Thinking Small, Acting Big: OpenAI Unveils GPT-5.4 Mini and Nano for the Subagent Era

This report announces OpenAI's GPT-5.4 mini and GPT-5.4 nano models, detailing performance improvements over prior models, multimodal and instrumental capabilities, deployment guidance (including a "subagent" architecture for planners and executors), and pricing targeted at large-scale developer use; it is a product/feature overview rather than a security incident.