Codex For Everyone — Development skill for Claude Code

OpenAI Codex for Everyone — learner kit

Practice timeline

The dates in the practice files belong to a fixed fictional case. Keep them unchanged for every class. Use the reporting period and as-of date supplied in the project or task card, regardless of the actual class date. For your own work, choose the period covered by your approved inputs.

O’Reilly live course with Mark Kashef

Practice files for a two-hour workshop. All Northstar and practice-input data is fictional. No GitHub account or Git knowledge is required for the Google Drive route.

Get the files

• Google Drive: open the learner folder. Download Codex-Course-Kit.zip and extract it. The folders are also available to browse.
• GitHub: choose Code → Download ZIP, then extract it. If you already use Git, clone this repository instead.

Follow along

1. Open 00-start as a local project in Codex for Labs 1 and 2
2. Read 00-start/PROJECT-README.md for the scenario and reporting dates
3. Copy the complete prompts from CLASSROOM-PROMPTS.md; they match the projected lab slides
4. For Lab 3, open 01-my-recurring-task as a separate project and start a fresh chat
5. Choose one supplied task example or approved inputs, create the skill, then check its saved output

Use [FOLDER-GUIDE.md](FOLDER-GUIDE.md) for the contents of every important folder, [START-HERE.md](START-HERE.md) for setup, and [RUNBOOK.md](RUNBOOK.md) for lab and recovery steps.

Plan mode

Type `/plan` in the Codex composer and select it to toggle Plan mode. Agree the approach, then turn Plan mode off before asking Codex to save or implement it. Commands vary by environment and access. [Official OpenAI command reference](https://learn.chatgpt.com/docs/reference/slash-commands)

Checks matter

Prepared examples are teaching fixtures, not proof that your run succeeded. Open the saved files, trace a claim t