gpt astra vs fable 5.1 at goldberg machine

gpt 6 astra – openai, landed on @OpenRouter less then hour ago, provider pinned to openai
fable 5.1 – anthropic, shipped sep 1

we put the two models on one job: a rube goldberg machine in three.js that presses a button and detonates a bomb

the setup: one self-contained html file, three.js from a cdn, everything else procedural – no textures, no models, no physics engine, every collision hand-written. the hard part sits in the brief: a domino may only fall once the previous one actually touches it, checked by real overlap every frame, never by a timer. same rule for the hammer hitting the button and the button firing the bomb. one continuous camera, its speed driven by whatever is moving. we recorded both scenes frame by frame – 1200 frames, 60 fps, exactly 20 seconds – and stepped both by hand to read the telemetry.

- cost
#1 astra – $1.84
#2 fable – $29.16

- time
#1 astra – 9m 56s
#2 fable – 1h 12m

- tokens
#1 astra – 45k
#2 fable – 360k

- lines of code
astra – 881
fable – 744

observations:

• we told it what we saw and nothing else – no diagnosis, no patch. we never edit a model's code. round two ran the whole chain to the blast.

• both files are deterministic. two runs each, identical state to twelve decimals, and neither model reached for math.random.

conclusion: 15.8x cheaper and 7.2x faster, and it still took a second round to get the ball into the bucket!

watch the full test via link: