OpenAI Codex CLI

OpenAI Codex CLI is a terminal-native coding agent that reads, executes, and modifies local codebases using advanced reasoning models like o3 and gpt-5.4.

Codex CLI transforms the terminal into an interactive development environment by combining OpenAI reasoning models with local execution capabilities. Built in Rust for high performance, it allows developers to scaffold files, run tests, and perform multi-agent code reviews without leaving the command line. The tool prioritizes security through granular approval modes (Auto, Read-only, and Full Access) and a local-first architecture that keeps source code within the user's environment. With support for multimodal inputs like screenshots and integration with the Model Context Protocol (MCP), it serves as a lightweight, open-source alternative to IDE-based agents for terminal-centric workflows.

https://github.com/openai/codex