Claude Fable 5 (max) vs Gemini 3.1 Pro (default)
Should you write with Claude Fable 5 (max) or Gemini 3.1 Pro (default)? On this page the only thing that changes is the model. Both wrote their own version of the scripts behind 10 of my What's AI videos, five drafts per script, and three judges from three model families scored every draft blind, with my finished script as the reference. Claude Fable 5 (max) leads overall, 89.7 to 80.1.
The verdict
Gemini 3.1 Pro (default) falls behind here mostly on voice. It trails Claude Fable 5 (max effort + 4.8 fallback) by about eleven points on Tone & Voice Match, the heaviest metric in the rubric, and by even more on Length Adherence. Put together, that's #94 against #5, a 926-point Elo gap, and Gemini doesn't take a single metric in this pairing. It is much cheaper, about fourteen cents per script against two and a half dollars, and much faster, around a minute and a quarter instead of nine. So I'd only reach for it if Gemini is already your stack and you plan to rewrite the voice yourself.
Pick Claude Fable 5 (max effort + 4.8 fallback) when the script has to match a real person's voice.
Pick Gemini 3.1 Pro (default) if you're already building on Gemini and need fast, cheaper scripts you'll rewrite.
How to read these numbers
Overall vs Elo. Overall is the weighted rubric score. Elo compares each model's five-draft average with every other model's, script by script, and counts gaps inside run-to-run noise as draws, so it rewards winning often and can disagree with overall. My own scripts score 90.9 on the same rubric, not a literal 100. Right now 2 of 167 ranked configurations reach it. A model above that line writes at that level on this rubric. That's not the same as beating my script line for line.
Reading the Elo intervals. Each 95% range comes from resampling every model's recorded run scores on each task and re-ranking. Comparing these separate ranges does not test the Elo gap between two models: far apart is strong evidence, and overlap isn't a tie. The tasks stay fixed, so the ranges say nothing about new tasks (the long version).
Metric by metric: where the gap comes from
Blue is Claude Fable 5 (max), orange is Gemini 3.1 Pro (default), and the solid bar takes the metric. The weight under each name is how much it counts toward the overall. Weighted by how much each metric counts, Tone & Voice Match does the most to put Claude Fable 5 (max) ahead: it leads there by 11.1 points. If you care about one thing, say voice or length, go straight to that row.
Cost, speed, and consistency
Quality is half the decision. The other half is what each script costs you, how long you wait, and how often you get a bad draft. The lead has a price: Claude Fable 5 (max) costs about 18x as much per script as Gemini 3.1 Pro (default).
| Claude Fable 5 (max) | Gemini 3.1 Pro (default) | |
|---|---|---|
| Overall / 100 | 89.7 | 80.1 |
| Writing Elo | 2392 | 1465 |
| Score spread across drafts (± overall std) | 1.360 | 2.580 |
| Cost per script (USD) | 2.522 | 0.143 |
| Avg time per script (min) | 9.1 | 1.3 |
| Open weights | No | No |
Green wins the row, and for spread, cost and time, lower wins. Cost is one script at recorded list prices, uncached and without judging, so your real bill will differ. Spread is how much the overall score moves across a model's drafts, and time is the average time to get one accepted script, retries included.
Want the script-by-script detail? Full scorecards: Claude Fable 5 (max) · Gemini 3.1 Pro (default). The whole scoring pipeline is on the methodology page.
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