Uploaded April 2026 | Updated September 2026, 2 weeks ago

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Learn how to use Codex to accelerate real-world coding workflows and developer productivity.

Created by @ExamProChannel

Course info: exampro.co/exp-codex-01

❤️ Support for this channel comes from our friends at Scrimba – the coding platform that's reinvented interactive learning: scrimba.com/freecodecamp

⭐️ Contents ⭐️
- 00:00 Introduction
- 01:33 Codex Essentials
- 03:02 The AI Certification Roadmap
- 06:51 Study Recommendations & Passing Requirements
- 09:23 Validity and Re-certification
- 11:26 Accessing the Code Repository Codeex Fundamentals
- 12:10 What is Codeex? Agentic Coding vs. Coding Harness
- 13:39 Common Use Cases and Skills
- 14:21 Understanding the Agentic Loop
- 15:40 OpenAI GPT Model Families
- 17:27 Deep Dive: Model Intelligence vs. Context Windows
- 21:52 Installation Requirements (Node.js & WSL 2)
- 23:00 Authentication: Subscription vs. API Keys
- 23:32 Checking Login Status and Account Info
- 24:33 Lab: Installing Codeex and "Hello World"
- 29:32 Using API Keys for Production and Automation
- 32:26 Setting Environment Variables for Keys
- 36:00 Subscriptions vs. API Token Billing
- 38:08 Managing the Context Window (400k Token Limits)
- 40:06 Truncation and Hallucination Issues
- 40:36 Commands: /clear and /compact
- 41:17 Lab: Managing Context History
- 50:27 Codeex Sessions, Threads, and Messages
- 51:25 Session Commands: /new, /resume, /fork, and /rename
- 52:48 Under the Hood: SQLite and JSONL Session Storage
- 1:01:01 Tracking Usage with Custom Scripts
- 1:13:53 Customizing the Status Line
- 1:22:05 Project Guidance via agents.md
- 1:23:09 Truncation Limits and Tracing
- 1:24:39 Lab: Creating Project Guidelines
- 1:41:08 Deep Dive: Plan Mode and Clarifying Questions
- 1:42:10 Project Lab: Building a Wolfenstein 3D Clone
- 1:53:00 Sandbox Security: Bubble Wrap and Seatbelt
- 1:53:56 Approval Policies (Untrusted, Request, Never)
- 1:54:50 OS-Specific Settings and Network Access
- 2:04:49 Permission Overrides: Auto Mode vs. Full Access
- 2:07:01 Creating and Troubleshooting Rules
- 2:32:50 Global vs. Project Configuration (config.toml) API, SDKs, and Extensions
- 2:36:19 Non-Interactive (Headless) Mode for CI/CD
- 2:43:35 OpenAI Interaction Layers: REST API vs. SDKs
- 2:50:04 Implementing the OpenAI Agents SDK
- 3:01:13 Working with the Codeex SDK
- 3:05:16 Using the Codeex Desktop Application
- 3:09:29 Installing the VS Code Extension
- 3:10:58 The Codeex App Server Protocol
- 3:12:24 Automated Workflows with GitHub Actions
- 3:18:07 Anatomy of Agent Skills
- 3:21:20 Discovery, Activation, and Execution
- 3:22:26 Skill Locations and Marketplace
- 3:23:01 Lab: Image Generation Skills
- 3:35:03 Project Lab: Building a Task Manager Skill
- 3:47:08 Optimizing Cost with Model and Effort Selection
- 3:48:14 Fast Mode for Inference
- 3:57:18 Connecting MCP Tools (Roblox Example)
- 4:10:21 Orchestrating Sub-Agents and Worker Teams

🎉 Thanks to our Champion and Sponsor supporters:
👾 @omerhattapoglu1158
👾 @goddardtan
👾 @akihayashi6629
👾 @kikilogsin
👾 @anthonycampbell2148
👾 @tobymiller7790
👾 @rajibdassharma497
👾 @CloudVirtualizationEnthusiast
👾 @adilsoncarlosvianacarlos
👾 @martinmacchia1564
👾 @ulisesmoralez4160
👾 @_Oscar_
👾 @jedi-or-sith2728
👾 @justinhual1290

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