Claude Fable 5.1 scores 69.4 on the Respan Index (#4), ahead of Step 5 Preview at 54.9 (#12). Claude Fable 5.1 leads on 5 of the 5 benchmarks both report. Step 5 Preview is 14x cheaper per token at list price.
* Estimated: no published scores in that category. How the Respan Index works
| LMArena WebDev (LMArena) |
| 1749 |
| 1570 |
Higher is better. Each score links to where it was published.