Claude Fable 5 (max) vs GLM-5
Should you write with Claude Fable 5 (max) or GLM-5? 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 82.8.
The verdict
Before you settle on GLM-5, know that GLM-5.3 sits far higher on this board, so look there before anything else if an open-weights GLM is what you're after. Against Claude Fable 5 (max effort + 4.8 fallback), GLM-5 is #66 against #5, a 700-point Elo gap. The biggest single miss is length, about fifteen points behind on Length Adherence. Flow is the other one: about nine points on Continuity & Emotion, a heavier metric in the rubric. So its scripts run off target and score lower on how each section leads into the next. GLM-5 does win on cost, about five cents per script against two and a half dollars, with open weights. For heavy-edit drafting it works. For a finished script, Fable.
Pick Claude Fable 5 (max effort + 4.8 fallback) for scripts that need to hit their length and flow without heavy edits.
Pick GLM-5 for very cheap open-weights drafting when you already run it and expect to edit.
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 GLM-5, 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, Continuity & Emotion does the most to put Claude Fable 5 (max) ahead: it leads there by 8.9 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 50x as much per script as GLM-5.
| Claude Fable 5 (max) | GLM-5 | |
|---|---|---|
| Overall / 100 | 89.7 | 82.8 |
| Writing Elo | 2392 | 1692 |
| Score spread across drafts (± overall std) | 1.360 | 2.400 |
| Cost per script (USD) | 2.522 | 0.050 |
| Avg time per script (min) | 9.1 | 3.1 |
| Open weights | No | Yes |
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) · GLM-5. The whole scoring pipeline is on the methodology page.
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