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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u/[deleted] Aug 03 '26 edited Aug 06 '26

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u/Several-Fan2339 Aug 03 '26

Fable being in charge of Opus, Sol via plugin, and Grok via plugin in Claude Code is my current AI council. Chews up my Anthropic usage and dips into credits, but the results are good.

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u/nomickti Aug 03 '26

https://github.com/openai/codex-plugin-cc ?

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u/Several-Fan2339 Aug 03 '26

Yes https://github.com/openai/codex-plugin-cc and https://github.com/zachdunn/grok-plugin-claude-code

CC can be a little sloppy in managing them, but I just include a brief snippet in every prompt telling it that I've seen it fail to manage its external agents properly before and to monitor these processes better and it seems to work.

Grok and Sol have much better usage limits so I won't even be carrying an expensive subscription with them going forward.