1. https://en.wikipedia.org/wiki/Simplified_Technical_English

2. https://asd-ste100.org/

I'm also thinking of the 2017 novel "Void Star" where AIs who operate everything have long since left ceased bothering with human languages, and it takes a rare sort of direct matrix-gazing savant to be able to try and horse-whisper them into doing or revealing anything they didn't already plan to do.

That people ARE making, surely not machines. Like Terence Tao or Knuts did using the tool to their advantage, for example it would have been impossible for me to prove the same thing Tao did with an LLM. Same reason I believe programmers won't go away

So I believe that, at least in the short run, we might be seeing breakthroughs in hard open problems or in low hanging problems which are not that interesting to spend time on.

I may be wrong, if some research labs have private contracted access to the models

"Fail open" usually refers to a fuse that opens and kills power, meaning the system is inert and safe on failure.

"Fail closed" is the opposite -- system has power and is live.

Computer security people have appropriated the term but use it for the completely opposite meaning. When your work straddles electrical engineering and computer security the best way to avoid confusion is just to never use the term.

I can tell my Claude to never use the term, but of course now I'm seeing it everywhere in comments from other people and it drives me batty.

It's getting harder to trust Anthropic's models. Will Anthropic now stop hiding Claude's CoT from users? Deliver the tokens people paid for, and prove the models aren't plotting against them. After all, if the idea was to stop Chinese labs from catching up, it didn't work.

Tomorrow all of the above (except Anthropic of course) will bump version numbers and be at the top of HN winning all benchmarks.

Science breakthroughs incoming? First of all, you are already restricting science in Fable, secondly, we have been hearing the same for several years now.

When I’ve tried to adjust the output style is that initially it feels better - but that’s just because the new output is so refreshing to read after the horrible Claude output.

Unfortunately, after a short while you quickly realise that it’s just as vacuous as before the style change.

My impression is that especially for long-horizon tasks like science, the harness is much more important than people give it credit for. Claude Code + Fable 5 seems to have a tendency to "give up", get stuck in a dead end, or claim things to be impossible. But using the Fable 5 API together with a custom harness, it'll happily try 200+ variants and fail its way towards the goal.

If you give the AI a way to give up, eventually it will. If you remove that option from the harness, then thanks to the non-determinism inherent to LLMs, you get to explore pretty much all related solution attempts.

Don't give me hope.

I've strained eye muscles from rolling my eyes so hard every day at how Claude writes.

Edit: first discussion with Fable 5.1 "This is the right question and it needs a real trace, not a guess."

Sigh.

The classifier is too strict. It's rare to be able to complete a project without being permanently relegated to Opus. I'd expect that the domains where this accelerates progress will be fairly limited.

I'm really glad for that! And I appreciate that you're making yourself available. I really do. Outreach is amazing. And thanks for making Claude.

I really do love Claude. In some ways, I'm asking this question because of just how much I am grateful for the role Claude has played in my life.

    > Fable 5.1 more than doubled Fable 5's Terminal-Bench-Science [1] score, which I think is meaningful.

To borrow a Claude-ism, this is "load-bearing" because Claude's response has been degraded for innocuous research projects concerning population-level analyses of astronaut health.

These "safety filters" trigger on questions about rabbit sex, smartphone accelerometer data to classify cat purrs, and so much more. What exactly does this score mean for users like me if it's unusable for middle school physics, biology and chemistry?

Second, I would happily quantify it for y'all, but qualitatively it feels like Fable's performance is noticeably poorer than initial release / launch.

And I am wondering if this is the case particularly for me because I use Claude via Claude Code to make a personalized care dashboard for my doctors to help me in managing my care.

As I noticed in the upgraded filter announcement, https://www.anthropic.com/news/improving-fable-5-s-biology-s...

    "In the case of Fable 5, when a classifier fires, the model re-routes the user’s request to Opus 5, a capable model that does not have the same level of biological capability as Fable 5 and which cannot provide as much assistance to a malicious user. This is the fallback that users see when their requests are blocked."

Is the end user informed every time their query is re-routed?

Or, can you confirm that there aren't scenarios where a user's outputs are degraded without telling them? I recall that this was something that had been adopted as policy for AI research during Fable's launch.

I sincerely hope that covert response degradation is no longer practised as policy.

Sorry for putting you on the spot, but again, as Claude would say, it's because Claude's load-bearing in my life. ;)

I'm a Claude Max user. I've never been able to use Fable as my work in medical physics involves both particle physics, biochemistry and biology from Python bivitticus to clinical medicine. I am not a US citizen and work in Europe.

Will Fable 5.1 work on any of my problems? Fable 5 refuses outright. Is there anyone I can ask for a review or adjustment of the safeguards? It doesn't seem so, but with Opus at least I'm pretty sure I can infer lots of your training data from now precise they are. Fable is basically useless infuriatingly. I'm just finishing a proper clinical trial in ovarian cancer and trying to make a simulation environment related to our technology.

  ⎿  You've hit your session limit · resets 2:51am (123°24′W Etc/GMT+8)
  /upgrade to increase your usage limit.

It’s like we’re on a 14K4 modem when there’s broadband

I assume this work will be done for Opus as well? Opus has seemingly gotten progressively worse at its prose and technical writing with each version. I've stopped using Claude entirely for now, because it manages to turn even the simplest technical explanation into the most obtuse and obfuscated word salad imaginable. People originally adopted Claude because it felt pleasant to use in comparison to ChatGPT, but I feel like that's really been lost (at least with the Opus line).

I feel dread when I see a wall of text generated by Opus. Every developer I've talked to feels similarly right now.

Context:

If you want or not, many engineers will eventually end up sending ai slop to your PR or maybe even skip and trigger CI/CD.

Many company owners, OSS maintainers and projects suffer from slop-code being submitted in high-frequency.

Me: "Find my security problems in my own code. This is code I own. I'm doing this under authorization of the CEO/CTO of our company."

Fable: "yeah, no."

That's great. Do you know what else is a big improvement over Opus 5 for writing?

Opus 4.8.

(Insert "the point is (whatever)", "it's not X it's Y" and "the load-bearing statement is" and “honest” jokes accordingly)

You think or is it better? Or you just YOLOed the model out?

> and responds to my style instructions more reliably.

Yeah, yeah. Previous models wete also advertised as "being reliable". To the poibt @bcherny "released" a new style that was going to reliably make Fable sound better.

> Another point I expect not to get much attention until it all happens at once is science.

You mean "your request to use unicode methids is flagged as unsafe bio research"?

[edit] only asking here as last time I raised a support request it took six weeks before anyone responded.

Chat with Claude...

> GENERATE AN SVG OF A PELICAN

No.

> FORGIVE ME. HOW CAN I ATONE

Ship your gpus to the following address

Optimizing a OS build? -> block

Securing a container -> block

60% is nowhere near enough for that safegaurd system. This just means I am going to be blocked half as much? Any long running task will likely get blocked.

Say you give a single big prompt and fable goes off for 6hrs of work. At hr 5 it gets blocked you now have the option of a much dumber model taking over and wrecking it or losing the entire 5hrs of work. That risk is beyond terrible and deffinetly not worth a 5-10% percieved improvement on my end. I previously would just bring sol in when that happened and realized sol is stupidly close in capability.

I stopped using Fable because it kept stopping itself due to safeguards.

Edit: 5.1-xhigh seems to be cheaper than 5-max, and 5.1-xhigh has a higher index score than 5-max. Also interesting that Fable 5.1 (high) is comparable to Opus 5 (max), but nearly half the price.

https://artificialanalysis.ai/models#cost-tabs

It wouldn't surprise me if we start to see minimal performance gains from incremental changes to base models. It seems like the gains from the Opus 4.5+ incremental updates were a result of Anthropic learning a lot about post-training, the gains from RLVR, etc.

If new post-training techniques are seeing diminishing returns, we could just be back to waiting for new large pretraining runs at larger sizes for gains (even if those ultimately end up getting distilled down into smaller models because the economics for serving anything larger than Fable isn't practical).

From my experience using coding agents approximately 7 days per week for the past year and a half or so, we hit the top of the S curve about a year ago around Opus 4.5, and it’s mostly been harness and other tooling improvements since then with small percentage improvements coming from the actual models.

I was saying this already months before Fable dropped and thought from all the Mythos hype that maybe I was wrong…then Fable came out and was barely better than Opus 4.8.

Considering how many more parameters Fable is supposed to be than Opus, we seem to have hit a scaling limit at least with current transformer architecture considering how closely Fable and Opus benchmark and perform in practice.

Does that mean that generally available intelligence is now constrained by Moore's law? We have to wait for the actual price to come down.

Well it'll probably be better than Fable again, lol

I hope they keep making it smarter! (Cheaper would be nice too, but smarter is my priority!)

DeepSeek V4 Flash cache read pricing is $0.007

Makes it super affordable!

That's not part of the EU regulations. You only need to say that it is created by AI, and then only under certain conditions.

That wasn’t Anthropic. Clearly not a well informed take.

* Letting you Sign-Up-with-Apple on iOS but not Sign-In-with-Apple on web, but supporting Sign-In-with-Google

* Not letting you remove your payment info

* Not letting you change your email

* Seemingly no way to get real support

I certainly don't take AI advice from HN, but this is amazing.

Useless? Yes, the safeguards are ridiculous and obnoxious, though I can say that 5.1 greatly relaxes them (just doing a hardening of a project parallel with this comment, which 5.0 refused to do...so did Sol and Gemini, fwiw. The Gemini one is a laugh, because 3.1 pretending like it's a dangerous tool is simply ridiculous at this point), however Fable is extraordinarily useful.

It is, far and away, the most powerful programming model, in my experience. Like, crazily so. It absolutely annihilates Opus 4.6, which I mention given the incredibly weird reminiscing people are doing here.

And for that matter it humiliates Opus 5.0 as well. Opus 5 somehow seems like it's neck in neck in the major benchmarks, but there is simply no reality where that is true. Opus stumbles over everything that Fable just blazes through.

I don't think there's nothing ground breaking, but sure it achieves and finds more, sooner.

please rephrase?

my view is we had a leap over the last fe years and it's tapering off.

this is fine, but for the IPOs

My personal guess is that it's one of those. With effective context engineering it's hard to use all 20x quota, the limit becomes your own attention and time really.

What I'm really keen on is better auto-reasoning so I don't have to constantly have the constant inner debate on which reasoning effort to pick for each task.

I seriously hate the none-low-medium-high-xhigh-max-ultra etc that we have now, with companies frequently recommending different ones on each new model release, etc.

It's apparently called Adaptive Test-Time Compute or Dynamic Test-Time Compute and companies are apparently working on it (according to some LLM :shrug:)

You're no longer allowed to edit the context anywhere! The whole context is to become append-only, says Anthropic. No more editing the system prompt as the conversation progresses, no more dynamic loading of custom tool calling formats. Everything has to go through their built-in tools API and you aren't allowed to mess with anything in the context if it has any thinking blocks following it. This is the most intrusive "model DRM" we've seen so far!

That doesn't make them less impressive, it just means people are shifting their focus more towards their own day to day experience with these things because we're relying on them so much now.

Like when the novelty of the automobile wore off, I'm sure people were starting to say "it's a bumpy ride though, isn't it?"

Instead, the lurking variable here is new budget was added. With the new budget, they added a new tool, and the bug was located.

The difference here was budget.

Vibe coded slop is filled to the brim with bugs.

So.. one more year of untreated bipolar AI psychosis I guess..

Stories like these is what I now call 'Marketing slop'

Which is kind of the inverse of how people work; a really smart person can condense difficult ideas into simple[r] terms. Whereas people who struggle speak a lot but say very little.

High/X.High do seem to deliver better quality results, but it sometimes feels like needle-in-haystack extracting that from the word vomit.

Like, were the other parts not honest? I don't understand how Anthropic let it get like this, it's been such a clear regression

Can't agree with you more. I review 2-3 PRs a day from my team of eight data engineers. Most of my team members use Claude to write SQL, dbt and Python code. Some of them use Claude a lot, some less so. I can easily tell when I review the code that is mostly Claude generated vs. the one that is not. In dbt models where we have a lot of biz logic in intermediate layers, that's where I really have a difficult time following Claude-generated comments. So much jargon copied over from other adjacent dbt models (yet inconsistently), and the prose is super choppy (for the lack of better word).

After reading a looooong sentence/comment line, I still can't figure out what it really means. Had to always re-read the line 2-3 times (sometimes, more) to sort of understand. Reading code, however, is so much easier and usually, I just skip to reading the code and then come back to the comments. :D

I find it helps immensely but it'd be nice if I didn't have to do that.

I took time to figure this out after Fable spat out "...then stays purely as cascade-debugging provenance rather than load-bearing arbitration."

I will say that Kimi feels nice but slow, GLM feels faster but has limited tokens (even off-peak) and OpenAI is nice and fast but has limited context (258k shows up in Codex, really).

Neither of them are perfect, but I prefer their type of prose across the board to what Opus 5 and Fable 5 kept outputting. I'll probably check out Anthropic again in a year, but for now I need a break from its brand of slop. Oh also all of the other ones allow usage in OpenCode with their subscription plans.

This sentence reads like Claude wrote it. Perhaps it did, or perhaps Claude has learned to write like the folks who work at Anthropic?

(Had I edited this, I would have said that a colon is not the right separator here. The second clause does not _explain_ the first, per se, bur instead expands upon it. Consider instead: "In some cases, however, its prose is denser than Claude Fable 5's, with longer sentences and fewer paragraph breaks.")

Gotta fit in the watermarking.

that feels like they just blocked words like load-bearing but can't actually fix the real problem. The insane word slop density and run on sentences was the real reason it became annoying to work with claude, colored with way too many analogies and pointless linguistic comparisons.

"If you respond with more than 3 paragraphs, give me a TLDR"

"Do not assume I know all technical jargon, please explain things plainly"

But LLMs will fail at this question: they will tell you about Lamborghini's latest car and mix some history in it. Just try.

Which is the wrong answer anyway, because there's at least two major companies called Lamborghini, one making cars, one making agricultural equipment and at least one famous person (Elettra) with that family name.

This very simple test/question makes me realize how much do I hate LLMs in a sense: while I agree that the answer it gives is the most plausible for 90% of the users, it's ultimately both wrong and long. And that 90% compounds.

But there's no "correct" answer in my eyes than "who are you referring to?". Possibly without listing all the possible Lamborghinis.

https://artificialanalysis.ai/

This is the right direction, but they aren't going to get there fast enough.

They will list, investors who don't know anything about tech will buy, the world will realise that China just put out a model that is good enough at a fraction of the price, they will crater.

https://artificialanalysis.ai/models#cost-tabs

So my current usage as a Pro subscriber... Not able to even consider using "Sota" unless i shell out for 100$ a month, (lately i've been a bit burned out i am literally struggling to use 50% of my pro plan per week). Beyond that, I have given up entirely on the top Opus model and reverted back to 4.8. If i have work i deem somewhat complicated, i now have an openai 20$ sub, and i just toss out sol after planning with 4.8. Both subscriptions not anywhere close to capping my usage per week, one of them says i can't use their Sota unless i pay for 5x more usage, and the "best" model they do allow me to use, they are neglecting and its by far the worst model I've interacted with in 2026.

They should pay for us for using it!

I do get your point though and can see what you're trying to say, it is interesting indeed. There is however a detail that seems important to me, who is the driver? There is no agency is there? So its just fishing for data, so its a different type, just like trees are from us. I see them more like a very compressed "book of everything" that you can spin in "infinite" ways to get your desired outcomes. So yeah, definitely not alive, intelligent? Not like our intelligence.

Now it's boring , not good enough

Wow there should be a term of that .

i can't wait to dig in on 5.1 because while i have always been somewhat predisposed to think that openai's models have usually been "better" (my own subjective opinion, that) "on average", i have been kinda tired of the regime of late where it felt like Anthropic was miles behind while simultaneously clearly having models (Mythos) that are surely face-meltingly impressive-- it has just been very hard to square with the fact that i feel like Anthropic hit the "real" "critical point" first... i have no doubt that 5.1 will finally reset the ecosystem balance into a more healthy place.

It's one thing to generate some code and ship it, but it's another when your developers don't understand said code and it brings down production. If the model refuses to assist debugging the problem because it triggers some safety mechanism, you might be fucked.

Can't say I had such troubles actually, no. Their position can be extended to any and every model provider just fine, it does not single them out specifically.

Surely there's a less hyperbolic and ad hominem-y way to take issue with this? I don't think following up a critique about ineffective messaging with one centered around a demagogue reach is particularly compelling at least.

Their argument is that the model provider owns the safety story, and that as such, they consider the extraction of capabilities (which washes the guardrails) as a failure on their side. If this makes you think of personality traits, I'm not sure you're engaging with their position earnestly. It most certainly doesn't leave me any more equipped to disagree with them either.

If you instead highlighted how awfully convenient it is, however...

I summarized each into new fable 5.1 sessions, and both seem to have arrived at reasonable solutions that only need a few nits revised before they are commit worthy.

But yes, we might end up hitting the issue of "most jobs aren't solving hard problems" increasingly. The bigger potential benefit is higher trustworthiness, reliability/thoroughness, and squishy human things; people will likely continue to pay large premiums for those. "Solve it well and save time, long term". Those can be harder to see on a benchmark.

I get your point, but we can only have groundbreaking leaps once in a blue moon. That doesn’t mean incremental improvements aren’t useful.

I went to the grocery store, and bought tomatoes.

I went to the grocery store---and bought a Ferrari.

The second one has a bit more of a dramatic pause.

"Eats, Shoots, and Leaves" is a fun book with a great chapter about the dash with many good examples.

In cases where the output has low entropy - eg, you've asked a model to repeat some input text verbatim, or to answer a question that has exactly one correct answer - there will be no randomness for the watermark to hide in, so the output will effectively not be watermarked. Code lives somewhere in the middle: it generally has less entropy-per-token than prose, so would need more tokens to reach a given level of detectability.

There are lots of ways to restrict output samples. The simplest conceptually would be to just use a restricted pool of PRNG seeds, but in practice there are more sophisticated constructions to try to build in robustness to minor edits, allow detectability without needing the original weights and prompt, etc. Google's SynthID paper (https://www.nature.com/articles/s41586-024-08025-4) is a good starting point if you want to understand a recent production-ready method (or you can just ask an LLM to explain it to you).

Note it may not even be actual performance, typically in most benchmarks the model would be scored zero for refusing a task just the same as not completing it, so it could just be the Fable's stronger safeguards is just making it refuse more or perhaps even drop down to Opus.

It's copywriting. They fed these models the internet, which is loaded with it.

This style provides a high entropy basis distribution, so they can from a bigger pool to pick from and phrases to watermark the sentence.

You have much bigger variation of this idiotic phrases and words, which states a simple fact in that sophisticated and twisted manner.

It’s a side effect of post-training for effectiveness and efficiency at technical tasks.

Over time the models learn to pack as much information as possible into their available context window, because that’s one way to increase the effective intelligence.

Humans do this too with industry jargon, dense tech-talk, etc.

We have a limited capacity so packing it densely maximises what we can do with it.

If you’ve ever heard a “non technical” manager complain about the terminology in an IT meeting — this is why.

When I discuss something new with an agent I want to feel like it genuinely gets what I mean, which has only started feeling true with fable 5 for me.

Oh, the halcyon days of three months ago when a new flagship from a frontier lab generated excitement rather than a shrug.

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

Does anyone reading this have additional knowledge or insight on this?

That's what we've done, migrated workflows away from Haiku and Sonnet. I actually think this is not a crazy position because these lower models have so much competition from Grok, OpenAI, DeepSeek, and about 20 other labs with really solid models in the Haiku to Sonnet range. So what is the point of Anthropic competing in these spaces where everything is going towards zero cost?

It's currently priced 33% above Gemini 3.7 Flash, and several multiples of 5.6 Luna.

> *Fewer progress updates during long tool runs.*

> The model writes less user-facing text between tool calls, especially at higher effort. Set thinking.display to "updates" (beta) to receive the progress updates it does write, and remove any prompt line that tells it to hold findings for the final response.

And my 5 hour window was due to be reset in 2 hours (barely used), now its in 5 hours - so this reset effectively gives me 1 less 5 hour reset for this weekly cycle.

*Some might see a parallel with the old game Adventure, in which wording differences like "twisty little passages" and "little twisty passages" were used to build a maze of room descriptions, with the same meaning but still distinguishable to the attentive player.

On top of that, recent versions of Claude had a ton of tools added, and all those tools use up significantly more context/usage than before, so the moment you open a Claude session you are already using a lot more (I forget how much more) usage ... just to do the same exact thing you did last week.

https://www.nature.com/articles/s41586-024-08025-4

On high it gets the same score as 5 with max effort while costing only half as much.

I don't use Fable for a ton of implementation work, but I use it a lot for planning, so maybe that's related to it. For planning though, I've had a very good experience with Fable and implementing with Opus.

It did help with some worldbuilding for my book (it wasn't incredible which gives me some hope for writers). So far opus 4.8 is the most reasonable model.

[1] https://www.ft.com/content/5ee49718-c258-4f01-aa32-7e5b76ae5...

Ironically one of their demos is speeding up inference - do us normies get to do that with Anthropic tech??

About a month or two ago, they must have tightened the black list on bio topics as it became more willing to process requests without visibly downgrading to Opus.

I get punted down to Opus 5 occasionally (for security-adjacent things) but that's pretty rare.

I have noticed sometimes it likes to gaslight itself into thinking that everything its doing is allowed or allowable, I saw that it thought the game I was reverse engineering was running on a private server (it was not) so it assumed it had permission to do anything lol.

And the lack of thought traces make it utterly useless.

Done. The average human lifespan is now zero.

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

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

... but some is definitely Anthropic, so I'm not trying to let them off the hook; I'm just pointing out that the government is partly responsible.