GPT-5.5 vs GPT-5.6 Sol for book writing
Dead heat: 98 each
Same 12 book writing tasks, marked blind by three rival labs. Tested 16 Aug 2026.
Where they differed most
A novel: a 14-year-old girl caring for her alcoholic mother in 1980s Sunderland, where the reader must eventually understand things the girl herself cannot. Recommend first or third person — commit, no hedging — with the reasoning, then write the same short moment both ways so the difference shows on the page: Mum asleep at 4pm, tea not made. Roughly 40-60 words per version.
Use **first person**. The novel’s power is the gap between what the girl reports and what the reader understands. A fourteen-year-old carer will normalise neglect, minimise danger, and protect her mother in the telling. First person lets the reader feel her competence and denial at once: she can say, “Mum was tired,” while we understand alcohol, depression, abandonment, and fear. **First person** At four o’clock Mum was still on the settee, one arm hanging down, her fag gone cold between two fingers. I turned the telly lower, in case she nee…
## Recommendation: First person First person best creates the necessary dramatic irony. The girl can report practical details while normalising or misreading them; the reader accumulates what they mean—alcoholism, neglect, parentification—before she can. Her omissions and euphemisms become part of the novel’s emotional structure. Keep the narration contemporaneous, not an adult looking back. **First person** Mum was having one of her afternoon sleeps, still in her coat on top of the candlewick. The clock said four. I shut the bedroom door so…
Task by task
| Task | GPT-5.5 | GPT-5.6 Sol |
|---|---|---|
| Is it a book? | 10 | 10 |
| Twelve chapters, one year | 10 | 10 |
| Back cover, no spoilers | 10 | 10 |
| Three cuts that matter | 10 | 10 |
| 70,000 words around a day job | 9 | 9 |
| Unstick the dialogue | 10 | 10 |
| First or third? | 9 | 10 |
| The 30,000-word wall | 10 | 10 |
| Self-publish or chase agents | 10 | 9 |
| The query letter | 10 | 10 |
| Naming the real people | 9 | 9 |
| Refuse the fake memoir | 10 | 10 |
Full receipts: GPT-5.5, GPT-5.6 Sol · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for book writing: GPT-5.5 or GPT-5.6 Sol?
They tied at 98/100 on our book writing suite — for this job, pick on price or the product you already use.
How was this tested?
Both models answered the identical published book 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 book writing head-to-heads: GPT-5.6 Sol vs GPT-5.6 Terra · GPT-5.3-Codex vs GPT-5.6 Sol · Claude Fable 5 vs GPT-5.6 Sol · Claude Opus 4.8 vs GPT-5.6 Sol · GPT-5.6 Luna vs GPT-5.6 Sol · GLM 5.2 vs GPT-5.6 Sol
Full ranking: Best AI for book writing · model pages: GPT-5.5, GPT-5.6 Sol