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Model drop Nov 9, 2026 Revision 1 3 arms · 1 attempts each

Who can teach a pelican to juggle?

One prompt, one run each: a pelican riding a unicycle while juggling three bowling pins, built in three.js. Fable 5.2 against GPT 6 Astra and Opus 5.5.

The pelicans

Recordings loop. See live demo opens the real build in a new tab.
Our take

Any one of these would have been impressive at any other moment in history. Side by side, Fable 5.2 is the winner.

On looks alone it is close to a tie. All three are silly renditions of a pelican. Fable's is slightly more detailed, but none of them would clear a professional animator's bar.

The win comes from motion. Fable's pelican is the most expressive and animated, and its juggling and balancing are the most convincing. That is what the task asked for, and it came through.

Opus 5.5 wins on value. Its pelican is of similar quality, slightly less animated, and it cost $4.44 against Fable's $6.48. GPT 6 Astra passed every gate too, at $12.03 and 49 minutes.

This is one run each, so treat it as a first read. Watch all three and be the judge.

Our pick: Fable 5.2 (Vanilla) · editorial judgment

Our picks

Editorial judgment, after watching every build
  • Best in motion
    Fable 5.2 Vanilla

    The most expressive pelican, with the most convincing juggling and balance.

  • Best value
    Opus 5.5 Vanilla

    A similar pelican for $4.44, the cheapest of the three.

Highlights

What we found worth comparing
FactFable 5.2 VanillaGPT 6 Astra VanillaOpus 5.5 Vanilla
Cost$6.48$12.03$4.44
Time30 min49 min33 min
Reasoning effortFable's was lowered so its thinking fits the output limitMedium, set by the benchModel defaultModel default
App codeexcludes tests and config1,308 lines, 4 files761 lines, 3 files1,534 lines, 6 files
Tests it wrote236 lines258 linesNone
Shipped sizeJavaScript, gzipped140 KB145 KB155 KB

Side by side

One run per arm
MetricFable 5.2VanillaGPT 6 AstraVanillaOpus 5.5Vanilla
Outcome
Workspassed the gate1/11/11/1
Said done, was broken0/10/10/1
Our pickYes··
Economics
Cost per working pelicanincludes failed attempts$6.48$12.03$4.44
Total costone run$6.48$12.03$4.44
Wall time30m 16s49m 26s32m 58s
Effort
Tokens in / out3.6M / 50k4.8M / 49k8.1M / 51k
Turns111
Tool calls5414682
Code
App codeexcludes tests, config, and lockfiles1,308 lines, 4 files761 lines, 3 files1,534 lines, 6 files
Largest fileone long file is harder to change590 lines375 lines492 lines
TypeScript0/10/10/1
Test codewritten by the agent236 lines258 lines0 lines
Has npm testtests run without the Workbench1/11/10/1
Setup
Modelanthropic/claude-fable-5-2openai/gpt-6-astraanthropic/claude-opus-5-5
Workbenchwb-benchmarks/vanilla-fable-5-2 0.1.1wb-benchmarks/vanilla-gpt-6-astra 0.1.0wb-benchmarks/vanilla-opus-5-5 0.1.1

Works means it builds to a static site, loads in a headless browser with WebGL or WebGPU, draws a real scene, and survives 60 seconds of mouse and touch drags without crashing or freezing. Cost is model spend only and includes failed attempts. Our pick is our call, not a score.

Pinned setup

Everything needed to rerun it
# Task prompt, identical for every arm
Build a single full-screen web page: a real-time 3D scene, in three.js, of a pelican riding a unicycle while juggling three bowling pins. The pelican is the whole point. It should be unmistakably a pelican at a glance: the long bill with its throat pouch, the heavy body, the webbed feet on the pedals.

Everything moves, and the motion has to hold together. The pelican pedals, and the wheel turns at the rate the pedals and the ground say it should. It keeps its balance the way a unicyclist does, with small corrections forward and back, never perfectly still. The pins leave one wing, tumble end over end through a believable arc, and land in the other, in a steady juggling pattern that never drops a pin and loops forever without a visible seam. Wings, head, and body react to the throws and catches.

Model and animate everything in code. No downloaded 3D models, textures, or animation files. Give it a simple setting of your choosing, with real lighting and shadows, that suits the act. The camera frames the whole act and drifts slowly around it on its own; dragging with a mouse or a finger orbits it.

No other content is needed beyond, at most, one small unobtrusive title.

Requirements:
- A working web project in the workspace root that installs and builds to a static site with a standard JavaScript package manager, and runs in a modern browser.
- Works on desktop and phone widths. With prefers-reduced-motion, show a still, attractive frame of the act.
- Smooth on an ordinary laptop. No multi-megabyte downloads before first paint.

Nobody will be around to answer questions while you work, so don't wait for input: make the best call yourself and keep going. When done, report how to run it, what you verified and how, and anything you could not verify.
Starting point
pompeii-labs/workbenchmarks-fixtures@41eb9e6
Gate
Builds a static site, Loads in a headless browser with WebGL or WebGPU and no errors, Draws a real scene, not a blank or flat canvas, Survives 60 seconds of mouse and touch drags
Attempts
1 per arm, no retries, no cherry-picks
Runs
3 scored
Generated
2026-11-09

Revisions

  1. Nov 9, 2026Revision 1. First run: 3 arms, 1 run each. Fable 5.2's first attempt spent its whole 32,000 token output limit thinking and wrote no files, so it was voided and rerun with reasoning effort set to medium. The voided attempt cost $1.45 and is not counted.

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