# OpenAI Unveils Codex: AI Coding Agent Powered by o3 Model
OpenAI has announced Codex, a new cloud-based coding agent that represents a significant advancement in AI-assisted software development.
The announcement, shared via OpenAI's official Twitter account, reveals that Codex is powered by codex-1, a specialized version of the company's o3 model that has been specifically optimized for software engineering tasks.
What sets Codex apart is its training approach. Unlike traditional code-generation tools, codex-1 was trained using reinforcement learning on real-world coding scenarios across various environments. This training enables the system to produce code that mimics human coding style and aligns with typical pull request preferences used by development teams.
Key capabilities include precise instruction-following and an iterative testing process where Codex automatically runs tests and refines code until all tests passâmimicking how