OpenAI announced GPT-5.4 mini and nano on March 17, 2026. The company says mini is more than 2x faster than GPT-5 mini while improving coding, reasoning, multimodal understanding, and tool use, while nano targets low-cost classification, extraction, ranking, and simpler coding subagents.
OpenAI introduced GPT-5.4 mini and nano on March 17, 2026 as smaller GPT-5.4 variants for low-latency coding, tool use, and multimodal workflows. The company positioned the models for high-volume API and subagent tasks where speed and cost matter more than maximum capability.
OpenAI Developers said on X that GPT-5.4 mini and nano are now part of the GPT-5.4 family for developer workflows. OpenAI positions mini as a faster coding and tool-use model for API, Codex, and ChatGPT, while nano is the lowest-cost option for lighter API workloads.
OpenAIDevs said on March 16, 2026 that subagents are now available in Codex. The feature lets developers keep the main context clean, split work across specialized agents, and steer individual threads as they run, while the official docs already describe PR review and CSV batch fan-out patterns.
GitHub used X on March 15, 2026 to spotlight the Copilot CLI `/fleet` command for routine maintenance work. GitHub’s official Copilot CLI materials now describe `/fleet` as a parallel sub-agent workflow that converges multiple runs into one decision-ready result.