OpenAI released a new coding model called GPT-5.3-Codex on February 5, 2026. The company says the model has improved reasoning and professional knowledge capabilities. It also operates 25 percent faster than its predecessor. Anthropic, one of OpenAI’s chief rivals, also released a new coding model the same day called Claude Opus 4.6. Earlier this week, OpenAI launched the Codex app for macOS, a new app interface for managing multiple AI agents at once.
A model that built itself
OpenAI says GPT-5.3-Codex is its first model that was instrumental in creating itself. According to Mashable, the Codex team used early versions to debug its own training and manage its own deployment. The team also used it to diagnose test results and evaluations. OpenAI wrote that its team was blown away by how much Codex accelerated its own development.
Anthropic said something similar about Claude Cowork recently. Engineers at OpenAI and Anthropic say almost all their coding is now done by AI. We don’t know exactly how much GPT-5.3-Codex was involved in its own development. But the news reveals how advanced frontier AI models have become, particularly in writing code.
Why self-improving AI matters
People who believe in the technological singularity talk about a tipping point. At that point, technology becomes self-improving and leads to an uncontrolled explosion of technological advancement. Now we have real-world examples of AI improving itself, at least according to the AI companies behind the announcements.
What the new model can do
OpenAI says Codex goes from an agent that can write and review code to an agent that can do nearly anything developers and professionals can do on a computer. The model is available now in the Codex app. Users can access it through OpenAI’s platform.
The release comes as competition heats up in the AI coding space. Multiple companies are racing to build more capable models. These models can handle complex development tasks and accelerate software creation. GPT-5.3-Codex represents OpenAI’s latest entry in this competitive field.
