GPT-5.4 API Developer Guide 2026: 1M Context, Computer Use, and 5 Reasoning Levels
GPT-5.4 is OpenAI’s most capable general-purpose model as of 2026, combining a 1,050,000-token context window, native computer use at 75% OSWorld accuracy, and five tunable reasoning effort levels in a single Chat Completions API drop-in. Released March 5, 2026, it replaces gpt-5.2 for most production workloads with no endpoint change required. What Is GPT-5.4? Release Date, Model Variants, and What’s New GPT-5.4 is OpenAI’s flagship general-purpose language model released on March 5, 2026, and it represents the first mainline model to combine frontier reasoning, native computer control, and a 1-million-token context window in a single architecture. Unlike earlier specialized variants — o3 for reasoning or gpt-5.2 for general use — GPT-5.4 integrates GPT-5.3-codex coding capabilities directly, making it a unified backbone for agentic, analytical, and conversational workloads. On launch day, it scored 75.0% on the OSWorld-Verified computer use benchmark, surpassing the human expert baseline of 72.4% — a first for any general-purpose model. On knowledge work (GDPval), GPT-5.4 matches or outperforms industry professionals in 83% of comparisons across 44 occupations. There are two production variants: gpt-5.4 (the standard model, priced at $2.50/$15 per million input/output tokens) and gpt-5.4-pro (optimized for high-stakes enterprise tasks at $30/$180 per million input/output tokens). Both share the same API surface and context window; the pro variant allocates more compute budget per inference by default. ...