OpenAI releases GPT-5.4 mini and nano with 3-4x price increases but major performance gains
OpenAI has released GPT-5.4 mini and GPT-5.4 nano, compact models optimized for coding and subagent tasks. The new models deliver significant performance improvements—GPT-5.4 mini reaches 54.4% on SWE-Bench Pro versus 45.7% for GPT-5 mini—but cost 3-4x more per input token than their predecessors.