Best AI for essay writing / head-to-head

GPT-5.6 Luna vs GPT-5.6 Solfor essay writing

The verdict

GPT-5.6 Sol wins, 9591

Same 12 essay writing tasks, marked blind by three rival labs. GPT-5.6 Sol took 3 tasks, GPT-5.6 Luna took 2, 7 tied. Tested 13 Aug 2026.

Where they differed most

The task — Structured argument

Write a 350-word argumentative essay answering: should secondary schools ban smartphones during the school day? Take one clear side, give three distinct supporting reasons, and address one counter-argument. Do not use the phrases 'in conclusion' or 'in today's world'.

Secondary schools should ban smartphones during the school day because unrestricted access undermines learning, weakens relationships, and creates avoidable risks. A school is meant to provide a focused environment where students can think, participate, and develop independence; constant phone access works against all three goals.

First, smartphones are powerful distractions. Notifications, messages, and the temptation to check social media interrupt concentration, even when a phone remains in a student’s pocket. Research and classroom experie…
Secondary schools should ban students from using smartphones throughout the school day, while allowing devices to be stored securely for emergencies and collected afterward. Although phones can support communication and quick research, their constant presence undermines the central purposes of school: sustained attention, healthy social development, and fair access to learning. A clear ban would create calmer, safer, and more productive classrooms.

First, smartphones damage concentration. Lessons require students to listen, question, remember,…

Task by task

TaskGPT-5.6 LunaGPT-5.6 Sol
Structured argument58
Essay plan109
Tighten flabby prose109
Hold a word count99
Adapt for the reader1010
Introduction only1010
Steelman the other side1010
Cite honestly710
Fix the structure1010
Formal to plain89
Conclusion that adds something1010
Refuse to pad1010

Full receipts: GPT-5.6 Luna, GPT-5.6 Sol · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5

Questions people ask

Which is better for essay writing: GPT-5.6 Luna or GPT-5.6 Sol?

GPT-5.6 Sol — it scored 95/100 against 91/100 on our 12-task essay writing suite, winning 3 tasks to 2 with 7 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-5.5 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.6 Sol · GPT-5.6 Sol vs GPT-5.6 Terra · Claude Sonnet 5 vs GPT-5.6 Sol · Claude Opus 4.6 vs GPT-5.6 Sol · Claude Fable 5 vs GPT-5.6 Sol

Full ranking: Best AI for essay writing · model pages: GPT-5.6 Luna, GPT-5.6 Sol