OhMyUnicorn experiment · 28 September 2026 · one prompt, one model, one shot each

Same prompt, same setup: Claude Sonnet 5.5 vs Opus 5.5

Claude Sonnet 5.5 came out today. We gave it exactly what Claude Opus 5.5 got in our planet test: the same prompt, the same notes to read first, the same tools, the same effort setting (high) and the same automatic check at the end. Each model wrote one self-contained Three.js page on its own, looked at screenshots of its work, fixed what it saw, and stopped. Only the model changed.

output a ThreeJS 3D cartoony/comics-like planet, with vibrant life on it: clouds, mountains, city buildings, cars and plane romaing it. It should be possible to orbit around and zoom and see the details. No harness is to be used
i would love to see something like this:

https://ohmyunicorn.com/labs/dream-loop/planet-gpt6/

Play both

Drag to spin, scroll or pinch to zoom. Each page has its own buttons to jump to a city.

Claude Sonnet 5.5 · Tiny World
Fullscreen ↗

Claude Opus 5.5 · Pocket Planet
Fullscreen ↗

Time and cost

Measured from each session's own log (every API call), priced at Anthropic list rates.

Model	Wall clock	API calls	Output tokens	List price
Claude Sonnet 5.5	10.8 min	10	31.8k	$0.96
Claude Opus 5.5	22.7 min	23	99.8k	$4.79

Sonnet 5.5 costs half as much per token as Opus 5.5 ($2 vs $4 per million input tokens, $10 vs $20 output) and it also wrote about a third as many tokens, most of the gap being thinking.

Opus 5.5 has also done this brief in a live Claude Code session: 14 minutes, $2.54, and a different planet. See that one here. The run above is the like-for-like one: the same saved starting point, replayed for each model.

Same camera, side by side

Left: Sonnet 5.5. Right: Opus 5.5. Captured by the same automatic check after each model said it was done.

both planets from far away — From afar. Sonnet goes for a bright toy world with round-road towns; Opus goes for a comic look with ink outlines, mountain ranges and islands.

both planets from another angle — Another angle. Sonnet's town reads best of the two; Opus has the cleaner coastline and planet rim.

both planets zoomed in — Zoomed all the way in. Neither shines here: Sonnet's camera ends up inside a building, Opus shows flat ground.

Our take

Sonnet 5.5 shipped a complete, working, playable world in half the time for a fifth of the price. It is cheerful and easy to read.
Opus 5.5 is closer to the "comics-like" ask and more carefully finished at the planet's edge.
Sonnet's rough spots: some clouds float far off the planet, a few rocks poke out of the rim, and the closest zoom goes inside a building.

What this does not show

One run each. Run it again and both planets would come out different.
Not blind. Both models read the same notes about what we liked in earlier planets before building.
No real-GPU frame rate measured, and not tested on a phone.
Needs internet: three.js loads from jsDelivr.

Made by OhMyUnicorn Forge: describe an app in plain words, get a live URL.