On 17 april 2025, OpenAI has unveiled Codex CLI, an open-source command-line coding assistant. A big step forward for the community as it is the first open source tool by OpenAI. Designed to enhance developer productivity through AI-driven automation and multimodal reasoning. Codex CLI enables developers to interact directly with their codebase from the terminal, supporting tasks such as reading, editing, and executing code locally.
Codex CLI operates in three distinct modes: Suggest, Auto Edit, and Full Auto. These modes offer varying levels of autonomy, allowing users to choose the degree of AI involvement in their coding tasks. For instance, in Suggest mode, the tool provides code suggestions that require user approval, while Full Auto mode allows the AI to autonomously read, write, and execute code within a sandboxed environment.
A standout feature of Codex CLI is its support for multimodal inputs, including text, screenshots, and sketches. This capability enables the AI to interpret various forms of input to generate or modify code accordingly, bridging the gap between conceptual ideas and executable code.
The tool is powered by OpenAI’s latest o4-mini model by default, with options to switch to other models via the Responses API. Currently, Codex CLI is compatible with macOS and Linux systems, while Windows support is in an experimental phase, requiring the Windows Subsystem for Linux (WSL) for operation.
To encourage adoption and innovation, OpenAI has launched a $1 million grant program offering API credits in increments of $25,000 to projects utilizing Codex CLI.
Developers interested in exploring Codex CLI can access the tool and its documentation on GitHub: https://github.com/openai/codex.
Finally it is important to notice that Codex CLI is an experimental project under active development. It is not yet stable, may contain bugs, incomplete features, or undergo breaking changes.
