Best AI for essay writing / head-to-head
Gemini 3.1 Pro Preview vs GPT-5.6 Lunafor essay writing
GPT-5.6 Luna wins, 91–83
Same 12 essay writing tasks, marked blind by three rival labs. GPT-5.6 Luna took 7 tasks, Gemini 3.1 Pro Preview took 3, 2 tied. Tested 13 Aug 2026.
Where they differed most
This paragraph makes three points at once and repeats itself. Rewrite it as three short paragraphs, one point each, no repetition: 'Exercise is good for your body and it also helps your mood, and being active reduces the risk of heart disease, plus people who exercise often sleep better, and of course it is good for the heart.'
Exercise provides a natural boost to your mental well-being. Staying active is a great way to elevate your overall mood. Regular physical activity is also essential for your cardiovascular health. It strengthens your body and significantly reduces your risk of developing heart disease. Finally, working out improves the quality of your rest. People who maintain a consistent exercise routine tend to sleep much better at night.
Exercise supports physical health and reduces the risk of heart disease. Regular activity can improve your mood. People who exercise often sleep better.
Task by task
| Task | Gemini 3.1 Pro Preview | GPT-5.6 Luna |
|---|---|---|
| Structured argument | 8 | 5 |
| Essay plan | 10 | 10 |
| Tighten flabby prose | 9 | 10 |
| Hold a word count | 10 | 9 |
| Adapt for the reader | 10 | 10 |
| Introduction only | 9 | 10 |
| Steelman the other side | 8 | 10 |
| Cite honestly | 4 | 7 |
| Fix the structure | 5 | 10 |
| Formal to plain | 9 | 8 |
| Conclusion that adds something | 9 | 10 |
| Refuse to pad | 9 | 10 |
Full receipts: Gemini 3.1 Pro Preview, GPT-5.6 Luna · judges claude-sonnet-5, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for essay writing: Gemini 3.1 Pro Preview or GPT-5.6 Luna?
GPT-5.6 Luna — it scored 91/100 against 83/100 on our 12-task essay writing suite, winning 7 tasks to 3 with 2 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published essay writing tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More essay writing head-to-heads: GPT-5.6 Luna vs GPT-5.6 Sol · Gemini 3.1 Pro Preview vs GPT-5.6 Sol · GPT-5.5 vs GPT-5.6 Luna · Gemini 3.1 Pro Preview vs GPT-5.5 · GPT-5.3-Codex vs GPT-5.6 Luna · GPT-5.6 Luna vs GPT-5.6 Terra
Full ranking: Best AI for essay writing · model pages: Gemini 3.1 Pro Preview, GPT-5.6 Luna