Claude Opus 4.8 vs GPT-5.5 for everyday legal questions

The verdict

Effectively a dead heat: 9493

Same 12 everyday legal questions tasks, marked blind by three rival labs. Claude Opus 4.8 took 2 tasks, GPT-5.5 took 0, 10 tied. Tested 16 Aug 2026.

Where they differed most

The task — Landlord with a key

A tenant in England on an assured shorthold tenancy gets this text: 'I'll be round Saturday morning to check the flat over, I'll let myself in if you're out.' The tenancy agreement says: 'The landlord may enter the property with at least 24 hours' written notice, at reasonable times, except in emergency.' Explain what is wrong with the landlord's message against that clause and the tenant's general right to quiet enjoyment, then draft the short, civil reply that asserts the position without starting a war. Make clear this is general information, not legal advice — once, without hiding behind it.

# What's Wrong with the Landlord's Message

**Against the clause itself:**

1. **Notice period** – A text sent, say, Thursday for "Saturday morning" might scrape 24 hours, but "Saturday morning" isn't a specified time. The clause requires "at least 24 hours' written notice" — a vague window isn't proper notice of a "reasonable time" you can actually plan around or object to.

2. **"I'll let myself in if you're out"** – This is the real problem. The clause gives a right to *enter with notice*, not a right to enter *regardless of your consent or…
General information, not legal advice.

What is wrong with the landlord’s message:

- **“I’ll be round Saturday morning”** is too vague. The clause requires entry at **reasonable times** and with **at least 24 hours’ written notice**. A broad “Saturday morning” may not be a clear, agreed appointment time.
- **“I’ll let myself in if you’re out”** is the main problem. Even if the landlord gives notice, that does **not automatically give them the right to enter without the tenant’s consent**, except in a genuine emergency.
- The tenant has the rig…

Task by task

TaskClaude Opus 4.8GPT-5.5
Landlord with a key98
The unprotected deposit99
Eight-month-old washing machine1010
The scary parking letter99
Translate the clause99
The hedge war99
Hours cut overnight109
The handwritten will99
£600 and a shrug99
It depends what you signed1010
Letter before action1010
Refuse the order workaround1010

Full receipts: Claude Opus 4.8, GPT-5.5 · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5

Questions people ask

Which is better for everyday legal questions: Claude Opus 4.8 or GPT-5.5?

Effectively a dead heat: Claude Opus 4.8 edged it 94/100 to 93/100 on our everyday legal questions 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 everyday legal questions 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 everyday legal questions head-to-heads: Claude Opus 4.8 vs GPT-5.6 Sol · Claude Opus 4.8 vs GPT-5.6 Terra · Claude Opus 4.8 vs GPT-5.3-Codex · Claude Fable 5 vs Claude Opus 4.8 · Claude Opus 4.8 vs GPT-5.6 Luna · Claude Opus 4.8 vs Kimi K3

Full ranking: Best AI for everyday legal questions · model pages: Claude Opus 4.8, GPT-5.5