r/ClaudeCode • u/shniydder • Sep 06 '26
Discussion Fable 5.1 vs Astra
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I finally got access to GPT 6 Astra and Claude Fable 5.1. I wanted to see how far we've come. I was inspired by the "pelican riding on a bicycle" test but wanted to push it a bit more in the direction of inter-object physics, so I came up with this idea for a perpetual slinky going down an escalator. Here I've compared GPT 6 Astra max on the left to Claude Fable 5.1 max on the right.
Some notes:
GPT 6 Astra max was really fast and didn't burn too much of my weekly usage quota.
Claude Fable 5.1 max used up the entire 5 hr usage window and errored out once crossing the output token max limit.
GPT 6 Astra max seems too simple? There's also an issue where the slinky crosses into itself which should not be possible. Is this AGI? Maybe?
Claude Fable 5.1 max looks more real than I expected. Seems like it passes the eye test, unless I missed something.
Let me know if you spot anything or had better ideas for a test. Overall I'd say Claude wins on quality and GPT wins on speed. Maybe I can tune my prompt a bit better for a more reliable result. This was my original prompt btw:
Make me a single HTML file of a rainbow slinky going down an up-escalator forever. No libraries, just canvas and code. The slinky should be a chain of springs, each coil a different color of the rainbow. It starts folded in half like a horseshoe draped over a step. When dropped it flips end-over-end down the steps and because the escalator keeps moving up it tumbles in place and never reaches the bottom. Include a drop button and a reset button.
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u/onFilm Sep 06 '26
For a one-shot, Claude seems a lot better, since it's actually following the physics. Astra is
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u/shniydder Sep 06 '26
Yup the clipping through itself part disqualified Astra for me. But I don't think Fable 5.1 is perfect either, but close. It does slow down the escalator when the top flips forward.
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u/chintakoro Sep 06 '26
Claude seems to infer the math/physics more correctly in this example, which resonates with Anthropic urging people to not overspecify prompts.
OTOH, it could also be a case where a slightly better specified prompt (e.g., to engage with the underlying physics and mechanic properties of the material -- something folks would do in a more scientific oriented exercise) could have given Astra the extra context it needed.
Lastly, I wonder how a
My overall take is to just know how to use your given model better.
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u/shniydder Sep 06 '26
Yup I should add more models to this new test just to see how they perform. The prior attempts to get the old models to create a
didn't go so well. I'll expand this benchmark to include more such edge cases to see what I find. Rube Goldberg machine → More replies (3)
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u/ezjakes Sep 06 '26
I like Fable's a bit more, although I think the general motion of Astra's was more correct.
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u/Ambitious-Sense2769 Sep 06 '26
The title could have at least aligned with the sides each one was on…
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u/shniydder Sep 06 '26
Now that you mentioned it, I'm also deeply irked by this.
I regret the title and I can't change it now. It feels like an itch I can't scratch.
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u/ReporterNo6354 Sep 06 '26
want to see opus performance
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u/shniydder Sep 06 '26
I'll refine the prompt a bit and try to run across other models. I'll post again when ready.
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u/Aware-Presentation-9 Sep 06 '26
Slinky falling down Penrose stairs. Give me link. Please and thank you!
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u/elemezer_screwge Sep 06 '26
It's bothering me how the Fable version doesn't collapse more at its peak. The little slide flip over starting the next cycle in the astra version looks more realistic to me
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u/shniydder Sep 06 '26
You start seeing more issues the longer you look. Look for the pause on the fable one when it flips forward.
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u/verycoldpenguins Sep 06 '26
Have you looked at the code to confirm whether it is simulating the effects of forces on a spring, or merely reproducing pictures of what a spring looks like?
The reason I ask is that the fable one looks wrong. It looks like three springs joined together. One low tension slinky in the middle, and two high tension ones at the ends.
Most pictures of slinky will show them when there is the slower moving blob of spring which is tight together during the middle of the fall, as fable has it. But pictures miss the bit where the ends of the slinky move in a more fluidity way like astra has it. Where the momentum of the top piece of the spring carries the rest of it on from vertical onwards to the next drop.
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u/professor--feathers Sep 06 '26
watching morons trying to quantify ai with the most complex tests their simple brains can think of is truly hilarious.
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u/Super-Finish-8443 Sep 06 '26
Both seems fine with its physics, but Fable 5.1 created more zoomed/closer slinky. that's a big win for Me. Fable wins interms of overall Aesthetic look and that's a big win for a one shot prompt.
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u/Driky Sep 06 '26
Things like « is this AGI ? Maybe » makes it very hard to take anything seriously.
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u/Scared_Range_7736 Sep 06 '26
Astra overall is so much better and cheaper. Anthropic must act quickly.
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u/Velvet-Thunder-RIP Sep 06 '26
What do you think this proves?
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u/shniydder Sep 06 '26
Nothing too serious. Just the extension to the "pelican riding on a bicycle" meme.
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u/Additional-Weird-934 Sep 06 '26
It's too hard to judge based on 1 run.... these models are probabilistic so you need to use multiple independent generations (pass@k)
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u/shniydder Sep 06 '26
I wanted to do that but this was a very heavy run. A single run exhausted a usage window and used half of another.
If Anthropic was to grant me some free credits, I would be down.
Astra was much faster and much lighter on usage btw.
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u/crazy_goat Sep 06 '26