OpenAI Releases GPT-5.4 Mini and Nano — Smaller Models Explicitly Built for Subagent Workloads

OpenAI Blog·high signal

OpenAI launched GPT-5.4 mini and nano, two smaller, faster variants of GPT-5.4 optimized for coding, tool use, multimodal reasoning, and high-volume API and subagent tasks. The models are explicitly positioned for agent-to-agent orchestration where running full GPT-5.4 at every node is cost-prohibitive. This is the first time OpenAI has shipped a model family with 'sub-agent workloads' as a named design target.