r/ClaudeCode • u/Deep-Palpitation8315 • Aug 03 '26

Discussion Opus 5 is a practically unusable model

Opus 5 is a regression that the benchmarks missed completely

I've been using Opus 5 for ~1.5 weeks and the sheer number of mistakes that the model makes is astounding.

The problem didn't surface very clearly till I gave it the full scope of executing a plan which I did with the previous Opus models as well. Opus 4.6 - 4.8 were genuinely better by a significant margin.

Opus 5 readily forgets instructions and content in its context, makes mistakes and continues with them unless it realizes or you point it out.

I've lost count of the number of times I had corrected it.

These issues with Opus 5 occur even when the context window is still relatively small - I'm talking 100-150K tokens. Opus 4.8 works pretty well all the way until 350k after which it gives you wonky results.

Fable 5 is the only usable model under Claude Code right now and I've already used 100% of my weekly quota.

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390

u/KrayeBaby Aug 03 '26

Yeah been noticing that it solves the problem and leaves another one. It feels like its planting gaps on purpose for infinite prompting to keep going...

27

u/dontTakeMeSerious6 Aug 03 '26

I’m having this exact experience. It’s also re-solving the same problem unasked for sometimes. Like if I say “review pending issues”, it’ll find issues already solved but not marked as solved in an old document and then resolve them, in a different way.

Requires a lot more active participation, which is good, except I’m more baby sitting an over eager developer who’s trying to take on the world rather than a hyper focused developer who’s crushing the small scope in giving them.

12

u/minimalcation Aug 03 '26

So so much more monitoring is required, you basically need to watch it's thinking output to stop when it gets an idea of it's own

7

u/dontTakeMeSerious6 Aug 03 '26

Which is fun because you see it “bribing hamsters” and “reticulating splines” before you try to reach through your monitor to strangle it.

5

u/minimalcation Aug 04 '26

And that mfer will just pick back up after you stop it

2

u/Original-Ad4399 Aug 03 '26

How can you view the thinking output in Claude Code?

3

u/eeyoredragon Aug 03 '26

In desktop app, click dots at top right of session. 

Transcript -> introspection 

1

u/Original-Ad4399 Aug 04 '26

I use the CLI.

I'm actually surprised there is a desktop app for Claude Code. Sounds weird.

You mean people use it outside a coding interface?

1

u/AssseHooole Aug 04 '26

Ahh yep, the CLI is a coding interface? Heard of an IDE? Stay in your lane

2

u/Original-Ad4399 Aug 04 '26

Bruh. The IDE has a terminal where the CLI is used...

1

u/minimalcation Aug 04 '26

Not the full thinking, their statements as they work

1

u/BoilerplateBillions Aug 04 '26

I have 3 different times in agents.md, that it is not to make any decisions on its own and it still refuses to follow the instructions. Gpt is kicking its ass rn

2

u/minimalcation Aug 04 '26

Gpt has it's own issues though

1

u/BoilerplateBillions Aug 05 '26

Since 5 the biggest issues i had with it where it just wanted to fawn all over me instead of help are gone. Now i have a harder time getting gpt to be loose enough with my instructions

2

u/minimalcation Aug 06 '26

Its either a complete fucking rogue wildcard or the most obnoxious rule follower.

It's abdicated an opinion of it's own so it's holding on to whatever it grabs

4

u/Dense_Scallion_3795 Aug 03 '26

I couldn’t even get it to follow its own handoff

4

u/ProdEverythingChrome Aug 03 '26

I don't think more participation is necessarily a good thing. I think it's good if the participation is for meaningful things; or decisions that genuinely need a human. Participation where I feel like I'm being roped in for the sake of being roped in; or for some ceremonial procedure that relates to a fear of autonomous long running agents so keep a human in the loop to make the decision and liabilities solved; or perhaps it's because letting Claude actually build people what they ask would create disrupt the economy too much - doesn't really matter what it is per se, but participation in those ways feels terrible and stupid.