AI Model Reviewer

LongCat 2.5 Preview in OpenCode 1.18.32

skills off

← Open in the gallerySame prompt, all models

Poster frame of LongCat 2.5 Preview's page
Open the original page

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).

ErrorGPU fluid simmax effortNeutral harness

Wall time 32m 02sCost $0 reported

Snapshot 4 of 4 saved during LongCat 2.5 Preview's run
  1. Snapshot 1 of 4 saved during LongCat 2.5 Preview's run
  2. Snapshot 2 of 4 saved during LongCat 2.5 Preview's run
  3. Snapshot 3 of 4 saved during LongCat 2.5 Preview's run
  4. Snapshot 4 of 4 saved during LongCat 2.5 Preview's run
Still snapshots saved during the run (no motion recording): 4 distinct frames.

Generation timelapse

Poster for generation timelapse

Generation timelapse (the agent's screen during the run, sped up). This is not the finished video. Download video (852 KB).

Review

No verdict yet.

The full review

Error. The harness ended the turn with an error (APIError: Upstream request failed: Endpoint is unavailable.); cause unknown, not counted against the model.

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.

  1. Attempt 1 Error this run32m 02s$02026-09-26
  2. Attempt 2 Stopped by us the cell's result14m 26s$02026-09-26

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, 664 characters. Every result for this prompt

Build a GPU-accelerated fluid simulation in a single HTML file using WebGL, no external libraries. Dragging the mouse or a finger should push colorful dye through the fluid, with a soft glow. Make it look stunning and run smoothly.

Build it as a self-contained index.html in the current directory, with WebGL/WebGL2 shaders you write yourself; no libraries and no CDNs; interactive with mouse or touch input. 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

Wall time 32m 02sFirst artifact at 9m 23s27 saved versions

Versions saved during the run

27 intermediate outputs, in the order the model wrote them.

Version 27 of 27
  1. Version 1 at 9m 31s thumbnailv1 9:31
  2. Version 2 at 11m 48s thumbnailv2 11:48
  3. Version 3 at 11m 58s thumbnailv3 11:58
  4. Version 4 at 12m 08s thumbnailv4 12:08
  5. Version 5 at 12m 18s thumbnailv5 12:18
  6. Version 6 at 12m 29s thumbnailv6 12:29
  7. Version 7 at 14m 11s thumbnailv7 14:11
  8. Version 8 at 14m 42s thumbnailv8 14:42
  9. Version 9 at 15m 58s thumbnailv9 15:58
  10. Version 10 at 16m 19s thumbnailv10 16:19
  11. Version 11 at 16m 29s thumbnailv11 16:29
  12. Version 12 at 16m 54s thumbnailv12 16:54
  13. Version 13 at 17m 05s thumbnailv13 17:05
  14. Version 14 at 17m 15s thumbnailv14 17:15
  15. Version 15 at 18m 32s thumbnailv15 18:32
  16. Version 16 at 18m 47s thumbnailv16 18:47
  17. Version 17 at 19m 03s thumbnailv17 19:03
  18. Version 18 at 19m 13s thumbnailv18 19:13
  19. Version 19 at 20m 30s thumbnailv19 20:30
  20. Version 20 at 20m 40s thumbnailv20 20:40
  21. Version 21 at 20m 50s thumbnailv21 20:50
  22. Version 22 at 21m 06s thumbnailv22 21:06
  23. Version 23 at 22m 34s thumbnailv23 22:34
  24. Version 24 at 22m 44s thumbnailv24 22:44
  25. Version 25 at 26m 34s thumbnailv25 26:34
  26. Version 26 at 26m 54s thumbnailv26 26:54
  27. Version 27 at 27m 10s thumbnailv27 27:10

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 8.4 MB; it is published as a scrubbed, compressed download rather than shown on the page.

Show all 122 steps

Loading the timeline…

Download the full transcript OpenCode session export, 75 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 $0, as reported by OpenCode (its own bill for the run).

Tokens by typeTokens$ per 1MCost
Input (uncached)92,399n/an/a
Cache write0n/an/a
Cache read3,785,856n/an/a
Output60,395n/an/a
Total computed from tokens
unknown
Total reported by the harness
$0

OpenCode 1.18.32 reported its own total; token counts x list prices shown beside it. No list price for longcat-2.5-preview-free in config/prices.json; no estimate computed. The harness reports reasoning tokens separately from output; here output includes them (29,031 visible + 31,364 reasoning), and both bill at the output rate.

Run notes

one prompt, agentic harness (self-review allowed)labelled re-run (of gpu_fluid_sim__opencode__longcat-2.5-preview)

  • frozen prompt (written): engine/prompts_written/gpu_fluid_sim.txt: Voxyz's own prompt verbatim (x.com/Voxyz_ai/status/2103088468762960378) + our fixed inputs (self-contained index.html, own WebGL/WebGL2 shaders, no libraries/CDNs, mouse/touch input) (supervisor 725c3fc2 05:53Z; zero results)
  • plain OpenCode config copy (providers only; no ECC instructions/agents)
  • opencode export written to a file (not piped)
  • Mode: interactive TUI in tmux (160x48), inside bubblewrap sandbox
  • Isolation audit: outside paths seen