# Claude Code and Codex: Setup for Beginners How to get Claude Code (Anthropic) and Codex (OpenAI) installed and working, written for someone who has never opened a terminal. Our advice is to run them in the terminal, and this guide walks you through it. The desktop apps are covered at the end as an option. Commands change over time. If one here stops working, the official pages are the source of truth: https://code.claude.com/docs/en/setup and https://developers.openai.com/codex/cli ## What these are, in one paragraph Claude Code and Codex are AI coding agents. Instead of chatting with an AI and copying its answers into files yourself, you point the agent at a folder on your computer and describe what you want. It reads the files, writes and edits code, runs commands, and shows you what it changed. Claude Code uses your Claude subscription. Codex uses your ChatGPT subscription. You only need one to start. If you already pay for one of them, start with that one. ## Why we recommend the terminal over the apps The apps are friendlier on day one. The terminal is better from day two onward, and the hard part takes about ten minutes. - **It is the full product.** New features, settings, and add-ons show up in the terminal version first, and some only ever live there. - **It runs anywhere.** The same commands work on your laptop, on a Zo server, or on any machine you can log into. The apps only run on your own computer. - **Everything you learn carries over.** Every guide, tutorial, and community answer assumes the terminal. Questions like "which folder am I in?" and "what did it just run?" stay simple. - **It is what you will automate.** Once you want the agent to run on a schedule or inside a script, you will need the terminal anyway. The terminal is not dangerous by itself. The agent asks permission before it changes files or runs commands, and you can say no. ## Before you start You need three things: 1. **A paid plan.** For Claude Code, a Claude Pro, Max, Team, or Enterprise plan; the free Claude plan does not include it. Compare and sign up at [claude.com/pricing](https://claude.com/pricing). For Codex, a ChatGPT plan that includes Codex (Plus or higher is the safe bet). Compare at [chatgpt.com/pricing](https://chatgpt.com/pricing), and see how much Codex each plan includes at [developers.openai.com/codex/pricing](https://developers.openai.com/codex/pricing). The entry plan (Claude Pro or ChatGPT Plus) is enough to learn on. Upgrade only once you keep hitting the usage limit. 2. **A computer.** A Mac (macOS 13 or newer), a Windows 10 or 11 PC, or Linux. 3. **A project folder.** Make an empty folder somewhere easy to find, for example `Documents/my-first-project`. The agent works inside whatever folder you start it in, so never start it in your whole home folder. ## Step 1: Open a terminal - **Mac:** press Command + Space, type `Terminal`, press Enter. - **Windows:** press the Windows key, type `PowerShell`, press Enter. The line you type on should start with `PS C:\`. If it does not show `PS`, you opened the old Command Prompt instead; close it and open PowerShell. - **Linux:** you probably already know. Usually Ctrl + Alt + T. A window with a blinking cursor is all a terminal is. You paste a command, press Enter, and wait for it to finish. ## Step 2: Install Copy the line for your computer, paste it into the terminal, and press Enter. Paste with Command + V on a Mac, or right-click or Ctrl + V in PowerShell. The installer may sit quietly for a minute while it downloads. That is normal. **Claude Code** Mac or Linux: ``` curl -fsSL https://claude.ai/install.sh | bash ``` Windows (PowerShell): ``` irm https://claude.ai/install.ps1 | iex ``` **Codex** Mac or Linux: ``` curl -fsSL https://chatgpt.com/codex/install.sh | sh ``` Windows (PowerShell): ``` powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex" ``` Both installers also exist as Homebrew and npm packages. Ignore those unless you already use them; the lines above are the recommended path, and the Claude one updates itself automatically. ## Step 3: Check it worked **Close the terminal window and open a new one.** The new window is what picks up the freshly installed program. Then type: ``` claude --version ``` or ``` codex --version ``` A version number means it worked. If you see "command not found" or "not recognized", see the fixes at the bottom. ## Step 4: Go to your project folder The terminal is always "standing" in one folder. Move it into your project folder with `cd` (change directory). Easiest trick: type `cd ` (with a space after it), then drag your project folder from Finder or File Explorer into the terminal window, and press Enter. To check where you are, type `pwd` on Mac or Linux, or look at the path shown on the PowerShell line. ## Step 5: Start it and sign in Type `claude` or `codex` and press Enter. - **Claude Code** opens your browser and asks you to log in to your Claude account. Approve it, then come back to the terminal. - **Codex** asks how you want to sign in. Choose **Sign in with ChatGPT** and approve it in your browser. The first time, it will also ask whether you trust the folder. Say yes only for folders you created or know. ## Step 6: Your first conversation Just type in plain English and press Enter. Good first prompts: - `What is in this folder?` - `Make a simple web page that says hello, with a button that changes the background color. Then tell me how to open it.` - `Explain what you just did like I am new to this.` When it wants to create a file or run a command, it shows you what it is about to do and asks. Read it, then approve or say no. To quit, type `/exit` or press Ctrl + C twice. Next time, open a terminal, `cd` into the folder, and type `claude` or `codex` again. ## Habits that save beginners - **One folder per project.** Keep each project in its own folder, and start the agent inside it. - **Read before you approve.** You do not need to understand every line. Do look for anything that deletes files, touches folders outside your project, or installs something you did not ask for. - **Save working versions.** Once something works, ask: `Set up git in this folder and save this as a working version.` Then if a later change breaks it, you can ask to go back. If you already use GitHub, the [Prompting and Persona Craft](https://www.classified.llc/guides/prompting-and-persona-craft.md) guide covers committing working builds. - **Ask it about itself.** "How do I…" questions about Claude Code or Codex are often fastest answered by asking the agent directly. - **Never paste passwords or API keys into the chat.** If something needs a key, ask the agent how to store it safely instead. ## Fixes for the common snags - **"command not found: claude" or "'claude' is not recognized".** First, close the terminal and open a new one. If it still fails, the program installed but your computer does not know where to look. Claude's official fix steps are at https://code.claude.com/docs/en/troubleshoot-install - **Windows says the script is not allowed to run.** Make sure you are in PowerShell (the line starts with `PS`), and for Codex use the full `powershell -ExecutionPolicy ByPass ...` line exactly as written. - **The install line printed an error with `<` or `403` in it.** That is usually a network, VPN, or company-firewall issue. Try another network, or use the desktop app below. - **Login opened the browser but nothing happened in the terminal.** Finish the approval in the browser, then go back to the terminal and press Enter. If it is stuck, quit and run `claude` or `codex` again. - **"You do not have access" after logging in.** Your plan does not include the tool. Check you are logged in with the paid account, not a free or work account. ## Optional: the desktop apps If the terminal is a hard no for now, both tools have desktop apps. They use the same engine and your same subscription, and you can move to the terminal later without losing anything. - **Claude Code:** download the Claude desktop app from https://claude.com/download and use its Code section. Setup guide: https://code.claude.com/docs/en/desktop-quickstart - **Codex:** use the ChatGPT desktop app, which includes Codex. Details: https://developers.openai.com/codex/app The tradeoff: the apps feel easier on day one, but they only run on your own computer, and some features and settings arrive in the terminal first. When you are ready, come back to Step 1. It is the same ten minutes. ## Using these with Zo If you build on Zo, you do not have to install anything on your laptop to get the benefit of your subscription. Connect your Claude or ChatGPT (Codex) subscription in Zo under Settings, then AI, then Providers, and Zo's own AI runs on your plan. See [Zo in 10 Minutes](https://www.classified.llc/guides/zo-in-10-minutes.md). Running Claude Code or Codex directly on your Zo server is a next step once the terminal feels comfortable.