OpenAI Releases GPT-5.4 Mini and Nano: $0.75/$4.50 and $0.20/$1.25 Per 1M Tokens, Built for the Subagent Era

OpenAI via r/singularity·high signal

OpenAI released GPT-5.4 mini and GPT-5.4 nano on March 17, 2026, positioning both as purpose-built subagent components for agentic pipelines. Mini features a 400K context window, scores 54.4% on SWE-Bench Pro (vs. flagship's 57.7%) and 72.1% on OSWorld computer use, at $0.75 input / $4.50 output per 1M tokens — 70% cheaper than base GPT-5.4. Nano targets classification, extraction, and routing at $0.20 / $1.25 per 1M tokens and is API-only at launch; mini is available in ChatGPT free tier via Thinking.