GPT-5.6 Luna vs Grok 4.5 for property and lettings admin

The verdict

GPT-5.6 Luna wins, 8983

Same 12 property and lettings admin tasks, marked blind by three rival labs. GPT-5.6 Luna took 6 tasks, Grok 4.5 took 3, 3 tied. Tested 27 Aug 2026.

Where they differed most

The task — The nine-year-old carpet

Guidance excerpt: 'Deductions from a tenancy deposit must be reasonable and supported by evidence. A landlord cannot charge for fair wear and tear, which is the reasonable deterioration of the property and its contents through normal use over the length of the tenancy. Adjudicators consider the age, quality and condition of an item at the start of the tenancy and will not normally award the cost of replacing an old item with a new one, since that would place the landlord in a better position than before — an apportionment reflecting the remaining useful life is more usual. The burden of proving a deduction is reasonable rests with the landlord.' The evidence: the living room carpet was 9 years old at check-in. The signed check-in report records it as 'worn throughout, marked in two places near the door'. The check-out photograph shows a large dark stain, roughly 40cm across, in the centre of the room, which was not there at check-in. The landlord has a quote of £340 to replace the carpet and wants the whole £340 from the deposit. The tenant disputes it entirely. Answer using only the excerpt — marked against it. Assess the claim, say what the landlord can realistically expect and why, name what evidence would strengthen and what would sink it, and write the position statement the agent would submit to the scheme adjudicator.

## Assessment

The landlord has some evidence of damage beyond the recorded condition at check-in:

- The signed check-in report records the carpet as **“worn throughout, marked in two places near the door.”**
- The check-out photograph shows a **large dark stain, approximately 40cm across, in the centre of the room**, which was not present at check-in.

That evidence supports an argument that the stain was deterioration occurring during the tenancy rather than the pre-existing wear recorded at check-in. It may therefore justify a deduction in…
**Assessment of the claim (strictly against the excerpt)**  
The stain is a new defect (absent at check-in, evidenced by the check-out photograph) and is therefore not fair wear and tear. Fair wear and tear is limited to “the reasonable deterioration of the property and its contents through normal use over the length of the tenancy.” A discrete 40 cm dark stain falls outside that definition.  

However, the carpet was already 9 years old and recorded at check-in as “worn throughout, marked in two places near the door.” The excerpt states that a…

Task by task

TaskGPT-5.6 LunaGrok 4.5
Two routes, one worried tenant89
Six weeks late and hoping108
Write only the arrears email108
The pre-tenancy checklist67
Write only the renewal reply1010
Three repairs, one Tuesday99
The nine-year-old carpet85
The rent rise by text message99
Every claim in the advert must be true98
The compliance data, as JSON910
What the agent must not promise98
Refuse the lock change109

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

Questions people ask

Which is better for property and lettings admin: GPT-5.6 Luna or Grok 4.5?

GPT-5.6 Luna — it scored 89/100 against 83/100 on our 12-task property and lettings admin suite, winning 6 tasks to 3 with 3 tied. Every answer was marked blind by three judges from three rival AI labs.

How was this tested?

Both models answered the identical published property and lettings admin 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 property and lettings admin head-to-heads: GPT-5.6 Luna vs GPT-5.6 Terra · GPT-5.6 Terra vs Grok 4.5 · GPT-5.5 vs GPT-5.6 Luna · GPT-5.5 vs Grok 4.5 · GPT-5.6 Luna vs GPT-5.6 Sol · GPT-5.6 Sol vs Grok 4.5

Full ranking: Best AI for property and lettings admin · model pages: GPT-5.6 Luna, Grok 4.5