A comprehensive training course for mastering OpenAI Codex CLI - the lightweight terminal-based AI coding agent.

This 5-hour hands-on workshop covers everything from basic installation to advanced multi-model configurations, custom MCP servers, and enterprise deployment patterns.

• 🚀 Installation & Setup: Multiple authentication methods, configuration strategies
• 🛡️ Safety & Security: Sandbox modes, approval policies, secure configurations
• 🎯 Core Features: Project memory (AGENTS.md), custom prompts, profiles
• 🔧 Advanced Capabilities: MCP integration, multi-model support, CI/CD workflows
• 💻 Practical Skills: Real-world exercises in Java, Python, and TypeScript

• Command-line experience
• Basic programming knowledge in at least one language
• Git familiarity
• Docker (for advanced exercises)

codex-training/
├── slides.md                     # Slidev presentation
├── exercises/                    # Hands-on labs
│   ├── java-spring-boot/        # Spring Boot REST API
│   ├── python-refactoring/      # Legacy code refactoring
│   ├── react-forms/             # React TypeScript forms
│   └── microservices/           # Multi-language microservices
├── config-examples/              # Sample configurations
│   ├── basic-config.toml        # Minimal setup
│   ├── advanced-config.toml     # Full features
│   └── mcp-servers.toml         # MCP configurations
└── scripts/                      # Utility scripts
    ├── setup.sh                  # Environment setup
    └── verify-install.sh         # Installation check

# Via npm (recommended)
npm install -g @openai/codex

# Via Homebrew
brew install codex

# Verify installation
codex --version

# ChatGPT account (recommended)
codex login

# Or use API key
export OPENAI_API_KEY="your-key"

codex "Create a hello world function in Python"

# Clone this repository
git clone https://github.com/kousen/codex-training
cd codex-training

# Install dependencies for slides
npm install

# Start the presentation
npm run dev

# Open browser to http://localhost:3030

Build a complete task management API with Spring Boot, including:

• CRUD operations with validation
• H2 database integration
• OpenAPI documentation
• Comprehensive test suite

Time: 60-90 minutes

Transform legacy Python code using modern best practices:

• Add type hints and documentation
• Implement design patterns
• Create pytest test suite
• Setup code quality tools

Time: 45-60 minutes

Create a production-ready registration form with:

• React Hook Form + Zod validation
• Accessibility compliance
• Multi-step workflow
• Full test coverage

Time: 45-60 minutes

Build an event-driven microservices system with:

• Multiple languages (Node.js, Python, Go, Java)
• RabbitMQ message queue
• Docker orchestration
• API gateway

Time: 90-120 minutes

• ✅ Terminal UI navigation
• ✅ Sandbox modes and approval policies
• ✅ Project memory with AGENTS.md
• ✅ Custom prompts and profiles
• ✅ Session management and resumption

• ✅ Model Context Protocol (MCP)
• ✅ Multi-model provider support (OpenAI, Anthropic, Ollama)
• ✅ Running as MCP server
• ✅ CI/CD integration
• ✅ Headless execution

• ✅ TOML configuration files
• ✅ Environment variables
• ✅ Shell environment policies
• ✅ Notification systems
• ✅ Logging and debugging

1. Start with Read-Only Mode: Get comfortable before making changes
2. Use AGENTS.md: Provide context for better results
3. Create Profiles: Separate development/production configurations
4. Review Generated Code: Never blindly accept AI suggestions
5. Leverage MCP: Extend capabilities with external tools
6. Test Thoroughly: Always verify generated code works correctly

# Basic usage
codex                          # Interactive mode
codex -n "prompt"             # Non-interactive
codex --resume                # Resume last session
codex --search "text"         # Search codebase

# Configuration
codex --profile dev           # Use specific profile
codex --sandbox-mode auto     # Set sandbox mode
codex --approval-policy never # Set approval policy

# Advanced
codex serve                   # Run as MCP server
codex doctor                  # Diagnose issues
codex login --headless        # Headless authentication
codex --list-sessions         # Show all sessions

• Official Codex Documentation
• Model Context Protocol
• Course Slides
• Exercise Solutions

Kenneth Kousen

• President, Kousen IT, Inc.
• Author & Technical Trainer
• [email protected]
• https://www.kousenit.com

Found an issue or want to contribute? Please:

1. Open an issue on GitHub
2. Submit a pull request
3. Share your experience

This training material is licensed under the MIT License. See LICENSE file for details.

• OpenAI for Codex CLI
• Anthropic for inspiration from Claude Code
• The open-source community for MCP tools

Ready to start? Navigate to the exercises directory and begin with Lab 1!