Kimi K3.1 Pro built a giant cat fight for $5.08, Sonnet cost 3x more

Yana Lialuke 29 Oct 2026 4 min read

models

Kimi K3.1 Pro built a giant cat fight in a city for $5.08, the cheapest of four models. Claude Sonnet 5.5 made the furriest cats and the best ending, at about $17, more than 3x the price. Two giant cats fight over a 2-storey ball of yarn until their giant owner shows up and chases them off.

The setup

All four models got the same brief and built the scene in three.js, entirely in code.

Models: Claude Sonnet 5.5, Kimi K3.1 Pro, GLM 5.3 Prime, Mistral Large 4
Kimi, GLM and Mistral through OpenRouter, Sonnet through a Claude subscription
One scene in plain HTML and three.js, no images or 3D models
Test date: Oct 28, 2026

Each model first built a city avenue with glass towers, cars, bus stops and people, and improved it over several rounds. Then each one rewrote its own scene into the cat fight.

The brief

The scene is 35 seconds of cartoon slapstick in the spirit of Tom and Jerry, with no blood and nobody hurt.

A close-up of the ginger cat's face: it blinks and its pupils go wide, then it steps back to reveal a tuxedo cat and the ball of yarn
Both cats wiggle and pounce at the same time and crash into each other
They bat the yarn back and forth like a pinball, through a bus stop, trees and cars, while people run
One cat gets tangled in the thread, the other jumps on top
The ginger cat stops and sharpens its claws on a glass tower, while the tuxedo cat licks its paw
The owner arrives, seen only from the knees down: slippers, a dress hem and a broom. The cats freeze with their fur on end
She chases them away, and her slipper taps next to the abandoned yarn

Four 3D city scenes from code with giant cartoon cats and a huge red ball of yarn among glass skyscrapers — The opening: the cats and the ball of yarn

The numbers

Kimi's, GLM's and Mistral's costs are what OpenRouter billed, failed attempts included. Sonnet ran on a subscription, so its cost is an estimate from its tokens at the API price. The totals cover every round, from the empty city to the cats, and the times are approximate.

Model	Cost, all rounds	Time, all rounds	Cat round alone
Kimi K3.1 Pro	$5.08	~2h 16m	$0.86
Mistral Large 4	$6.24	~4h 08m	$1.30
GLM 5.3 Prime	$9.58	~1h 55m	$3.62
Claude Sonnet 5.5	~$17.01	~1h 55m	~$1.85

Kimi rewrote its scene into cats in one answer: 17 minutes and $0.56, plus $0.30 for the new opening. GLM's first attempt spent its whole budget on reasoning and returned nothing, and Mistral's answer was cut off by the length limit. Both had to start again with one file per answer.

Four cat fights

Four 3D scenes of a ginger cat and a tuxedo cat pouncing at each other over a giant red yarn ball on a city avenue — The pounce

Four 3D scenes of a giant ginger cat scratching a glass skyscraper, with cracks across the facade and falling glass — Claws on the tower

Four 3D scenes of giant legs in pink slippers and a dress hem walking down a city avenue as the cats run — The owner arrives

Claude Sonnet 5.5 – the furriest cats, with whiskers and fluffy tails, the tangle in the thread and the best ending: the owner's pink slippers next to the yarn
Kimi K3.1 Pro – every beat of the script is there, but the cats are built from capsules, and the camera often sits right against a cat's body
GLM 5.3 Prime – the cats look like segmented caterpillars. The opening shows a blurry ear instead of a face, and the ending is a plain red or green screen, with the camera stuck inside the yarn or a tree
Mistral Large 4 – cartoon cats with huge yellow eyes, the owner in a polka-dot dress and a broom. Its first version showed an empty blue frame for 16 seconds

Sonnet's cats look the most like cats. Kimi gets the whole script on screen for the lowest price.

Our take

Kimi K3.1 Pro is the price pick: $5.08 for the whole job and under a dollar for the cat round. Every beat of the script is in place. Sonnet 5.5 is the quality pick, with cats you would recognize, at more than 3x the price. GLM 5.3 Prime cost nearly twice as much as Kimi and ended on a blank screen.