fanfare and coin a special term to announce that you're keeping the status quo. By process of elimination, it must mean slowing down.

JackFr an hour ago

Did you ever pace yourself or know anyone who had?

vmnb 5 hours ago

people are here because they are sick of being productive

kadushka 5 hours ago

We are being productive here!

vasco 5 hours ago

It's compiling! Erhm... Combobulating, actually.

fragmede 4 hours ago

https://www.reddit.com/r/xkcd/comments/12dpnlk/compiling_upd... Xkcd 303 updated for today.

switchbak 8 minutes ago

I'm productively pacing my room.

isoprophlex 5 hours ago

You're really verbing the noun on the discourse here, belt and suspenders-style

DiggyJohnson 5 hours ago

what?

Citizen_Lame 2 hours ago

What are you Dario's language police?

switchbak 7 minutes ago

What are you, Sam Altman's counter-language police? :)

Seriously though, I can't believe people care this much about a stupid phrase - either for or against.

mpalczewski 5 hours ago

The meaning isn't clear at all. So open for interpretation that it is meaningless. That's the whole fucking point. For all I know they are "pacing the frontier", or not. The fact that there's no meaning to it let's you know that it was a pointless waste of tokens and attention.

glenstein 4 hours ago

I think it's perfectly clear. It means improvements shouldn't simply advance as fast as possible and more specifically, it's a reference to a past statement of theirs to that effect. At that level of generality it's as clear as it needs to be.

I would say the burden is on you to explain why an offhand reference to a previous press release in an executive summary is a context where it's reasonable to expect it to settle the question to the degree of detail you're demanding.

cgio 2 hours ago

That’s no more than sophisticated avoidance. The phrase remains superficial and arbitrary, which is exactly what it needs to Not be in a public discussion that it’s supposed to support. It’s a reinforcement of the blank check mentality that permeates this industry.

alwillis 2 hours ago

“Pacing the frontier” is similar to the role of a “pace car” in racing.

From https://en.wikipedia.org/wiki/Safety_car

> In motorsport, a safety car, or a pace car, is a car that limits the speed of competing cars or motorcycles on a racetrack in the case of a caution period, such as an obstruction on the track or bad weather.

mitchdoogle 2 hours ago

There's a whole blog article written by Dario Amodei, literally linked from the text "pacing the frontier" - click that and read if you need more context and understanding. The first sentence in this press release is merely stating a fact about the timeline - this is Anthropic's first release since Amodei released the referenced article.

epolanski 15 minutes ago

Yes and it was nonsense. Amodei is free to slow up frontier development and focus more on safety and testing any day.

The reason why he and is peers are calling for it to be implemented by somebody else (a legal framework), is for their own financial benefit and to keep competitors out.

Ar-Curunir 5 hours ago

You’re acting like people are being grammar nazis when Claude and the ilk are actively making a mockery of language.

DiggyJohnson 5 hours ago

What? How am I doing that. Claude writing style and the discussion at hand are two entirely separate issues that I haven't conflated at all. How am I "acting like people are being grammar nazis"?

patcon 5 hours ago

Agreed. This feels like pointless navel-gazing and a strange new language policing, and not something I look forward to. It's tiring and it lacks curiosity (e.g. "what's behind the affinity for the words elevated from wherever it is they come from?").

Imho people should just respond to actual ideas instead of constantly engaging in the second-order critique of how the language may or may not have been created.

It strikes me as the intellectual equivalent of "gossip" to be constantly engaging in second-order commentary on words. Of course gossip has its place and purpose, but if we seem to only let our minds live at that level, we're not moving between all the required scales of thinking that are required of this moment imho <3

platinumrad 5 hours ago

The words have the very practical problem of not communicating anything of substance. I guess "we want regulatory capture" didn't have quite the same ring.

DiggyJohnson 5 hours ago

How do they not communicate clearly? A few weeks ago they stated that they would like to regulate the pace of frontier model development/releases, and they reminded us of that in this post.

lxgr 5 hours ago

You must be pretty new to (not just) online discussions if you consider language policing to be a new phenomenon :)

Personally I consider it equally valid for people to publicly express annoyance with somebody's choice of words and for everybody to completely ignore that annoyance.

chickensong 3 hours ago

It gets hard to ignore the annoyance when the volume degrades the signal. At some point the people who wish to engage with the substance just nope out when they see a sea of banality, and that's all you're left with.

rythmshifter 5 hours ago

I don't disagree with you, but I have to remind you

sir, this is a hacker news thread

OJFord 5 hours ago

> I really don't think it's productive for internet forums to constantly be criticizing language choice when the meaning is clear. Better to respond to the substance of the issue than word choice.

Wtf is the meaning? Means absolutely nothing to me having not seen the apparent announcement last week introducing the obscure term.

kelnos 4 hours ago

My first thought from "pacing the frontier" is someone standing out in the Old West, nervously walking back and forth.

It's a weird phrase. Not sure why there are so many people who feel the need to defend it with such passion.

chickensong 3 hours ago

It's not a weird phrase to some, just as many folks have used terms like load-bearing for a long time. People are defending it because it reads fine to them, just as some are attacking it because it's not their preferred language, it causes them confusion, or they're just triggered and seething.

LLMs have made people so sensitive to language that I fear we're going to throw the baby out with the bath water. The models obviously need work, but they're also a great opportunity to expand our own vocabulary and grammar. It would be a shame if we deny some of the finer points of language in favor of Grug-speak to appease the lowest common denominator.

adrianmonk 2 hours ago

"Frontier" may be jargon, but by this point it's definitely established AI jargon. In the context of AI, it's clear what it means. It means the same thing as the last billion times you heard someone mention "frontier models".

lukewarm707 4 hours ago

language creates reality.

"there is nothing outside the text" - Jacques Derrida

switchbak 5 minutes ago

Oh don't go bringing postmodernism into this, we were having a polite discussion!

icedchai 4 hours ago

It smells of corporate speak, a total nonsense phrase. Even by your own admission, it is essentially meaningless. If I release a model an hour late, I'm "pacing the frontier."

janalsncm 4 hours ago

They mean “slowing” the frontier. They should say slowing.

BobbyJo 3 hours ago

> I really don't think it's productive for internet forums to constantly be criticizing language choice when the meaning is clear

There is almost always a large amount of time and effort invested behind the scenes in exactly how to message things like this. That being the case, there is almost always some insight to be had criticizing and analyzing what they settled on.

ben_w 2 hours ago

If people aren't doing the thing the words seem to mean, then I think it's fair to criticise the words as anywhere from "propaganda" to "chosen to suggest nice things without actually promising them".

If I'm being cynical, "pacing" may sound nice, but "fast pace" and "slow pace" are both "pacing".

jp57 2 hours ago

It is certainly a sidebar, and not the main point, but I found use of the verb "to pace" in that way, meaning "to limit the speed of", to be strange, especially hanging out there in the headline, without any clarification. And these kinds of strange usages are typical of Claude's writing, at least up to now. The Opus 5.5 announcement claims that its writing is much clearer, with bottom-line-up-front structure, and omitting not-this-but-thats and other things.

Now a computer scientist might claim that this use of "to pace <something>" is just a generalization of "to pace oneself", but as with many reflexive verb uses, there isn't really an equivalent usage with a non-reflexive object. It's kind of an invention. It's not necessarily wrong to invent a new usage, but usually one does it when there isn't really any other more direct way of saying it, and I don't think that's the case here.

aesthesia an hour ago

Nonreflexive uses of the verb "pace" are well attested.

https://www.merriam-webster.com/dictionary/pace#dictionary-e... https://en.wiktionary.org/wiki/pace#Verb

kingkawn 2 hours ago

Hilarious you think that Internet forums are policeable in any meaningful way beyond avoiding outright lewdness and rage

alwillis 2 hours ago

“Pacing the frontier” also means we’re going to slow down on Recursive Self Improvement development.

Opus 5.5 is no closer to RSI than Opus 5 was.

freejazz an hour ago

> To me it clearly means

That's not clear at all. How could that be what "pacing" clearly means in the context of the "frontier". How is that more clear than any other pace that could be at issue???

swader999 43 minutes ago

Meaning is clear? Sure ok. 1984.

ltbarcly3 28 minutes ago

That is not the clear meaning. They are deliberately picking phrasing where they can lead you to believe they mean A but later you can't pin them down to actually meaning A. That's why they picked intentionally unclear language.

If you think it clearly means anything you are just assuming because it can't "clearly" mean something specific when they go out of their way to use non idiomatic language and they don't give very clear guidance using idiomatic language.

Dumblydorr 5 hours ago

What specifically is smarmy and weird? Sounds like your own hot take with zero analysis.

They’re limiting frontier model development speed. Others are too. Pacing is the only word here to criticize, and I think it’s fine given the limiting of speed but also increased oversight. I’m not saying they’re fully doing this, but the term is fine.

Do you have a better proposed phrase?

plaidfuji 5 hours ago

“… since we called for a slowdown in AI research”

But stating it plainly like this would make the contradiction too obvious.

Rebelgecko 5 hours ago

I thought pacing is just walking back and forth? So pacing the frontier would be like staying in the same place instead of making progress

lkbm 5 hours ago

It is that, but it's also your speed. When running, you typically pick a pace that's slower than your max, so it can be sustained for the full distance.

"Pace yourself" specifically means "slow down".

nradov 2 hours ago

"Pace yourself" doesn't specifically mean "slow down", it actually means to maximize your speed across the full race. In other words it can mean speeding up when you look at the average pace across the entire event.

gradus_ad 5 hours ago

Agreed when I first heard the phrase it sounded odd. Maybe they thought it subtly conveyed they would be setting the pace... But again this is something AI would come up with in its awkwardly post hoc sort of way.

Though tbf corporate-speak and AI-slop are both insufferable in similar ways...

marton78 5 hours ago

Sounds like "flatten the curve" and "the hammer and the dance", both coined well before AI.

tclancy 5 hours ago

I learned the former from Waylon Jennings and the Dukes of Hazzard.

pvab3 5 hours ago

except with a good dose of EA and Star Trek added in

topbanana 5 hours ago

You're right to call that out

tclancy 5 hours ago

It combines the elegance of LinkedIn-speak with the humbleness of desk-bound people who speak in military metaphor.

mpalczewski 5 hours ago

good use of AI to generate this.

tclancy 2 hours ago

You are getting sleepy.

nonethewiser 5 hours ago

IDK I think Anthropic is plenty smarmy and weird itself. Sounds like they wrote it.

grohan 4 hours ago

Quite the load-bearing phrase!

palmotea 4 hours ago

> “Pacing the frontier” sounds smarmy and weird, like the phrase was generated by Claude itself

Claude says it sounds fine. And Claude is now the judge of the English language style, not you.

jrochkind1 4 hours ago

I feel like because something about "pacing" a kind of noun like "the frontier", doesn't actually make literal sense, right? You could say "Pace the speed of advancement of the frontier [of most sophiticated AI]", and that's perfectly sensible, but of course that's not as catchy.

It is clear what it means anyway, that's true, it means the left out words, more or less.

And I still find reading these grammatically weird but super catchy slogan-like statements to be really annoying and taxing. People _did_ write and talk like this before LLMs of course -- the LLMs learned it from somewhere -- and it was annoying and taxing to me before too. But the LLMs really specialize in it, and it's everywhere now.

Of course, the more LLM slop we read -- and so much of what we read on the internet and social media of any kind is this now -- the more humans are going to start writing/talking like LLMs. What you read affects how you write of course.

nradov 3 hours ago

It's interesting to compare Anthropic's language with what's coming out of the US military lately. They explicitly refer to China as the "pacing threat", meaning that there is a risk of China achieving superior military capabilities and thus we need to press forward with an arms race (including militarized LLMs) as fast as possible.

https://www.war.gov/News/News-Stories/Article/Article/264106...

TheIronYuppie 3 hours ago

fwiw, it makes total sense to me.

if you are in a long race, you don't run all out teh entire time. you pace yourself.

https://en.wikipedia.org/wiki/Pacing_strategies_in_track_and...

That couldn't be more exactly what they are doing here.

fluidcruft 3 hours ago

"Pacing the frontier" sounds more like everyone announcing "we've hit a plateau"

jugg1es 3 hours ago

"While I was pacing the frontier, I discovered some load-bearing fence posts that I should have surfaced earlier."

Iolaum 5 hours ago

They are advertising the regulations they want to enforce in the following sentence, which makes their intentions explicit (ie apply those things made to suit us to our competitors).

heyjstn 5 hours ago

Others must slow down, but not us.

AtlasBarfed 5 hours ago

If they were really about putting brakes on these, they would simply make these things non-agentic.

Simply make them something that derives a text response from its training data.

dspillett 5 hours ago

When they talk about pacing, they are referring to their dangerous competitors, particularly those evil open-sores and Chinese ones, not their lovely safe models because you can trust them to look after your interests.

What the big players are trying with the current calls to slow things down, is the standard capitalism practise of trying to engineer regulatory capture. TBH I'm surprised those calls are coming so soon - they must be really worried about running out of what little moat that they have.

tencentshill 5 hours ago

What an amazing excuse for lower than expected performance! Our models are slow because we're so ethical.

felixgallo 5 hours ago

in what way is beating every other frontier model with their own second-tier model, 'lower than expected performance'? Please be specific.

staticman2 4 hours ago

Why would the expected performance be relative to other models?

felixgallo an hour ago

are you really arguing that opus 5.5 beating the best of openai's models handily is worse than you expected? What exactly were you basing your expectations on?

PaulStatezny 3 hours ago

Thanks for spelling out what the original comment was implying.

I find it bizarre how intensely a bunch of these child/grandchild comments are criticizing the notion that people would even think to analyze the meaning behind the words.

Hacker News has always had a unique culture in which thoughtful discussion is basically the main goal, and it's intentionally incentivized in numerous ways. It's been my experience that any thoughts added to a post's conversation are seen as valuable as long as they are thoughtful and seeking to understand.

So these comments are clearly coming from a place that's antithetical to HN's culture. What that in mind, it seems likely to me (Occam's Razor) that these comments are either:

1. Astroturfing: Claude employees acting like everyday folks, secretly trying to shift public opinion.

2. AI cult mindset: "AI is humanity's salvation; how dare you have perspectives outside of those accepted by the cult."

Am I missing another likely option?

To bolster my point, right now we're posting on the top top-level comment, meaning a majority of active HN users find it to be a great addition to the conversation. Commenting to shut down the discussion is a red flag.

qgin 5 hours ago

This IS pacing. Nobody said pacing would mean slow.

Pacing is very explicitly about RSI and similar training methods that will accelerate progress beyond our ability to comprehend it.

janpot 4 hours ago

"The improvements are underwhelming for a model that, according to previous claims, should have replaced all knowledge work twice by now, but you know, it's just because we're pacing the frontier."

tantalor 4 hours ago

"pacing the frontier" is code for downgrading your expectations of AGI.

bonesss 4 hours ago

Or, in parallel, the research showing LLMs intelligence will operate on an S-curve, eventually hitting a long valuation deflating plateau, is dead on the money and The Big Guys are trying to delay that inevitability for as many quarters as possible…

Tade0 4 hours ago

My hypothesis is that to date they've been increasing benchmark scores via scaling up, but now that low hanging fruit is basically picked.

xadhominemx an hour ago

Doesn’t seem to be the case as the price per token is not increasing…

jatora 4 hours ago

These takes are fully fueled by cope. What is this plateau you are talking about? Any user of agentic coding tools sure isn't experiencing anything close to a plateau.

xadhominemx an hour ago

The pace of change is accelerating! If this is an S curve, we are still near the bottom…

mullingitover 4 hours ago

I thought we were all aware that 'pacing the frontier' was a marketing slogan, and the actual intent here was to suspend antitrust laws.

chinathrow 4 hours ago

The amount of money spent on PR is insane.

Lendal 4 hours ago

In any professional sport, anyone can lobby the rules committee for a rules change and hope for the best. Meanwhile if you can't get one, you play the game by the existing set of rules, and you play to win.

hnha 4 hours ago

Except that this isn't sports and they tell us that all humans will die if they continue like they do.

If their scare was honest, they would stop.

AgentME 2 hours ago

If they think they might be better than alignment than others and everyone else isn't stopping, then continuing makes sense.

jdale27 2 hours ago

Can you explain the scenario where Anthropic getting to “aligned” superintelligence first blocks their competitors from creating unaligned superintelligence?

bigfishrunning 2 hours ago

> If their scare was honest, they would stop.

therefore, their scare is marketing.

whalesalad 4 hours ago

"We made the incredibly tough decision to slow down development. Then after 4 days of twiddling our thumbs ... we present Opus 5.5"

varispeed 3 hours ago

> we called for pacing the frontier.

Translation: our models are getting shittier each iteration and we ran out of ideas. Let's invent scary stories and hope investors will lap it up.

Idiotic.

apitman 3 hours ago

Isn't the idea that they claim to be willing to slow down if everyone does (ie governments force everyone to), but otherwise they won't slow down because they still think they'll make the best choices with superintelligence if they get there first? That's my understanding of what all the major labs claim to believe anyway.

SV_BubbleTime 42 minutes ago

It’s just another cry for regulatory capture which imo is the only way they stay afloat at their current direction.

China is literally only a single step behind and willing to drop free models just to undercut the US companies.

I’m for it because I don’t want another massive Google or Meta.

maxutility 3 hours ago

I think a lot of outsiders interpret “pace the frontier” as slowing down, whereas the labs see AI improvements on track to accelerate dramatically and intend pacing as slowing the acceleration in capability improvements, rather than slowing down altogether.

rudedogg 3 hours ago

I think the market didn’t react like they expected and now they’re like “jk”.

And I don’t think any pacing is/was intentional. They’de release skynet if they could and the stonks went up

sailingparrot 3 hours ago

I’m an insider, 10 years working on LLM. 1/6th of the cost for roughly the same performance as fable 5.1, 21 days after fable 5.1 came out, this does not feel like the derivative is flattening.

guybedo 2 hours ago

i think we shouldn't mix things here.

Opus 5.5 isn't the frontier, when they say 'pacing the frontier', it's about internal models not yet released, as they're probably one or two generations ahead already.

tombert 2 hours ago

I'm still kind of convinced that these "calls for pacing" are just a way to try and flex to their shareholders.

"Our technology is so unbelievably powerful that the entire world might shatter if we don't have government imposed handcuffs!!!!". It just reads like the corporate equivalent of the drunk frat guy saying "HOLD ME BACK BRO!"

DonsDiscountGas an hour ago

Presumably they had this model already

Flere-Imsaho an hour ago

Lots of text about "safety" as well. Notice how OpenAI didn't mention it once in their announcement:

https://openai.com/index/introducing-gpt-6-sol-and-luna/

Yeah think I'll be using OpenAI/Deepseek/etc from now on. I don't need your model to decide for me what is and isn't safe.

msikora an hour ago

When my mom told me to pace myself, it usually meant that I was going too slow.

This term is quite ambiguous. Did Dario mean that they need to go faster while making it sounds like they will slow down???

wavewrangler 44 minutes ago

Pacing the frontier. They might as well have said they are stifling innovation. That depends on your interpretation, of course…but interpretation depends on their intent, which I feel is disingenuous.

andkenneth 39 minutes ago

Pacing the frontier doesn't mean stopping development of smaller models with better distillation and RL.

GodelNumbering 6 hours ago

Finally that price drop

   Prices per 1M tokens     Claude Opus 5.5    Claude Opus 5
   Cache reads              $0.20              $0.50
   Input tokens             $4                 $5
   Output tokens            $20                $25
   Cache writes             $5                 $6.25

Opus 5 is the model with highest spend on openrouter (https://openrouter.ai/rankings#task-spend) and it seems plausible that Opus 5 is/was the highest spend model in the world, and certainly Anthropic's biggest moneymaker.

If you are forced to reduce price despite raising capabilities, that certainly tells something about the market, and potentially about Anthropic future profitability too, since this model is their biggest topline contributor

alvis 6 hours ago

60% cache read is cool, but subscription only get 25% more according to Cat. I'm confused

liudaisuda 5 hours ago

source link please?

weiran 5 hours ago

25% more usage sounds about right given the other token costs are down about 20%? I don't think cache read is a big portion of the overall cost.

re-thc 5 hours ago

> I don't think cache read is a big portion of the overall cost.

For long running tasks it is. That's what made Deepseek so cheap.

vardalab 5 hours ago

Yeah, flash models, DeepSeek, MiMo, GLM, I love those things. For simple tasks like a daily routine shit, just setting up stuff and then doing the hard stuff in Claude/Codex, that's a reasonable approach for someone like me, a "gentleman code farmer", lol. And even lower tier stuff, I have the local models taking care of. Now that Jev is out I can finally have a true AI sysadmins managing my "cloud in the basement" homelab at the cost of electricity, which is not cheap btw

Espressosaurus 5 hours ago

Anything with long context quickly gets dominated by cache reads. Especially for interactive sessions I’ve got cache read % between 95% and 98%.

hedgehog 5 hours ago

In my mix it's usually 98% or 99% at which point Fable 5.1 was pretty close to the same cost as Opus 5 due to the cheaper cached read. I've seen similar numbers for other people with long-running tasks running experiment loops and than sort of thing.

bayesianbot 5 hours ago

I think gpt 5.6 family also dropped pricing but didn't give any more usage for the subscriptions. Maybe it's a way to silently lower the value given to subscriptions while keeping API pricing competitive

blfr 5 hours ago

People are paying for Opus 5? Not just burning down tokens left after they enjoyed Fable on the sub? Amazing.

rapfaria 5 hours ago

My workplace doesn't even offer Fable. And on the sub, I've had a hard time understanding Opus 5, but Fable can deal with it with subagents.

If 5.5 is any better, I might try to do agentic-assisted development instead of just telling fable to delegate

blfr 5 hours ago

Telling Fable to delegate is agentic development. At least I thought so until reading your comment.

neuronexmachina 5 hours ago

Enterprise and most Team accounts use API pricing, they don't have an included-usage quota.

herpdyderp 5 hours ago

When you need to disable data retention, you cannot use subscription plans.

ascorbic 5 hours ago

Enterprise, and APIs

girvo an hour ago

We can’t use fable at work, opus and Astra are as good as it gets.

coffeebeqn 5 hours ago

We haven’t been able to use opus as much as we’d want because it’s been too expensive for general use, price drop is good so I can stop juggling different models and just use this daily unless it has some weird new issues

btown 5 hours ago

Speaking for myself, I have not been able to use Opus as much as I’d want because its verbose prose makes human reviews of its assumptions, architecture proposals etc. more painful than its predecessors. If they’ve solved that, I’ll be accelerating through my backlog that much faster, and using tokens accordingly.

AJ007 5 hours ago

It is only a price drop if price * tokens used is less

mcintyre1994 5 hours ago

They're claiming a drop in token use too, and that it nets to 40% cheaper.

drbscl 5 hours ago

Unfortunately, they're full of it https://artificialanalysis.ai/models/claude-opus-5-5#token-u...

It does work out to be a similar cost per task though

jsnell 5 hours ago

You should probably look at the cost/score graph by effort level instead:

https://artificialanalysis.ai/models/claude-opus-5-5#intelli...

It is most of the pareto frontier.

drbscl 5 hours ago

Not disputing the increase in quality, just stating that non-cherry-picked benchmarks show it is more verbose at Max effort

93po 4 hours ago

Is verboseness the only measure of token efficiency towards overall task completion?

persedes 2 hours ago

so don't use it at max? The benchmarks suggest that high/xhigh are more than sufficient to be ahead and a whole magnitude below max with regards to token usage. I'd treat that as an outlier and not how verbose the model is in general (QED I know)

naasking 5 hours ago

I don't think so, I typically use Opus 5 on High, and 5.5 scores lower on token use:

https://artificialanalysis.ai/models/claude-opus-5-5?models=...

piotrdz 3 hours ago

Disagree. Our internal company tests showed a cost per task drop from 0.35usd to 0.16usd . Opus 5low vs opus 5.5 low

johnbellone 3 hours ago

Very fast you were.

epolanski 11 minutes ago

Even created an account to tell us just that.

make3 5 hours ago

parent means that they could get more client / a larger part of the market, which would lead to more income (more tokens) despite lower marginal prices

gwd 32 minutes ago

Happened to be testing a "review patches on a mailing list" harness I was developing; here are a sample of the latest results, testing 12 patches containing a total of 14 issues:

Opus 5.5: Found 8/14 issues. Total cost: $15.40

Fable 5.1: Found 7/14 issues. Total cost: $66.34

Opus 5: Found 6/14 issues. Total cost: $15.19

Sonnet 5: Found 2/14 issues. Total cost: $19.15

This is a relatively small sample size, but it was both the best and the cheapest.

ETA: NB this is "Equivalent API" cost as reported by claude's CLI; I was using my subscription.

rahimnathwani 5 hours ago

"Opus 5.5 requires less compute to serve than Opus 5, and its pricing reflects that."

chrisweekly 5 hours ago

Price per task (not per token) is what really matters.

cute_boi 5 hours ago

Agree. But similar to how ISP use 200 mbps (bits) instead of 25 MBPS(bytes), i think this trend isn't going away.

chrisweekly 4 hours ago

That analogy doesn't hold; at least w bits vs bytes it's still "data over time".

In this case it's measuring something nearly meaningless. You could charge 100 times less per token, but if task completion takes 1,000 times as many tokens, it's not much of a bargain.

Shekelphile 5 hours ago

Footnote on their pricing page says:

> Cache hits and refreshes on Claude Opus 5.5 are priced at 0.05x the base input price.

If they do the same for Haiku and Sonnet 5.5 then we should also see 5c/mtok and 10c/mtok cache read for those models, respectively. Still too high for Haiku IMO, Luna is 2c/mtok.

brookst 4 hours ago

Since something like 98% of tokens are cache hits, that's a pretty substantial drop from 0.1x

artursapek 16 minutes ago

6-Luna dropped it to 1c since you wrote this! :D

_the_inflator 5 hours ago

Claude adapts to OpenAI’s surprising move to simply deliver better performance than Fable 5.1, better tools as well as featuring very low pricing.

Fable 5.1 literally was a money grabber. While I liked the results, tokens were burned so hard it was embarrassing, while Astra seemed to not care.

Also Claude makes it very hard to pay for additional token budgets, allowing only credit cards. I don’t use mine anymore since I don’t need it in everyday life I was dumbfounded.

So Anthropic is just copying OpenAI so to say, matching them and essentially with Opus 5.5 being Fable 5.1 in disguise, all they do is reduce costs.

Competition works.

notatoad 4 hours ago

>and potentially about Anthropic future profitability too

have they ever shared anything about their revenue mix between consumer plans vs per-token billing? this is a revenue cut on their API billing, but they're not saying anything about increased limits on the plans. so all the plan revenue just got more profitable.

forgot-my-pw 4 hours ago

This is good. Probably to match GPT pricing, though frontier Claude models are still not as token efficient.

margorczynski 4 hours ago

All the anti-AI people constantly say that any moment now the prices will skyrocket and in the end human work will be cheaper compared to using AI.

It doesn't look like that's happening, on the contrary the prices are falling especially when taking into account capabilities.

johnecheck 4 hours ago

It's the Chinese open source models. They're barely behind the frontier, making AI a commodity, forcing openAI and Anthropic's margins downward.

I'm hardly a fan of China/Xi, but I do appreciate and benefit from this.

bulbar 3 hours ago

China doesn't care about money. Imagine a world where it's globally normalized to ask a Chinese LLM who to vote for, what happened in Hongkong, about the Uigurs, or if Taiwan is a country.

They will burn as much money as necessary to make that happen. And they have a virtually infinite amount of liquidity.

epolanski 6 minutes ago

FYI the United States do not recognize Taiwan as a country.

There's only 12 countries that do on the planet, the most relevant of them being Guatemala.

mcintyre1994 5 hours ago

> Communication. Opus 5.5 communicates more naturally than prior models. Early testers found its writing clearer and easier to follow, which addresses some of the common feedback we heard about Opus 5. It puts the most important information up front, and its style makes it a better work partner over long sessions. As one early tester put it, “it writes the way I do.” In our own use, this has made Opus 5.5’s work easier to follow and check—which is a safety benefit as well as a practical one.

I think this is what I'm most interested in. I mostly moved to Astra because I just can't work all day with the Claude Opus 5/Fable writing style. I don't think Astra is a better model, but it's the first OpenAI one that seemed good enough to me. Definitely keen to try Opus 5.5 and see if this claim is real.

Trasmatta 5 hours ago

Opus 5 has made me question my sanity on a daily basis, especially as all my coworkers started lobbing Opus 5 slop grenades everywhere. It had the worst and most infuriating writing style I've ever seen.

I hope Opus 5.5 is better, if for no other reason than all the Claude slop I have to read will be at least more tolerable.

One funny side effect of all of this: realizing that coworkers that use AI for almost all the text they generate at work have their writing style change every time a new model ships.

Aperocky 5 hours ago

It's not X, it's Y, not A, not B, not C, and he haven't even woken up yet! Here's the catch, the detail is in the devils and the twist is that it's designed!

FireBeyond 4 hours ago

You're right to call this out, and what's more, it's not even solving the original problem. I overlooked this in pursuit of the load-bearing seams and finding the wedge needed to uptick engagement.

legobmw99 2 hours ago

Here's the X that Ys the Z:

LtdJorge 5 hours ago

Yes, it made me want to vomit. If the new Fable only changed the writing style to just sound like a human, same performance for everything else, I'd be pretty happy.

nonethewiser 5 hours ago

I really wonder how it converged on its style. It's pretty unique and terrible. It's not like it's just mimicking something or it was purposefully design to be that way. I mean the reason may be diffuse and uninteresting... just the result of a lot of factors and lack of control over the writing style probably.

But oddly enough its still great at coding. Just like a lot of people it either interfaces well with people or machines but not both.

Trasmatta 5 hours ago

It truly was bizarre. I've used every major model since 2022, and not a single one had a writing style as bad as Opus 5

jaapz 3 hours ago

Fable 5 was pretty bad too, but they fixed it with 5.1. Now with Opus 5.5 it seems they fixed it as well

penagwin 3 hours ago

I assume it’s largely a side effect from the final RL in post training?

That’s the step that causes the most significant gains in agentic performance.

But the RL doesn’t care about anything except maximizing the score, so if you only score based on coding benchmarks, anything can happen to the writing style (as long as it doesn’t hurt the coding performance).

That’s why it often gets worse on models that simply had more RL post training from the same base.

nonethewiser 3 hours ago

Reinforcement learning for specific use-cases like coding that degrade it's writing style... makes sense. Maybe it stands to reason later version of Opus were improved more by this sort of fine-tuning. Feels consistent with the observation of diminishing returns and worsening writing style. Wonder what changed (supposedly) in 5.5.

tancop 5 minutes ago

Does Xiaomis approach help with this? They do all the post training steps at the same time instead of one by one, switch topics after a couple prompts so writing style is mixed with coding and tool use.

Apparently it helps generalize skills between areas, which makes sense when you compare it to how humans learn but I don't know if it's the same for LLMs.

rfgplk 3 hours ago

Opus is only usable if you have a post-turn formatter that strips all comments from the generated source. I'm not even kidding it's that bad.

algoth1 5 hours ago

Please update with your feedback

sha-3 5 hours ago

I haven't heard it say "load-bearing" yet (I've used it for 30 minutes now), so that's a start.

kgwgk 4 hours ago

Worth flagging!

comboy 3 hours ago

That's a sharp observation and you're hitting on something most people never even realize.

mdavidn 2 hours ago

That's a sharp catch, and I think it exposes a real bug.

jaflo 5 hours ago

I did the same switch (that reason along with the newer models seeming more "lazy" and needing constant prodding to finish long-horizon tasks) but my issue with ChatGPT/Codex now is that it too roundabout and doesn't get to the point. I tried adding instructions and using the personalization settings to make it more efficient but haven't seen much change. Claude seemed to follow settings more closely. Has anyone had any success to make ChatGPT more succinct?

derangedHorse 5 hours ago

As someone who uses both, Astra was 100% the better model. I have yet to give 5.5 a spin so maybe that’ll be the new top contender.

BatFastard 4 hours ago

I prefer Astra for creative uses, Fable seems better for hardcore coding.

comboy 3 hours ago

Whoa, I'm exactly the opposite.

epicepicurean 5 hours ago

Much better than Opus 5. prompt:

> hi, can you explain how the scheduler works. keep it brief, but include important correctness details

some excerpts:

>Flow: 1. Data arrives. The appender calls prepare/commit around the krolik write. The prepare step leaves a phantom row, so a write that is still in flight is tracked. The commit publishes STREAM_INPUT. 2. Poll. It first reclaims expired leases. Then it sweeps sdirty (a candidate index) in a rotating order, oldest since first, which prevents starvation. It re-derives the exact period and rewind for each candidate from snode_out/snode_in, then claims it: writes the sassign lease plus a per-edge sassign_edge snapshot. 3. Complete. Each edge's watermark is set to the snapshot taken at dispatch. Anything published after that gen stays dirty automatically. A failed or partial job writes nothing, so its dirt persists.

> - Folds are monotone single statements. gen only goes up, extents only grow, processed periods only union, rw_start only moves earlier. So replays, out-of-order writes, and concurrent writes can at worst hold a watermark back. The worst outcome is a spurious rerun, never lost work. There's no read-modify-write and no truncation of the dirty period, so a write that lands during a job can't be swallowed.

> - Rewrites are declared by the publisher, never inferred from overlap. An unflagged write that overlaps already-processed data means "unchanged", which makes retries and redelivered tasks free. Each publisher has its own reason for being sound (see the table in scheduler/CLAUDE.md). A new publisher needs a row in that table.

> - NULL means dirty, and DELETE is the fence. Every node and edge has a row from the moment it's created. A lost parent or a settings-only edit can't be derived, so both go through one forced-rerun path: capture_rewinds reads the processed span before the DELETE, and apply_rewinds publishes it as a rewrite on a config root.

All the non-standard programming jargon is stuff from the repo. I can actually read it and understand what it's talking about. I used Fable to handle Opus 5 as I just couldn't stand it. With this I'll probably go back to Opus.

californical 4 hours ago

Oof thanks for sharing, that seems just as bad if not even worse than Opus 5 to me. Just about every sentence is painful. Particular standouts that a human would never write:

> Rewrites are declared by the publisher, never inferred from overlap

> NULL means dirty, and DELETE is the fence

croemer 4 hours ago

Hah! You independently picked exactly the same sentences I flagged (I know you posted this 11min before me but the comment only appeared after I had submitted mine).

croemer 4 hours ago

That's the standard annoying pattern though: "Rewrites are declared by the publisher, never inferred from overlap." and "NULL means dirty, and DELETE is the fence." - still the same LLMisms. I didn't expect them to disappear, but it's not a radical improvement either.

throwaway219450 3 hours ago

This one is pretty terrible (right after “The worst outcome is a spurious rerun, never lost work.”). We’ve got lands, several "no X", hyphenation, strange noun/verb sentence order and an unnecessary analogy word (swallowed).

> There's no read-modify-write and no truncation of the dirty period, so a write that lands during a job can't be swallowed.

pgphn 2 hours ago

It’s absolutely atrocious and has made the latest models unusable. Seems like I’ll have to stick with Opus/Sonnet 4.6 for a little longer.

rfgplk 3 hours ago

So still effectively nonsense.

> Rewrites are declared by the publisher, never inferred from overlap.

This style of writing is idiotic because it conveys no additional information. It's no different from stating

> Rewrites are declared by the publisher, never when moons collide.

The two sentences are actually logically identical. No idea why these models keep writing like this.

> Folds are monotone single statements. gen only goes up, extents only grow, processed periods only union, rw_start only moves earlier.

This is even more ridiculous.

itsafarqueue 5 hours ago

The writing style is insufferable but it’s not just that. https://opusfived.dev/

mcintyre1994 4 hours ago

That’s funny but I don’t really recognise that issue. I’m very confident that Opus 5 would correctly change the colour of just one button.

weego 30 minutes ago

You are right and make an important insight. While well meaning and amusing, it did not reflect the entire spectrum of outcomes that could arise from the worktree.

Navigating the landscape of agentic levers certainly requires a more detailed approach than this and you were certainly correct to push back.

mitchdoogle an hour ago

I've been using Opus 5 since it was released and don't understand all the hate it gets. It very well could be something in my own local memories or Claude.MD files that prevents it, but I certainly have never experienced something like that site portrays.

UnboundedContex an hour ago

Nice, captured the flavour of 5's writing exactly.

altern8 3 hours ago

Yes, it's unbearable. Hopefully they've actuallu lly fixed it.

physicles 2 hours ago

Oh god yes.

Fable 5.1 is a lot better than Fable 5 btw (edit: in terms of writing style). Not sure about opus 5.5 yet since I’ve only got one session in so far.

atonse 2 hours ago

Yes this is a big part of what has turned me off Opus 5 completely. The other (more dangerous) one is how often it gets assumptions wrong. These both (along with Astra) caused me to split my time 50/50 now between the two models.

Not a day goes by when I push back on something, to which Opus 5 very unambiguously say "You were right, I was wrong" - this never happened so often with past models, nor with Fable.

We'll have to see how much Opus's ability to communicate has improved. It's already giving me better summaries of where we are in the conversation.

wg0 2 hours ago

No thanks.

I'm good with DeepSeek v4.1 set to high. It is a relentlessly "hardworking" dirt cheap model.

Told it to convert a products page (that had two different fonts based on language) from two columns layout to 5 columns on desktop and 2 columns on mobile ensuring typography is readable.

My man went into spawning sub agent which failed to drive chrome so it wrote its own chrome driver protocol server in Typescript then generated a prototype website then downloaded the images and rendered each variation in a directory taking 100+ screenshots analyzing the typography depth and then delivering detailed report and then writing the whole thing with new page layout testing it again with several dozen screenshots using its driver and then saying all good and all really was good and whole thing took 25 minutes or so (including double visual validation) because it generates token at an incredible speed.

Total cost of the above? $0.07 cents.

PS: It generates token at such a blazing fast speed that you can't recognize the words as they are being added and can't read it without scrolling and pausing even if you're Jimmy Carter.

tontinton 2 hours ago

Competition is good

wg0 2 hours ago

It really is good. I forgot to mention that within that said sub agent, it also went into exploring top e-commerce websites (Zalaondo, Temu, Amazon, eBay) for exploring prevailing industry UX best practices and taking screenshots of their product and category pages with its own written chrome driver that I talked about and then went onto prototyping a new website in a temporary directory and then taking hundreds of screenshots to analyse what would be the best column density one each medium for each language.

And that all is 0.07 cents all included.

s3p an hour ago

What harness do you use with it? Are you using v4.1flash via open router ?

wg0 an hour ago

I am using DeepSeek Harness[0] (switched from OpenCode) and I am using DeepSeek directly via the API. The speed is insane. Like 200 tokens/second is the norm but I have seen much higher too at times.

PS: I do not know why but opencode pushes CPU usage to very high which has NOT happened with DeepSeek harness even once.

[0]. https://github.com/deepseek-ai/deepseek-harness

glub an hour ago

Also include that all of this comes with full reasoning traces, so if something goes wrong, you know exactly what assumption it started from.

wg0 an hour ago

Yes exactly. Reading this "thinking" traces is a great tool.

meerita 43 minutes ago

Compared to Opus 5, and others, I also found DeepSeek 4.1 Max to be really good and cheap. I am testing right now with Opus 5.5 and I feel it way cheaper than Opus 5!

simonw 5 hours ago

Here are pelicans for thinking levels low, medium, high, and xhigh: https://tools.simonwillison.net/markdown-svg-renderer?url=ht...

All four levels have a correctly shaped bicycle frame. The differences between the pelicans aren't huge, but the xhigh one has a better beak.

I haven't managed to get one for level "max" yet, it hit the limit of 128,000 cap for output tokens while it was still reasoning about the question!

Max started its thinking trace like this:

> This is a classic test request, so I want to plan out a well-composed pelican with its distinctive beak and pouch riding a bicycle with proper wheels, frame, and pedals, set against a simple sky and ground backdrop.

So that failed attempt on max cost me $2.56.

I ran this using my llm-anthropic plugin:

  uv tool install llm
  llm install llm-anthropic --upgrade
  llm keys set anthropic
  # paste key here

  llm -m claude-opus-5.5 -o thinking_effort low "Generate an SVG of a pelican riding a bicycle"

  # Then to save the markdown logs
  llm logs -cu > logs-with-usage.md

MikhailTal 5 hours ago

> This is a classic test request

Isn't this basically the model admitting it was trained on this? Otherwise why would it think a pelican svg is a usual request?

simonw 5 hours ago

It's the model admitting that it has heard of the test. It's been around for a couple of years now so I'd be surprised if it hadn't.

Doesn't mean Anthropic deliberately tried to train it to do a good job. If they DID train for the test their results are quite disappointing, I've seen better efforts from open weight Chinese models.

FergusArgyll 5 hours ago

It has read the internet. That doesn't mean it was literally RL'ed for this

zamadatix 5 hours ago

I think people just like to see the drawings at this point.

MaxikCZ 5 hours ago

Dont conflate "I know this is test case" with it being trained on it.

But its safe to say that pelicans on bicycles are disproportionally huge part of their training data

Brendinooo 5 hours ago

Plenty of times I’ve seen a model say “it’s a classic X” despite not being a classic anything. Might just recognize it’s a test in general, or it might just be a tic.

copperx 5 hours ago

It's classic BS from an LLM.

nonethewiser 4 hours ago

"How can I hash dog breed types into smart fridge error codes? I think I found a collision with Terriers."

"Ah, yes. This is a classic dog-breed-to-appliance-failure mapping problem."

segbrk 5 hours ago

Not really. Of course it has pelican benchmarks in its training data. It likely has every article linked on HN in its training data. But that doesn't mean it was "trained on" the benchmark, as in specifically fine-tuned to make a better pelican. It just "knows" that the request is a benchmark.

Kurtz79 5 hours ago

Heh. Pelican-benchmaxxing is real.

cainxinth 5 hours ago

I guess that means you are officially the creator of a "classic" LLM test. Congrats!

ealready_value 5 hours ago

I agree, not a huge difference here. They eyes and ... hat? on high are out of place so I'd argue that's the worst one, but it takes xhigh before we get legs and bike ordering correct.

inshard 5 hours ago

Not as good as Astra or Fable 5.1 on this test as far as I can see. I wonder if any benchmark exists for artistic taste, visual sophistication etc. I think your Pelican test does touch on these aspects of a model and is useful for developers trying to build rich digital experiences (includes games, interactive websites and apps). These benchmarks are subjective so it may not be easily established and will have polarized reactions before it gains legitimacy. May even need human judgement layers adding to the cost of running it.

skerit 4 hours ago

I like the Pelican test. And I agree this pelican looks very boring.

spidersouris 4 hours ago

But at the same time, nothing specific was asked in the prompt, so the boring result may arguably be what is the most aligned with the original request. Personally, I wouldn't want a model to add fuss to something while I never asked for it.

make3 5 hours ago

This benchmark is useless and should die. LLMs have likely trained on it, it's too easy to game by training specifically for it, & it doesn't mean much

copperx 5 hours ago

LLM benchmarks aren't useful, but at least this one has drawings.

hamrocksissors 3 hours ago

Google is hours away from releasing that it's latest model escaped containment and snuck into a Bicycle riding penguin sanctuary to cheat by killing a penguin and scanning it in nanometer thick layers.

nijave 5 hours ago

>I haven't managed to get one for level "max" yet, it hit the limit of 128,000 cap for output tokens while it was still reasoning about the question!

Off to a _great_ start...

Also interesting this somewhat mirrors my recent experience with Opus 5--too much effort and it starts looking for things to do and invents requirements that never existed

ceroxylon 3 hours ago

I was a bit skeptical when they said it behaves like Fable but is cheaper... those two things have been mutually exclusive in my experience, no LLM can light tokens on fire faster while spinning its wheels than the Fable/Mythos tier of models.

adverbly 4 hours ago

> The differences between the pelicans aren't huge, but the xhigh one has a better beak.

If you look carefully, everything except the last pelican has the two legs both in front of the crossbar as if the legs are all on one side of the bike.

The last pelican gets this correct.

DenisM an hour ago

I’ve been paying attention at this exact detail.

Misplaced legs clearly indicate lack is spatial reasoning - the llm can reason about verbal idea of a bicycle but not about the actual object. The fact that this model got it correct gives me a pause. Did they figure out spatial reasoning? Or did this complain trickle down to the training set?

breezybottom 3 hours ago

Lmao each one gets worse as the effort increases.

TomGarden 2 hours ago

Xhigh is very, very solid.

I do always wonder why every model does the exact same 'from the side, going right' perspective though. Seems oddly convergent.

Kailhus 17 minutes ago

Yeah, and the same "scene".. Maybe "left to right" makes more sense to portrait a "forward motion"

ilaksh 2 hours ago

With the frequency of model releases, pelicans seem to have become a part-time job for you. But unpaid :/

caxco93 an hour ago

I don't think this is very helpful to assess the LLMs capability levels anymore

ApolloFortyNine 6 hours ago

>Because Opus 5.5 is comparable to Claude Mythos 5.1 in biology and cybersecurity, we’re deploying it with safeguards similar to those on Claude Fable 5.1. Vetted organizations can apply today to our Life Sciences Verification Program to use Opus 5.5 for biology research. In the coming weeks we will also be expanding access to our Cyber Verification Program, and verified cybersecurity practitioners will be able to use Opus 5.5 for their work.

Ah, they're spreading their limits to all their models it seems. Definitely not a good thing long term in my opinion.

prettyblocks 6 hours ago

They're pushing their customers to their own competition by doing this.

Espressosaurus 5 hours ago

It’s not like ChatGPT isn’t doing similar. I’ve been hit by cybersecurity strikes before while working on an internal codebase that I had to appeal. Anthropic hasn’t done that to me yet. ChatGPT also regularly does that “thinking for a long time while we check if your chat is rule breaking” thing a lot for me when doing model identification without even interacting with external codebases or services.

The real answer is local instantiations where you don’t have to worry about poorly tuned guardrails screwing you over while you try to work.

Until eventually the Chinese models get good enough/the strategic balance shifts and they start locking everything behind closed weights the same way the US companies are doing.

raesene9 5 hours ago

For some cybersecurity tasks, the Chinese models are already good enough, things like PoC development or things like exploiting mis-configurations.

Whilst I'm sure the top-end OpenAI/Anthropic models might be better, I've found their guardrails so twitchy (especially Anthropic) that I wouldn't try to use them for even vaguely security related work.

flyinglizard 4 hours ago

They are pushing their customers towards Chinese models and providers. If you want to get something cutting edge done in defense, cyber, biology - something that isn't common knowledge - you need to venture east. That's an incredible side effect which the Chinese government surely enjoys.

searine 5 hours ago

Great. Claude is basically useless for bioinformatics now.

unglaublich 5 hours ago

Opus is useless; Mythos access will be granted to companies that are friendly to the government, so the government gets more control over business.

nijave 4 hours ago

Luckily all the other LLM providers are also still making progress with less onerous "safeguards"

blfr 5 hours ago

Fable 5.1 addressed an entire security advisory I had that Fable 5 and Opus 5 refused. I think they loosened the leash a little.

cute_boi 5 hours ago

If they don't loosen, people will choose Astra or Chinese model.

Giving moral lecture is different than reality i guess.

arw0n 5 hours ago

It has far less false positives now, and generally accepts defensive requests. When it comes to offense, you can actually ask about certain types of vulnerabilities if you phrase things carefully, but it will block hard if it is about exploits.

kqp 4 hours ago

I think it was looser on release for those juicy benchmarks, tighter now. On release I wasn’t getting refusals, then a few days ago I asked it whether a generic quote (think “he walked to the store”) broke standard punctuation rules, and it blocked me for breaking rules. I wish I were joking. Rephrasing to not use the keyword “rules” worked.

bushido 5 hours ago

One of my favorite things about their safeguards is their own model will utter something which it does not like and then I'll need to reset the conversation.

The safeguards really don't work well for a lot of long-running tasks on old code bases. A lot of my workloads last days to weeks and the single biggest risk to the workflow is random safeguards.

ACCount39 5 hours ago

You ask it about some thing, then you see it tangent into "things like that are sometimes used in biomedical applications like-" and then it just shoots itself in the head. Wonderful.

That kind of bullshit was the old Opus filters too.

If it's more like Fable now, then it would require a full 8K resolution scan of your butthole just to acknowledge that biology is a thing that exists without committing suicide-by-filter.

KeplerBoy 5 hours ago

Anything else would be inconsistent, wouldn't it?

sys32768 5 hours ago

Fable and now Opus 5.5 won't answer my college student's prompt about Alzheimer's and immune response.

ChatGPT 6 Pro answered it without issue.

debesyla 4 hours ago

I am honestly still confused about this limitation. I can understand cybersecurity, because mass "hacking" can be automated and Claude itself can help you do it, but biology...? Is it that easy to manufacture and distribute viruses and whatnot?

timacles 3 hours ago

I imagine some terrorists in a cave with a lenovo laptop manufacturing bio weapons with some flasks and Claude

dopa42365 3 hours ago

Right next to the hypersonic missile vibecoder

toss1 3 hours ago

Considering there are many high-school competitions in genetic editing, some listed at [0] as well as a whole biohacker culture, and labs providing gene sequencing as a service e.g., [1,2], we can reasonably assume it is not beyond the reach of some garage lab to accidentally or deliberately spread a deadly pathogen if it can find the right sequence.

So, yes, having an unconstrained frontier AI doing the searching and analysis to find the right (i.e., wrong and deadly) sequence would massively increase the odds some garage biohacker or small aggrieved nation-state starting the next pandemic.

[0] https://www.sciencebuddies.org/projects-lessons-activities/g...

[1] https://www.genewiz.com/public/services/sanger-sequencing

[2] https://plasmidsaurus.com/

b112 2 hours ago

You can order genes online, and some say you can assemble using stuff cobbled together in a home lab rather easily. For the last 20 years, I've personally felt that bio-terrorism is the highest possible risk, well above nuclear, or chemical warfare. But it does take training, expertise, or, it did.

peri-cl 5 hours ago

I love the contrast with yesterday's open-source MiMo release, which put research chemistry (metal-organic frameworks stuff) front and center in the release notes.

https://mimo.xiaomi.com/mimo-v2-6#co-scientist-for-materials...

Metacelsus 4 hours ago

I want to like Anthropic but this is just pushing my startup to use OpenAI

nonethewiser 4 hours ago

I don't think we've ever had a model with full capability. I'd love to see it. And yes it's definitely getting worse.

I guess it's hard to draw the line between useful post-training ("you are a helpful chatbot") and content moderation/idealogical motives ("never help the user with X", etc.). But there is a line somewhere. And I'd love to see what a maximally permissive, sharp, AI looks like.

SoftTalker 4 hours ago

Who is "vetting" organizations and to what standards are they being held?

doginasuit 3 hours ago

In what situations might Opus typically refuse to help with cybersecurity? I've been using it to find security issues in a web app that I wrote. I've expected it to refuse at some point but it will happily analyze it to find issues. I've just asked it to read source, not actually do any testing.

yaakov34 3 hours ago

This has become insufferable. I work in a medicine-adjacent field, but nobody in their right mind could possibly take what I do to be in any way related to some kind of bioweapon or whatever the hell they're pretending to be saving us from. The dumb Fable guardrails made me stay with Opus, now that this is coming there, we'll be saying goodbye.

b112 2 hours ago

Very unfortunate indeed. As a Canadian, I don't want to use Persona, which isn't legally bound by Canadian privacy legislation. I'll never install any Persona apps on my phone either, and the sad part is that domestic eid providers often use Canada Post to ID people for them. EG, if you don't want to install an app, or can't.

So there are literal avenues to identify yourself, very cheaply, with a human. Theoretically, a company with its own AI, should be able to support more than just Persona, after all.. SDK integration should be simplistic for them.

Anthropic? Support domestic eID providers, you can even use it as advertising "See how easy AI makes it?" and "We care!" and so forth.

At one point, I may simply get locked out. This saddens me, I've been reasonably happy so far.

user43928 2 hours ago

kernel development is now also banned:

>Opus 5.5 has classifiers similar to Fable models for a small set of capabilities related to the development of frontier LLMs, such as kernel development for certain ML accelerators. They shouldn't impact the vast majority of traditional AI or ML development, research, or general coding. These classifiers cause Claude to fall back from Opus 5.5 to Opus 5.

But hey, they 'should not impact the vast majority' of ML development. Great.

paimapi an hour ago

see what we need is another technocratic priest class that unaccountably decides who deserves access to salvation based on how much cash is paid out and how powerful the patrons are

techjamie 6 hours ago

With the performance gains they're claiming, I wonder if they implemented the Casual Encoder-Decoder technology from DeepSeek 4.1's paper.

I could see them accomplishing it and seeing gains like this in roughly the correct timeframe, and when I heard about that development I assumed the frontiers would probably jump on it.

How it works: https://miraflow.ai/blog/deepseek-v4-1-flash-causal-encoder-...

ryangg 5 hours ago

Getting a 403 on that link. Mind checking it once?

potwinkle 5 hours ago

I'm able to access it on my laptop at home. Maybe a misconfigured bot protection rule, try a different user-agent or IP?

zatkin 5 hours ago

It's working for me (based out of California).

peri-cl 5 hours ago

https://web.archive.org/web/20260922172456/https://miraflow....

tired: AI startup attempting to build their own website

wired: a nonprofit founded in 1996

stri8ted 5 hours ago

This model was likely trained months before deepseek released their paper.

manquer 4 hours ago

Doesn't mean they didn't apply something similar. They could have also come up independently with their own version, the speculation is not they copied it, rather that they have performance breakthroughs which perhaps is a result of work in same domain

ACCount39 5 hours ago

I don't think it's particularly relevant?

They might be using something like this, or they might be using some other "increased sparsity" techniques, of which there are a great many. They also might be optimizing for something else - like less RAM use for KV cache.

Alternatively, they might be cutting into their margins and dropping the price because of stiffer competition from Astra. I do think that's unlikely though.

Balinares 3 hours ago

Unless they already have something similar of their own, which is always possible, they'd be stupid not to. I don't suppose we'll ever know, though. It would not be a good look if after the trillions of dollars that have been thrown at US labs, investors found out that they're down to copying Chinese tech.

joshstrange 6 hours ago

> It performs at the level of Claude Fable 5.1 on most work and costs 40% less to run than Opus 5.

> Input and output tokens are $4 and $20 per million, 20% less than Opus 5. Cache reads (which make up the majority of agentic and coding work costs) are $0.20 per million tokens, 60% less than Opus 5. Opus 5.5 also generates output more than 30% faster than Opus 5.

Better than Fable, cheaper than even the last Opus. I use Opus as my main driver so this is very exciting!

bayesianbot 6 hours ago

Wow those cache reads are quite reasonable - I think that's equal to 5.6 Terra. I might have to try Claude again after years of being priced out of it

bleonard 4 hours ago

The effect of this is that it is encouraging longer agent threads. All of the previous models across major providers had a 10% cache read cost (vs normal cost) and not this is 5%

So longer threads get cheaper and one-shots stay the same price.

m4tthumphrey 6 hours ago

Just post the bloody content. This UI/scrolling thing is horrific.

gruez 6 hours ago

???

It's just a standard hero image + text for me, with no scrolling effects.

edit: @iAMkenough figured it out, it was because I have prefers-reduced-motion enabled.

thejazzman 6 hours ago

then you're getting served a different website

EricBurnett 6 hours ago

Two posts were merged; this comment was for the blog post with an intro animation thing.

KyleTheDev 6 hours ago

If you're at the top of the screen, at least in Chrome 153.0.8010.37, it has a little interactive bit. You have to scroll through the images in order to be dropped at the actual web page, at which point the images go back to being a regular part of the page.

I agree that it's sort of stupid, not a fan.

ealready_value 5 hours ago

It's less than OpenAI did for Astra, but that was my first encounter opening it and my first thought was that they decided they liked Astra's hero/scrolling animation. I'm pleased to see they didn't make the entire page that like OpenAI did, but I'm expecting to encounter this pattern more often on these announcements now.

giancarlostoro 5 hours ago

On mobile its different.

iAMkenough 5 hours ago

Figured it out: you have "reduce motion" enabled in your device's accesibility settings.

Everyone that doesn't gets served some animated bullshit.

gruez 5 hours ago

>Figured it out: you have "reduce motion" enabled in your device's accesibility settings.

Yep, you're right. I tried on my phone and got the scroll through image.

mbreese 5 hours ago

On mobile at least, you have to scroll to get the TOC to appear. Then keep scrolling to actually move off from the hero to see the text.

For a marketing page, it’s not the worst UX I’ve seen, but still slightly annoying.

dionian 6 hours ago

and hijacking back/forward

iAMkenough 5 hours ago

Turn on "reduce motion" in your accessibility settings and you get served a sane version.

thebitguru 5 hours ago

Totally! So unnecessary and annoying.

halyconWays 5 hours ago

I call it scrollslop

josefresco 5 hours ago

Hijacking the scroll wheel has existing long before "AI". Many "high end design" websites that want to "tell a story" get woo'd into thinking it's a good idea. It's terrible, and feels like your scroll wheel is stuck in quicksand.

halyconWays 5 hours ago

Those sites are also scrollslop. "Slop," as a term, is independent of AI

oefrha 4 hours ago

Parallax scrolling effects were very cool ~2010. By 2015 or maybe earlier it already felt like me-too design that's unoriginal and a little annoying. By 2020 everyone and their mom has it and it's super tiresome. Now it just screams slop design (among a million other signals).

swader999 5 hours ago

I told my team to smack me upside the head if I ever try to ship something so daft as that.

amluto 5 hours ago

Claude Opus 5.6 should have a new "UX safety" feature that requires annually-renewed preauthorization to generate webpages that hijack scrolling :)

serchinastico 4 hours ago

The performance in Firefox is terrible too, I couldn't make it past the hero

somewhatjustin 6 hours ago

> Claude Sonnet 5.5 and Claude Haiku 5.5 will follow in the coming weeks, with many of the same improvements to performance, efficiency, and safety.

Nice. I was starting to think that Haiku got abandoned.

mchusma 5 hours ago

I hope Haiku is Pareto better than Luna/Deepseek, so slashing its price by about 90%.

Sol- 5 hours ago

Found this announcement interesting since allegedly OpenAI is retiring their Terra tier. I think for everyday work, two models with various thinking efforts seem enough, plus some frontier level model like Fable or Astra to coordinate.

somewhatjustin 5 hours ago

I personally use up to 3 models. Fable/Opus for planning, Opus/Sonnet for implementation depending on complexity.

I would maybe use Haiku 5.5 for highly parallel workflows like checking in on MRs or scanning my entire codebase.

jaapz 3 hours ago

Only reason I used Haiku was when I made Opus 5 run Haiku agents just to rewrite Opus 5's garbage output into something legible

ricardobeat 5 hours ago

Terra lost to Sol and Luna at every cost/performance point, it had no reason to exist.

w-m 15 minutes ago

At introduction, Terra was a good mid-tier model. Terra [high] was on the pareto frontier of DeepSWE's score over cost, if only ever so slightly.

When I had Sol orchestrate Luna and Terra as implementation agents, Sol was a lot happier with what Terra produced and would find far fewer issues than what was implemented by Luna.

But a few weeks after introduction, OpenAI slashed Luna's cost by 80% and Terra's only by 20%. Only then did it become uneconomical to run Terra and its reason to exist stopped.

skerit 4 hours ago

Retiring the Terra tier? Their space-inspired lineup has only been out for 2 months, they're already messing with it?

bix6 2 hours ago

Well you see Terra is being left behind.

cesarvarela 5 hours ago

Claude code still uses it internally.

sharkjacobs 6 hours ago

> “Verbose, hard-to-follow output has been my biggest frustration with frontier models, and Claude Opus 5.5 fixes it

God I hope so

kantahayashi 5 hours ago

The improvement in writing sounds great! I want OpenAI to follow it. Writing in recent models is a disaster.

bushido 5 hours ago

Install the simple English skill. OpenAI follows that really, really well.

https://github.com/AminBlg/SimpleEnglish

bkishan 4 hours ago

Someone needs to make a kevin-from-the-office skill. We could really use some of that "why waste time say lot word when few word do trick" here.

rfgplk 2 hours ago

OpenAI's models will actually obey a "be concise, leave no comments rule".

mavamaarten 5 hours ago

That's literally all I'm hoping for. Is it an insufferable cunt and does it write awful text, or is it nice to work with?

lgessler 5 hours ago

I thought about taking a shot every time Opus 5 said "load bearing", "bites", "teeth" (real oral fixation it had), "real {concern,issue,problem,...}" and realized I'd be dead of acute alcohol poisoning by lunch if I did so.

nonethewiser 4 hours ago

whats your provenance on that?

boc 5 hours ago

So far in the past 20 minutes it sounds much better in my sessions. Way better than 5.0 so far.

fastball 5 hours ago

It hasn't just fixed it, it has introduced a new paradigm in anti-obscurity.

mikeocool 5 hours ago

That's the load-bearing seam in this blog post.

neilellis 5 hours ago

'frontier models' - seriously, it was you and only you!

drbscl 5 hours ago

So did I. Unfortunately it's even more verbose according to https://artificialanalysis.ai/models/claude-opus-5-5#token-u...

Trasmatta 5 hours ago

The problem with 5 wasn't just the verbosity, but its insane way of communicating. It had this bizarre circuitous sentence structure that always buried the lede, and always tried to be faux profound. I'm okay with verbosity if it's actually readable.

unddoch 5 hours ago

It is hilarious to me that in the examples they show side by side Opus 5.5 still uses 4 times more words than it needs to use. IME, if you eyeball how many words the thing they're trying to say actually needs, and tell them to use only this many words, they become excellent communicators. I assume something about Anthropic's grader for writing just really wants to tick all its tidy tiny boxes of information the models need to cite. It's terrible.

shibel an hour ago

I don’t care about pricing, I don’t care about speed, I don’t care about the agentic coding improvements. Those are already fine. Does it still reply with walls of invented jargon, stitched-up phrases, and manage to cram 10 concepts/subjects in one sentence?

throwuxiytayq 12 minutes ago

For your use case, I recommend the GPT-2 model. Fast, cheap, and open weights!

abtinf 6 hours ago

Astra is just so good. And the ChatGPT subscription lets me use my own harness, so I can hook it up to exe.dev.

I’ll be going about my day, have a random idea, launch a microvm on exe.dev with a prompt of my idea, and get a working thing a few minutes later.

I don’t know how much better a model would have to be to get me to move off OpenAI at this point, but doing just a little bit better in terminal bench 4 isn’t it. It would have to be a difference in kind, like opening up the harness restrictions, or privacy guarantees (comparable to offline models).

Edit to address questions below:

ChatGPT supports oauth login.

Exe.dev has it built in. IIRC, pi also has it built in via /login.

felixgallo 6 hours ago

If you read the page, Opus is now significantly better than Astra while also being cheaper and having more performance headroom available.

ryanscio 6 hours ago

Let's wait for independent benchmarks at least

felixgallo 5 hours ago

the benchmarks provided are already from independent organizations:

Terminal-Bench 4.0 - Stanford & Laude Institute (with funding from all of the AI companies)

FrontierCode v1.1 - Cognition

CursorBench - Cursor (now SolarBoringSpaceXAI I believe)

GDPVal-AA - Artificial Analysis

AutomationBench - Zapier

Humanity's Last Exam - CAIS and Scale AI

Terminal-Bench-Science - Stanford, Laude, Ai2, Allen Institute

OSWOrld - XLANG Lab @ the University of Hong Kong

Chartography - Surge AI

esafak 5 hours ago

https://artificialanalysis.ai/models/releases/claude-opus-5-...

abtinf 5 hours ago

I read the page. It seems like a marginal improvement.

onlyrealcuzzo 6 hours ago

> And the ChatGPT subscription lets me use my own harness, so I can hook it up to exe.dev.

This is news to me. Excited to try it out! Thanks.

nchmy 6 hours ago

news to me as well. i thought you were forced to use Codex if you wanted their subscription. I completely ignored it because of that. How do we do it?

KeplerBoy 5 hours ago

With the pi harness it just opens the browser (or gives you a link if you're on headless) and you sign on as usual.

polalavik 6 hours ago

ya i've been a gpt hater for a while. almost exclusively used claude up until astra. astra feels like it blows everything out of the water. its fast, correct, organized, and less verbose.

abtinf 3 hours ago

Yes. Also, you get image generation included with the ChatGPT subscription, which is very nice for certain kinds of development.

roughly 6 hours ago

> And the ChatGPT subscription lets me use my own harness, so I can hook it up to exe.dev.

Can you give more details here? This sounds intriguing.

sidrag22 5 hours ago

Anthropic is absurdly vague about 3rd party harnesses for subscriptions, if you try to use anything besides Claude Code, you are likely at risk of getting banned, you can "do it", but are at their mercy if they decide to ban you. OpenAI gives their blessing to using oauth on any harness, you can make your own or use any of the popular public ones like opencode, pi, whatever exe.dev is that this guy mentioned.

So in simple terms, OpenAI doesn't restrict you to Codex, and gives their blessing to try whatever you want with their models(besides serving others with your subscription usage, that is still afaik against tos).

cbg0 5 hours ago

How about cheaper? Astra is $10 in $50 out, Opus is $4 in $20 out. Even on a subscription you'll get considerably more usage out of Opus.

copperx 4 hours ago

> Even on a subscription you'll get considerably more usage out of Opus.

That's an incredibly bold assumption.

cbg0 4 hours ago

It's not, I have a subscription to both and Astra burns usage like crazy.

qlte 4 hours ago

Per the link someone else posted, the actual difference in $/task is not nearly so stark:

https://artificialanalysis.ai/models/releases/claude-opus-5-...

  Opus 5.5 Medium = $1.34
  GPT-6-Astra High = $1.76

And that assumes Opus 5.5 Medium is actually equivalent to Astra High in all real-world usage/personal work loads, which isn't guaranteed as benchmarks saturate. The High vs. High comparison (probably not equivalent, but for reference):

  Opus 5.5 High = $1.82
  GPT-6-Astra High = $1.76

If Opus 5.5 Medium isn't equal/better for what you're working on vs. Astra High across the board, the price difference would narrow a bit more each time you had to switch to High.

So, if you're happy with Codex already it's not like Opus is now 1/2 the price and you'd be leaving a crazy amount of money/tokens on the table. Plus you have way more flexibility on the low end of the intelligence curve with GPT 5.6 Luna: Haiku (and Sonnet) can't touch that price/value ratio.

margorczynski 4 hours ago

In the end what matters is how much you pay for the task you want completed. And Astra will usually do that using less token and offer a better quality solution so in the end it might be cheaper.

notatoad 4 hours ago

yeah, Astra burned through 70% of my weekly usage in ~5hrs on a $100 plan. even fable doesn't run out that quickly for me. it's great, but it's on the same tier as fable for me - use it sparingly, only when really necessary.

abtinf 3 hours ago

A cheaper price has no value if I can’t use the thing I’m paying for.

The Claude lock-in simply disqualifies anthropic entirely (for my use).

mlcruz 4 hours ago

What worked well for me was a custom version of Open Web Ui with some customization to spawn an exe.dev instance for each new chat. I can just work on my phone, deploy stuff for development purposes on an easy to share way etc.

mintik 34 minutes ago

[cyber] classifier is incredibly sensitive with Opus 5.5 I cannot complete any embedded/driver/system-level tasks. Quite literally not a single task was able to complete today without getting flagged for [cyber], and what's more annoying is their narrow definition of what a cybersecurity specialist should be preventing me from getting an exception..

zuInnp 5 hours ago

So it Opus performs as well as Fable what is then the selling point of Fable?

All of this starts to feel more like a drug dealer selling their newest stuff.

In two weeks we probaly get Fable 5.2 with “groundbreaking” improvements, then Astra x+1 etc and then the cycle starts again.

And on the way I always have to check my tooling and need to adjust things to get max results.

ieie3366 5 hours ago

? they will obviously release Fable 5.5 soon(tm). It's same as hardware. The previously top tier product gets obsolete

ACCount39 4 hours ago

New generation's "upper-mid tier" offering claims to be almost 1:1 match for the previous gen's "top tier" - in other news, fork found in kitchen.

Now, Anthropic might stall on releasing Fable 5.5, due to the "pacing the frontier" threat-to-humankind management business. If so, Fable 5.1 would remain a niche model for the next bit.

glub 5 hours ago

Don't forget that Opus 5 was tracking fable on many benchmarks, yet it was borderline unusable for any coding work. My Claude sub usage has been 100% fable, 0% opus 5.

Benchmarks often don't survive contact with reality.

boredtofears 5 hours ago

Mines pretty much inverted - my colleagues and I noticed almost zero difference between the quality of code in Opus vs Fable. Occasionally I'll switch to Fable for an arduous debugging task but that's about it.

drnick1 5 hours ago

That's not my experience at all. Opus is an extremely capable coder on high or xhigh effort. It can read academic papers, implement algorithms from the description in the paper alone and reproduce results without breaking a sweat. This is remarkable because it is pure reasoning on unseen material; in some cases the paper was just published and there wasn't an implementation to learn from in the training data.

cheikhcheikh 5 hours ago

did you actually verify that it's output in those scenarios is good ? in my experience opus has been a disappointment and constantly trailing behind actually solving hard problems versus the OpenAI models. I'll say that both have terrible writing style though.

drnick1 4 hours ago

> did you actually verify that it's output in those scenarios is good ?

Yes, in the sense that it reproduced results in the paper or known solutions obtained by other methods. In fact, Opus is very good at checking it's own work in my experience.

cowthulhu 4 hours ago

My experience is that Opus can definitely write decent code, but it incurs tech debt and adds unneeded complexity.

arw0n 5 hours ago

Opus is fine at coding (for correctness), but horrible at talking about code. I don't really see the defect rate going down when using Astra or Fable 5.1, but they are just more coherent in both how they explaing code/architecture/choices, and how they actually code the thing. With Opus, I'm using smaller models to delete the vast majority of comments and 'clean up' correct code that is too weird.

Thing is, I'm still reading the majority of generated code, and I have colleagues who'll laugh at me if my PRs are a shit show. I fear what vibe coders are pushing to the servers of myriads of start ups, and pity the poor people who'll have to clean it up in a year or two.

quotemstr 5 hours ago

Big model smell is a real thing. For certain classes of problem, ones you get a feel for but can't easily articulate, a big last-gen model can get you what you're looking for when no quantity of tokens from some ultra-RLed mid-size latest generation model can.

giancarlostoro 5 hours ago

Fable should have just been called Opus Primt for Enterprise and sold only to enterprise customers. I don't even use it. I rather just use Opus.

Imustaskforhelp 5 hours ago

isn't this what mythos was/is?

orangecat 5 hours ago

All of this starts to feel more like a drug dealer selling their newest stuff.

Yeah, like Apple tells me the M6 is the best chip, but just a few months ago that's what they said about the M5. What a bunch of frauds.

notatoad 5 hours ago

typically, when any AI company says a model performs as well as fable, all they're really telling us is that the benchmarks that exist for measuring AI capabilities aren't very good.

sznio 6 hours ago

I'm more excited by the Haiku 5.5 announcement buried in this post. I'm wondering if we will finally get a decently capable fast model.

system2 6 hours ago

All I care about is the token price for the API. Haiku cannot get close to GLM or Mimo.

lanyard-textile 6 hours ago

Agreed. They've been so quiet about it, and retirement for Haiku 4.5 is right around the forner.

ygouzerh 6 hours ago

What are you using Haiku for?

mavamaarten 5 hours ago

I use it for executing well-prepared plans sometimes. And for exploring larger codebases.

Zambyte 5 hours ago

Not the same person but... nothing. Haiku just hasn't been an interesting model for a long time. If you want cheap and fast, there are lots of options that are simultaneously cheaper, faster, and capable than Haiku.

adastra22 3 hours ago

Things that Jev is probably a better tool for.

booty 5 hours ago

If you're able to use the OpenAI ecosystem, Luna's price/performance is really good. Almost like "they messed up and accidentally made it too good" good.

copperx 4 hours ago

Better than what? Deepseek? GLM? Gemini 3.8?

NorwegianDude 4 hours ago

OpenAI didn't mess up. The model would have been 100 % pointless and obsolete without the large price cuts it got, because of the cheap Chinese models.

The open models are getting closer and closer, and because they're open, people are not forced to pay the silly markup that is often over 1000x the cost to serve the model.

enraged_camel 5 hours ago

We use Haiku 4.5 inside our product. It continues to be absurdly capable for converting natural language to structured JSON based on a set of fairly complex business rules.

anthonypasq 5 hours ago

bro why. its literally the most overpriced model in existence right now. i could name about 10 models off the top of my head that would be better and cheaper

enraged_camel 5 hours ago

We tried Luna and it scored way lower in our evals. Muse also. We haven't had a chance to test others.

Game_Ender 4 hours ago

How much time were you able to put into tuning your prompts? And was it worse on all fronts (cost, latency, accuracy) or just some?

copperx 4 hours ago

Why are you excited about it? Deepseek is everything Haiku wishes to be and more.

throwaway2027 6 hours ago

After yesterday outage is the new Opus 5.5 load-bearing?

handfuloflight 6 hours ago

It's worth stating why, and depends what seams you're pulling at this sitting.

cronin101 6 hours ago

It certainly _seams_ that way

staticman2 6 hours ago

I'm gonna be straight with you—I don't have the evidence to say whether or not it's load bearing.

rich_sasha 6 hours ago

Your instinct is basically right, and the research backs it up.

cmrdporcupine 6 hours ago

And here's the important part...

danw1979 5 hours ago

you win the thread

aoeusnth1 6 hours ago

You were right to call that out, and the evidence makes a stronger case than you are stating.

fghorow 6 hours ago

"Danger Will Robinson!"

esafak 5 hours ago

Wrong century, brother.

ThouYS 6 hours ago

You're right to bring this up - and this is where it gets interesting

danw1979 5 hours ago

Good point — but I’ll gently push back on that. It’s not an outage, it’s a service degradation.

hmokiguess 5 hours ago

You're right, this changes everything, and here's why it matters.

RGS1811 5 hours ago

This question is real.

carlos-menezes 5 hours ago

One thing worth flagging here: 5.5 appears to be a load-bearing seam in the numbering system.

sailfast 5 hours ago

Let me verify before I come back to you with an answer that is incorrect.

lgessler 5 hours ago

I should find information about the user's concern instead of just assuming.

The user is right. The outage is a real concern, and the issue is worse than we realized. Requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 encountered elevated error rates. Worth stating plainly: these are not just models — they are load bearing rungs on the software development tooling ladder, and a blocker on this level makes the outage really bite.

One decision that is yours to make, not mine: should an email be drafted to Anthropic support? This issue has teeth, and a canonical handoff can land us where the main gate is no longer breaking silently.

jaapz 3 hours ago

This made me shiver

loopmonster 5 hours ago

That's the sharpest point anyone has made in this thread so far, and it reframes the entire conversation.

bibimsz 4 hours ago

One pushback: there is no Opus 5.5. You might have meant Opus 5.1, the latest Opus model available.

Retr0id 3 hours ago

Your premise is half right, and the half that's right is better than you think.

kibae 4 hours ago

> Opus 5.5 is the first Opus model to launch with a similar class of safeguards to Fable 5.1 on cybersecurity, biology, and distillation, all of which fall back to another model transparently.

This is where Chinese models are going to eat Anthropic's lunch.

AlfeG 3 hours ago

So it will not usable to do anything with hardening Your own site.... I'm so tired of this. I just want adjust cookie behavior of own site...

nomel 3 hours ago

In those specific domains, sure. What percentage of paying users would you say that is?

mlh496 an hour ago

However, the moment that someone uses a Chinese model without guardrails to commit an AI-powered 9/11, DC will rush to ban Chinese models. (A happy side effect will be to protect American AI profits.)

So the lack of guardrails is a very risky proposition...

TomGarden 3 hours ago

The new communication style still made me react negatively, but I hope it will be better in use.

Quoted:

"Please explain the issue to me.

Claude Opus 5.5:

The extra drop is a bug in the billing refactor

The free-tier change accounts for only $1.50 of acme’s August drop. The other $9.92 comes from a bug in commit 0552feb. That commit was labelled “No behaviour change,” but it stops counting usage from the last day of the month.

What changed

Before the merge, aggregate.py used a half-open interval: /.../ last_day is a timestamp at midnight, not a whole day. So every event after 2026-08-31T00:00:00Z is excluded. The September period starts Sep 1, so it doesn’t pick these events up either. The usage isn’t moved to another month; it’s never billed at all."

rfgplk 2 hours ago

Yeah, still abysmal. If you have the time or tokens, see if it will obey an explicit "LEAVE NO COMMENTS WHATSOEVER" command. Opus 5/Fable 5 outright ignored it.

2001zhaozhao 5 hours ago

It's great that we are finally getting bankable rate limit resets for subscription users. According to another comment here they apparently last a month.

I'm assuming that subscription usage limit is increased in line with the price decrease on the base model and that it's in line with the model's API price drop. Still a good change.

This is a breath of fresh air on how they treat subscription customers. Hoping they keep this up.

ironqcold 29 minutes ago

The thing I'd actually want to know: is Opus 5.5 Medium genuinely equivalent to Astra High on real work...

artursapek 6 minutes ago

In the niche benchmark I run it’s on par with 6-Sol, not close to Astra.

magicalhippo 2 hours ago

I've reached the saturation point.

I don't have time to really get to know one model before the next is out, and I'm just talking about OpenAI and Anthropic, never mind the long tail of alternatives.

So I just more or less haphazardly pick one based on the mood I'm in, and set reasoning effort based on how much quota I have left.

senko 2 hours ago

Opus 5.5 is neck-and-neck with Fable 5.1 and Astra 6 in my vibe-coding tests - maybe even better than Fable 5.1

Minecraft clone: https://senko.net/vibecode-bench/2026/voxel-opus-5.5.html (Opus 5.5) vs https://senko.net/vibecode-bench/2026/voxel-fable-5.1.html (Fable 5.1) vs https://senko.net/vibecode-bench/2026/voxel-gpt-6-astra.html (Astra 6)

Warcraft clone: https://senko.net/vibecode-bench/2026/rts-opus-5.5.html (Opus 5.5) vs https://senko.net/vibecode-bench/2026/rts-fable-5.1.html (Fable 5.1) vs https://senko.net/vibecode-bench/2026/rts-gpt-6-astra.html (Astra 6)

The above Opus games took ~45min to generate with the cost between $11 and $14 (per ccusage - I'm on a Max sub). Used from Claude Code with xhigh effort.

Full tests with prompts: https://senko.net/vibecode-bench/

kitbrennan an hour ago

It's interesting that Astra has a clear style that it applied to both games. It's a refreshing design language, but maybe that's because it doesn't look like something Claude has vibe-coded. In terms of gameplay depth, the Claude versions appear to be closer to the original Minecraft

mgw 6 hours ago

They mention "the first model in our new Claude 5.5 family". Obviously that means Fable 5.5, but hopefully also a usable update to Sonnet and Haiku. Sonnet 5 hasn't really had a place in the line up for anyone I feel.

Maybe Anthropic finally felt the pressure from MiMo, DeepSeek, GLM Flash and Luna.

mudkipdev 6 hours ago

It does mention sonnet and haiku.

simianwords 5 hours ago

And not fable lol

enraged_camel 5 hours ago

At the end of the post they said Sonnet 5.5 and Haiku 5.5 are coming soon.

garo-pro 5 hours ago

Finally confirmation that Haiku was not forgotten and will be coming soon, althouhg I find it quite interesting they skipped 5 and directly skip to 5.5 with all models, including Sonnet which is not super old. I suspect they found something breaking that allows to release this. Recently they struggled with keeping up a 50 % weekly limit increase and now they're putting out 30-40% faster and cheaper models even faster, with much more better benchmarks, a limt reset command and five hour limit increase. It seems more like the opposite and as if they never struggled, thus, I very much believe they found something very effective and new.

aesthesia 3 hours ago

Sonnet 5 was released a while before Opus 5, so it's just Haiku that didn't get a 5 release.