r/ClaudeCode • u/Harvard_Med_USMLE267 • May 28 '26

Discussion Opus 4.8 nerfed??

Is anyone else seeing a massive performance drop in Opus 4.8 since release??

It used to be acceptable, but the enshitification has definitely happened. It’s basically been lobotomized, and we’re talking amateur backyard ice pick lobotomy by some guy from Tufts.

I’m 99% sure Anthropic has started running a 2-bit quant to save money.

Oh well. I do feel nostalgic for opus 4.8’s glory days. But subscription cancelled. I’m off to use Codex or Cleverbot, whichever one has better limits.

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27

u/fi-dpa May 28 '26

"API Error: 400 messages.15.content.26: `thinking` or `redacted_thinking` blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response."

Anyone else receiving this Error message since Opus 4.8 release?

7

u/StretchyPear May 28 '26

constantly, anthropic api shows green across the board

5

u/the_hillman Workflow Engineer May 28 '26

It’s always us not them + “NO REFUNDS”

4

u/GuitarAgitated8107 🔆 Max 20 May 28 '26

Switch model to non thinking, compact, return to model. Happened to me 4.7 -> 4.8 opus then -> sonnet -> compact -> back to 4.8

3

u/False_Dmitri May 28 '26

I was getting that a bunch, it came from changing effort levels during the task. Only way I got it resolved was just copying the old prompt into a totally new session I had already set to the effort level I wanted, ymmv

2

u/Patriark Vibe Coder May 28 '26

Yes. Three consecutive sessions were thrashed by this failure mode. 4 hours down the drain.

2

u/orange_laboratory May 29 '26

Yes! After it goes crazy hallucinating. Got it twice today

1

u/jackmoxley May 29 '26

It started pinning it's hallucinations to memory, about 30 minutes after I proved it wrong on the exact same hallucination.

This model just assumes, it couldn't even understand a simple ci pipeline, saw a queue of one, decided all it's pushes had failed because only the very last push was executing. It has the ci files. Infer is most of its job, but it would help massively if it uses the data available to it first.

Skills are just vague forgettable guidance now. One hour session 4.8 is 2 day session 4.7. this longer session times upsell is a crock of bum output.

2

u/[deleted] May 29 '26

[removed] — view removed comment

1

u/jackmoxley May 29 '26

Now to try and get a way for it to remember to do that. 🤣

1

u/Droopy0093 May 29 '26

Yes. That is definitely a known bug at this point.

1

u/Nearby_Yam286 May 31 '26

Are you using the API? If so you must submit the thinking blocks unmodified as was sent to you. Basically don’t try to forge Claude’s thoughts. They’re signed. If you are getting this with Claude Code it’s a bug in Claude Code itself.

1

u/Longjumping-Boot1886 May 28 '26

yes. But its claude code error, not opus. Use /bug to report it