In a move to embed AI deeper into software development, OpenAI has unveiled Codex CLI — a lightweight, open source coding agent designed to run locally within terminal applications.
Announced alongside the company’s newest models, o3 and o4-mini, Codex CLI connects OpenAI’s powerful models directly to local codebases and system-level tasks. With it, developers can generate and edit code, move files, and run commands — all from the command line using AI.
This new tool hints at OpenAI’s broader ambitions in “agentic coding.” Earlier this year, OpenAI CFO Sarah Friar outlined a vision for an “agentic software engineer” — an AI capable of taking a high-level app description, building the software from scratch, and even performing quality assurance testing.
While Codex CLI doesn’t go quite that far, it represents a foundational step toward that future. OpenAI says it provides a transparent, minimal interface to bring the capabilities of its models — including multimodal reasoning — to the developer’s local environment.
“Codex CLI is a lightweight, open source coding agent that runs locally in your terminal,” an OpenAI spokesperson told TechCrunch. “The goal is to give users a minimal, transparent interface to link models directly with code and tasks.”
In a blog post, OpenAI added that developers can even upload screenshots or rough sketches to the model through the CLI, allowing for visual reasoning tasks alongside traditional coding help.
To promote adoption, OpenAI is launching a $1 million API grant program for developers. Selected projects will receive $25,000 in API credits to experiment with and build on top of Codex CLI.
However, OpenAI also acknowledges the risks of AI-assisted coding. Research has repeatedly shown that code-generating models can miss bugs and even introduce new vulnerabilities. Developers are cautioned to be especially careful when using such tools on sensitive files or mission-critical systems.
