Towards AITowards AIToneBench

Model Comparison

Kimi K3.1 Pro vs Claude Haiku 5.5

Kimi K3.1 Pro (max) leads Claude Haiku 5.5 (max effort) by 219 Elo, and their 95% ranges sit 144 Elo apart. Among 83 models, each ranked by its best configuration, Kimi K3.1 Pro is #7 and Claude Haiku 5.5 is #18. Cost per script: $0.251 for Kimi K3.1 Pro (max) and $0.103 for Claude Haiku 5.5 (max effort).

Last updated , from board data generated at 22:06 UTC.

Kimi K3.1 Pro
2205 Writing Elo of Kimi K3.1 Pro (max), its best configuration#7 of 83 models · 82.5/100 Writing Score · $0.251 per script1 configuration on the board
Claude Haiku 5.5
1986 Writing Elo of Claude Haiku 5.5 (max effort), its best configuration#18 of 83 models · 80.8/100 Writing Score · $0.103 per script5 configurations on the board

Picks and Verdict

PickKimi K3.1 Pro

Kimi K3.1 Pro (max)

Pick Kimi K3.1 Pro (max) for scripts you plan to film, since it leads Haiku's best by 219 Elo with separate ranges for $0.251 a script.

PickClaude Haiku 5.5

Claude Haiku 5.5 (xhigh)

Pick Claude Haiku 5.5 (xhigh) for bulk drafts at $0.029 a script and 3.6 minutes, about a ninth of Kimi's price.

Kimi K3.1 Pro is the clear writer here, and Claude Haiku 5.5 is the clear bargain. Kimi K3.1 Pro (max) leads Claude Haiku 5.5 (max effort) by 219 Elo with separate 95% ranges and wins nine of the ten scripts. Ranked by best configuration, that's the #7 model of 83 against the #18 model. Haiku at max effort costs $0.103 a script, well under half of Kimi's $0.251, but it takes 12.6 minutes against 5.5. Claude Haiku 5.5 (xhigh) is the setting I'd actually weigh: $0.029 and 3.6 minutes, about a ninth of Kimi's price, for 298 Elo less. Haiku needs its thinking, with 493 Elo between low and max effort, and I wouldn't go under xhigh. Kimi's one row, at max, ranks above all five Haiku settings. Reading them side by side, I'd notice Kimi's hooks first, more than five points higher, then its visual cues and YouTube structure. Haiku holds the target length a bit better and has the cleaner Slop Score. For a script I'm filming, Kimi at max is worth the extra money. For bulk drafting, Haiku at xhigh costs next to nothing.

Disclosure: Claude Haiku 5.5 comes from the same lab as one of the four judges, Claude Opus 5.5. The other three sit outside its lab, so it is never 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 Kimi K3.1 Pro 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).
Kimi K3.1 ProClaude Haiku 5.5
ConfigurationWriting Elo95% RangeWriting ScoreCost / ScriptTime / ScriptReasoning TokensConfiguration Rank
Kimi K3.1 Pro (max)22052166 to 224682.5$0.2515.5 min19,487#14
Claude Haiku 5.5 (max effort)19861947 to 202280.8$0.10312.6 minN/A#34
Claude Haiku 5.5 (xhigh)19071868 to 194180.0$0.0293.6 minN/A#45
Claude Haiku 5.5 (high)17061669 to 174778.0$0.0121.5 minN/A#57
Claude Haiku 5.5 (medium)16011550 to 165076.7$0.00670.8 minN/A#69
Claude Haiku 5.5 (low)14931442 to 153375.2$0.00450.5 minN/A#81

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. N/A under Reasoning Tokens means the board has no separate reasoning count for that route.

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.

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

Kimi K3.1 Pro (max)Claude Haiku 5.5 (max effort)Solid bar: higher score in that row

Kimi K3.1 Pro (max) scores higher on six of the nine metrics and Claude Haiku 5.5 (max effort) on two, with one tie. Weighted by each metric's share of the Writing Score, Hook Strength does the most to put Kimi K3.1 Pro (max) ahead, with a 5.2-point lead on that metric. The weight beside each metric is its share of the Writing Score.

Tone & Voice Match19% weight
77.0
76.4
Writing Craft & Clarity13% weight
77.8
77.8
Substance, Accuracy & Value15% weight
88.2
85.6
Continuity & Emotion14% weight
80.8
78.7
YouTube Best Practices12% weight
79.7
76.8
Hook Strength10% weight
83.4
78.2
Length Adherence8% weight
95.4
97.3
Slop Score5% weight
85.0
86.0
Visual Cue Quality4% weight
84.9
80.9

Consistency Across Drafts

Kimi K3.1 Pro (max)Claude Haiku 5.5 (max effort)
Score spread across drafts (±)1.651.55
Lowest script score80.4 Script 778.2 Script 10
Highest script score85.5 Script 982.6 Script 4
Range across scripts5.14.4

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 Kimi K3.1 Pro (max) minus Claude Haiku 5.5 (max effort), and the higher score is in bold.

ScriptKimi K3.1 Pro (max)Claude Haiku 5.5 (max effort)Gap
Script 1 opinion / warning explainer81.380.3+1.0
Script 2 news-analysis / skeptical explainer83.280.7+2.5
Script 3 personal roadmap / opinion81.980.8+1.1
Script 4 short explainer82.082.6-0.6
Script 5 news-analysis / opinion explainer84.281.7+2.5
Script 6 founder announcement / personal origin story83.081.1+1.9
Script 7 personal technical walkthrough / agentic workflow case study80.480.0+0.4
Script 8 product release announcement / personal observation82.181.3+0.8
Script 9 career guide / hiring analysis85.581.5+4.0
Script 10 engineering process walkthrough / presentation adaptation81.378.2+3.1

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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