Model Comparison
Claude Fable 5 vs Claude Sonnet 5
Claude Fable 5 (max effort, Opus 4.8 fallback) leads Claude Sonnet 5 (max effort) by 380 Elo, and their 95% ranges sit 282 Elo apart. Even Claude Fable 5's lowest-rated configuration, Claude Fable 5 (high), ranks above Claude Sonnet 5 (max effort). Among 78 models, each ranked by its best configuration, Claude Fable 5 is #6 and Claude Sonnet 5 is #23. Cost per script: $3.20 for Claude Fable 5 (max effort, Opus 4.8 fallback) and $0.696 for Claude Sonnet 5 (max effort).
Last updated , from board data generated at 01:13 UTC.
Picks and Verdict
PickClaude Fable 5
Claude Fable 5 (high)
Pick Claude Fable 5 (high) as the main writer at $1.34 a script, 297 Elo above Sonnet's best and done in under five minutes.
PickClaude Sonnet 5
Claude Sonnet 5 (high)
Pick Claude Sonnet 5 (high) when the budget decides, at $0.121 a script and about two minutes a draft.
Two Claude models, and both Fable settings sit above both Sonnet settings with ranges that never touch. Ranked by best setting, Fable is the #6 model of 78 and Sonnet 5 the #23 model. I'd use Claude Fable 5 (high). It sits 297 Elo above Claude Sonnet 5 (max effort), costs $1.34 a script against $0.696, and finishes in less than half the time. You pay about twice as much, and you get the stronger script sooner. Claude Fable 5 (max effort, Opus 4.8 fallback) adds 83 Elo on top, but the two Fable ranges overlap, so the board cannot separate them, and max costs more than twice as much as high. Sonnet gains more from thinking, 207 Elo from high to max effort, and its max effort drafts land closest to the requested length of anything here. It still ends well short of Fable's cheaper setting. Claude Sonnet 5 (high) costs $0.121, about an eleventh of Fable at high, and its drafts swing a lot. If twelve cents a script is your ceiling, Sonnet at high works. Otherwise I'd go straight to Fable at high.
Disclosure: both models come from the same lab as one of the four judges, Claude Opus 5.5. The other judges sit outside that lab, so neither is scored by its own lab alone (how the panel works). The judge analysis measures how much each judge favors its own lab.
How to Read the Writing Score, Writing Elo and 95% Ranges
Writing Score and Writing Elo. The Writing Score (0 to 100) is the weighted average of the nine metric scores: seven from the judges, Length Adherence from code and the Slop Score half from each. The Writing Elo is a rating from pairwise comparisons: on each script, each configuration's average across its drafts is compared with every other configuration's, and gaps within the draft-to-draft variation count as draws. Elo rewards winning often, so the two can put configurations in a different order.
Elo ranges. Each 95% range shows how far a configuration's Elo could move if the drafts had come out slightly differently. It comes from resampling every configuration's recorded draft scores on each reference script and ranking again. Comparing two separate ranges does not test the Elo gap between them: ranges far apart are strong evidence for the order, and overlapping ranges do not mean a tie. The reference scripts stay fixed, so the ranges say nothing about new scripts. The methodology page has the full description.
All Thinking Levels of Both Models
Every ranked configuration of Claude Fable 5 and Claude Sonnet 5, scored on the same 10 scripts by the same four judges.
- Each row is one configuration: the model at one thinking level. The dot is its Writing Elo, a rating from pairwise comparisons of the scores on each script, and the bar is its 95% range: how far that Elo could move if the drafts had come out slightly differently.
- When two bars overlap, the board cannot order those two configurations. Bars far apart are strong evidence for the order.
- The table under the chart lists the same configurations in the same order and adds the Writing Score (the 0 to 100 consensus of the judges and code), cost, time and configuration rank (the place among all configurations on the board).
Shaded rows are the configurations chosen for the metric comparison below.
| Configuration | Writing Elo | 95% Range | Writing Score | Cost / Script | Time / Script | Configuration Rank |
|---|---|---|---|---|---|---|
| Claude Fable 5 (max effort, Opus 4.8 fallback) | 2239 | 2186 to 2298 | 82.9 | $3.20 | 12.5 min | #12 |
| Claude Fable 5 (high) | 2156 | 2102 to 2204 | 81.9 | $1.34 | 4.9 min | #22 |
| Claude Sonnet 5 (max effort) | 1859 | 1812 to 1904 | 79.2 | $0.696 | 12.0 min | #45 |
| Claude Sonnet 5 (high) | 1652 | 1602 to 1703 | 76.6 | $0.121 | 1.9 min | #58 |
Cost is one script at the API list price of the route used, uncached and without judging. Time is the average for one accepted script, retries included.
Computed Findings Across Thinking Levels
Each finding is computed from the configurations above. Where two 95% ranges overlap, the board cannot order those two configurations.
- Best Configurations Head to Head. Claude Fable 5 (max effort, Opus 4.8 fallback) leads Claude Sonnet 5 (max effort) by 380 Elo, and their 95% ranges do not overlap (2186 to 2298 against 1812 to 1904), which is strong evidence for that order.
- Every Claude Fable 5 Configuration Ranks Higher. Both Claude Fable 5 configurations rank above both Claude Sonnet 5 configurations: the lowest-rated, Claude Fable 5 (high) at Elo 2156, still beats Claude Sonnet 5 (max effort) at Elo 1859. Their 95% ranges do not overlap.
- Lowest Thinking Levels Head to Head. At their lowest thinking levels, Claude Fable 5 (high) at Elo 2156 and $1.34 per script leads Claude Sonnet 5 (high) at Elo 1652 and $0.121 per script by 504 Elo. Their 95% ranges do not overlap.
- Same Level Name, Side by Side. Claude Fable 5 has the higher Writing Elo at every level name both models use: high and max. The 95% ranges do not overlap at any of them. Level names come from each provider, so the same name does not promise the same reasoning budget.
- Cheapest Configuration Overlapping the Top One. Claude Fable 5 (high), at $1.34 per script, is the cheapest configuration whose 95% range overlaps that of Claude Fable 5 (max effort, Opus 4.8 fallback), at $3.20 per script: 2102 to 2204 against 2186 to 2298, so the board cannot separate them. Claude Fable 5 (max effort, Opus 4.8 fallback) costs about 2.4 times as much per script.
- Cheapest Claude Fable 5 Configuration Above Claude Sonnet 5's Best. The cheapest Claude Fable 5 configuration with a higher Writing Elo than Claude Sonnet 5 (max effort), at Elo 1859 and $0.696 per script, is Claude Fable 5 (high), at Elo 2156 and $1.34 per script. It costs about 1.9 times as much per script.
- Lowest to Highest Thinking Level. Claude Fable 5 moves +83 Elo from high to max effort, at about 2.4 times the cost per script. Claude Sonnet 5 moves +207 Elo from high to max effort, at about 5.8 times the cost per script.
Writing Elo at Each Shared Level Name
| Level | Claude Fable 5 | Claude Sonnet 5 | Gap | 95% Ranges |
|---|---|---|---|---|
| high | 2156 | 1652 | +504 | Separate |
| max | 2239 | 1859 | +380 | Separate |
Gap is Claude Fable 5 minus Claude Sonnet 5 at the same level name, using each model's highest-rated configuration at that level.
Two Chosen Configurations Compared
Pick one configuration of each model to compare their metric scores, consistency across drafts and per-script scores. Each menu starts on the model's best configuration.
Scores by Metric
Claude Fable 5 (max effort, Opus 4.8 fallback) scores higher on eight of the nine metrics and Claude Sonnet 5 (max effort) on one. Weighted by each metric's share of the Writing Score, Tone & Voice Match does the most to put Claude Fable 5 (max effort, Opus 4.8 fallback) ahead, with a 5.6-point lead on that metric. The weight beside each metric is its share of the Writing Score.
Consistency Across Drafts
| Claude Fable 5 (max effort, Opus 4.8 fallback) | Claude Sonnet 5 (max effort) | |
|---|---|---|
| Score spread across drafts (±) | 1.96 | 2.39 |
| Lowest script score | 81.2 Script 8 | 75.7 Script 4 |
| Highest script score | 86.4 Script 7 | 81.5 Script 9 |
| Range across scripts | 5.2 | 5.8 |
Spread is how much the Writing Score moves between a configuration's drafts, and lower is steadier. Green marks the better number in each row.
Scores by Script
Writing Score on each reference script. Gap is Claude Fable 5 (max effort, Opus 4.8 fallback) minus Claude Sonnet 5 (max effort), and the higher score is in bold.
| Script | Claude Fable 5 (max effort, Opus 4.8 fallback) | Claude Sonnet 5 (max effort) | Gap |
|---|---|---|---|
| Script 1 opinion / warning explainer | 83.1 | 77.4 | +5.7 |
| Script 2 news-analysis / skeptical explainer | 83.7 | 78.9 | +4.8 |
| Script 3 personal roadmap / opinion | 81.6 | 78.1 | +3.5 |
| Script 4 short explainer | 81.6 | 75.7 | +5.9 |
| Script 5 news-analysis / opinion explainer | 82.5 | 80.9 | +1.6 |
| Script 6 founder announcement / personal origin story | 82.9 | 81.1 | +1.8 |
| Script 7 personal technical walkthrough / agentic workflow case study | 86.4 | 81.2 | +5.2 |
| Script 8 product release announcement / personal observation | 81.2 | 79.3 | +1.9 |
| Script 9 career guide / hiring analysis | 83.2 | 81.5 | +1.7 |
| Script 10 engineering process walkthrough / presentation adaptation | 82.8 | 78.0 | +4.8 |
Scorecards and Thinking Pages
Each configuration name in the table above opens its own scorecard.
Compare With Another Model
Pick a second model. A pair with its own written match-up opens that page, and any other pair opens in the comparison tool.
Nearby Match-Ups by Best Writing Elo
Every configuration wrote five drafts for each of the same 10 briefs, from the same prompt. Generation was closed-book, with the prompt as the only source and no web search or other tools. Each judge scores every draft once: Claude Opus 5.5 at medium effort through the Claude Code subscription, GPT-6.1 Sol at medium reasoning through the Codex CLI, GLM 5.3 Flash through OpenRouter, and Jev 1.13, a typed judge from TypeSafe that answers each metric as a multiple-choice question. The channel's finished script is their reference for the voice, and it gets no score on the board itself.
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