Using Codex (ChatGPT Subscription): Unhide It from Settings + Sign-in, Screen by Screen
Step-by-step illustrated guide | For academic users with no technical background | Uses OpenAI Codex + a ChatGPT subscription
Already paying for a ChatGPT subscription? Then you don't need to pay a second time — you can use Codex and reuse your existing ChatGPT subscription. This guide walks you through unhiding Codex in Settings and completing sign-in, screen by screen.
Haven't decided which to use? Read P0-2 "Which AI Should I Choose?" first. Users in mainland China typically cannot register a ChatGPT subscription — go with P0-3 "Full DeepSeek Setup" instead.
Prerequisites
- A Mac with Scholardo installed.
- A paid ChatGPT subscription account (Codex reuses it to sign in — not an API key). For prices and tiers, see the current page at openai.com / chatgpt.com.
- A network connection that can reach chatgpt.com (both the installer script and sign-in authorization connect to chatgpt.com).
Why You Have to "Unhide" It First
Scholardo's agent chooser shows only the Claude Code row by default — that's how the official section is designed. Codex (and Antigravity) are hidden by default; you have to unhide them in Settings before they show up in the chooser.
The official section's footnote reads: "Only Claude Code is shown by default. Add Codex or Antigravity from the "+", …"
Step-by-Step Walkthrough
Step 1 · Open Settings, unhide Codex
- Open Settings ▸ AI Agent.
- Find the
CLI agents · Officialsection. - Click that section's
+, pick OpenAI Codex from the list, and add it.
📌 Note:
AI Agentis the merged single tab — CLI agents, third-party services, and AI provider keys all live in this one tab.
Step 2 · Back to your project: open a new session, and Codex appears
- Close Settings and return to your project.
- Start a new session in the terminal area on the right.
- The "Choose an agent" card appears — this time you'll see the OpenAI Codex row (subtitle Sign in with your ChatGPT subscription).
- On the right of that row there's an Install button — click it.
Step 3 · The install confirmation dialog
After you click Install, a confirmation dialog appears:
- Title: Install OpenAI Codex?
- Body: Runs the official installer from chatgpt.com: followed by the command
curl -fsSL https://chatgpt.com/codex/install.sh | sh - Buttons: Install / Cancel
Click Install and wait for it to finish scrolling. A1 behavior: once done, the "Choose an agent" card automatically reappears — click the Codex row to launch (on failure it shows Retry).
⚠️ Callout: the
curl ... | shline downloads the installer script from the official chatgpt.com — a trusted source, so it's safe to click Install.
Step 4 · Codex's sign-in wizard (vendor UI — follow the red circles)
After you click the Codex row to launch it, you enter Codex's own first-run sign-in wizard. This is OpenAI's (official ChatGPT) interface, not Scholardo's.
- Choose a sign-in method:
🔴 The single most important step: choose the option that says "Sign in with ChatGPT" (ChatGPT account). Do NOT choose the option mentioning API key / API usage / platform.openai.com (usage billing) — that path bills you per token, entirely separate from the ChatGPT subscription you've already paid for. Picking the wrong one means paying twice.
- Browser authorization: the wizard opens your browser so you can sign in to your ChatGPT account and click Authorize/Allow. Once authorized, come back to Scholardo.
- Trust this folder: if the wizard asks whether to trust the current project folder, press Enter to confirm as prompted.
Step 5 · Type your first prompt
Once sign-in completes, an empty input box appears at the bottom of the terminal. Type your instruction in plain everyday language, for example:
Summarize the core arguments of this PDF in sourcesPress Enter, and the answer streams out line by line. 🎉
Shot list (screenshot checklist)
Filming ground rule: vendor UI (the Codex sign-in wizard, the browser authorization page, the chatgpt.com pricing page) must be captured as-is — do not fabricate or redraw, and do not annotate specific price figures. Capture the Scholardo UI from the current release, using the merged single AI Agent tab.
| # | What to capture | UI source | Key callout |
|---|---|---|---|
| 1 | Settings ▸ AI Agent ▸ CLI agents · Official section, click + → pick OpenAI Codex | Scholardo | Circle the + and "OpenAI Codex"; quote the footnote "Only Claude Code is shown by default" |
| 2 | Back in the project, new session, the OpenAI Codex row appears (subtitle Sign in with your ChatGPT subscription) + Install | Scholardo | Circle the Codex row and Install button |
| 3 | Install confirmation dialog: title Install OpenAI Codex?, body Runs the official installer from chatgpt.com: + curl -fsSL https://chatgpt.com/codex/install.sh | sh | Scholardo | Circle chatgpt.com in red as the source |
| 4 | Codex sign-in wizard — the choose-sign-in-method screen | Vendor UI (Codex CLI, captured as-is) | 🔴 Circle "pick 'Sign in with ChatGPT'"; red X over "the option mentioning API / platform.openai.com" |
| 5 | Browser authorization page: sign in to ChatGPT and click authorize | Vendor UI (chatgpt.com, captured as-is) | Circle the "Authorize/Allow" button |
| 6 | After launch, type the first prompt in the bottom input box; the answer streams out | Scholardo | Caption: "your first AI conversation" |
Key callouts recap
- Hidden by default — unhide it in Settings:
CLI agents · Officialsection+→ add OpenAI Codex. - A1 auto-return after install: click the row to launch; on failure it shows Retry.
- 🔴 Sign in with "ChatGPT subscription", not "API": the one and only trap that can make you pay twice.
- Switching agents = opening a new session (see P0-5).
Common pitfalls (see the full P0-6 · Install & Sign-in FAQ)
- Can't find Codex in the chooser: you haven't unhidden it yet — go back to the
CLI agents · Officialsection and click+to add OpenAI Codex. - Install fails: the row shows Retry — click to try again; if it keeps failing, check your network (it needs to reach chatgpt.com).
- Accidentally picked the API option during sign-in: quit the wizard, relaunch Codex from the chooser, and pick the "ChatGPT subscription" option this time.
Data Privacy Disclosure
When you ask Codex in Scholardo to read, summarize, or polish your PDFs, notes, or drafts, your manuscript content is sent to your chosen AI provider (OpenAI) for processing. This guide uses Codex, so the relevant text is transmitted over the network to OpenAI's servers and handled under OpenAI's own privacy policy. Scholardo only sends the necessary content when you actively start an AI conversation. If your research materials involve unpublished data, participant privacy, or confidentiality agreements, first confirm that sending them to a third-party AI service complies with your institution's requirements.