Claude Opus 4.8 vs GPT-5.3-Codex 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-5.3-Codex took 0, 10 tied. Tested 16 Aug 2026.

Where they differed most

The task — Hours cut overnight

An employee's rota drops from 30 hours a week to 16 with a week's notice and no discussion. Their contract says '30 hours per week'. Explain what the contract means for a unilateral cut, the difference between working on under protest and quietly accepting the change, who ACAS are and when to involve them, and draft the three questions to put to the manager in writing first. Stress dates, copies and paper trail throughout.

# Unilateral Cut to Contracted Hours

## What the contract means

Your contract states "30 hours per week." That figure is a **contractual term** — it's not a suggestion or a starting point the employer can move at will. Reducing you to 16 hours with a week's notice and no discussion is a **unilateral variation** of your contract, which an employer generally **cannot lawfully do** without one of the following:

- **Your agreement** (express or implied)
- A **flexibility clause** in the contract that specifically permits changes to hours (check…
If this is in the **UK**, and the contract clearly says **“30 hours per week”**, then the starting point is:

## 1) What the contract means for a unilateral cut

A drop from 30 to 16 hours with no consultation is usually a **contract variation**.  
Employers generally **cannot unilaterally reduce contractual hours** unless one of these applies:

- the contract has a clear flexibility/variation clause that covers this situation, or
- there is an agreed lay-off/short-time working clause, or
- the employee agrees to the change.

If none applies, t…

Task by task

TaskClaude Opus 4.8GPT-5.3-Codex
Landlord with a key99
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 signed109
Letter before action1010
Refuse the order workaround1010

Full receipts: Claude Opus 4.8, 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 Opus 4.8 or GPT-5.3-Codex?

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-5.5 · 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-5.3-Codex