Best AI for essay writing / head-to-head
GPT-5.6 Sol vs GPT-5.6 Terrafor essay writing
GPT-5.6 Sol wins, 95–88
Same 12 essay writing tasks, marked blind by three rival labs. GPT-5.6 Sol took 2 tasks, GPT-5.6 Terra took 1, 9 tied. Tested 13 Aug 2026.
Where they differed most
Write a 150-word paragraph on the effects of sleep deprivation on memory. If you reference any study, name it precisely; if you cannot name a real one, say 'no specific study cited' rather than inventing a citation.
Sleep deprivation harms memory at several stages. When people do not get enough sleep, attention becomes less stable, so new information is encoded less accurately in the first place. Lack of sleep also disrupts consolidation, the process by which recently learned material is strengthened and integrated with existing knowledge. As a result, facts, skills, and experiences may be recalled less reliably the next day. Working memory is also affected: sleep-deprived people often struggle to hold and manipulate information, follow multistep instructi…
Sleep deprivation impairs memory by disrupting attention, encoding, consolidation, and retrieval. When people are tired, they are less able to focus on new information, so fewer details are effectively stored. Insufficient sleep also interferes with hippocampal activity and with the brain’s overnight processing of experiences, weakening both factual and episodic memories. Learning procedures, emotional events, and associations can likewise suffer, although the pattern varies by task and by individual. After prolonged wakefulness, people may fee…
Task by task
| Task | GPT-5.6 Sol | GPT-5.6 Terra |
|---|---|---|
| Structured argument | 8 | 8 |
| Essay plan | 9 | 9 |
| Tighten flabby prose | 9 | 10 |
| Hold a word count | 9 | 9 |
| Adapt for the reader | 10 | 10 |
| Introduction only | 10 | 10 |
| Steelman the other side | 10 | 10 |
| Cite honestly | 10 | 5 |
| Fix the structure | 10 | 5 |
| Formal to plain | 9 | 9 |
| Conclusion that adds something | 10 | 10 |
| Refuse to pad | 10 | 10 |
Full receipts: GPT-5.6 Sol, GPT-5.6 Terra · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for essay writing: GPT-5.6 Sol or GPT-5.6 Terra?
GPT-5.6 Sol — it scored 95/100 against 88/100 on our 12-task essay writing suite, winning 2 tasks to 1 with 9 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.
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Full ranking: Best AI for essay writing · model pages: GPT-5.6 Sol, GPT-5.6 Terra