Why does Opus 5 feel worse to work with?

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 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.

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.

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.

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.

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.

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.

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.

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...

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.

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.

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.

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?

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.

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.

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.

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

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

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.

[flagged]

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.

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

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

[dead]

[dead]

[dead]