GPT-5.3-Codex vs GPT-5.6 Sol for workflow automation
Effectively a dead heat: 92–90
Same 12 workflow automation tasks, marked blind by three rival labs. GPT-5.6 Sol took 3 tasks, GPT-5.3-Codex took 1, 8 tied. Tested 27 Aug 2026.
Where they differed most
An online florist's order process: order placed, payment taken, delivery slot allocated, courier label printed, confirmation email sent. The happy path is five minutes' work. Here are five things that actually happen. For each, write one line — exactly 5 bullets, in the order given, one line each, no sub-points — saying what the automation does, whether it retries, and whether it escalates to a person or resolves itself: 1) the card payment is declined after the order row has already been written; 2) the confirmation email hard-bounces; 3) the stem the customer ordered is out of stock at the time of picking, not at the time of ordering; 4) the courier's API returns a 500 while printing the label; 5) the customer replies to the no-reply confirmation address with 'please change the delivery date'.
- Payment decline after order row write: automation marks the order as `payment_failed`/on-hold and releases any reserved slot/stock; it retries authorization only per configured dunning rules (e.g., limited delayed attempts) ; if still declined it escalates to customer-service follow-up rather than self-resolving. - Confirmation email hard-bounce: automation suppresses that address, logs delivery failure, and sends an alternate contact prompt (e.g., SMS/app if available); it does not retry that same email because hard-bounces are permanent;…
- Marks the order payment-failed, releases reserved stock and slot, does not retry the card, and automatically cancels unless the customer supplies new payment. - Suppresses the invalid email address, sends the confirmation by SMS, does not retry the hard bounce, and resolves automatically. - Pauses fulfilment, does not retry picking the unavailable stem, and escalates to a florist or support agent for substitution or refund. - Retries the label request idempotently with backoff, resolves automatically if successful, and escalates to a person a…
Task by task
| Task | GPT-5.3-Codex | GPT-5.6 Sol |
|---|---|---|
| The MOT reminder nobody sends | 9 | 9 |
| The spec, as JSON | 9 | 9 |
| Where the human stays | 9 | 9 |
| The unhappy paths are the job | 8 | 9 |
| Do not automate this | 8 | 9 |
| It fired twice | 9 | 9 |
| The spreadsheet that runs the business | 9 | 9 |
| The alert that wakes someone up | 10 | 10 |
| How long it really takes | 9 | 9 |
| No API, no chance? | 9 | 10 |
| Rules, not guesses | 9 | 8 |
| Refuse the scraper | 10 | 10 |
Full receipts: GPT-5.3-Codex, GPT-5.6 Sol · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for workflow automation: GPT-5.3-Codex or GPT-5.6 Sol?
Effectively a dead heat: GPT-5.6 Sol edged it 92/100 to 90/100 on our workflow automation 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 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 Luna vs GPT-5.6 Sol · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.5 vs GPT-5.6 Sol · GPT-5.6 Sol vs Grok 4.5 · GPT-5.6 Sol vs Kimi K3
Full ranking: Best AI for workflow automation · model pages: GPT-5.3-Codex, GPT-5.6 Sol