Model Comparison
Claude Fable 5.2 vs Claude Sonnet 5.5
Claude Fable 5.2 (xhigh) leads Claude Sonnet 5.5 (max effort) by 177 Elo, and their 95% ranges sit 91 Elo apart. Among 87 models, each ranked by its best configuration, Claude Fable 5.2 is #2 and Claude Sonnet 5.5 is #3. Cost per script: $2.22 for Claude Fable 5.2 (xhigh) and $1.38 for Claude Sonnet 5.5 (max effort).
Last updated , from board data generated at 17:52 UTC.
Picks and Verdict
PickClaude Fable 5.2
Claude Fable 5.2 (high)
Pick Claude Fable 5.2 (high) over Sonnet's max effort, since their ranges overlap and it costs $1.22 a script and 4.0 minutes against $1.38 and 14.3.
PickClaude Sonnet 5.5
Claude Sonnet 5.5 (xhigh)
Pick Claude Sonnet 5.5 (xhigh) when the bill comes first, at $0.302 a script and 3.1 minutes, about a quarter of what Fable at high costs.
Speed decides this one for me. Claude Fable 5.2 (high) and Claude Sonnet 5.5 (max effort) sit 15 Elo apart, 2511 against 2496, and their 95% ranges overlap, though overlap alone does not test their difference. Fable at high costs $1.22 a script and takes 4.0 minutes. Sonnet at max costs $1.38 and takes 14.3. Best against best, Claude Fable 5.2 (xhigh) leads Sonnet's top setting by 177 Elo with ranges that don't overlap: the #2 model of 87 against the #3 model, each ranked by its best configuration. Sonnet has the steeper ladder, 766 Elo from low to max effort against Fable's 258 from low to xhigh, and Fable's max effort lands 27 Elo under its xhigh for about 2.6 times the price. Claude Sonnet 5.5 (xhigh) stays cheap at $0.302 and 3.1 minutes, but Claude Fable 5.2 (low) sits 153 Elo above it with separate ranges, at $0.460 and 1.4 minutes. Sonnet at max keeps small edges over Fable at high on substance, continuity, length and visual cues, each under half a point, and its drafts are steadier. I'd make Fable 5.2 at high my default, keep its xhigh for the scripts I record, run its low for volume, and leave Sonnet's max off.
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 5.2 and Claude Sonnet 5.5, 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.
- Each bar describes one configuration. Overlap alone does not establish a tie or decide their order. Comparing these ranges does not directly test the difference between a pair.
- 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 5.2 (xhigh) | 2673 | 2630 to 2717 | 85.6 | $2.22 | 7.4 min | #3 |
| Claude Fable 5.2 (max effort) | 2646 | 2599 to 2689 | 85.5 | $5.75 | 19.9 min | #4 |
| Claude Fable 5.2 (high) | 2511 | 2455 to 2555 | 84.8 | $1.22 | 4.0 min | #5 |
| Claude Sonnet 5.5 (max effort) | 2496 | 2435 to 2539 | 84.6 | $1.38 | 14.3 min | #6 |
| Claude Fable 5.2 (medium) | 2422 | 2370 to 2469 | 84.3 | $0.561 | 1.8 min | #11 |
| Claude Fable 5.2 (low) | 2415 | 2370 to 2454 | 84.1 | $0.460 | 1.4 min | #12 |
| Claude Sonnet 5.5 (xhigh) | 2262 | 2215 to 2299 | 83.2 | $0.302 | 3.1 min | #15 |
| Claude Sonnet 5.5 (high) | 1956 | 1908 to 1996 | 81.0 | $0.092 | 1.0 min | #35 |
| Claude Sonnet 5.5 (medium) | 1776 | 1734 to 1816 | 79.4 | $0.065 | 0.6 min | #62 |
| Claude Sonnet 5.5 (low) | 1730 | 1695 to 1765 | 78.9 | $0.061 | 0.7 min | #66 |
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. The 95% ranges describe individual configurations; overlap alone establishes neither a tie nor an order for a pair.
- Best Configurations Head to Head. Claude Fable 5.2 (xhigh) leads Claude Sonnet 5.5 (max effort) by 177 Elo, and their 95% ranges do not overlap (2630 to 2717 against 2435 to 2539), which is strong evidence for that order.
- Lowest Thinking Levels Head to Head. At their lowest thinking levels, Claude Fable 5.2 (low) at Elo 2415 and $0.460 per script leads Claude Sonnet 5.5 (low) at Elo 1730 and $0.061 per script by 685 Elo. Their 95% ranges do not overlap.
- Same Level Name, Side by Side. Claude Fable 5.2 has the higher Writing Elo at every level name both models use: low, medium, high, xhigh, 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 Claude Fable 5.2 Configuration Above Claude Sonnet 5.5's Best. The cheapest Claude Fable 5.2 configuration with a higher Writing Elo than Claude Sonnet 5.5 (max effort), at Elo 2496 and $1.38 per script, is Claude Fable 5.2 (high), at Elo 2511 and $1.22 per script. Their 95% ranges overlap. It costs less than the configuration it beats.
- Lowest to Highest Thinking Level. Claude Fable 5.2 moves +231 Elo from low to max effort, at about 13 times the cost per script. Claude Sonnet 5.5 moves +766 Elo from low to max effort, at about 23 times the cost per script.
Writing Elo at Each Shared Level Name
| Level | Claude Fable 5.2 | Claude Sonnet 5.5 | Gap | 95% Ranges |
|---|---|---|---|---|
| low | 2415 | 1730 | +685 | Separate |
| medium | 2422 | 1776 | +646 | Separate |
| high | 2511 | 1956 | +555 | Separate |
| xhigh | 2673 | 2262 | +411 | Separate |
| max | 2646 | 2496 | +150 | Separate |
Gap is Claude Fable 5.2 minus Claude Sonnet 5.5 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 5.2 (xhigh) scores higher on all nine metrics. Weighted by each metric's share of the Writing Score, Hook Strength does the most to put Claude Fable 5.2 (xhigh) ahead, with a 3.0-point lead on that metric. The weight beside each metric is its share of the Writing Score.
Consistency Across Drafts
| Claude Fable 5.2 (xhigh) | Claude Sonnet 5.5 (max effort) | |
|---|---|---|
| Score spread across drafts (±) | 1.44 | 1.22 |
| Lowest script score | 83.6 Script 10 | 83.0 Script 10 |
| Highest script score | 88.0 Script 9 | 86.7 Script 9 |
| Range across scripts | 4.4 | 3.7 |
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 5.2 (xhigh) minus Claude Sonnet 5.5 (max effort), and the higher score is in bold.
| Script | Claude Fable 5.2 (xhigh) | Claude Sonnet 5.5 (max effort) | Gap |
|---|---|---|---|
| Script 1 opinion / warning explainer | 83.7 | 84.2 | -0.5 |
| Script 2 news-analysis / skeptical explainer | 85.4 | 84.8 | +0.6 |
| Script 3 personal roadmap / opinion | 85.5 | 84.0 | +1.5 |
| Script 4 short explainer | 85.4 | 85.0 | +0.4 |
| Script 5 news-analysis / opinion explainer | 86.1 | 84.8 | +1.3 |
| Script 6 founder announcement / personal origin story | 85.9 | 84.6 | +1.3 |
| Script 7 personal technical walkthrough / agentic workflow case study | 87.3 | 85.0 | +2.3 |
| Script 8 product release announcement / personal observation | 85.1 | 83.9 | +1.2 |
| Script 9 career guide / hiring analysis | 88.0 | 86.7 | +1.3 |
| Script 10 engineering process walkthrough / presentation adaptation | 83.6 | 83.0 | +0.6 |
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.
← All comparisons