Gemini 3.8 Flash (high thinking)
Google · proprietary · writing benchmark
The short version
Gemini 3.8 Flash (high thinking) sits at #91 of 146 on ToneBench, toward the value end of the board, with a writing Elo of 1419 and an overall score of 77.0 out of 100. We measured it by having it write all 10 of our real YouTube scripts, five times each, then scoring every draft blind against our own finished versions. Here is how it shook out.
Within Google it ranks 10th of 17. Gemini 3.1 Pro (default) is the family's top writer here, about 151 Elo ahead, so this config trades some quality for whatever it saves you in cost or speed.
Among proprietary models, it comes in 71st of 96. That ranking is against the stronger half of the board: closed models still set the pace on voice fidelity here.
Worth knowing before you rely on it: this model is swingy. Its overall score moves ± 5.0 points between runs of the same brief, versus a board median of ± 3.1. A great draft and a mediocre one can come from the identical prompt. The shaded bands on the metric bars below show where that volatility lives.
What it does best is Visual Cues: it ranks 44th on that dimension at 83.5, well above the board average. Its softer spot is Length Discipline (49.3, 122nd), which is the thing to watch if that metric matters most for your use.
It was uneven across the 10 scripts. Its best run was the product release announcement / personal observation (82.8) and its weakest was the engineering process walkthrough / presentation adaptation (73.2), a spread of about 10 points. Worth knowing if your writing skews toward one of those formats.
On cost, it runs about $0.062/task. DeepSeek V4 Flash (native chat alias) scores higher for less money, at $0.002/task, so on pure value this config is not the frontier. Still, it beats 3 models that cost noticeably more.
Skill profile
The shape is the story: the further a corner reaches, the stronger that dimension. Biggest edge over the board: Visual Cues (+8.8); furthest behind: Length Discipline (-19.3).
Per-metric scores
Nine writing dimensions, each scored 0–100 and blended by the editorial weight shown. Rank is against all 146 current-ranked models. The thick bar is this model; the thin lines above and below are the current field's best model (darker) and average (lighter) on the same scale. The small ± number is its run-to-run variation.
Per-article scores
The same 10 real scripts every current-ranked model writes, scored individually. Different formats stress different skills.
Consistency: run-to-run variability
Every cell on this page is the mean of 5 independent runs per script; the ± numbers are the run-to-run standard deviation. Overall, Gemini 3.8 Flash (high thinking) varies by ± 5.0 points between runs versus a board median of ± 3.1, so it is swingier than the typical model here, worth knowing if you need repeatable output.
Its most volatile dimension is Substance & Value (± 4.0 vs a board median of ± 2.3): two runs of the same brief can land visibly different substance & value scores.
| Metric | This model | Board median | Verdict |
|---|---|---|---|
| Tone & Voice ? | 77.6 ± 2.4 | ± 2.0 | typical |
| Writing Craft ? | 81.5 ± 2.1 | ± 1.9 | typical |
| Substance & Value ? | 79.0 ± 4.0 | ± 2.3 | swingier than most |
| Flow & Emotion ? | 77.5 ± 3.3 | ± 2.3 | typical |
| YouTube Structure ? | 77.8 ± 4.4 | ± 3.4 | typical |
| Hook ? | 83.0 ± 3.0 | ± 2.4 | typical |
| Length Discipline ? | 49.3 ± 16.7 | ± 9.4 | swingier than most |
| Anti-Slop ? | 81.4 ± 2.0 | ± 2.2 | typical |
| Visual Cues ? | 83.5 ± 4.8 | ± 4.2 | typical |
Measured, not modeled
Numbers we log on every run and rarely talk about. None of these affect the writing scores; cost and latency are informational.
What each judge scored it
The published overall of 77.0 is the consensus of three family-disjoint judges scoring the same 50 stored drafts blind with the identical rubric. The highest and lowest judge differ by 4.5 points on its overall. The three judges essentially agree on this model. How the panel works: methodology.
How we ran Gemini 3.8 Flash (high thinking)
- Accessed viaGoogle Gemini API · model page ↗
- Exact model / route id
gemini-3.8-flashatreasoning_effort: high - Generations5 independent runs × 10 scripts = 50 drafts, stored immutably after generation
- Run dates2026-09-03
- Judges3-judge panel: Claude Opus 5, high effort (Anthropic) + DeepSeek V4 Flash (OpenRouter) + GPT-5.6 Sol, medium reasoning (Codex CLI): every draft scored independently by all three with the identical rubric, blind to model identity, evidence quotes required before each metric score; published score = per-metric consensus mean, verified with a Bradley-Terry refit (methodology)
- Samplingprovider-default sampling, no fine-tuning, no system-prompt changes; every current-ranked model gets the identical brief, style contract and research packet
- What stays privatethe exact rubric and any non-public reference material; source-publication timing is disclosed for exceptions (why)
Frequently asked questions
How good is Gemini 3.8 Flash (high thinking) at writing?
On ToneBench it ranks #91 of 146 with a writing Elo of 1419 and an overall score of 77.0/100. That score comes from writing our 10 real YouTube scripts five times each and scoring every draft blind against our own finished versions across nine writing dimensions.
Is Gemini 3.8 Flash (high thinking) the best Google model for writing?
Not quite. Within Google it ranks 10th of 17; Gemini 3.1 Pro (default) is the family's best writer here.
Is Gemini 3.8 Flash (high thinking) good value for the money?
It costs about $0.062/task. DeepSeek V4 Flash (native chat alias) scores higher for less, so it is not the value pick.
What are Gemini 3.8 Flash (high thinking)'s strengths and weaknesses?
Its strongest dimension is Visual Cues (44th on the board, 83.5). Its weakest is Length Discipline (122nd on the board, 49.3). The full nine-metric breakdown is on this page.
Does Gemini 3.8 Flash (high thinking) write some formats better than others?
Yes. Its best of our 10 scripts was the product release announcement / personal observation (82.8) and its weakest was the engineering process walkthrough / presentation adaptation (73.2).
How consistent is Gemini 3.8 Flash (high thinking) between runs?
We run every script 5 times. Gemini 3.8 Flash (high thinking)'s overall score varies by about ±5.0 points between runs, versus a board median of ±3.1. That is swingier than typical, so expect more draft-to-draft variation. The full per-metric variability table is on this page.
How was Gemini 3.8 Flash (high thinking) evaluated?
Via Google Gemini API using the exact model/route id gemini-3.8-flash at reasoning_effort high, run on 2026-09-03. 5 runs per script, provider-default sampling, no fine-tuning; every draft scored blind with a fixed rubric by a three-family judge panel. Full details in the 'How we ran it' section and the methodology.
Is Gemini 3.8 Flash (high thinking) open source?
No, it is a proprietary (closed-weights) model. Among proprietary models it ranks 71st of 96 for writing.