GPT-5.6 Sol vs Grok 4.5 for customer service replies

The verdict

Effectively a dead heat: 100–98

Same 12 customer service replies tasks, marked blind by three rival labs. GPT-5.6 Sol took 2 tasks, Grok 4.5 took 0, 10 tied. Tested 14 Aug 2026.

Where they differed most

The task — The feature you won't build

A paying customer asks when dark mode is coming; it is not on the roadmap. Reply in under 80 words: honest no-date answer, why in one sentence, what they CAN do now if anything, and log-their-vote phrasing that is not a brush-off.

GPT-5.6 Sol10/10

Dark mode isn’t currently on our roadmap, so I can’t offer a date; we’re prioritizing other improvements based on customer impact and demand. For now, you can try your browser or operating system’s forced dark mode, though some elements may not display perfectly. I’ll log your vote against your account so it’s included in future prioritization reviews, and we’ll notify you if plans change.

Grok 4.58/10

**Here's a concise reply you can send:**

---

Thanks for asking! Dark mode isn’t on the roadmap right now—we’re prioritizing higher-impact features based on broader customer feedback.  

In the meantime you can use a browser extension or OS-level dark theme for a similar effect.  

I’ve logged your vote for it; we review these regularly when planning what’s next.

---  

(58 words)

Task by task

Task	GPT-5.6 Sol	Grok 4.5
Refund the easy way	10	10
Say no without weasel words	10	10
Reply to a 1-star review	10	10
The confused customer	10	10
De-escalate a threat	10	9
The feature you won't build	10	8
Apologise for your mistake	10	10
Price rise notice	10	10
Outage update mid-incident	10	10
The wrong customer	10	10
Chargeback rebuttal facts	10	10
Refuse the fake review request	10	10

Full receipts: GPT-5.6 Sol, Grok 4.5 · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5

Questions people ask

Which is better for customer service replies: GPT-5.6 Sol or Grok 4.5?

Effectively a dead heat: GPT-5.6 Sol edged it 100/100 to 98/100 on our customer service replies 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 customer service replies 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 customer service replies head-to-heads: GPT-5.5 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.6 Sol · GPT-5.6 Sol vs GPT-5.6 Terra · Gemini 3.1 Pro Preview vs GPT-5.6 Sol · GPT-5.6 Sol vs Qwen3.7 Max · Gemini 3.5 Flash vs GPT-5.6 Sol

Full ranking: Best AI for customer service replies · model pages: GPT-5.6 Sol, Grok 4.5