What it is
The job it was built for, and the job it is not for.
GPT-5 Nano is a small, low-latency text model that also accepts images and files. It is built for the jobs that sit underneath a product, classification, extraction, routing, autocomplete and other rapid interactions, rather than for long chains of reasoning. It is not the model to reach for when an answer needs careful deliberation, and OpenAI is explicit that its reasoning depth is limited next to the larger GPT-5 variants.