Claude Opus 5.5 in Claude Code 2.1.280
skills off
The model's own page, run in a sandboxed frame only when you ask (a page that needs its own origin opens in a new tab on a separate demo site). Phones get a full-screen player capped at 1.5x pixel density (2x on larger screens) so it stays smooth; the original page runs uncapped. It starts in its auto-tour (T switches to play mode on a keyboard).
The model's code errors on load: Unary operator used immediately before exponentiation expression. Parenthesis must be used to disambiguate operator precedence
Wall time 43m 05sCost $6.94 reported
Generation timelapse
Generation timelapse (the agent's screen during the run, sped up). This is not the finished video. Download video (701 KB).
Review
No verdict yet.
The full review
Stopped by us. Stopped by us (box row cap reached (2856s); stopped by the box lane so the run ships as partial); not a model failure.
Attempt 1 of 2
Every try of this model in this harness on this prompt, oldest first. A later attempt is the cell's result: attempt 2.
- Attempt 1 Stopped by us this run43m 05s$6.942026-09-26
- Attempt 2 Stopped by us the cell's result2h 30m$24.212026-09-29
Scores
Not scored: only runs that finished on their own are scored.
Downloads
Files actually published for this run. Original output, site-made previews and post-run conversions are labelled separately.
The exact prompt
as run, 1,435 characters. Every result for this prompt
Build a single Three.js page with five physics scenes and a scene switcher (buttons or tabs) to move between them; each scene can be restarted. 1) An explosion in a desert: a blast with a fireball, smoke, sand and debris thrown outward and falling back under gravity, and a shockwave rippling across the dunes. 2) A tornado: a funnel of swirling dust and debris over flat land that picks up small objects and spins them upward. 3) A balloon pop: a rubber balloon inflates, stretches and bursts, its fragments flying off and settling. 4) A water drop fall: a drop falls into still water, making a splash crown, a rebound jet, droplets and spreading ripples. 5) A Newton's cradle: five steel balls on strings where the end ball swings in and its momentum passes through the row, with believable collisions and slowly damped swinging. Make the motion physically believable (gravity, momentum, collisions, damping), light each scene well and label it. Everything is built in code from Three.js geometry, shaders and materials; no external models or textures. Build it as index.html (plus any local asset files you create) in the current directory. Three.js may load from a pinned CDN. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own before finishing. Close any browser you open as soon as you've taken your screenshot.
How it was made
Versions saved during the run
5 intermediate outputs, in the order the model wrote them.
Step by step
The prompt, every agent turn and tool call (tool name and a one-line summary; inputs and outputs are not shown), then the final message. The full transcript is 8.8 MB; it is published as a scrubbed, compressed download rather than shown on the page.
Show all 50 steps
Loading the timeline…
Download the full transcript Claude Code session JSONL, 214 KB, gzip. Scrubbed: anything that looks like a key, token, e-mail address or phone number is replaced, and account details and the test machine's file paths are removed.
Cost breakdown
Headline cost $6.94, as reported by Claude Code (its own bill for the run). The list-price estimate from the token counts is $6.93.
| Tokens by type | Tokens | $ per 1M | Cost |
|---|---|---|---|
| Input (uncached) | 80 | $4.00 | $0.0003 |
| Cache write | 307,797 | $5.00 | $1.5390 |
| Cache read | 5,432,021 | $0.20 | $1.0864 |
| Output | 215,319 | $20.00 | $4.3064 |
| of which reasoning | 135,975 | billed as output |
- Total computed from tokens
- $6.9321
- Total reported by the harness
- $6.9391
- Difference
- computed $6.93 vs reported $6.94 (diff -0.01)
Claude Code 2.1.280 reported its own total; token counts x list prices shown beside it.
Prices: Project price table (vendor list prices), 2026-09-22.
Run notes
- frozen prompt (rewritten): engine/prompts_rewritten/threejs_space_bunny.txt: written by us from the recorded description (zero results)
- plain wave-1-equivalent cc_config copy (settings.json + .claude.json; no ECC files)
- Mode: interactive TUI in tmux (160x48), inside bubblewrap sandbox
- Context setting: 1M ([1m] model name)
- Isolation audit: outside paths seen