Model Scorecard
Claude Fable 5 (max effort, Opus 4.8 fallback)
Anthropic · proprietary
Claude Fable 5 ranks #7 of 87 models on the November 2026 ToneBench board, and Claude Fable 5 (max effort, Opus 4.8 fallback) is its best configuration, #17 of 151 configurations, with a Writing Score of 82.9/100 and a Writing Elo of 2165. One script costs $3.20 at API list price.
Last updated , from board data generated at 17:52 UTC.
Rank, scores, the nine metrics, the 10 reference scripts, cost and setup for one configuration (a model at one reasoning setting). Key Results sums it up; the section links below it jump to the detail.
Key Results
- StandingClaude Fable 5 ranks #7 of 87 models, and this is its best configuration. As a configuration, it is #17 of 151 configurations by Writing Elo (2165), in the top 20. Its 95% range (2102 to 2218) overlaps 13 other configurations, ranked #15 to #28.
- MetricsBest-ranked: YouTube Best Practices (84.3, 4th of 151 configurations, +7.9 against the board median). Lowest-ranked: Hook Strength (78.0, 94th of 151 configurations, -1.6 against the board median).
- ScriptsFrom 81.2 on Script 8 (product release announcement) to 86.4 on Script 7 (personal technical walkthrough): a 5.2-point spread across the 10 reference scripts.
- ConsistencyIts Writing Score moves ± 2.0 between drafts of the same script, against ± 2.5 for the median configuration: typical.
- ValueGPT-6 Sol (max) ranks higher and costs about $0.126 per script, against $3.20 per script for this one.
Louis's PickThis is the strongest Claude Fable 5 setting, but Claude Fable 5 (high) costs about $1.86 less per script and its Elo range overlaps this setting's, so I'd start there.
More Context Behind These Results
Writing Elo comes from comparing its average on each script with every other configuration's average on that same script; a gap smaller than the draft-to-draft variation counts as a draw (what the ranges can and cannot show).
On YouTube Best Practices, its best-ranked metric, more of the open loops, re-engagement beats and calls to action a video needs are already there. Hook Strength ranks in the bottom half (94th of 151 configurations), so plan on rewriting the opening.
The script format moves its score. If most of your scripts look like its best or weakest format, that result is a better guide than the average.
Among proprietary models, Claude Fable 5 is 7th of 53. As a configuration, it is 17th of 108 proprietary configurations. It also sits above every open-weight configuration; the best of them, GLM-5.3 (max), is configuration #22.
All Settings of Claude Fable 5
Claude Fable 5 is also on the board at other effort settings, and none of them rank above this one. The thinking-level page for Claude Fable 5 charts how quality, cost and time change with the setting.
| Setting | Configuration Rank | Writing Score | Writing Elo | Cost / Script | Time / Script |
|---|---|---|---|---|---|
| max effort, Opus 4.8 fallback this page | #17 | 82.9 | 2165 | $3.20 | 12.5 min |
| high | #28 | 81.9 | 2070 | $1.34 | 4.9 min |
Skill Profile Across the Nine Metrics
Each corner is one metric on a 0 to 100 scale; the further out, the higher the score. A corner outside the dashed line beats the board median. Hover or tap a point for its exact score, and a metric name for what it rewards.
Scores by Metric
Nine metrics, each scored 0 to 100 and weighted into the Writing Score; the weight sits under each name. Rank is out of all 151 ranked configurations.
Scores by Reference Script
Every ranked configuration writes five drafts for each of the same 10 briefs, and each score is the mean of those drafts. The rank and board median compare it with every configuration on that script, which separates a weak result from a hard script. The result on the format closest to your own work is the most relevant.
Consistency Between Drafts
Every score on this page is the mean of 5 drafts per script. The ± is the standard deviation between those drafts: the larger it is, the more two drafts of the same script can differ.
Compared with the typical model, it varies most on Hook Strength: ± 5.7 between drafts against ± 2.7, so two drafts of the same script can score quite differently there. On the same comparison, it's steadiest on Length Adherence: ± 3.1 between drafts against ± 6.6.
Consistency by Metric
| Metric | This model | Board median | Verdict |
|---|---|---|---|
| Tone & Voice Match ? | 80.6 ± 1.1 | ± 1.9 | steadier than most |
| Writing Craft & Clarity ? | 77.5 ± 2.4 | ± 1.5 | more variable than most |
| Substance, Accuracy & Value ? | 84.9 ± 1.5 | ± 2.1 | typical |
| Continuity & Emotion ? | 84.4 ± 1.2 | ± 1.5 | typical |
| YouTube Best Practices ? | 84.3 ± 1.6 | ± 2.4 | typical |
| Hook Strength ? | 78.0 ± 5.7 | ± 2.7 | more variable than most |
| Length Adherence ? | 94.7 ± 3.1 | ± 6.6 | steadier than most |
| Slop Score ? | 84.6 ± 1.2 | ± 1.6 | typical |
| Visual Cue Quality ? | 81.2 ± 1.7 | ± 2.9 | steadier than most |
Cost, Time and Tokens per Script
Logged on every run; none of these figures affects the Writing Score. Time is the average time to one accepted script, retries included. Cost is one script at the API list price.
Scores by Judge
Four judges score the same 50 stored drafts blind against the same rubric: three LLM judges from three labs, plus Jev, a typed judge from TypeSafe that rates each metric on five described quality levels. No single judge's taste decides the result. The Writing Score of 82.9 combines their scores with the parts computed in code (Length Adherence and half of the Slop Score). The highest and lowest judge are 12.0 points apart on its Writing Score. That is close to the board median of 13.4. Each judge also has its own scale, so every card shows that judge's score against its average across the board. How the panel works.
Evaluation Setup
How this exact configuration was run and judged: route, model ID, dates, sampling and prompt.
- Accessed viaClaude Code (Anthropic subscription).
- Exact model / route id
claude-fable-5atreasoning level: max. - Generations5 independent runs × 10 scripts = 50 drafts, stored after generation and never edited.
- Run dates2026-10-08 to 2026-10-10.
- JudgesClaude 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 from TypeSafe. One call per judge per draft. All four score every draft on their own, blind to which model wrote it. The three LLM judges use the identical rubric and have to quote evidence before they score a metric. Jev answers the same rubric as one question per metric, choosing among five described quality levels, and writes no text. Seven metrics are the plain average of the four judges. Length is computed from the spoken word count, and Slop is half computed (lexical scans minus the spoken-dash penalty) and half judged. The Writing Elo is cross-checked with a Bradley-Terry fit of the same pairwise results (methodology).
- Sampling and promptThe provider's default sampling, with no fine-tuning and no system-prompt changes. Every current-ranked model gets the same prompt, about 13,000 tokens (the count shifts a bit with each model's tokenizer): a style guide built from Louis's voice and storytelling guides, the target length, and the brief with its research packet. Generation is closed-book on every route: the prompt is the only source, with no web search, browsing, code execution, file access or other tool (generation).
- What stays privateThe exact rubric and any non-public reference material. Each script is normally benchmarked before its video is published, which lowers the odds that a model has seen the reference, though it does not rule it out (why).
Frequently Asked Questions
How Good Is Claude Fable 5 (max effort, Opus 4.8 fallback) at Writing?
Claude Fable 5 ranks #7 of 87 models on ToneBench, and this is its best configuration. This configuration is #17 of 151 configurations, in the top 20, with a Writing Elo of 2165 and a Writing Score of 82.9/100. The ranks come from full YouTube scripts written in the voice of Louis-François Bouchard and judged blind, with the channel's finished script as the reference. The benchmark measures long-form scripted writing, so the result does not carry over to every kind of text.
Is Claude Fable 5 (max effort, Opus 4.8 fallback) the Best Anthropic Model for Writing?
No. Claude Fable 5 is 6th of 13 Anthropic models. The top one is Claude Opus 5.5, through Claude Opus 5.5 (xhigh), about 539 Elo ahead of this setting.
Is Claude Fable 5 (max effort, Opus 4.8 fallback) Good Value for the Money?
It costs about $3.20 per script. GPT-6 Sol (max) ranks higher and costs less.
What Are the Strengths and Weaknesses of Claude Fable 5 (max effort, Opus 4.8 fallback)?
Its best-ranked metric is YouTube Best Practices (84.3, 4th of 151 configurations, +7.9 against the board median), and its lowest-ranked is Hook Strength (78.0, 94th of 151, -1.6). The Scores by Metric section shows the board median and the board's best for each one.
How Was Claude Fable 5 (max effort, Opus 4.8 fallback) Evaluated?
It was run through Claude Code (Anthropic subscription), with the exact model/route ID claude-fable-5 at reasoning effort max, first run on 2026-10-08. It wrote each script 5 times with the provider's default sampling and no fine-tuning. The Evaluation Setup section and the methodology page have the details.
Does Claude Fable 5 (max effort, Opus 4.8 fallback) Have Open Weights?
No. It is a proprietary model: its weights are not public. Among proprietary configurations it is 17th of 108 for writing.