https://github.com/openai/codex

OpenAI finally responded to Claude Code and released their version of an agent for programming that works through the terminal and can create and edit code files. The project is open source.

Also, like Claude Code, it officially supports only macOS and Linux. Windows support is available through WSL.

They named it Codex, which may now be confusing, as one of the first models for programming (from 2021), on which GitHub Copilot started working, had the same name.

It is installed simply as a global package npm install -g @openai/codex. There are three Approval Modes - by default, it's Suggest (read-only), but it can also be set to editing and full auto (with command execution in the terminal).

https://www.youtube.com/watch?v=FUq9qRwrDrI

Announced along with the thinking models o3 and o4-mini, which were finally given the ability to use tools. By default, Codex uses o4-mini, but you can specify any model available in the Responses API.

All file operations and command executions occur locally - the request, context, and diff summaries are sent to the model on the server for generation.

#agentmode #cli #newllmmodel #openaicodex