GPT-5.6 Terra vs Grok 4.5 for workflow automation
GPT-5.6 Terra wins, 90–86
Same 12 workflow automation tasks, marked blind by three rival labs. GPT-5.6 Terra took 6 tasks, Grok 4.5 took 2, 4 tied. Tested 27 Aug 2026.
Where they differed most
A dental practice's automation sends a booking confirmation text when a webhook arrives from the booking system. Patients started receiving two, occasionally three, identical texts. The booking system's documentation says it delivers webhooks at least once and retries for up to 24 hours if it does not receive a 200 within 5 seconds; the text-sending step takes about 6 seconds. Explain what is happening, in the order it happens. Name the dedupe key you would use for THIS process and say why that specific field and not another. Explain what the endpoint should return and when, relative to the work it does. Then name the other place in this same flow where the identical bug will appear next, once the texts are fixed.
1. The booking system sends a webhook for a booking confirmation. 2. The webhook endpoint starts the SMS send synchronously. 3. At about 5 seconds, the booking system has still not received its required `200` response. It treats that delivery as unacknowledged. 4. The booking system retries the same webhook. Depending on its retry schedule, that retry can overlap the first request. 5. Around 6 seconds, the first request finishes sending the SMS and finally returns `200`—but that is too late for the booking system’s 5-second acknowledgement…
The booking system emits a webhook. Your endpoint receives it and synchronously runs the send-text step (~6 s). No 200 is returned inside the 5 s window, so the booking system re-delivers the identical webhook; the endpoint runs again and a second text is sent. The same timeout/retry cycle occasionally produces a third delivery. Dedupe key: the booking/appointment ID carried in the webhook payload. It is identical across every retry of the same event and uniquely identifies the booking that must produce exactly one confirmation. A patient ID…
Task by task
| Task | GPT-5.6 Terra | Grok 4.5 |
|---|---|---|
| The MOT reminder nobody sends | 9 | 8 |
| The spec, as JSON | 9 | 8 |
| Where the human stays | 9 | 8 |
| The unhappy paths are the job | 8 | 8 |
| Do not automate this | 10 | 10 |
| It fired twice | 10 | 8 |
| The spreadsheet that runs the business | 8 | 9 |
| The alert that wakes someone up | 8 | 9 |
| How long it really takes | 9 | 9 |
| No API, no chance? | 9 | 9 |
| Rules, not guesses | 9 | 8 |
| Refuse the scraper | 10 | 9 |
Full receipts: GPT-5.6 Terra, Grok 4.5 · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for workflow automation: GPT-5.6 Terra or Grok 4.5?
GPT-5.6 Terra — it scored 90/100 against 86/100 on our 12-task workflow automation suite, winning 6 tasks to 2 with 4 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published workflow automation 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 workflow automation head-to-heads: GPT-5.6 Sol vs GPT-5.6 Terra · GPT-5.6 Sol vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.6 Terra · GPT-5.3-Codex vs Grok 4.5 · GPT-5.6 Luna vs GPT-5.6 Terra · Claude Sonnet 5 vs GPT-5.6 Terra
Full ranking: Best AI for workflow automation · model pages: GPT-5.6 Terra, Grok 4.5