Fugu Ultra v2 vs Claude Fable 5.1
Fugu Ultra v2 took 22 min 51 s and $4.66 at list price, Claude Fable 5.1 took 5 min 38 s and $1.42 at list price. Fugu Ultra v2 took 4.1× as long and cost 3.3× as much.
Fugu Ultra v2
Sakana AI · $30.00/M out · 7 HN pts
Claude Fable 5.1
Anthropic · $50.00/M out · 1,630 HN pts
Only Claude Fable 5.1 has CLI runs here (Claude Code).
Breakout
Make a Breakout game I can play right now with the keyboard or the mouse. Give it several levels, a score and some juice.
Specs and numbers
| Fugu Ultra v2 | Claude Fable 5.1 | |
|---|---|---|
| Maker | Sakana AI | Anthropic |
| Made in | Japan | US |
| Released | 11 Sep 2026 | 1 Sep 2026 |
| Price in, per M tokens | $5.00 | $10.00 |
| Price out, per M tokens | $30.00 | $50.00 |
| Context | 1,000,000 tokens | 1,000,000 tokens |
| Weights | closed | closed |
| Hacker News points | 7 | 1,630 |
| Time for the one prompt | 22 min 51 s | 5 min 38 s |
| List price of the one prompt | $4.66 | $1.42 |
Claude Fable 5.1 was cheaper: $3.24 less at list price. Claude Fable 5.1 was faster: 17 min 13 s less in total.
In the recording, Fugu Ultra v2's Breakout game plays; Claude Fable 5.1's stopped painting. Fugu Ultra v2 has no pelican: not run yet. Fugu Ultra v2 has no watch: not run yet. Fugu Ultra v2 has no landing page: not run yet. Fugu Ultra v2 has no logo: not run yet. Fugu Ultra v2 has no About page: not run yet.
Rebuild this screen experiment: Claude Fable 5.1's rebuild matched the screenshot at 78%; Fugu Ultra v2 was not in it. Tea Garden experiment: Claude Fable 5.1's game passed 5 of 5 checks; Fugu Ultra v2 was not in it.