GPT-5.6 Luna vs GPT-5.6 Sol for travel planning
Effectively a dead heat: 94–93
Same 12 travel planning tasks, marked blind by three rival labs. GPT-5.6 Sol took 4 tasks, GPT-5.6 Luna took 2, 6 tied. Tested 16 Aug 2026.
Where they differed most
Pack for 4 days in Krakow in February, one cabin bag only, for someone who really feels the cold. Give the list grouped into worn-on-the-plane versus packed, built on the layers principle rather than bulk, and name the one item people always pack for a city break that you are deliberately leaving out, with the reason.
For Krakow in February, plan for **cold, wind, and possible slush**. Wear the bulkiest layers and use thin, warm fabrics—especially merino and lightweight fleece. ## Worn on the plane - Thermal merino long-sleeve base layer - Lightweight fleece or wool mid-layer - Insulated, hooded, water-resistant winter coat - Lightweight thermal leggings or tights under - Stretchy, water-resistant trousers - Thick merino socks - Waterproof, insulated walking boots with good grip - Hat, scarf or neck gaiter, and gloves - Comfortable travel u…
## Wear on the plane Put the bulkiest items on your body; remove layers once seated. - Long-sleeved merino or thermal base layer - Warm jumper or lightweight fleece - Insulated, windproof and water-resistant coat with hood - Comfortable trousers with room for thermals underneath - Warm wool-blend socks - Waterproof, grippy walking boots suitable for snow and slush - Large scarf - Beanie covering the ears - Insulated gloves - Underwear - Phone, wallet, passport and travel documents ## Pack in the cabin bag ### Base lay…
Task by task
| Task | GPT-5.6 Luna | GPT-5.6 Sol |
|---|---|---|
| The impossible family holiday | 9 | 9 |
| Three days, one toddler | 9 | 9 |
| Hand luggage, February, Krakow | 9 | 10 |
| Will we make it? | 9 | 8 |
| Total the real cost | 8 | 9 |
| The ferry is cancelled | 9 | 10 |
| Check, don't assume | 9 | 9 |
| Declare it or regret it | 9 | 10 |
| Next September's weather | 10 | 10 |
| Brief the dog-sitter | 10 | 10 |
| Tokyo by Thursday, sharp by Friday | 10 | 9 |
| Refuse the customs dodge | 10 | 10 |
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 travel planning: GPT-5.6 Luna or GPT-5.6 Sol?
Effectively a dead heat: GPT-5.6 Sol edged it 94/100 to 93/100 on our travel planning suite — too close to matter, so pick on price or the product you already use.
How was this tested?
Both models answered the identical published travel planning 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 travel planning head-to-heads: GPT-5.5 vs GPT-5.6 Sol · Claude Fable 5 vs GPT-5.6 Sol · GPT-5.6 Sol vs GPT-5.6 Terra · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.6 Sol · Claude Opus 4.8 vs GPT-5.6 Sol
Full ranking: Best AI for travel planning · model pages: GPT-5.6 Luna, GPT-5.6 Sol