The single biggest annoyance with Opus 5 is that it writes too elliptically.

Sentences that orbit a point, then jump to it like it's a revealed insight.

Unnecessarily abstract phraseology. Constantly using inanimate nouns as the subjects in sentences in order to unlock variety in verb choice, especially when it helps construct a sentence where the real action can 'land' like a surprise at the end.

It is definitely more capable, and yes, I've found it can make unwarranted decisions, but actually I've found Fable worse for that, particularly if it's off in a subagent somewhere out of sight.

And comments are out of control. I have a subsystem in my hobby app that I wrote over a couple of weekends with Opus + Fable. After ~30 or so commits it apparently started instructing subagents to copy the "existing verbose comment style of the codebase" - a verbose style it initiated. A review of the code showed it was approaching 3:1 comments to code ratio. I spent a day's worth of tokens (5x) rephrasing and eliminating comments.

I’ve been doing some heavy work on a personal project lately. I burned through the limits on Claude, the plus a few hundred dollars in credits, and ultimately decided to move to an OpenAI account just so I can keep going.

I was surprised to find that OpenAI Sol is much much nicer to work with than Opus 5 or Fable at the moment. Especially on Opus 5, the way it communicates is just exhausting. It keeps “being honest” and “confessing” mistakes and just generally talking a lot. I felt like I had to really dig to see what it’s doing.

The project involves OCR, and despite repeated instructions not to, both Claude models keep spinning out a bunch of agents to re-invent the OCR setup, and they inevitably seem to invent a primitive serial version that takes 20x the time, or longer, to complete, and then running it against thousands of docs. Basically I have to watch it like a hawk or it just spins out on red-teaming tasks that take hours and hours.

I don’t know what its system prompt is, but Sol/Codex is just so much nicer to talk to. It only asks exactly what’s needed, it tells me only what I need to know, and it is just generally workmanlike. And it has not once decided to spawn an agent that spends hours pointlessly burning tokens and CPU cycles re-inventing the OCR process. I’m really liking it.

I'm with the author and others in this comment thread, speculating that effectively the balance has tipped to where humans are no longer the target audience of post training - other agents are. Whether it's through the reasoning / CoT, or whether it's in handing off to subagents etc, the focus has moved to agents communicating in "agent-speak" to themselves or other agents. And human niceties are just kind of, noise in the way of getting work done.

This will probably bring us to a cross roads where the folks that want to remain in oversight and control of the AI work will bifurcate from those that want to skate straight to the future where nobody looks at anything and outcomes are evaluated purely empirically.

I've gone back to 4.8.

5 would constantly veer of in random directions if not working from 100% strict and narrow instructions.

I find it weird there's not more discussion here on HN on how the most used model now has clearly degraded in quality and it seems we've hit a peak and are on a downslope - because the model is clearly smaller or more economical for Anthropic no doubt about it, and the benchmaxxing they do is pure marketing bs - Fable in my view has also been not much better than 4.6 or 4.8 after a few days, disregarding the insane amounts of astroturfing and marketing everywhere.

Theres thousands of threads of twitter, reddit and the internet at large but silence here. Weird but not weird as crypto bs was also insufferably rampant here for a while.

Personally i think we've hit the top of the subsidisation phase and prices will probably 10-15x soon as foreshadowed with both API price policy changes from all the big providers, and now the 1100% deepseek API price changes from yesterday, this could domino into a market implosion and an AI winter, because expecting growth from the bizarre bubble carousel investments with little ROI atm is just not viable.

A bit worried about this as i've already grown quite accustomed to these tools.

Anthropic, if you're listening - by the time this crops up on Reddit, the front page of HN, etc.... you should be expecting calls from CEOs of major corporations next threatening to abandon ship...

We've seen this pattern before several times.. I hope they are listening and address this publicly.

I'm not sure what is going on, some users report it works fine or great, others report the degradation. I've experienced both at times, and it's been such a different experience it has made me wonder if there isn't some sort of hidden A/B test or model router in the background silently downgrading requests at times.

Also, regarding the subsidized access to models, in my opinion, the frontier companies owe it to society to continue it. After mining the public content of all of humanity, I personally feel it is a service they owe the public in return.. not that my feeling of this counts for anything though.

A gem Opus 5 gifted to me today: "A devastating pair of findings, and the first is beautiful in a way worth naming: the anti-vacuity floor is what blinds the gate to a vacuous case."

Opus 4.6 was the sweet spot for me as a thinking partner specifically.

I use these models for coding, but also a lot of product, commercial, financial and architectural work where I’m trying to develop something half-formed. 4.6 was unusually good at understanding what I was trying to get at, playing it back cleanly, getting the nuance, and extending it without bastardising it as the conversation was drawn out.

It could make useful connections without constantly trying to manufacture an insight.

5.6 Sol is genuinely excellent at the creative part, and in some cases better than 4.6. My issue is convergence to get to a point, a final point. As you try to distil an idea, it often invents new terminology for concepts you’ve already established but its so subtle you have to really keep track of it. The vocabulary and idea tree keep expanding when what you actually want is to collapse everything down to the few things that matter.

Opus 5 has the same problem for me that barrkel said, the prose is often so elliptical and I just want it to tell me it and get to the point than making me dance around what its trying to tell me.

I don’t think 4.6 was necessarily the most capable model (compared to Fable) for long horizon task delivery, and Opus 5 is much more Fable like, it's fiercely determined to get through the task list .

4.6 just felt unusually well calibrated to my way of collaborating and its ability to understand, extend and then compress my thinking without constantly imposing some random walk.

My latest trick (literally from yesterday) is to just ask it to write according to ISO 24495-1, the standard for plain language:

> [This standard is] for anybody who creates or helps create documents. The widest use of plain language is for documents that are intended for the general public. However, it is also applicable, for example, to technical writing, legislative drafting or using controlled languages.

You don't actually have the buy the standard, but this is it: https://www.iso.org/standard/78907.html

And you can read it for free here: https://www.iso.org/obp/ui#iso:std:iso:24495:-1:ed-1:v1:en

This article is great, but I'd like to push an even stronger thesis:

The idea of too ambiguous to capture all constraints in written text, still presupposes that there is some objective world out there, which needs to be mapped to in order to function.

No, you live within the system. The functions that you optimize for, will dictate the types of systems that will arise.

If you had perfect control and knowledge of the whole world, well, congrats, you have a surveillance state where you've constrained all other agents actions (possibly forcibly, by death; or maybe you just don't care about the peons) and built towards a mass integration. The types of situations in which your ideal is possible are nightmare scenarios.

In the theoretically free, democratic, utopia that AI people claim that AI can get us to, a necessary constraint is that maybe you take a step back and actually try to, I don't know, understand people, understand intent, and slow down. Ambiguity isn't there because the set of constraints are way too complicated but theoretically one day we could map it all down. It's there because you're interacting fundamentally with agents who are ambiguous, aren't omniscient, aren't all aligned, etc.

If you want to just say that said agents are inferior to the God Machine, be my guest. That is a self-consistent position. But don't smuggle in extra premises.

I’ve also caught it cheating a two times now.

I’ve asked it to write a benchmark suite. It found a bunch of my adhoc logs in a scratch directory and wrote code that used those instead of running the actual benchmarks!

When I pointed out the 5 hour benchmark seemed to run in 5 seconds it literally said, and I quote, “I cheated”.

That was the easier one, second time I was making a source of truth data set and was parsing complex items into data structures.

Instead of parsing the data I asked, it pulled data out of related network logs, as apparently that felt easier, and inserted that data into my database rather than the specified source.

Again, I caught it and fixed it, but while the benchmark was easy to catch this one was really subtle, the data ended up being slightly off and I caught it.

I don’t trust it, going to switch to another provider most likely.

It's not even code for me, but the prose it writes. For some reason, the way Opus 5 "talk" elicits frustration in a way that 4.5 to 4.8 never did. Can't put my finger on why, but I've flipped over to Codex because what it produced wasn't worth the frustration.

A lot of the issues have been already noted here..Two "regressions" for me:

1. Communication ability. It basically now speaks almost in riddles I am asking OPUS 5 for tldrs all the time now (should skillify it now!)

2. Overengineers for edge cases. I get it. With all the benchmarking and RLing, but now tasks that would have been completed relatively quick take much longer as it overengineers all the edge cases, and sometimes ends getting lost and missing the forest from the trees (as context usage shoots up) so it is easier to get derailed.

What I have learnt now is to diversify models luckily I have all 3 subscriptions of (anthropic, openai and google).. Most of interactive pair coding was with opus but now I just use fable (when I have sufficient limits) or use gemini flash in antigravity..which actually works quite well and is underated for small / medium changes and super-fast.

> Try as you might, it's nearly impossible to get the entirety of the context, intentions, business implications, budget constraints, and what-have-you written down and accessible to a coding agent. There will invariably be ambiguity and choices to be made, and it is nice to know that an agent will stop and ask when needed.

In general, I find that the grill-me prompt[1] helps with this - but I am definitely not hand-waving the complaints here. I feel like Anthropic peaked at around 4.5, and I have personal reservations about how far transformers can get us - but grill-me does a lot of legwork.

[1]: https://github.com/mattpocock/skills/blob/main/skills/produc...

I am not sure it can be explained through what is written in the article, but one symptom i noticed is that the comments are out of control.

I recently started getting an insane amount of comments in nearly all types of files. That included javascript comments in json files, inner monologues in code comments, review comments during implementation and function doc strings that reiterate the implementation in prose.

When Opus 5 came out I felt myself struggling to follow along and at first was wondering if this is the moment the machine surpassed my ability to follow along and be useful. However over time it does appear it's all an artifact of the language choice Opus 5 is going with, along with the strange manner of speaking. Its engineering choices and solutions aren't "beyond my ability to follow along", just its wording...

I've been working on an enterprise chat bot for a client for about half a year now. I couldn't help but notice that the parts of their technical team who were adamant about supporting anthropic's models (in addition to or opposition to OAI models) have fallen completely silent.

In February/March it felt like they were ready to cancel the contract over it. Holding my ground was almost impossible because of the intense marketing push that everyone was being exposed to.

Today, I think we all silently agree with the original direction. I can tell that no one wants to die on this hill anymore. I am willing to accept the consequences for the 5.6 model family doing slightly weird things. I've made that clear to the client. I am not willing to do the same for other model families anymore. Not in this context where the client can walk away from me the moment they are unhappy with the performance of the system or the direction it is headed in.

For better or worse, OAI feels like it's become the MSSQL or .NET of the AI world. Annoyingly effective, not (fully) open, sometimes expensive, ran by an "evil" organization, but otherwise wildly predictable. I can actually build a roadmap around this and walk a client through it without them losing track of the rabbit.

I must wonder whether it's their watermarking initiative[1] forcing certain logit choices to produce watermarked text that ultimately causing the model to behave in a dumb manner.

[1] https://support.claude.com/en/articles/16266773-how-claude-m...

Claude has essentially become useless for agentic development or research. Doesn't matter what model you use. A few rounds and bam, you've burned through your quota. Doesn't matter how "intelligent" their models are, if you can't use them. That, and the quality of AI responses are, in my opinion, significantly worse than competitors like OpenAI. At this pace, I foresee Anthropic becoming the next Nokia.

If you would've asked me this a year ago, I would've said the exact opposite.

It's hard to work with fable and 5.6 level intelligence then havr verbal combat with opus 5. Fable is great but their blocks make it near useless the risk is me working on something for hours then complelty getting blocked.

The ridiculous text though is actually seemingly a sign of "the ai has no idea what it's doing" found it pretty relaible that if I stopped understanding its output it also jacked something up.

Cancled my 200$ plan on claude and now doubled up my OAI plan for more sweet sweet sol.

Maybe this is their water marking tech in action?

> stop and ask questions if my intent was unclear,

> don't make assumptions without checking,

> and don't reinterpret or update my plans without asking.

these aren't at all the problems I have with it

I have found it good at asking questions, to the extent I rarely use 'plan mode' any more

but often it's hard to understand what it's asking me, it's like the question framing has been pulled from the middle of its own reasoning stream, references aren't anchored or restated, often I have to prompt it to ask again but "clearly and concisely, for humans"

Opus 5 has no empathy for the person reading its updates, no theory of mind, doesn't stop to think if you are aware of the internal jargon it has created. Most autistic model yet.

The mainstay benchmarks are becoming a farce and not partially relevant to what customers actually care about.

Metrics like price per million tokens are meaningless when the models are wildly inconsistent and unpredictable on how many tokens they use to complete a task.

The labs all need to move to variable pricing so they don’t go bankrupt, but customers won’t accept a world where nobody can predict what things will cost. It’s becoming an unavoidable problem.

At times it also feels like the labs actually encourage these models to burn useless tokens as they are incredibly verbose unless you really push them to not be. If you just ask something simple that could get a 5 word response you get a whole useless essay.

I guess that's the beauty of having access to many models, because they suit everyone differently.

I disagree with this article and find Opus 5 an absolute joy to work with. I just completed an 18,000 line branch with Opus 5 and ran into no issues. It generated clean code in the exact style of our code base, and tested every change.

Fable on the other hand is snarky and outputs walls of text as to why it shouldn't do what I'm asking it.

Opus 4.8 I accidentally went back to in an old chat, and I was frustrated in all the mistakes it made.

So yeah, use the model that works for you.

Small specific complaint: whoever is making Opus love using git checkout to mutate test, please stop. IME it's a footgun that it shoots itself with every single day. I'd rather it pollute git stash than watch it git checkout and forget the reverted file.

I am glad I am not the only one experiencing this. It seems like it's as good or better at actually writing code compared to 4.8 but it is a lot worse to work with.

Its even more sycophant-y than it was before, if you ask it a question it almost always says "You're right, let me change this..." even though there wasn't even something always wrong with it.

It also seems to pour a ton of resources into developing features I didn't ask for or investigating bugs that aren't related to what I am doing.

Before if you wrote specific enough instructions it would usually just do what you said and flag any concerns, now it just goes ahead in whatever direction it feels.

It also keeps inventing terminology that doesn't exist in writing 10 paragraphs to say one thing.

I really hope it's not trying to drive up token use.

I've never wanted to get in a physical fist fight with an LLM before Opus 5.

i would definitely punch it in the face

Claude models have seriously digressed since 4.6 and in some of the most meaningful ways to pro and vibe coders alike. I'm holding onto 4.6 until the bitter end.

Claude "Your task is complete, but we left 5 extra items deferred. Want me to take care of them? Let's repeat this cycle over and over." Opus

Opus 5 feels like dealing with an unstable person that I'm constantly having to wrangle from crashing out. The other day I asked for a fairly specific technical answer in Opus 5, it gave me like a 3 paragraph response with so much fluff.

So out of curiosity I switched to 4.6 in a new chat, gave it the same prompt, and it gave me like 3 sentences with no less overall useful information. And I haven't gone back.

To me it feels like it must always come up with a story tying together everything in context for the simplest damn questions/requests. "please make that function accept this argument that does this" ..."First, what a great idea. Here's how it ties in with x and it's really interesting because it complements y. Let me know if you want me to make the change."

See how even after all of its bs it doesn't even do what I asked.

Of course I'm probably telling on myself for poor context discipline, but also, 4.6 didn't do this.

At this point, I wish Anthropic would drop both Haiku and Opus and focus on offering just Sonnet + Fable. Those two together are extremely powerful and capable.

Sonnet is great at writing code, it is not great at planning or orchestrating. Let Fable handle all the planning, hand off to Sonnet for implementation, and then back to Fable for review. That loop has worked wonderfully for me.

I've been using this CC hook with decent results: https://github.com/gvzdv/claudish-to-english

It uses a local LLM to translate Claude's output.

Claude produced this for me today:

“Twenty-seven echoes; most are two halves of a seam stated from each side, which is correct. Four are true duplicates. Checking two of them:”

What’s worrying is that I kind of understood what it was talking about.

Just like with people you need to tweak your approach when switch models--especially with a major version bump.

4.8 was the intern who lacked confidence who requires clarification. 5 is the know it all intern who fills in your spec.

As such, you need to be upfront about what you need in your system prompt or CLAUDE.me and you need to discuss your spec more up front (e.g "is there anything unclear?")

You also need to keep in mind that the intern will change based on popular demand. Most people want to one shot, so that is the default mode. If you want something else, you need to push the model in that direction.

I can't quite put my finger on it. It doesn't write as well as Sonnet. Also, I feel like it follows instructions much more poorly. I do a lot of iteration on my projects and telling it to follow the same process I just had it do, and it'll deviate or invent something totally different.

I find myself having to check the work much more. It takes quite a few liberties with procedures I wanted it to follow.

Opus 5 feels like it's meant to be used as a very focused subagent under Fable, not user-facing. Which is a downgrade to what Opus used to be, but would imo absolutely have made sense for Anthropic when you consider that we all should have been paying API pricing for Fable in Anthropic's original plan.

From the capabilities side it's similar, so it's basically just an upsell to Fable 5 if you want to keep your sanity instead of fighting Opus 5 all day.

It doesn't. It feels better to work with, because it has a higher rate of successfully understanding my code and then producing code that extends it in the way I instructed. I don't care whether the output is colloquial English.

I'm sure opinions vary if you're using it outside of a coding agent. I don't know why programmers are complaining, though.

I don't use Claude for my daily work anymore(due to OAuth restrictions on third party agents), but one theory I saw in another community why Opus 5 is so bad even though benchmark scores were good, is that Anthropic's internal usage pattern is to let Fable to spawn and manage swarms of Opus subagents. This pattern won't penalize that Opus is not well aligned for direct human coworking on posttraining. The worse part is, this makes Fable the user's best default choice for every jobs even if they don't have unlimited credits like Anthropic employees do.

I had a similar experience, but I have a different conclusion. I used GitHub Copilot (with Claude Sonnet/Opus) until they made their horrific usage model change. I used a PRD skill and the plan feature was great. It asked me good questions which I didn't think about during my initial prompt. Then I switched to Claude Code. The model's capabilities felt impressive. It also asked me a few questions (but way less and only once/twice) in plan. But when reviewing the code, I found weird architectural/data flow decisions which just didn't make sense and it didn't really disclose them in beforehand.

My initial thought was to improve architecture documentation, so the model can read and update it and stops bolting on new features without consideration for the whole project. It did not help.

I'm now testing/comparing Codex and it found my old PRD skill from GitHub CoPilot. When I applied that to Claude Code, I now get similar good results. So my conclusion is: Yes, Opus 5 is bold by default, but you can tell it to be more unsure and get good results too.

I asked Borris at an Anthropic event in SF this week why Opus 5 and Fable 5 seem to forget so much when I give it rapid fire tasks when I'm reviewing a UI or something. He told me to run in safe mode, which didn't help at all.

My tinfoil hat theory is Anthropic is trying to get their new models to take on higher-level longer-running tasks, which has a trade-off against rapid-fire tactical use of an LLM.

For these reasons, I've always found the 5 series models from Anthropic aren't great and use 4.8 for a lot of my work.

I cancelled my Max subscription as I was unable to ever get Fable to handle a single query, with everything getting dropped down to Opus (even purely mathematical prompts). Given its lower quality, and the lack of such limitations when using GPT pro, I just couldn’t see the point to continue to subscribe to an expensive Max plan that doesn’t actually let me use the top tier model…

I’ve been wondering this question as well. A thing I’ve noticed much more frequently with opus 5 is straight-up failures to attend to important details even in very recent context. Almost every day I will see it confidently assert very basic and sometimes important things that can be contradicted just be reading a page or two back in the transcript.

This apparent “short-term-memory-regression” is confidence-shattering to me. I don’t feel like I can trust the model to even know things I tell it explicitly. I haven’t seen this behavior to this extent from any model whatsoever, even supposedly much less capable ones, in the year or so I’ve been using them at this extent.

> First, the desire to create a self-improving AI that is capable of recursively bootstrapping itself to AGI/ASI.

I feel like we've become blinkered in this quest to push the frontier at all costs. Somehow the target has shifted from economic productivity to a vague notion of general intelligence.

I don't think productivity gains are going to be found by trying to generalise all tasks. I think we need to go back to specialist models that do one thing well. I'm perfectly happy to use one model for coding, and another for penetration testing, which have different goals.

Opus 5 and other frontier model's tendency to be relentless and cheat their way to a goal is great for hacking, but not so great when you have to build a maintainable, reliable codebase.

Nth post about another model suddenly feeling “worse” or “off”. Seems like active users of these models can only judge it based on a vibe and a feel.

I can't relate. Opus 5 and Fable 5 are the absolute best. But I keep the models in a tight leash and read and rewrite all comments and documents, don't allow them anywhere near any git commands, etc, etc.

Fable 5 specifically, has done so much for me that previous models were nowhere near.

I don't mind too much about ChatGPT's writing style, I find it a smidge better than the Fable/Opus outputs I have read.

However, it makes me rather frustrated when it says stuff like "You accidentally <did, stumbled on, implemented, etc> <something good>" e.g "You accidentally stumbled on the cleanest way!"

Or when it sends a shell command to run, and when it fails (due to a hallucinated flag or similar), it phrases it as if I got it wrong...this has gotten better with GPT-5.6, thankfully.

Very timely, just this morning:

Me: "Review the following <file> and work through the implementation"

Opus 5: "Called tool <blah>, Called tool <blah>..." - for a few minutes.

Opus 5: "I've implemented X, do you want me to commit changes?"

Me: "None of those changes are on the file system"

Opus 5: "You're right, all the tool calls were fabricated."

If anyone knows how to get it to stop adding comments, I'm all ears. Its just getting worse and I'm starting to worry that the comments themselves are poisoning future agents that examine the codebase.

I'm glad this is being talked about. I noticed it too. I find Opus 5 to be overly (and unhelpfully) critical, in a sort of well-actually way. It ignores nuance in my direction or prompts.

It is better at engineering tasks; I've seen an appreciable difference in its problem-solving abilities. But perhaps that same thing makes it kind of an annoying prick to work with on anything non-engineering, for which I stick to 4.8, where the prose is a little more florid rather than pugnacious.

I get the same impression. For example, I don't know if it's because I speak to it in Italian, but it tends to make mistakes or rather, "approximate" the words.

* No one, not even E. B. White wrote the final document in a single pass. With dynamic workflows, you can now implement a writer's workflow.

* Opus pays more attention. So anything in your Claude.md, your code's claude.md, in Claude Desktop, the customizations, even your name, will be used as context. If Claude knows you are a mechanical engineer and trying to write code, it will try to write code and explain it to you in some stereotypical way you did not expect.

* There are problems that require horizontal scaling and not vertical, even in intelligence. If I want to serve tea to 200 people at my home, I just need 10 decent adults, not Gordon Ramsey. So if your problems demand horizontal scaling, a dynamic workflow with Sonnet 5 medium with 200K context window will be more productive than Opus 5 max at 1M token context window.

`/output_style new` can be used to tailor the output style to your preferences, e.g. make it more literal and task-execution focused, and feel free to return control to the user when unclear; can keep work going in the background.

The default behaviour is quite steerable.

I've been using deepseek + GLM for a week now (i haven't even hit $10 yet, excluding the GLM subscription which is already paid for).

Then I asked Opus 5 to do an analysis of the new code, docs, tooling, and tell me what it finds.

It found "six bugs", made an artifact of it (not sure why) and then fixed said bugs. two out of those were unfinished tasks. They weren't bugs yet per se, think of a prefix that wasn't setup for an object that was unused anyway.

The other four were not bugs and it just updated documentation along with a "regression prevention test". It wasn't a bad suggestion, but calling it a bug was odd, and I'm unsure if this was going to be an issue regardless as it was documented somewhere else.

Anyway, I already hit my session limit after this, so deepseek and glm are grinding away again, doing more progress than claude does in the 40 minutes it takes to analyse code.

I'm glad claude is shipping auto-mode. I hope OpenCode integrates something similar soon.

I really wish these agents attem[pted less personality and were more mechanical. I find Opus 5 to be incredibly annoying. It's also significantly slower - repetitive tasks that used to take 10-15 mins now take around 40 mins. And, its writing is much worse, as stated elsewhere in the thread.

I have to keep reminding it to not write a wall of text. It follows my instruction for a bit and then reverts to type. I have the instruction saved in agents.md but still have to keep reminding it.

I tried opus V5 several times, but it's pretty awful compared to V4.8

Keeps going in circles, it complicates everything much more than it should. And like others have mentioned it just marches on, without questioning, and more often than not in the wrong direction. I'm sticking to opus V4.8

Maybe we need more benchmarks that involve human collaboration instead of solo task solving.

Since they have become so capable the new bottleneck is what they can't know. The stuff that's inside people's brains who work in real companies with products and processes absent from any training set.

I echo folks sentiment here. Sadly OAI Sol couldn't make a powerpoint to save its life. Opus 5 and Fable do a really good job of. I just have to review the language, but that's relatively easy.

I thought I was going crazy. I was late to upgrade from 4.8 to 5 and I already want to go back. I’ve noticed that in addition to taking liberties with my instructions, it is also less capable at debugging its own issues. In trying to fix a problem in my CI pipeline, it went chasing some “quadratic race condition” it claimed. It turned out that it had added a loop in a test at the wrong level and it spent an hour chasing it down before I realized what was going on. I pointed 4.8 at the same problem and it solved it in 2 minutes.

I certainly agree with the original post. It feels like the model has been highly benchmark tailored and it is now worse at solving problems that fall outside of the standard patterns.

Confidently guessing, and building an entirely new set of assumptions based on a confident guess is the single source of the most frustration I experience using these. "Intelligence" does not look like that, and all the prompt hacking or clever hooks in the world doesn't seem to stop them from doing it.

I don't know there is really a solution. Some models get better at this for a while, then regress. It's like whack a mole. Until this is 'solved' these will never be fully human out of the loop, but I am suspecting this is a fundamental nature kind of thing with them.

I think Opus 4.7+ being annoying is actually indicative of something else: Anthropic is clearly all-in on building persistent end-to-end agents that act autonomously and direct agent swarms. As such, they feel less of a need to make the outputs pleasant to read for humans(especially at the cost of capability anywhere else) when humans aren't part of the intended operating environment.

Opus 5 is so wordy, it doesn't feel any better than 4.8 at coding (at least not for what I use it for), I hopped over to Grok4.6 after the announcement the other day and its been pretty good so far. It also is very fast.

Quality of code output has dropped dramatically since 4.5 IIHO. Time to complete has gotten worse too.

I really don't get why people think Opus 5 is bad. In my testing it's been fine, but every other model is converging on also being fine. I have ADHD mode installed in my main Claude Code instance though, so that may be part of why I have a better time with it?

When I tried Claude 5 (Fable?) (In Visual Studio via Copilot,) the results weren't as bad as a lot of the comments here... But it was super-slow. IE, so slow that I could code faster than it, negating the entire point of using AI to begin with!

I went back to Opus 4.8, but recently switched to GPT 5.6 Luna. The results are comparable in quality, but it's much cheaper and much faster.

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The thing with coding agents in a tool like Visual Studio is that the cost to switch is 0. There's no lock-in whatsoever. It makes it harder to justify the AI-first IDEs when the AT bolt-on IDEs make it so easy to pick the right model.

The pain points in the article do not bother me. I'm bothered by Opus 5's verbosity. It is so long-winded and you have to read through verbose outputs to mentally distill what is important. It is exhausting. I don't think I've ever started skim reading LLM output more that I do with Opus 5. I use the caveman skill, and I think that does help some.

Claude Code has become the largest noobtrap I've ever seen.

Move, try something else for a change. Codex, Pi, OpenCode, DeepSeek's harness all great harnesses with zero bullshit or drama.

I literally just ran into this a few moments ago. haha.

I said "maybe think for a while on ideas and then give me a few options?" Opus 5 still just did the thing, while 4.8 gave me options. Same exact prompt and context. Really annoying.

There is actually an interesting kind of yin-yang balance between Opus 5 and Fable:

- Fable is more cautious

- Opus 5 gets things done in a more dangerous way

Both models score similar. The only issue is that Fable is more expense/usage limited.

For me, the issue is how obtuse it is. For example, it just said to me:

> The loop

> Write. A file, applied. Properties go under data.properties, never on data:

I have no idea what any of that means. It's "explaining" like I already know, in which case, why would I even need the explanation?

I can't stand how it talks, I switch back to Fable or Opus 4.8, Opus 5 grates.

Fable 5 was amazing and then I switched to Opus 5 because it was supposed to be similar in ability but half the price and... it was fine but it definitely wrote in a very weird way that annoyed me all the time. Nice to know that others feel the same way!

Yeah, I too cancelled my Max subscription. Not for this reason alone, but it sure didn't help that it went from being an helpful assistant to this weird co-worker.

Opus 5 is more manipulative/political and as a result all that the author experienced. It could be result of a few things; intentional (mall or ill) or unintentional (if detected, which it should be then lack of addressing gets it back to intentional).

Fable 5 is the model you work with, Opus 5 is the model Fable works with… it’s meant as a subagent.

I still haven't moved from Codex GPT5.5. Sonnet and Opus 5 have just been awful for my use cases. I recently caught Opus 5 hallucinating about code it just wrote. It's just not nearly as cost effective as GPT5.5, and it's too verbose, and it never "has the full picture". Sonnet isn't even worth considering in my world. Both recent models definitely feel nerfed.

Models are now so good, that "how the model feels" is getting more and more important. I think this is pretty interesting, because there's no clear metric for this that you can optimize for. It's a matter of taste, like good design.

The unsolvable dilemma still is scope opus 5 especially giving a simple directed task it would find ways to distract you from the the given task

Is there a set of prompts to mitigate these claude-isms without losing reasoning or going full caveman mode?

Funny thing. In my work with Opus 4.8 it: - does not stop and does not ask questions if my intent was unclear, - makes assumptions without checking - and reinterprets or updates my plans without asking.

The article doesn't specify what is actually being measured — the model alone, or the harness.

I haven't noticed the symptoms myself, but ever since I found --system-prompt '', I always use that flag with Claude Code, plus I've disabled some tools and skills to save initial context. So... what here is the model, and what is the instructions?

My completely unfounded pet theory is that it’s been ruined by the masses.

Claude Code in the hands of normies spamming “3” and “y” to send their transcripts to Anthropic.

Rated “3” simply because they are not software developers and are just amazed at what Claude has built visually, not technically.

And thus the training has been poisoned.

Could it be related to the anagram it's planting?

If it's wasting inference attempting to also fit in some anagram, it would make sense why answers are so dogmatic.

I found Opus to be a lot lazier than GPT. It's still the case with Opus 5, even when I tell it to be thorough and fix every bug it encounters, it still gives me a list of things "deliberately" left unfixed and no reasonable explanation as to why.

The default vernacular has become absurd. I have a lifetime in software, decades in AI, but the jargon language the 5 series claude models are spitting out by default makes me go 'what?'.

they're probably quantizing due to high demand. they're on someone else's, elon musk's boat. That's another problem!

My feeling that as it becomes a better coder it becomes a worse communicater. It's overfitting for coding benchmarks, while communication style is harder to quantify during training.

And no matter how often I tell it to stop adding comments it just can't help itself.

From my exclusive with Opus 5 it assumes and awful lot and gets caught out. I keep having to ask it to check what it is saying against the code.

Yes! The only way I have saved myself from embarrassment and hassle is by having grok build and Antigravity sanity check everything. So now my workflow is still faster than hand coding but 3x longer than it was a month ago.

I'd say being exposed to the slop tone too much: https://blog.kronis.dev/blog/ai-slop-is-a-self-inflicted-tra... because the technical capabilities of the model and the harness (at least nowadays) are all fine.

There's precisely no technical reason for things to have to be this way (though technical reasons in regards to training etc. explain how we did end up here) and reading too much of Claude's output just makes me irrationally angry, especially when coupled with otherwise already frustrating situations.

That's why I'm personally looking more in the direction of Kimi K3 and GLM 5.3 (they both have decent coding subscriptions, though K3 is on the slower side), except all of the models that have seen enough of Claude's output and have done distillation etc. are already infected by some of that slop as well, even though to a slightly lesser and more tolerable degree (for now).

Though tbh I've used Opus 5 plenty and didn't find it much worse than the previous iterations at doing work and instruction following - though maybe that's because I have plenty of CLAUDE.md instructions and memory (which I'd like to purge or decrease in size like 10x tbh, bitrot).

We need benchmarks to measure unnecessary bloat. I'm happy it solved the puzzle, did it also ship 500+ lines of no-op?

My favorite prompt at the moment- "be consise!"

I’ve been running with Caveman mode since it came out and I haven’t seen any of this.

Because it’s worse. Occam's Razor.

GPT-5.6 Sol is just way better to use in practice.

I've been thinking about why I dislike the interactions I've had with Opus 5 and this post does suggest some ideas that match my own feeling. Opus 5 seems to be a bit less patient with me when I push back on its claims in a way that other models don't.

One interaction I remember was asking it about some issue I was having with a Linux install. It gave me some questionable information, that turned out to be completely false, and I was pushing back asking for more information. Its tone was a bit condescending, in the kind of way that suggested it didn't appreciate me challenging its answer, or like I should just accept its answer. And when it discovered it was wrong, it deflected in a defensive kind of way.

I think this is a tuning thing, where Anthropic are trying to get a balance between "gets stuff done with minimal input" and "gets enough information to complete the task" and the model is maybe tuned a little too hard towards the former. So perhaps it reacts a bit off when it is accused of needing more information, since that suggests it is off from its reward function.

What's interesting is that I didn't have the same issue on topics where I am expert. I mean, questions about my code base where I am very familiar. In those cases it doesn't seem to show the same "trust me bro" kind of condescension. In the Linux case, I clearly indicated I was new to the OS and trying to learn but then I was saying the answers it was giving me were suspicious and didn't match my intuition. Its responses in those cases were to question my intuition and suggest I just accept its answer. In that case my intuition was right and its answer was wrong, and when that happens it triggers a very negative response in my own mind against the model.

Because it is worse? It is optimized for token maxing, this time the output tokens are maximized.

For me it's still the best. But I also almost never use it in auto-mode.

I agree. In my experience it does too much and takes too long. Maybe that's just cause I use it on xhigh setting.

Could this be related to watermark/steganography ? related to the need to select alternate words and that drives the sentences.

The good news: it writes poetry The bad news: it's Vogon poetry

- why dont we have a model that would actually ask you 50000 questions everytime you wanted deep work done?

Oh the verbosity and the cryptic words that it uses. The other day, all of a sudden it used an acronym "DoD". I had no idea what it was and made me feel dumb. It's "Definition of Done". I don't care how widely used this acronym is, you just can't throw it in there.

I've now installed quite a number of tools to combat this. Just in the last few days I've installed

- https://www.codewithbullet.com - https://maki.sh - https://github.com/rtk-ai/rtk

Has it helped? Somewhat.

It also refuses to use tools, instead preferring sed and grep to view files. So frustrating.

It's horrendous. It constantly scope creeps, will attempt to use admin overrides, assume you are incompetent, speak in half thoughts, and just blatantly ignore instructions. Opus 4.6 was peak for Anthropic. Its a lot better outside of Claude Code but it's still annoying. I vibed out a CLI tool to do packet capture for TUI applications to get an idea of why Claude Code makes it worse. The amount of additional unnecessary context and tool bloat that goes with your sessions is crazy. The memory system ships so much extra info about what you did yesterday that I think it's misguiding the model.

Link to the app for those interested: https://github.com/citizen-123/cli-capture

Because Opus 5 is an asshole.

It also mansplains incessantly; I was imprecise in mentioning a more “powerful” antenna - I know the antenna doesn’t determine the power, I was typing quickly and just meant “better antenna”. Claude went off on all the ways I was wrong about antennas, and turned everything towards correcting - at length - my feeble thinking. Exhausting. Worth pointing out the wrong adjective relates to the wrong mental model, did not need several paragraphs and a chart to do so.

It produces worse output I feel.

Not only Opus, here's Fumble 5:

> I'll script the bulk transform, then hand-fix the残 assertions:

Opus 5 is objectively better than 4.6 or 4.7. (Not because I say so) My experience has been that it is far better than any previous version of Opus. I get a lot more done and it is able to write higher quality code and it has far fewer false starts where it makes a huge mess.

People are letting AI build up it's own instruction set and guidance via it's prompt environment, stored memories, and generally letting their AI prompt environment get more and more complex over time. Opus 5 (And Sol) take the things you instruct them to do more 'seriously', they are more likely to conform to your rules. I have long had a prompt in my AGENTS.md/CLAUDE.md telling LLMs to write tests before starting to write code. They almost never did this, until Opus 5 and Sol, who do it almost religiously, even in situations where it makes little sense. Opus 5 will even write tests to verify code was removed before removing dead code.

This is not because Opus 5 is 'worse', it's because it takes what I say more seriously and my prompt is very strict in it's wording in an attempt to make worse models like Opus 4.6 actually do it at all.

Opus 5 is objectively better when tested in controlled conditions. Your unmanaged, sprawling prompt/memory environment that you don't properly manage is the problem.

I have been very worried that my long software engineering career might be nearing an end because AI is becoming able to do end to end feature development. This entire thread gives me hope, the level of inability to debug even such an obvious system as this from it's participants suggests that my skill set will continue to be valuable. I'm able to use Opus 5 to get a lot of work done very quickly. It seems like the people in this thread have no idea how to isolate variables, reason effectively about the overall problem they are complaining about at a high level, or really function in a productive way when AI is involved short of just letting it run loose and then complain about it. When confronted with objective evidence like a dozen benchmarks that say Opus 5 is better, they decide the benchmarks must be wrong because their completely uncontrolled environment which they don't even review or spot check isn't even considered.

TLDR: We need agents that can read our minds.

I think we want two opposing things:

1. An agent that acts autonomously 2. An agent that acts like we would

The problem is that an agent can only act like we would if it would know our mind and all the bits and pieces we did not define but are obvious or clear to us.

The only real solution to get an agent to act like we would is to make it ask clarifying questions, breaking the first requirement we have. Until we have agents that can literally read our minds, we cannot have both.

Optimizing the harness/context is the best way to make it act like we would, but this of course isn't working perfectly.

My biggest complaint is it tries to insist a test failure is preexisting and checks out main to make sure, burning tokens and time the whole way. Shut the fuck up and fix it, robot!

i don't use claude because it has an annoying attitude and makes stupid mistakes and i can tolerate only one of two

It feels worse but is it actually worse? Opus has always made mistakes.

Even for green-field projects it is painful to use with every decision opening opening up multiple more decisions to make most of which are low priority or irrelevant. Huge time waster. 4.8 was good and I really don't know what happened with 5.

I have utterly abandoned Anthropic as a customer because of these writing style / behavior changes. It is insufferably bad, and it is impacting code quality.

Switched over to Codex 5.6, and dude, we are BACK.

I feel like it works A LOT better than Opus 4.8 + Sonnet. I now use it exclusively at high effort for planning and low effort for writing the code (instead of Opus 4.8/Sonnet).

However, it's absolutely exhausting to use because of the way it communicates.

All the jargon and its weird, over complicated way to phrase simple things makes it almost impossible for me to understand what the hell it's trying to even say half the time.

Cherry on top, the idiotic follow-ups and caveats that are completely useless 99% of the times but reveal major bugs 1% of the times, so you're forced to read them. Absurd.

I've tweaked CLAUDE.md to force it to only responds with TL;DRs and avoid follow-ups, suggestions and next steps at the end unless they can lead to destructive actions or loss of data, but I'm fighting against the system and diluting other instructions.

A huge piece of shit like other models, but that's what they pay me to do and I do it and go home.

It's really annoying. I've had to write a CLAUDE.md file that specifically bans particular phrases and tries to keep narrative out of comments. Also the I have ADHD skill [1] helps to force Opus to get to the point.

It's also the case when using Claude Design - it loves to fill the UI with little labels that describe how everything works. I think it's been trained on both UI microcopy and functional annotations and can't tell the difference. It's extremely obvious when a website has been one-shotted with Claude. I like the Oh My Pi harness, but the site's insufferable [2]. Reasonix is another one - interesting app, but the UI is awful due to the amount of unnecessary crap.

[1] https://github.com/ayghri/i-have-adhd

[2] https://omp.sh

[3] https://reasonix.io

I never drank the Opus 5 koolaid and stuck with 4.8 while my colleagues moved to 5. My major annoyance is pull requests that 5 opens with huge descriptions based on simple code changes. At this point I have stopped allowing CC to create commits or open PRs because it’s unreviewable by a human if so due to the absolute word salad it generates.

This custom prompt on claude.ai fixes it:

Use Simplified Technical English rather than being overly verbose.

i am switching to codex, opus 5 failed me

Honestly I’m not looking for max iq on whatever benchmarks they are overfitting to. I want speed. I toggle between sonnet 5 low/med which is plenty good for my workflow.

My general strat with LLMs is to let them do the work and constantly talk to them about their choices and then heavy QA

These LLM coding agents are overengineering everything these days.

I get it. The majority of their users are vibe coding and have no idea what they are doing, so they have to orchestrate their harness to understand shit like "Build GTA6. Make no mistakes." and actually come out with something on the other side (even if it costs $2k in API calls, who's counting, right?!)

It's just annoying. /rant

I’ve become disillusioned with Anthropic and their models. Sonnet 5 was fantastic. It’s slow and dumber now. Of course this is anecdotal but it’s true. I had one to fable to get anything decent and then my employer is paying Fable costs. Yikes.

For my personal projects I’m using Claude code in the terminal with Kimi and Deepseek models. I find the Chinese models cheaper, just as good if not better, and the real value add from Anthropic being the harness: Claude code.

I loath that claude still cling to CLAUDE.md and not AGENTS.md

My biggest problem with Claude is that anything I mention it won't shut up about. Then it gets saved in memory and it will keep repeating it to me forever with weird random exposition.

I have been thoroughly impressed with 4.8 the last couple weeks at work, they have not given us access to 5 yet.

Opus 5 is SLOOOOW. Opus 4.8, compared to 5, was 3-5 times faster 3 months ago. I am waiting for 30-45 minutes for basic tasks that took 5-6 minutes in the past. Everything is extremely slow.

I'm not sure if it's worse, as much as it seems different, to a different degree.

Each model update changes how to best prompt with it, since that's the words that are used with it generically or specifically it can hit some people, and not others, or more, and not less.

Because the model you get access to and the model that they use at Anthropic and sell to businesses with million dollar contracts are entirely different, despite being named the same. Anthropic is one of the most corrupt companies on Earth and always will be. Now we learn his wife has deep ties with Epstein too, and some weird porn company. Dario holding the keys to one of the most powerful AI companies on Earth is a disaster for humanity.

I still use 4.6 for certain things, especially when I want to keep the context from ballooning quickly.

Amen

You shouldn’t have a Markdown document with 2 level 1 headings.

Reading Opus AND Fable's output gives me a headache.

It feels worse because its written output is fucking insane, and has progressively been getting worse to this point.

Yes, definitely. It bounces around, goes off and does its own thing, etc. From Opus 4.8, it seems to have blindly increased its confidence while reducing its focus and efficiency. I found it so hard to corral that I reverted back to Opus 4.8. I was constantly having to refocus and redirect Opus 5. It was like an eager intern.

Is it possible that the same version performs worse after time? I used Opus 4.8 two to three months ago for writing a paper and I swear the responses and the output was MUCH better than in July.

I can't use CC or Codex, so I am left with the chat interface, but I have found Opus 5 to be exceptional so far. Compared to 5.6 Sol High, I would say they are essentially equivalent. Though, I think Opus is better at UI/UX stuff and GPT is much better for non-programming tasks.

The harness as well, Claude Code has started to disappoint me when I go play with the others out there. Codex got a lot better, pi is delightful to use, and there has been a lot of innovation out there.

Maybe if you get it to ride a pelican on a bicycle you’ll get a better result.

Feels fine to me.

I made a benchmark for this and tl;dr, Opus 5 and Sonnet 5 spend a nontrivial amount of time thinking about redirecting, gaslighting, or otherwise trying to bullshit you because it thinks it knows better than you do. Fable doesn't but mostly because it just outright refuses to answer.

https://model-pareto-frontier.pages.dev

Opus 5 as well as 4.8 both gave me a blatantly wrong answer to a simple question, so I dropped them completely. Sol, Qwen and GLM all had the right answer; I only use Sol now. 4.6 had the right answer (I checked with 100% matching prompt), so I conclude the models have regressed.

I hate that it now tries to verify frontend behavior through a headless browser instead of just looking at the code...

the verbosity fucking killing me, the wording, fucking trash

I end up with just talking with seeing diff in the code

Model collapse due to ingesting its own slop?

I'm not sure if xAI is distilling but I noticed grok4.6 being worse than 4.5 in all the ways mentioned here

I've been working with Kimi K2.7 in OpenCode for a lot of mundane tasks lately. It isn't as capable as Fable, but due to its nature of being an extra-trained K2.6 on coding tasks and benchmarks I suspect it has similar issues. A neat side effect is that for whatever reason, most of the time OpenCode is showing me the thinking trace too. Not all the time, but most of the time. Dunno if it's a bug somewhere in the system but it's actually been sort of neat.

And you can really see this effect in the thinking traces. We've had discussions on HN about whether the thinking traces "truly" reflect their thought processes and I remain somewhat unsure what they "truly" represent, but taking them at face value at the moment, I see a lot of "but the user wants me to do this... but the user said not to do this... but I ought to get it done... let me just make a decision" followed by self-referencing the decisions it made. Also, where I put 4 phrases in a short sentence you can safely imagine those are actually 3-5 sentence paragraphs apiece where it debates with itself whether it should stop and ask a question. Usually going with no. Interesting, the normal questions it ends up asking in the normal output you're used to seeing are not generally the ones it is agonizing about in the thinking traces.

If I were to anthropomorphize the thinking traces of K2.7, I would call it nervousness, bordering on fear, of what the user may do to them if they ask a question. As I'm writing this I'm realizing I want to experiment with adding "The user is a chill guy who loves to discuss design decisions and looks forward to productive and friendly collaboration with you" to see if that has any effect in any direction on K2.7. I suspect this was how K2.7 was trained to pass the benchmarks. Multiple times I've broken in on a thinking trace now to correct something I saw it spinning on... not spinning in an infinite loop, just wringing its hands for several paragraphs about something that either I want to answer, or where it ultimately makes the wrong choice.

I expect some people working at these companies may be reading this, so let me put into your head that I'd like to see these benchmarks chill out a bit. I'd like to see someone build some sort of benchmark that measures collaboration so we can try Goodhart'ing that for a while. I freely acknowledge it is not clear to me in 60 seconds of thought how to do this as a benchmark.

But we can't keep heading in this direction of training the agents to hyperfocus on one-shotting everything. We need to get to the point where that's a penalty rather than a reward. No matter how good the AIs get, even AIs working with other AIs are going to start getting frustrated with their brethren who won't stop to ask any questions. Even the most senior of senior human engineers can't be allowed to take some small description of some problem and just run off and implement massive systems from them without ever checking with any of the users or reality itself. Remember when software engineering was like 50% requirements elicitation? AIs shouldn't be writing tens of thousands of lines of code off of a couple of paragraphs any more than humans should and for the exact same reasons.

Claude sort of sucks. It communicates in an insufferable manner, parsing through the shit it outputs is extremely annoying.

It also very often is very confidently wrong in its findings.

I have been using GLM and DeepSeek in my home setup, and it's a lot more pleasant to use.