Model Scorecard
GPT-5.6 Luna (ultra)
OpenAI · proprietary
GPT-5.6 Luna ranks #30 of 87 models on the November 2026 ToneBench board, and GPT-5.6 Luna (ultra) is its best configuration, #65 of 151 configurations, with a Writing Score of 78.8/100 and a Writing Elo of 1731. One script costs $0.026 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
- StandingGPT-5.6 Luna ranks #30 of 87 models, and this is its best configuration. As a configuration, it is #65 of 151 configurations by Writing Elo (1731), in the middle third of the board. Its 95% range (1690 to 1772) overlaps 13 other configurations, ranked #58 to #71.
- MetricsBest-ranked: Length Adherence (91.8, 42nd of 151 configurations, +7.0 against the board median). Lowest-ranked: Tone & Voice Match (71.9, 93rd of 151 configurations, -2.1 against the board median).
- ScriptsFrom 76.0 on Script 7 (personal technical walkthrough) to 80.8 on Script 9 (career guide): a 4.8-point spread across the 10 reference scripts.
- ConsistencyIts Writing Score moves ± 2.1 between drafts of the same script, against ± 2.5 for the median configuration: typical.
- ValueMiMo-V2.6-Flash (thinking on) ranks higher and costs about $0.0057 per script, against $0.026 per script for this one.
Louis's PickOf the two GPT-5.6 Luna settings, this is the one I'd use. If you're not tied to GPT-5.6 Luna, GLM-5.3 Flash (max) ranks clearly higher for no more per script.
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).
Tone & Voice Match ranks in the bottom half (93rd of 151 configurations), so budget time for a voice pass.
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.
It outranks 41 configurations that cost at least 50% more.
Among proprietary models, GPT-5.6 Luna is 23rd of 53. As a configuration, it is 54th of 108 proprietary configurations. The best open-weight configuration, GLM-5.3 (max) at configuration #22, outranks it.
All Settings of GPT-5.6 Luna
GPT-5.6 Luna is also on the board at other effort settings, and none of them rank above this one. The thinking-level page for GPT-5.6 Luna charts how quality, cost and time change with the setting.
| Setting | Configuration Rank | Writing Score | Writing Elo | Cost / Script | Time / Script |
|---|---|---|---|---|---|
| ultra this page | #65 | 78.8 | 1731 | $0.026 | 3.1 min |
| medium | #85 | 76.7 | 1533 | $0.0065 | 0.5 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's steadiest on Substance, Accuracy & Value: ± 1.2 between drafts against ± 2.1.
Consistency by Metric
| Metric | This model | Board median | Verdict |
|---|---|---|---|
| Tone & Voice Match ? | 71.9 ± 2.6 | ± 1.9 | typical |
| Writing Craft & Clarity ? | 74.7 ± 1.5 | ± 1.5 | typical |
| Substance, Accuracy & Value ? | 84.8 ± 1.2 | ± 2.1 | steadier than most |
| Continuity & Emotion ? | 77.2 ± 1.6 | ± 1.5 | typical |
| YouTube Best Practices ? | 76.6 ± 2.7 | ± 2.4 | typical |
| Hook Strength ? | 80.6 ± 2.9 | ± 2.7 | typical |
| Length Adherence ? | 91.8 ± 5.2 | ± 6.6 | typical |
| Slop Score ? | 83.9 ± 1.6 | ± 1.6 | typical |
| Visual Cue Quality ? | 78.4 ± 2.2 | ± 2.9 | typical |
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 78.8 combines their scores with the parts computed in code (Length Adherence and half of the Slop Score). The highest and lowest judge are 13.4 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 viaCodex CLI (OpenAI subscription) · model page ↗.
- Exact model / route id
gpt-5.6-lunaatreasoning level: ultra. - Generations5 independent runs × 10 scripts = 50 drafts, stored after generation and never edited.
- Run dates2026-10-11.
- 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 GPT-5.6 Luna (ultra) at Writing?
GPT-5.6 Luna ranks #30 of 87 models on ToneBench, and this is its best configuration. This configuration is #65 of 151 configurations, in the middle third of the board, with a Writing Elo of 1731 and a Writing Score of 78.8/100. 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 GPT-5.6 Luna (ultra) the Best OpenAI Model for Writing?
No. GPT-5.6 Luna is 7th of 13 OpenAI models. The top one is GPT-6 Sol, through GPT-6 Sol (max), about 570 Elo ahead of this setting.
Is GPT-5.6 Luna (ultra) Good Value for the Money?
It costs about $0.026 per script. MiMo-V2.6-Flash (thinking on) ranks higher and costs less.
What Are the Strengths and Weaknesses of GPT-5.6 Luna (ultra)?
Its best-ranked metric is Length Adherence (91.8, 42nd of 151 configurations, +7.0 against the board median), and its lowest-ranked is Tone & Voice Match (71.9, 93rd of 151, -2.1). The Scores by Metric section shows the board median and the board's best for each one.
How Was GPT-5.6 Luna (ultra) Evaluated?
It was run through the Codex CLI (OpenAI subscription), with the exact model/route ID gpt-5.6-luna at reasoning effort ultra, first run on 2026-10-11. 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 GPT-5.6 Luna (ultra) Have Open Weights?
No. It is a proprietary model: its weights are not public. Among proprietary configurations it is 54th of 108 for writing.