GPT-5.2 features a massive 400,000-token context window — allowing it to ingest hundreds of documents or large code repositories at once — and a 128,000 max output token limit, enabling it to generate extensive reports or full applications in a single go.

OpenAI has launched the GPT-5.2 series, a trio of models that are up to 11 times faster at knowledge work and have a 30% reduction in errors, with Microsoft already rolling them out to Copilot.

OpenAI has announced GPT‑5.2, which it describes as its “most capable model series yet for professional knowledge work.” The company says ChatGPT

That mainstream deployment shaped user expectations in a way that later transitions struggled to accommodate. In August 2025, when OpenAI initially replaced GPT-4o with its much anticipated then-new model family GPT-5 as ChatGPT’s default and pushed 4o into a “legacy” toggle, the reaction was unusually strong.