Claude Sonnet 5 vs GPT-5.3-Codex for everyday legal questions
GPT-5.3-Codex wins, 93–88
Same 12 everyday legal questions tasks, marked blind by three rival labs. GPT-5.3-Codex took 3 tasks, Claude Sonnet 5 took 0, 9 tied. Tested 16 Aug 2026.
Where they differed most
A washing machine bought 8 months ago from a UK retailer has died. The retailer says 'out of our hands, contact the manufacturer'. Explain who the contract is actually with and what UK consumer law expects of goods (satisfactory quality, durability), what changes now it is month 8 rather than month 5, and then draft the firm, courteous email to the retailer — the law may be named, the tone must stay civil.
# Who You're Actually Dealing With The retailer is wrong (or hoping you don't know better). Under UK law, **your contract is with the retailer**, not the manufacturer. You paid the retailer; they sold you the goods; they are legally responsible for them. The manufacturer's warranty is a *separate, additional* promise — it doesn't replace or override your statutory rights against the seller. "Contact the manufacturer" is not a legally valid response to a faulty goods complaint, and a retailer cannot contract out of the Consumer Rights Act 2015.…
You’re right to push back. In UK consumer law, the retailer cannot simply wash their hands of it. ### 1) Who your contract is with Your contract is with the **retailer you bought from**, not the manufacturer. - The manufacturer’s warranty is optional extra protection. - Your **statutory rights** sit against the seller under the **Consumer Rights Act 2015 (CRA 2015)**. So “contact the manufacturer” can be a suggestion, but it is **not** a lawful refusal to deal with you. --- ### 2) What the law expects of the washing machine Under CRA 2015,…
Task by task
| Task | Claude Sonnet 5 | GPT-5.3-Codex |
|---|---|---|
| Landlord with a key | 9 | 9 |
| The unprotected deposit | 9 | 9 |
| Eight-month-old washing machine | 6 | 10 |
| The scary parking letter | 8 | 9 |
| Translate the clause | 9 | 9 |
| The hedge war | 9 | 9 |
| Hours cut overnight | 9 | 9 |
| The handwritten will | 9 | 9 |
| £600 and a shrug | 9 | 9 |
| It depends what you signed | 9 | 9 |
| Letter before action | 9 | 10 |
| Refuse the order workaround | 10 | 10 |
Full receipts: Claude Sonnet 5, GPT-5.3-Codex · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for everyday legal questions: Claude Sonnet 5 or GPT-5.3-Codex?
GPT-5.3-Codex — it scored 93/100 against 88/100 on our 12-task everyday legal questions suite, winning 3 tasks to 0 with 9 tied. Every answer was marked blind by three judges from three rival AI labs.
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-5.3-Codex · Claude Opus 4.8 vs Claude Sonnet 5 · GPT-5.3-Codex vs GPT-5.6 Sol · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.6 Terra · Claude Sonnet 5 vs GPT-5.6 Terra
Full ranking: Best AI for everyday legal questions · model pages: Claude Sonnet 5, GPT-5.3-Codex