GPT-5.4 is here. -Massive Context Window (≈1M+ tokens) -That’s more than double GPT-5.2’s ~400k token window -Lower hallucinations -Agent-like behaviour -Fast mode introduced (1.5x faster output)
GPT-5.4 Thinking and GPT-5.4 Pro are rolling out now in ChatGPT. GPT-5.4 is also now available in the API and Codex. GPT-5.4 brings our advances in reasoning, coding, and agentic workflows into one frontier model.
