A bilingual guide to using OpenAI Codex in real projects
CLI · Desktop App · IDE Extension · Web/Mobile

Last updated: June 16, 2026
Live Site · Korean README

Codex 101 is a practical, bilingual guide for people learning or rolling out OpenAI Codex. It covers the main Codex surfaces, setup decisions, safety controls, configuration, MCP, workflow automation, and prompt patterns.

The guide is written from the official OpenAI Codex documentation first, then manually reviewed before publishing. Because Codex changes quickly, treat the live guide as a learning companion and always confirm critical model, pricing, security, and availability details in the official docs.

• First-time users: read sections 04-06 for setup and first run, then 10 for sandbox/approval basics, and 14 for OpenAI Docs MCP.
• Professional users: read sections 12-14 for AGENTS.md, config.toml, and MCP, then 15-17 for sessions, automation, and prompt contracts.
• Example-driven readers: open the live site and the use-case gallery to start from real workflows instead of feature lists.

• Rechecked developers.openai.com/codex/models first again; the recommendation order stayed gpt-5.5, gpt-5.4, gpt-5.4-mini, and gpt-5.3-codex-spark.
• Added the June 12 ChatGPT release-note caveat that GPT-5.2 models are no longer available in ChatGPT, while keeping the separate Codex model-page wording for gpt-5.2 and gpt-5.3-codex deprecation in ChatGPT-authenticated Codex.
• Tightened the Codex rate-card wording: token-based pricing is now the main rate card for most customers, GPT-5.5 is listed at 125 input / 12.50 cached input / 750 output credits per 1M tokens, and legacy average-message rates are only for the remaining unmigrated Enterprise subset.
• Audited the official use-case catalog again: 60 official cards, 60 local cards, 0 missing local/extra IDs, 0 local promptEn/promptKo gaps, 0 official prompt mismatches after HTML-entity normalization, and 0 multiline Korean prompt regressions.
• Used the logged-in Chrome session to recheck X, Threads, and LinkedIn. X returned a blank readable body, Threads exposed only search-shell text, and LinkedIn exposed navigation shell only, so no new social-only claim was added.

• Rechecked developers.openai.com/codex/models first: gpt-5.5 remains the top Codex recommendation, with gpt-5.4, gpt-5.4-mini, and gpt-5.3-codex-spark in their existing fallback/fast/research-preview lanes.
• Reflected the June 11 Codex app 26.609 release: rate-limit reset banking, Developer mode for Browser/CDP work, /init in the app composer, expanded Enterprise Computer Use, and Windows Computer Use per-app access controls.
• Rechecked pricing, quickstart, config/profile, app settings/features, remote connections, Sites, Bedrock, MCP, hooks, plugins, and skills through the fresh Codex manual. No model-order, remote-control, or Sites setup reversal was needed, but Quickstart now clearly foregrounds the standalone installers.
• Rechecked OpenAI Platform/API docs and kept those notes separate from Codex product guidance. GPT-5.5 remains the latest API model guidance, while Codex pricing/API-key availability still needs scope-specific reading.
• Audited all 60 official Codex use cases after excluding collection pages. The catalog count, local/official IDs, promptEn, promptKo, and multiline Korean prompt shape are clean.
• Rechecked OpenAI launch/customer-story surfaces. The June 11 Ona acquisition announcement is captured only as pre-closing enterprise execution direction, not as an enabled feature, model, plan, platform, preview/GA, or feature-flag change.
• Chrome social checks for X, Threads, and LinkedIn were kept conservative in that run; the June 13 follow-up used logged-in X/LinkedIn people pages and moved the sourced people/tips into a separate research note.

The site currently supports Korean and English. Use the language toggle in the top-right corner of the live page, or update the translation blocks in i18n.js when contributing.

This is a static site. No build step is required for basic review.

open index.html
open use-cases.html

codex-101/
├── index.html          # Main Codex 101 guide
├── use-cases.html      # Use-case gallery
├── app.js              # Theme, language, navigation, interactions
├── i18n.js             # Korean/English translation content
├── use-cases-data.js   # Use-case gallery data
├── style.css           # Responsive styling
└── images/             # Screenshots and explainer visuals

Contributions are welcome for corrections, translations, screenshots, examples, and workflow tips.

git clone https://github.com/<your-username>/codex-101.git
cd codex-101
open index.html

After reviewing your change locally, open a pull request with a short explanation of what changed and which page or section you checked.

This project is released under the MIT License.

Made by @swhan0329
Built with the help of AI. Pull requests are welcome.