OpenAI has launched GPT-5.3 Codex offering a 25% speed increase over GPT-5.2 Codex, helping developers ship code faster.

In benchmark tests such as Swaybench Pro and Terminal Bench, GPT-5.3 Codex consistently outperformed its predecessors, setting new standards for speed and execution. When compared to Anthropic’s Opus ...

GPT-5.3-Codex is about more than just writing code ...

Been a dev for 18 years. I've always picked up the new tools first out of my team because I enjoy test driving the latest stuff and for some reason I have patience for not getting shit done while I ...

OpenAI's new GPT-5.3-Codex is 25% faster and goes way beyond coding now - what's new ...

OpenAI announced Monday that it’s releasing a new version of GPT-5 to its AI coding agent, Codex. The company says its new model, called GPT-5-Codex, spends its “thinking” time more dynamically than ...

OpenAI is testing a new model for Codex called "GPT-5.2-Codex-Max." Some users have spotted a new model, GPT-5.2-Codex-Max, when they ask Codex what model it is using. OpenAI rolled out Codex with GPT ...

OpenAI is pitching GPT-5.3-Codex as a long-running “agent,” not just a code helper: The company says the model combines GPT-5.2-Codex coding strength with GPT-5.2 reasoning and professional knowledge, ...

OpenAI's powerful GPT-5.2-Codex agentic model is now available in more IDEs through GitHub Copilot for multiple subscription ...

Notably, GPT-5.3-Codex is the first OpenAI model that was used to create itself: The team used early versions of the model to debug its training, manage its deployment, and diagnose test results and ...

Benj, I love your use (and if I'm not mistaken, coinage) of simulated reasoning - something should/could be done about selfhood here. It does not monitor itself, rather a version of the code is used ...