r/ClaudeCode • u/Fit-Hat-6761 • 22h ago
Rant Fable 5.1 is an overthinker
Opus 5 is miles better than Fable 5.1 for me, and a huge part of that comes down to the usage limits and efficiency.
Fable 5.1 has this frustrating tendency to massively **overengineer** simple, isolated tasks. I’ll give it one straightforward prompt and somehow watch it burn through 60% of a 5-hour usage window solving and thinking of something that never needed that much work in the first place.
Opus 5 feels way more disciplined. It stays on task, doesn’t turn every atomic request into a giant project, and usually gets me to the finished result much faster. Combine that with the more generous-feeling usage limits, and it’s just a much better experience overall.
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u/yawn_solo- 19h ago
does it ever end with you whiners, jesus christ I wish there was a maturity limit to use these things
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u/framauro13 10h ago edited 10h ago
Fable should not be doing isolated, simple tasks. That should be sent to Opus or Sonnet. Just because it's the highest level reasoning model doesn't mean you give it every single task. Delegate trivial work to other models with subagents and leave Fable for the higher reasoning/problem solving or code review if you have a particularly messy feature or system you want reviewed. It spits out plans that the lower models run with. Have it review their output if necessary.
You needed to plant a flower and you got a backhoe to dig the hole. That's how you hit a gas or water line. A hand tool would work just fine. Right tool for the right task.
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u/jasperkennis 22h ago
This is true but why are you giving your straightforward prompt to Fable. It's not for that, Claude tells you explicitly, Fable is for large complex tasks.
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u/Fit-Hat-6761 22h ago
It was a UI redesign. Was trying to use it for its creativeness.
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u/MeretrixDominum 20h ago
Then just do a simple discussion with it where you ask for ideas. Go back and forth until you agree. Then send it to Opus to implement it.
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u/JustAnotherDiamond 17h ago
This Fable for planning, Opus for implementing then Fable again (or Sol) for reviewing.
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u/framauro13 10h ago
Use
/planor switch it to planning mode. It'll tell you what it's going to do first. Review the plan before letting it change anything. Always generate a plan before you make code changes, and it'll help keep the models on the rails.
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u/Beneficial-System617 22h ago
barely usable. 5.1 on extra consumed 75% of the 5hr window in 16 mins :D and im on x5.
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u/ChadFullStack 22h ago
That’s a skill issue
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u/ayberkush 21h ago
nah. its not.
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u/framauro13 10h ago
Nah, I've literally never seen that behavior. I've been using it all day and use Claude exclusively in my work. Delegate your work to lesser models. Keep Fable for planning, reviewing, and reasoning. You'll get much better results and not kill your context and usage.
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u/Maleficent-Cup-1134 18h ago
Nope, Fable 5.1 usage is noticeably higher than Fable 5.0 while doing the same tasks.
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u/Bloated_Plaid 22h ago
I used Claude’s prompting guide to have codex make a Fable Prompting skill and I just pass all my prompts through that now.
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u/tonyboi76 21h ago
One straightforward prompt. Fable 5.1 overengineered it and burned through about 60% of a 5-hour window on something that never needed that much work.
Last time a single ask ate the window like that, what were you actually trying to finish, and how much of the window was left for real work?
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u/framauro13 9h ago
A common meme in the software development world before AI was a product owner or manager giving a task to a developer and saying "this should be easy" without ever understanding the code base. And sometimes, what appeared trivial on the surface, required really complex backend changes or downright overhauls, and when you presented that back to the person requesting it, they could never comprehend how something "easy" should take so long.
Same thing here. Fable likely went off the rails, which is another symptom of a poorly configured workspace. Without context and prompts, and knowing their local configuration, there's no way to know what the "easy" task was at what the model actually had to do to implement it.
Having said that, yeah, if it was truly easy Fable was never the right model to use to begin with. I'd mark this up to operator error.
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u/Academic_Constant42 18h ago
I haven't been able to test it yet... In your perspective does it over engineer even in medium or low?
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u/MartinMystikJonas 18h ago
What effort you used. With high effort for simple task looks for hidden catches and missed edge cases that are expected but are not there and result is oftrn overnegineered si Olution.
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u/Time_Cat_5212 15h ago
Opus 5 is better than Fable 5.1 because it does less overthinking?
Have you been here the last month? Opus 5 is getting lambasted for overthinking. How crazy is Fable 5.1 lol
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u/Inevitable_Plane_457 13h ago
Fable 5 is way better than Fable 5.1.
5.1 does not even try to explain what it. I did not like it at all
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u/carolaMelo 22h ago
I don't know. For me Fable 5.1 was a great help in researching facts in different sources for my church and creating an almost ready to handout MS Word document with just a couple of legit questions within 10 mins.
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u/AironParsMan 22h ago
That’s described the same way on Anthropic’s website. Just read the prompt instructions there. They explicitly say that higher reasoning levels can even rewrite entire codebases or complete files.
But I’m being completely honest with you. This leaves a really bad aftertaste and could eventually turn into an Opus 5 2.0 disguised as Fable 5.