Codex updates at a furious pace, but many people are stuck at the starting line: how do you register an account? How do you pay for Plus? Desktop, CLI, IDE extension, mobile — which one should you use? CodexGuide, open-sourced on GitHub, exists to solve exactly these problems. It is a complete guide from registration to real-world use — free, continuously updated, and paired with an online reading site.

What CodexGuide Contains

The guide is organized in four layers — "know the entry points, get tasks running, build a methodology, accumulate team knowledge" — with core modules including:

• Entry-point map: from the CLI to the desktop app and IDE extension, helping you sort out the positioning and use cases of each surface in one pass
• Subscription tutorial: the registration and payment flow for Codex Plus — topping up yourself is more stable than finding someone to do it for you
• Mobile usage: connect, via the ChatGPT phone app, to Codex running on your desktop or a remote dev box, so you can keep viewing, approving, and adjusting tasks away from your computer
• Hands-on cases: 13 typical scenarios, including Codex x Draw.io MCP for auto-drawing architecture diagrams, Codex x GitHub Actions for auto-fixing failing CI, and Codex x Obsidian for building an AI knowledge base

Quick Start with the Desktop App

The most-used surface today is the Codex desktop app; its engineering capabilities stand out, particularly computer use and browser control.

The guide covers the full flow from download and installation through subscribing to Plus in detail.

💡 Tip: The Plus subscription tutorial spares you the cost and risk of finding someone to top up for you. Charging your own account is more stable.

Remote Control from Your Phone

Mobile Codex is not a standalone app — it is the Codex entry inside the ChatGPT phone app. Think of it this way: Codex runs on the desktop app or a remote dev box, and the phone side connects to those environments so you can keep viewing, replying to, approving, and adjusting tasks when you step away from the computer.

In actual use, as long as Codex is running on the computer, you can direct tasks from your phone at any time — vibe coding from anywhere.

Selected Hands-On Cases

The hands-on cases are the guide's biggest highlight, each with detailed replication steps:

• Codex x Draw.io MCP: have AI auto-draw architecture diagrams
• Codex x GitHub Actions: auto-fixing failing CI, field-tested
• Codex x Obsidian + LLM Wiki: building an AI knowledge base
• Codex x remote dev box: running tasks remotely from your phone

How to Get It

• GitHub repository: search for CodexGuide — open-sourced under the MIT license
• Online reading site: linked from the GitHub repository, with a nicer reading experience
• Community-driven: PRs welcome — help add cases and improve the docs together

💡 Tip: the guide auto-checks for updates via Codex to keep its content in sync with the official docs. Codex itself updates fast, so star the repository to catch updates promptly.