Elevated errors on Claude Opus 5

Not sure if it’s just me but in Codex, GPT-5.6-Sol and IIRC older 5.5 models can stop dead in the track a couple times a day saying “model is at capacity” (paraphrasing). Then I wait a minute or two and ask it to continue and it’ll more often than not happily use the same model. These frequent mini “outages” are pretty annoying especially if one isn’t supervising. Claude has had long outages but I haven’t run into this kind of mini outages on a daily basis recently.

Yes, it’s way off field in many things, gets into weird minutia without seeing a way out, and it’s often seeing a clear sequence of work but then halts on a statement like “ok I’m going to start now.” Then after expiring the cache when I notice and ask why didn’t it the response is “no reason starting now!”

I see this behavior constantly in 5 - the quality of opus and fable have degraded constantly since 4.6 was such a riotous success

Quality of output of both Fable and Opus seems to have gone down quite a bit over the past week. Many mistakes.

It is aggressively proactive in ways that make it very hard to use. I had to turn down the effort level to “low” to stop it from going off in random directions every couple of turns.

Yeah I noticed informing me of mistakes it made during sessions. It felt really off when it informed me of a mistake it almost made but caught it before it landed.

I'm not getting this, is it a joke?

Opus 5 is Heisenberg?

You forgot <sarcasm></sarcasm>

Yes I had a similar experience with Opus 5. It is very token efficient, fast, and gets reasonable part of the work right but makes a LOT of mistakes. In a month+ use of Fable completed each task without ANY errors. Opus could not complete a single of ~5 tasks without some issue or the other - either not getting it fully right or actually introducing regressions. To their credit it was able to catch regressions and fix competently. It seems like a pre Opus 4.6 model in terms of reliability with a lot more power and spiky intelligence. When it gets things right it's powerful and efficient but without reliability I had to 'downgrade' to Opus 4.8 forcibly (since it was not a default option on claude code). I really miss Fable on the pro plan and will likely churn to K3.

I also found it to forget some obvious cases in a quite simple flow (validate the email address of a user who register), that surprised me a lot. Maybe it's because I got used to Fable? But I am quite sure Opus 4.8 wouldn't have make this mistake. If I had time I would try the same prompt with it to see. Anyway, back on 100% Fable for me.

I don't know what I could be doing differently to you but I found Opus 5 to be more reliable than even myself at times. Maybe your stack is unusual or you have conflicting commands in your prompts vs CLAUDE.md (that really confuses it)? It could be anything but this huge error bar in delivered quality is one of the biggest issues with LLMs.

Getting to grips with each new model does require some tweaking and experimentation. So far I've found Opus 5 to repeatedly pause its work and give me some seemingly randomly invented decisions to make.

Same here, also it lies often to me or implements something else that what was planned. It feels quite strange to see it say casually "I didn't tell you the full truth on X" when I notice the issues. At the same time, maybe it is more honest?

I do not experience any regressions, I don't really notice much difference either.

Maybe it's my harness but I haven't seen it introducing regressions.

Do you not have unit tests, or how does it introduce regressions? You can tell it how to run the test suite in CLAUDE.md

People's lives revolve around Claude like a crackhead around his or her dealer.

AWS is hosting those models on different infrastructure. So I guess Amazon is better at hosting their models than they are.

Or it just gets a lot less traffic.

We actually tracked this over the last year, bedrock is significantly better than the anthropic direct endpoints

Indeed. Your link points at today's outage number 1. This thread here is about outage number 2. We're currently undergoing outage number 3.

The post that ends up on front page is usually the one for the previous outage due to the way the algorithm works.

There are tens of HN front page posts about GitHub outages. Why not Anthropic's?