OpenAI has launched GPT-5.3-Codex, a state-of-the-art model that excels in handling complex development tasks and managing large projects without losing context. This model acts as a full-fledged agent capable of planning steps, working with tools, and operating in real work environments. It is faster than its predecessor and stronger in reasoning, suitable for coding, analysis, research, documentation, and product-related development tasks.

Interestingly, OpenAI used Codex to help create itself, involving the model in its own development cycle.

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