GPT-5.4 Nano is the most lightweight and cost-efficient model in the GPT-5.4 family, purpose-built for speed-critical, high-volume tasks. It supports text and image inputs and is optimized for low-latency use cases such as classification, data extraction, ranking, and sub-agent execution within larger systems. As a significant upgrade over GPT-5 Nano, it prioritizes responsiveness and efficiency, making it ideal for background pipelines, real-time systems, and distributed agent architectures where minimizing cost and latency is essential.