Towards AITowards AIToneBench

Model Comparison

Claude Fable 5 vs Claude Haiku 5.5

Claude Fable 5 (max effort, Opus 4.8 fallback) leads Claude Haiku 5.5 (max effort) by 230 Elo, and their 95% ranges sit 142 Elo apart. Even Claude Fable 5's lowest-rated configuration, Claude Fable 5 (high), ranks above Claude Haiku 5.5 (max effort). Among 78 models, each ranked by its best configuration, Claude Fable 5 is #6 and Claude Haiku 5.5 is #16. Cost per script: $3.20 for Claude Fable 5 (max effort, Opus 4.8 fallback) and $0.103 for Claude Haiku 5.5 (max effort).

Last updated , from board data generated at 01:13 UTC.

Claude Fable 5
2239 Writing Elo of Claude Fable 5 (max effort, Opus 4.8 fallback), its best configuration#6 of 78 models · 82.9/100 Writing Score · $3.20 per script2 configurations on the board
Claude Haiku 5.5
2009 Writing Elo of Claude Haiku 5.5 (max effort), its best configuration#16 of 78 models · 80.8/100 Writing Score · $0.103 per script5 configurations on the board

Picks and Verdict

PickClaude Fable 5

Claude Fable 5 (high)

Pick Claude Fable 5 (high) for a script that needs my tone, since it scores about three points above Claude Haiku 5.5 (max effort) on Tone & Voice Match and returns in under five minutes.

PickClaude Haiku 5.5

Claude Haiku 5.5 (xhigh)

Pick Claude Haiku 5.5 (xhigh) for cheap drafts at $0.029 each, since it comes back in 3.6 minutes instead of 12.6 for under a third of the max effort price.

Claude Haiku 5.5 is the model here that needs its thinking. From high to max effort it gains 286 Elo with separate ranges, where Claude Fable 5 gains 83 and its two ranges overlap. That doesn't make the match-up close: both Fable settings sit above all five of Haiku's. Ranked by best setting, Fable is the #6 model of 78 and Haiku 5.5 the #16 model, and even Claude Fable 5 (high) leads Haiku's best by 147 Elo with separate 95% ranges. It's quicker too, under five minutes against almost thirteen, at $1.34 instead of $3.20 for Fable's top setting. On the Haiku side I'd run xhigh. Max effort sits 82 Elo higher with ranges that just clear each other, but it costs $0.103 against $0.029, and one level below xhigh Haiku drops 204 Elo. Haiku at max effort does edge Fable at high on substance, length and slop, all by less than three points. Fable's leads are wider, three to six points on tone, continuity and YouTube best practices. For a script that goes on camera I'd take Fable at high, and Haiku at xhigh covers the drafts.

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 Haiku 5.5, scored on the same 10 scripts by the same four judges.

How to Read the Chart
  • 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).
Claude Fable 5Claude Haiku 5.5
ConfigurationWriting Elo95% RangeWriting ScoreCost / ScriptTime / ScriptConfiguration Rank
Claude Fable 5 (max effort, Opus 4.8 fallback)22392186 to 229882.9$3.2012.5 min#12
Claude Fable 5 (high)21562102 to 220481.9$1.344.9 min#22
Claude Haiku 5.5 (max effort)20091972 to 204480.8$0.10312.6 min#31
Claude Haiku 5.5 (xhigh)19271883 to 196580.0$0.0293.6 min#41
Claude Haiku 5.5 (high)17231679 to 176078.0$0.0121.5 min#53
Claude Haiku 5.5 (medium)16201572 to 167076.7$0.00670.8 min#62
Claude Haiku 5.5 (low)15041461 to 155075.2$0.00450.5 min#74

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.

Writing Elo at Each Shared Level Name

LevelClaude Fable 5Claude Haiku 5.5Gap95% Ranges
high21561723+433Separate
max22392009+230Separate

Gap is Claude Fable 5 minus Claude Haiku 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 (max effort, Opus 4.8 fallback)Claude Haiku 5.5 (max effort)Solid bar: higher score in that row

Claude Fable 5 (max effort, Opus 4.8 fallback) scores higher on four of the nine metrics and Claude Haiku 5.5 (max effort) on five. Weighted by each metric's share of the Writing Score, YouTube Best Practices does the most to put Claude Fable 5 (max effort, Opus 4.8 fallback) ahead, with a 7.5-point lead on that metric. The weight beside each metric is its share of the Writing Score.

Tone & Voice Match19% weight
80.6
76.4
Writing Craft & Clarity13% weight
77.5
77.8
Substance, Accuracy & Value15% weight
84.9
85.6
Continuity & Emotion14% weight
84.4
78.7
YouTube Best Practices12% weight
84.3
76.8
Hook Strength10% weight
78.0
78.2
Length Adherence8% weight
94.7
97.3
Slop Score5% weight
84.6
86.0
Visual Cue Quality4% weight
81.2
80.9

Consistency Across Drafts

Claude Fable 5 (max effort, Opus 4.8 fallback)Claude Haiku 5.5 (max effort)
Score spread across drafts (±)1.961.55
Lowest script score81.2 Script 878.2 Script 10
Highest script score86.4 Script 782.6 Script 4
Range across scripts5.24.4

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 Haiku 5.5 (max effort), and the higher score is in bold.

ScriptClaude Fable 5 (max effort, Opus 4.8 fallback)Claude Haiku 5.5 (max effort)Gap
Script 1 opinion / warning explainer83.180.3+2.8
Script 2 news-analysis / skeptical explainer83.780.7+3.0
Script 3 personal roadmap / opinion81.680.8+0.8
Script 4 short explainer81.682.6-1.0
Script 5 news-analysis / opinion explainer82.581.7+0.8
Script 6 founder announcement / personal origin story82.981.1+1.8
Script 7 personal technical walkthrough / agentic workflow case study86.480.0+6.4
Script 8 product release announcement / personal observation81.281.3-0.1
Script 9 career guide / hiring analysis83.281.5+1.7
Script 10 engineering process walkthrough / presentation adaptation82.878.2+4.6

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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