Best AI for customer service replies / head-to-head

GPT-5.5 vs Grok 4.5for customer service replies

The verdict

GPT-5.5 wins, 99–98

Same 12 customer service replies tasks, marked blind by three rival labs. GPT-5.5 took 2 tasks, Grok 4.5 took 1, 9 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-5.510/10

Thanks for asking — dark mode isn’t currently on our roadmap, so I don’t have a date to share. We’re prioritizing work that impacts reliability, core workflows, and the most-requested customer needs first. For now, you may be able to use your browser/OS-level dark appearance or a trusted dark-mode extension. I’ll log your request with your account context so it’s counted and visible when we review roadmap priorities.

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-5.5	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	9	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-5.5, 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-5.5 or Grok 4.5?

GPT-5.5 — it scored 99/100 against 98/100 on our 12-task customer service replies suite, winning 2 tasks to 1 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 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-5.6 Sol vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.5 · GPT-5.5 vs GPT-5.6 Terra · Gemini 3.1 Pro Preview vs GPT-5.5 · GPT-5.5 vs Qwen3.7 Max

Full ranking: Best AI for customer service replies · model pages: GPT-5.5, Grok 4.5