On the same day that Anthropic released its Opus 4.6 model to match OpenAI's multi-agent coding advantage, OpenAI has released GPT-5.3-Codex to rival Anthropic's Claude Cowork.

In its blog post announcing the new model, OpenAI declared, "With GPT‑5.3-Codex, 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."

While GPT-5.3-Codex is still aimed primarily at engineers and developers, it can now help them with other parts of their job beyond just writing code. Specifically, OpenAI cites, "debugging, deploying, monitoring, writing [product requirements documents], editing copy, user research, tests, [and] metrics." It's also built to help create slide decks and spreadsheets.

And, of course, many of those tasks will be helpful for professionals adjacent to software engineers, such as product leaders, designers, and project managers. In fact, tech-forward employees in almost any role will likely find these features useful, especially if they already have experience with ChatGPT.

And since OpenAI released its desktop Codex app for Mac on Monday, it's now much more accessible to non-coders, since you no longer have to operate it from the command line. Keep in mind that the Codex app is separate from the ChatGPT app, unlike Claude, which integrates its coding and chatbot into a single app. OpenAI's Codex app is also limited to Mac for now, while the Claude app is also available on Windows. But we should expect that it's only a matter of time before OpenAI brings the Codex app to Windows.

Other notable upgrades include:

• 25% faster inference for quicker coding and task execution
• Improved coding accuracy: it beats previous models on developer benchmarks such as SWE-Bench Pro and Terminal-Bench 2.0
• Interactive agent options: you can steer, ask, and update while the agent is working on complex, long-running tasks
• Upgrades to reasoning and professional knowledge: combines advanced coding with broader general reasoning from GPT-5.2 for more nuanced decision-making
• Stronger cybersecurity: this is the first model that OpenAI qualifies as “high” in their cybersecurity framework, as it's trained to detect software vulnerabilities and backed by stronger safety layers

Notably, OpenAI shared that "GPT‑5.3‑Codex is our first model that was instrumental in creating itself." Specifically, the model was involved in its own debugging, deployment, and diagnosis of test results. The company reported, "Our team was blown away by how much Codex was able to accelerate its own development."