OpenAI Launches Codex: An AI Assistant For Developers

OpenAI has just introduced Codex, a new cloud-based AI assistant designed to help developers with software tasks.

It’s now available to ChatGPT Pro, Team, and Enterprise users, with support for Plus and education users coming soon.

Codex runs on codex-1, a model specially trained for software engineering. It can write features, fix bugs, answer code questions, and propose pull requests — all in parallel. Each task runs inside a secure environment loaded with the user’s code, making it safe and easy to track.

Codex is easy to use: just type a prompt in ChatGPT, click “Code” or “Ask,” and it starts working. It edits files, runs tests, and even shows live progress. Tasks can take from 1 to 30 minutes, depending on how complex they are.

“Codex provides verifiable evidence of its actions through citations of terminal logs and test outputs,” OpenAI explained. Users can review these results, ask for changes, or directly merge them into their code.

Codex can also read special instructions from AGENTS.md files inside your codebase. These files help it understand your testing process and coding standards. Still, “codex-1 shows strong performance even without AGENTS.md files,” OpenAI stated.

Codex also recently fixed a bug in the Astropy library’s separability_matrix function. A user noted: “Suddenly the inputs and outputs are no longer separable? This feels like a bug to me.” Codex identified the issue and proposed a patch that was accepted — showing its practical value.

OpenAI calls this a “research preview,” meaning it’s still being improved. They stress the importance of safety, transparency, and human oversight: “It still remains essential for users to manually review and validate all agent-generated code before integration and execution.”