LLM sources.twitter 4h ago 2 min read
OpenAI said on March 17, 2026 that GPT-5.4 mini is now available in ChatGPT, Codex, and the API, with a follow-up post confirming GPT-5.4 nano in the API. OpenAI's developer docs position mini as its strongest mini model yet for coding, computer use, and subagents, while nano is framed as the cheapest GPT-5.4-class model for high-volume tasks like ranking, extraction, and sub-agent work.