Lightweight terminal-based coding agent with local execution and cloud integration

Codex CLI is a lightweight coding agent that runs directly in your terminal. Built by OpenAI and written in Rust, it provides a local-first experience for developers who want to collaborate with an AI agent without leaving the command line. It supports macOS, Linux, and Windows, and can be installed via a shell script, npm, or Homebrew. For those who prefer an IDE integration, it is also available as an extension for VS Code, Cursor, and Windsurf.

Traditional AI coding assistants often require a browser or a plugin, and their code suggestions may need manual copy-pasting into the local environment. Codex CLI solves this by running locally on your machine, with direct access to your files and system. It can execute commands, run scripts, and manage files in your current working directory. This eliminates the friction of switching contexts and enables a tighter feedback loop between natural language instructions and actual code execution.

Codex CLI's key feature is its ability to act as a coding agent that can understand natural language tasks and carry them out locally. It integrates with your existing ChatGPT plan (Plus, Business, Edu, or Enterprise), allowing you to leverage your subscription for agentic capabilities. Alternatively, it can be used with an API key for more granular control. The agent is context-aware: it operates within your terminal's current directory and respects the project structure, making it suitable for code generation, refactoring, debugging, and file management tasks.

The repository is organized around several key directories. codex-rs/ is the Rust core, containing sub-crates for analytics, agent identity, agent graph store, application server, and communication protocols. The codex-cli/ directory provides the Node.js-based CLI wrapper and package scripts. Support for environments and skills is organized under .codex/, and the .devcontainer/ directory enables containerized development and secure sandboxed execution. This modular structure separates the core agent logic from the user-facing CLI and the execution environment.

Installation is straightforward. On macOS or Linux, run:

curl -fsSL https://chatgpt.com/codex/install.sh | sh

On Windows:

powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"

Or use npm:

npm install -g @openai/codex

Once installed, simply run codex to start the agent. You will be prompted to sign in with your ChatGPT account to use your plan, or you can configure an API key. The agent then works in your current directory: you can ask it to add tests, refactor this file, or explain this code snippet.

Codex CLI is ideal for developers who want a terminal-native agent for automating repetitive coding tasks, exploring a codebase with natural language queries, or performing batch file operations. It suits those who already have a ChatGPT plan and want to use it directly from the command line. However, it is not a full-fledged IDE plugin; it operates in the terminal, not within an editor buffer. While it runs locally, agentic actions (file editing, command execution) carry inherent risks—especially in sensitive environments. The project's .devcontainer/ setup offers a sandboxed mode for safer experimentation, but users should still exercise caution with automatic file modifications and command execution.