Codex Explained: Everything You Need to Know
In this video, I’ll walk you through OpenAI Codex—step by step. Whether you’re just starting out or already experimenting with the Codex CLI or Codex IDE extension in VS Code, this tutorial covers everything: installation, setup, features, reasoning levels, context window, pricing, modes, agents.md, cloud tasks, and my honest review after two weeks of daily use.
We’ll build a real-world feature (a JSON to YAML converter for AllDevNeeds.com) to see Codex in action. Along the way, I’ll break down:
1. Codex CLI tutorial → installation with npm or brew, terminal usage, setup commands.
2. Codex IDE extension in VS Code → how it compares to Cursor and Windsurf.
3. Reasoning Effort in GPT-5 → Minimal, Low, Medium, High reasoning levels explained.
4. Agents.md file → how it works like Claude Code’s claude.md for rules, context, and workflow.
5. Codex Modes → Chat Mode, Agent Mode, Full Access Mode (and which one you should avoid).
6. Context window → how to use Codex’s 400K context without polluting it.
7. Deep Search integration → using your Codex subscription for internet-powered research.
8. Cloud tasks → pros, cons, and when (or if) you should use them.
9. Pricing explained → Free vs Plus vs Pro plans.
10. Codex vs Claude Code → my honest thoughts after using both.
If you want to learn how to set up Codex, use Codex CLI, and make the most of AI coding tools, this is the complete guide.
Timestamps:
00:00 - Background For Codex Tutorial
00:19 - Our Example
00:33 - Codex CLI Installation
00:39 - Codex IDE Installation
00:52 - Codex Reasoning Levels
01:42 - Codex Basics
02:07 - Agents.md File
02:49 - Codex Pricing
03:05 - Codex Modes
03:53 - Codex Context Window
04:34 - Deep Search
05:00 - Codex Cloud Tasks
05:29 - My Honest Opinion
Resources:
1. AllDevNeeds, Daily Tools for Developers - AllDevNeeds.com
2. Codex CLI - https://developers.openai.com/codex/cli
3. Codex IDE - https://developers.openai.com/codex/ide
Tags:
#codextutorial #openaicodextutorial #openaicodexclitutorial #aicodingtutorial #codingaitutorial #openaitutorial #aiagenttutorial #tutochatgptcodex #cursoraicodextutorial #codex #openaicapitutorial #openaiclituorial #codexsetup #codex1 #howtosetupcodex #codexterminaluse #codex5minutesetup #codexcli #codexone #howtousecodex #codex1 #codexdemo #codexforwebdev #codex2025 #codexcliinstall #learncodex #openaicodexsetup #codexwalkthrough #vscodecodexsetup #howtousecodexcli