Mastering Claude Code, Subagents, Skills, Agent Teams, MCP, and Workflows

This course is designed for developers, AI enthusiasts, and professionals who want to develop real-world AI applications using LangChain, OpenAI, Hugging Face, and Python. Rather than focusing solely on theory, this course takes a practical, project-oriented approach. Throughout the course, students will directly build a total of 15 high-quality AI applications, including chatbots, CSV analysis tools, resume screening systems, invoice extraction bots, support assistants, marketing tools, and text-to-SQL applications. I created this course to make complex AI concepts easy to understand and to ensure modern LLM development is accessible to everyone. Many learners struggle to understand how tools like LangChain, embeddings, memory systems, vector databases, and AI agents interact in real-world applications. This course guides you step-by-step through clear explanations, hands-on coding sessions, and actual implementation workflows. By the end of the course, students will confidently understand how to design, build, and deploy AI-powered applications using the latest generative AI technologies.

This course is designed for those who want to go beyond simple AI chatting and actually get work done using AI agents. Many students are already using ChatGPT or Claude, yet they still struggle with repetitive tasks, scattered workflows, excessive research, and low productivity. The problem usually doesn't lie with the AI itself, but in knowing how to organize work systematically, give clear instructions, and build reliable workflows. In this course, we provide a step-by-step guide on the practical application of Claude Cowork. Rather than focusing solely on theory, we practice through practical examples such as project management, browser automation, meeting preparation, persistent memory systems, skills, plugins, and desktop control. This course explains everything in a simple and practical way so that even beginners can easily follow along. By the end of the course, students will understand how to utilize Claude Cowork as a true productivity assistant for research, planning, organization, automation, and daily tasks.

This course is designed to help learners build solid AWS cloud engineering and architecture skills through hands-on projects and practical demonstrations. Students will learn how to build secure AWS environments, manage scalable computing infrastructure using EC2 and Auto Scaling, configure networking via VPC and Load Balancers, and implement cloud-native storage and database solutions using S3, Aurora, and MySQL. Throughout the course, I will guide students step-by-step using hands-on labs, architectural explanations, and real-world deployment scenarios commonly used in modern cloud environments. I focus on simplifying complex AWS concepts into easy-to-understand lessons while helping students avoid common mistakes made during cloud deployment, security configuration, and infrastructure scaling. By the end of this course, students will not only gain the confidence to design secure, scalable, and cost-effective solutions on AWS but will also be prepared for the AWS Solutions Architect Associate certification exam.

This course is designed for developers, DevOps engineers, cloud engineers, and IT professionals who want to master advanced Kubernetes concepts used in real-world production environments. Throughout the course, students will engage in hands-on projects and real-world deployment scenarios, learning how to build secure, scalable, and production-ready Kubernetes infrastructure. Rather than focusing solely on theory, this course emphasizes practical implementation, troubleshooting, and best practices utilized by modern DevOps teams. One of the biggest challenges students face when learning Kubernetes is understanding how all components interact within large-scale environments. Many learners struggle with topics such as RBAC permissions, persistent storage, namespaces, network policies, StatefulSets, Kustomize, and secure cloud deployments. This course addresses these issues step-by-step through clear explanations, guided labs, and examples that mirror actual production environments. Students will learn step-by-step how to organize Kubernetes resources, secure workloads, manage application configurations, deploy stateful applications like MongoDB, and automate multi-environment deployments using Kustomize. Additionally, the course covers how to deploy applications to Google Kubernetes Engine (GKE) and configure Ingress, TLS certificates, monitoring, and scaling strategies. By the end of this course, students will have the confidence to design, secure, deploy, and manage advanced Kubernetes environments used in professional DevOps and cloud engineering workflows.

While studying Spring Security, you've probably wondered at least once: "I've built the login, but how do I handle authorization?" "How are authentication and authorization implemented in real-world practice?" This course is a practical, project-oriented lecture designed to solve those exact concerns. Instead of just explaining concepts, we implement them exactly as they are used in real services by: 👉 Building on an actual TodoApp project 👉 Integrating with a database 👉 Managing user permissions 👉 Handling validation In particular, I will provide easy, step-by-step explanations for the parts many students find difficult: Method-level authorization Access control within templates Validation using regular expressions Through this course, I will help you confidently say, 👉 "I can actually use Spring Security." 🚀

This course goes beyond simple grammar explanations and focuses on developing C++ programming skills that can be applied immediately in the field. Throughout my teaching, I have directly addressed common challenges faced by many learners—such as struggling to understand the STL or feeling confused by file handling and exception handling concepts. Based on this experience, I provide step-by-step explanations to ensure even complex concepts are understood easily and clearly. Furthermore, this course is not just about delivering theory; it is structured around: 👉 "Why this concept is necessary" 👉 "How it is used in actual code" 👉 "How it is applied in professional practice"

This course is designed to help even those new to MySQL understand it easily, starting from the basic concepts of DBMS and progressing step-by-step to the ability to write SQL that can be applied in real-world practice. To solve the problems learners frequently encounter (e.g., SQL syntax is difficult, not knowing how to write queries, or not understanding the flow of data processing), the course is structured with repetitive theory and practice, helping you naturally build your skills through a hands-on approach. In particular, the focus is not on simple memorization of syntax, but on understanding "why it is written this way" through the process of handling actual data.

This course explains everything from the basics of MySQL to its practical application in a step-by-step manner, making it easy to understand even for those learning databases for the first time. Rather than just providing simple theoretical explanations, the course focuses on real-world problem scenarios and teaches you how to write SQL and handle data through hands-on practice. The curriculum is systematically structured to cover the entire process, from DBMS concepts to MySQL installation, basic SQL syntax, data manipulation, and the use of functions. In particular, the goal is to help you understand "why it is written this way" through repetitive practice and to develop the ability to write queries on your own.

This course is a practical, hands-on guide for those who want to learn how to maximize development productivity in the AI era. Beyond simply learning how to use AI, we focus on how to utilize Claude Code in a real-world development environment and how to produce "proper results." Many developers use AI but still face issues such as: ❌ Inconsistent results ❌ Poor code quality ❌ Increasing project complexity To solve these problems, this course teaches you how to utilize AI as a "development partner" rather than just a tool through: ✔ Spec-based workflows ✔ Structured command systems ✔ Sub-agent and automation strategies Furthermore, you will gain the experience of completing and deploying a full application from start to finish by integrating with real-world services such as Firebase, Figma, GitHub, and Vercel.

This is an introductory course designed for those learning Rust for the first time, structured to help you learn step-by-step from the basics. Many learners encountering Rust for the first time often find it difficult due to: - Unfamiliar syntax - The burden of memory concepts - Differences from existing languages (C/C++) To solve these problems, this course helps anyone understand Rust naturally through: 👉 Easy explanations 👉 Step-by-step curriculum 👉 Repetitive practical examples Rust is a modern systems programming language that offers both safety and performance, making it a very important technology in the future development landscape. Build a solid foundation of Rust's core basics through this course.

This course is a practical, hands-on guide to automating repetitive tasks and maximizing work productivity using ChatGPT and Python. You will learn step-by-step how to use AI to automate daily repetitive tasks such as Excel work, report writing, sending emails, and data organization. Starting as a non-developer myself, I have taught AI automation to thousands of students, and I have compiled only the methods that can be used immediately in actual business environments. This course focuses not on complex theories, but on **"automation techniques you can use right today."** 👉 The goal is to turn ChatGPT into more than just a tool, but into **your own personal work assistant (Jarvis)**.

"Life is short, you need Rookiss." In the first lecture of Rookiss's Pinpoint Lesson series - Introduction to Claude Code, you will easily learn the overall concepts related to Claude Code and agents through self-developed visualized teaching materials.

This is a practical introductory course designed to help general office workers utilize generative AI as a business partner rather than just a simple tool. The objective is to develop the ability to use AI safely while complying with security and copyright standards, based on an accurate understanding of its operating principles and limitations. From the core principles of prompt engineering to streamlining text-based tasks such as planning, reporting, emailing, and minutes-taking, as well as Excel data analysis and the use of images and PDF documents, students will learn step-by-step. This helps drastically reduce time spent on repetitive tasks and secures the practical capability to handle multiple roles. Beyond individual use, the course covers how to build team-level work templates and standards. It is an action-oriented curriculum designed to ensure that participants possess work automation assets that can be applied immediately to their jobs after completion, leading to productivity improvements across the entire organization.

This course is not about non-developer office workers learning coding itself, but rather an education focused on developing the ability to solve business problems directly using AI agents. Previously, one had to rely on IT departments or outsourced development when problems arose, but we are now in an era where you can design alongside AI and create immediate prototypes to implement task automation. The core competencies required for this are problem definition, establishing solution strategies through AI collaboration, and the ability to build the necessary tools yourself. In particular, by utilizing Codex CLI, existing ChatGPT users can practice agentic coding immediately without additional costs, allowing non-developers to quickly gain practical experience. The curriculum is structured step-by-step, covering everything from understanding changes in the AI agent era to development basics, terminal usage, Codex CLI-based agentic coding, problem structuring, Django web app development, and the creation of actual task automation apps. Learners can secure task automation capabilities by directly building applications applicable to real-world work, such as To-Do lists, checklists, schedule management, meeting minutes, and summarization tools. The entire course is designed as a modular micro-learning system composed of short units, allowing for rapid learning of necessary content and immediate reuse during work.

Simple tutorials alone make it difficult to apply in practice. I will clearly pass on my professional know-how, covering complex state management and multi-agent design methods.

Are you feeling stuck trying to implement an agent that goes beyond a simple chatbot? Based on my own trial and error and know-how from official documentation, I will show you how to build intermediate-level agents that can be immediately applied to real-world tasks.

Document (SDD) → Code Automation. Make the system work instead of typing prompts. Build your own AI development agent with Skills, Sub-agents, and Commands, and complete monetization services through 5 real-world projects.

This course is a video lecture that covers essential development environment setup and basic VS Code usage for React.js and Vue.js frontend learning. It provides step-by-step guidance from environment setup to utilizing basic features that enhance productivity, with a focus on hands-on practice.

AI is only as good as you are. Master "Vibe Coding" through a three-step process: AI utilization, foundational core knowledge, and project development. For those who want to learn Vibe Coding properly, we deliver the unchanging core concepts—applicable to any AI—in bite-sized pieces.

"Why did the AI write this code?" or "Why can't it remember what I just said?" The frustration you encounter when using AI tools like Claude Code stems from not knowing how the tool actually works. This course flings open that black box. Over 25 lessons, we will build our own Coding Agent from scratch that functions exactly like real-world professional tools—giving the LLM 'eyes' to see files (Read), 'hands' to fix code (Edit), and 'feet' to execute commands (Bash). This isn't just about learning how to use a library. You will gain hands-on experience by implementing code to understand how AI perceives project structures, why it loses its memory during long conversations, and how to solve those issues technically (Sliding Window, Summary). Through this process, you will evolve from being a mere 'user' of AI tools to an 'AI provider' who understands the underlying principles and can customize and evaluate tools to fit your specific needs.

Can you create a service with your ideas even if you don't know how to code? With AI, it is possible! In this course, you will experience the entire process of turning an idea into a real web service using "Vibe Coding" tools used in the industry, such as Gemini, Lovable, Antigravity, Cursor, and Claude Code. You won't just learn how to use the tools; you will master a new way of service development in the AI era—from planning and deploying to integrating payments. Point 1. Master 5 Core Vibe Coding Tools - Hands-on practice with core features and applications of Gemini, Lovable, Antigravity, Cursor, and Claude Code - Understanding the Vibe Coding development method of collaborating with AI Point 2. Building a Real Service Without Coding - Hands-on process of planning and implementing a book recommendation web service - Understanding the entire service creation flow: Idea → Development → Deployment Point 3. Practical Skills for Service Launch and Operation - Understanding domain purchase, server setup, and the deployment process - Learning core operational technologies such as payment module integration and SEO settings

This course is a video lecture that covers essential VS Code auto-completion features including Emmet syntax, which is crucial for React.js and Vue.js frontend development, along with core content for efficient coding. Through examples and tips that can be immediately applied to work and learning, it guides you to increase productivity and enable faster and more accurate UI development.

Build a Kiwoom Securities API-based automated stock trading system from scratch using the core features of Claude Code (MCP, Agents, Skills). It's perfectly fine for beginners. Get started with Claude Code right now!

This course is designed for those who want to go beyond simple AI chatting and actually get work done using AI agents. Many students are already using ChatGPT or Claude, yet they still struggle with repetitive tasks, scattered workflows, excessive research, and low productivity. The problem usually doesn't lie with the AI itself, but in knowing how to organize work systematically, give clear instructions, and build reliable workflows. In this course, we provide a step-by-step guide on the practical application of Claude Cowork. Rather than focusing solely on theory, we practice through practical examples such as project management, browser automation, meeting preparation, persistent memory systems, skills, plugins, and desktop control. This course explains everything in a simple and practical way so that even beginners can easily follow along. By the end of the course, students will understand how to utilize Claude Cowork as a true productivity assistant for research, planning, organization, automation, and daily tasks.

A current startup CTO will share vibe coding knowledge gained through actual services and various outsourcing projects.

No coding knowledge required, build your very first service with Google Stitch An all-in-one AI development workflow that connects everything from planning to deployment in a single stream

You will learn how to create a $50,000 MVP (Minimum Viable Product) using Claude Code, which even non-majors can easily learn. We are now in an era where anyone can build software and start a business without spending a fortune. I have opened this course with the intention of helping you take your first steps into this new era by learning together!

"Can I build an app without knowing a single line of code?" This course is a 6-day journey that answers that question with a resounding "Yes, you can." In the process of creating a random lunch menu picker app by conversing with AI, you will learn how to write prompts to order an app from Claude on the first day. From there, you will add features day by day—including adding/deleting items, slot machine animations, permanent data storage, statistical charts, and sharing functions—to create a high-quality app ready for the App Store. Each lesson offers three challenge courses tailored to your level, allowing both those unfamiliar with code and those with coding experience to grow at their own pace. What you truly learn in this challenge is not just code, but how to ask the right questions to AI—a skill that applies everywhere, not just in app development.

Learn how to use chatGPT in practice to dramatically increase your work productivity, and apply it directly to your work, from document writing to data analysis!

AI does the coding, I get the results! Maximize practical programming skills, achievable even for beginners!

Evolve Obsidian from a simple notepad into a personal knowledge database and build an AI assistant that understands your notes and documents using Claude Code. Create custom workflows to automate repetitive tasks and complete a knowledge system where daily work and learning compound and transform into your own unique expertise.