OpenAI Codex CLI
Terminal coding agent built on OpenAI reasoning models
Description
OpenAI Codex CLI is a first-party terminal coding agent built by OpenAI, launched in April 2025 and rewritten from TypeScript into Rust. The tool reads, modifies, and executes code on a local machine through OpenAI's frontier reasoning models, including the o3 and GPT-5 families. Codex CLI shares its name with the deprecated 2021 Codex API but is an entirely separate product category.
Key Capabilities:
Rust-built CLI with low memory footprint, installable through npm with a single command
Three approval modes covering read-only Suggest, file-editing Auto Edit, and sandboxed Full Auto
Network-disabled, directory-sandboxed execution with Docker isolation on Linux
apply_patch, shell, update_plan, and multi_tool_use primitives for atomic file edits and command execution
Multimodal input support for text, screenshots, and diagrams
ChatGPT Plus and Pro subscription authentication as an alternative to per-token API billing
Built-in @github commands for pull request management and repository queries
Experimental multi-agent collaboration for splitting planning from execution
Responses API backend with support for o3, o3-pro, GPT-4o, and GPT-5 models
Plugin ecosystem covering Neovim, VS Code, and JetBrains integrations with 150+ community tools
Apache 2.0 licensed with a $1M open-source grant program for ecosystem projects
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