GPT-5.3-Codex – Expanding Codex to the full spectrum of computer work

Summary: GPT-5.3-Codex improves coding and computer tasks with state-of-the-art performance on SWE-Bench Pro (57%) and OSWorld (64%), featuring mid-task steerability, 25% faster speeds, and advanced cybersecurity capabilities. It partially self-developed by assisting in its own training and deployment.

What it does

It performs complex coding workflows end-to-end with interactive mid-task control and enhanced speed, supporting multiple platforms including app, CLI, IDE, and web.

Who it's for

Developers and technical users requiring advanced coding assistance and workflow automation across various environments.

Why it matters

It accelerates software development by improving accuracy, speed, and security while enabling interactive control during tasks.