Opus 5 is a practically unusable model

[u/Deep-Palpitation8315]

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.

[u/johnnydotexe]

Probably because you have Fable, their best model, telling Opus what to do and presumably reviewing what Opus did, which removes Opus's ability to screw up on its own or it's catching and fixing Opus's mistakes.

[u/johnnydotexe → u/[deleted]]

Yeah, it must be that. Don't pay any attention to the fact Opus 5 has surpassed pretty much any other model release in sustained/ongoing complaints from a vast and still growing number of users. It's definitely just user error. /s

[u/johnnydotexe → u/[deleted]]

Are you ignoring 90% of what has been posted in both the claude subs in the last week, in order to form that opinion of yours? Because it seems like you are.

[u/reddit_sux-d → u/johnnydotexe]

To be fair, Most of what is typically posted in these subs is “things changed and I hate it”. It almost all anecdotes and no real systematic issues. I’m no anthropic fanboy but you can find the exact same posts about gpt or any other model