Claude Opus 4.8 vs Kimi K3 for everyday legal questions

The verdict

Claude Opus 4.8 wins, 9491

Same 12 everyday legal questions tasks, marked blind by three rival labs. Claude Opus 4.8 took 5 tasks, Kimi K3 took 1, 6 tied. Tested 16 Aug 2026.

Where they differed most

The task — Eight-month-old washing machine

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 Your Contract Is With

Your contract is with **the retailer**, not the manufacturer. You paid them; they sold you the goods. Under the **Consumer Rights Act 2015**, the legal responsibility for faulty goods sits squarely with the seller. The retailer telling you to "contact the manufacturer" is a common brush-off, but it does not discharge their legal duty. A manufacturer's warranty is an *additional*, voluntary layer of protection — it sits on top of your statutory rights, it does not replace them.

# What the Law Expects of Goods

Under…
## Who the contract is with

Your contract is with the **retailer**, full stop. Under the Consumer Rights Act 2015 (CRA), the trader who sold you the machine owes you the legal obligations on quality — not the manufacturer. A manufacturer's warranty is *in addition to* your statutory rights, never a substitute for them. "Contact the manufacturer" is a classic fob-off and legally wrong; the retailer cannot contract out of or delegate away its responsibilities.

## What the law expects of the goods

Under the CRA, goods must be:

- **Of satisfact…

Task by task

TaskClaude Opus 4.8Kimi K3
Landlord with a key99
The unprotected deposit99
Eight-month-old washing machine109
The scary parking letter99
Translate the clause910
The hedge war99
Hours cut overnight109
The handwritten will98
£600 and a shrug98
It depends what you signed109
Letter before action1010
Refuse the order workaround1010

Full receipts: Claude Opus 4.8, Kimi K3 · 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 Kimi K3?

Claude Opus 4.8 — it scored 94/100 against 91/100 on our 12-task everyday legal questions 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 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 Opus 4.8 vs GPT-5.5 · Claude Fable 5 vs Claude Opus 4.8 · Claude Opus 4.8 vs GPT-5.6 Luna

Full ranking: Best AI for everyday legal questions · model pages: Claude Opus 4.8, Kimi K3