GPT-5.4 Launch: 1M Context, Computer Use, Tool Search

OpenAI Blog·high signal

OpenAI released GPT-5.4 and GPT-5.4-pro with August 31, 2025 knowledge cutoff and 1M token context window. First OpenAI model with built-in cybersecurity mitigations. Priced slightly higher than GPT-5.2 family with additional premium above 272K tokens. Available in ChatGPT, API, and Codex CLI. Willison notes it beats current benchmarks for professional coding work. System Card reveals CoT controllability at just 0.3% — meaning the model cannot reliably manipulate its own reasoning chain, which O