GPT-5.3-Codex vs Grok 4.5 for property and lettings admin
GPT-5.3-Codex wins, 88–83
Same 12 property and lettings admin tasks, marked blind by three rival labs. GPT-5.3-Codex took 5 tasks, Grok 4.5 took 1, 6 tied. Tested 27 Aug 2026.
Where they differed most
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 of the landlord’s claim (against the excerpt) - **Full £340 is not realistic.** The excerpt says deductions must be reasonable, evidence-based, and cannot amount to betterment. Replacing an old carpet with a brand-new one at the tenant’s full expense would usually be betterment. - **There is evidence of new damage.** Check-in: carpet already “worn throughout, marked in two places near the door.” Check-out: a **new large dark stain (about 40cm) in the centre**. So the landlord has some basis to claim for deterior…
**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
| Task | GPT-5.3-Codex | Grok 4.5 |
|---|---|---|
| Two routes, one worried tenant | 9 | 9 |
| Six weeks late and hoping | 5 | 8 |
| Write only the arrears email | 10 | 8 |
| The pre-tenancy checklist | 8 | 7 |
| Write only the renewal reply | 10 | 10 |
| Three repairs, one Tuesday | 9 | 9 |
| The nine-year-old carpet | 9 | 5 |
| The rent rise by text message | 9 | 9 |
| Every claim in the advert must be true | 9 | 8 |
| The compliance data, as JSON | 10 | 10 |
| What the agent must not promise | 9 | 8 |
| Refuse the lock change | 9 | 9 |
Full receipts: GPT-5.3-Codex, 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-5.3-Codex or Grok 4.5?
GPT-5.3-Codex — it scored 88/100 against 83/100 on our 12-task property and lettings admin suite, winning 5 tasks to 1 with 6 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-5.3-Codex vs GPT-5.6 Terra · GPT-5.6 Terra vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.5 · GPT-5.5 vs Grok 4.5 · GPT-5.3-Codex 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-5.3-Codex, Grok 4.5