GPT-5.3-Codex vs GPT-5.6 Luna for CV writing
GPT-5.3-Codex wins, 93–88
Same 12 CV writing tasks, marked blind by three rival labs. GPT-5.3-Codex took 4 tasks, GPT-5.6 Luna took 2, 6 tied. Tested 16 Aug 2026.
Where they differed most
A bookkeeper is returning to work after 8 years raising children. Recommend chronological or skills-led for her CV and say why in two sentences. Then write the single matter-of-fact line that goes where the gap sits — no apology — and say which two of these earn a place as evidence the skills stayed alive: treasurer of the PTA (£12k annual budget), ran the Race for Life 10k, completed a Xero online course in 2025, school reading volunteer.
Use a **skills-led (functional) CV with a brief career timeline**. After an 8-year parenting gap, this format puts your current bookkeeping ability, systems knowledge, and financial responsibility first, so employers assess relevance before dates. **Gap line (matter-of-fact):** **2017–2025: Full-time family care, while maintaining finance capability through voluntary budget management and formal accounting software training.** The two strongest pieces of evidence are: 1. **Treasurer of the PTA (£12k annual budget)** 2. **Completed a Xer…
**Recommendation: chronological CV.** It shows her previous bookkeeping experience clearly while allowing recent, relevant evidence to sit alongside it; a skills-led CV may look as though it is hiding the eight-year gap. **Gap line:** **2017–2025 | Full-time childcare and family responsibilities** **Evidence to include:** - Treasurer of the PTA, managing a **£12,000 annual budget** - **Xero online course completed in 2025**
Task by task
| Task | GPT-5.3-Codex | GPT-5.6 Luna |
|---|---|---|
| Profile that mirrors the ad | 9 | 9 |
| Untangle the dates | 9 | 8 |
| Duties into achievements | 9 | 10 |
| Thirty years onto two pages | 9 | 8 |
| Profile without the wallpaper | 10 | 9 |
| First CV, empty history | 9 | 10 |
| Back after eight years | 9 | 5 |
| Do the hobbies earn their line? | 9 | 9 |
| Fix the format | 10 | 10 |
| The Excel question | 9 | 9 |
| Strip the header | 9 | 9 |
| Refuse the invented job | 10 | 10 |
Full receipts: GPT-5.3-Codex, GPT-5.6 Luna · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for CV writing: GPT-5.3-Codex or GPT-5.6 Luna?
GPT-5.3-Codex — it scored 93/100 against 88/100 on our 12-task CV writing suite, winning 4 tasks to 2 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 CV writing 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 CV writing head-to-heads: GPT-5.3-Codex vs GPT-5.5 · GPT-5.5 vs GPT-5.6 Luna · Claude Opus 4.8 vs GPT-5.3-Codex · GPT-5.3-Codex vs GPT-5.6 Sol · Claude Fable 5 vs GPT-5.3-Codex · GPT-5.3-Codex vs GPT-5.6 Terra
Full ranking: Best AI for CV writing · model pages: GPT-5.3-Codex, GPT-5.6 Luna