Hello, this is Gym Coding!

Lately, I've been posting card news on Instagram, Threads, and YouTube communities. Many people have been commenting, asking, "How do you make these?" or saying, "You're really good at making card news."

So I am preparing a proper video about it! To give you the conclusion first, these card news are all being created using Claude code.Without any separate design tools or AI image generators, it's possible with just a Claude subscription for 0 won in additional fees.

The core of this lecture is "direct control instead of outsourcing" — it's not about leaving it to AI and getting different results every time, but about controlling it with rules to systematically produce consistent results!

I plan to upload it as an additional lecture tomorrow (April 21st). For those taking this course, I will provide the actual card news HTML source I use along with card news creation skills, so you can apply them directly to your own brand's card news instead of just watching the video!

👉View card news examples on Gym Coding Instagram

😊 To those currently enrolled

Those who are currently taking the Claude Code Complete Master course can watch the new lecture immediately at no additional cost. It will be added to the existing curriculum tomorrow, so please check it out.

And if the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would be grateful if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now is an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Since its launch, more than 4,700 people have taken the course, and a wide range of people, including not only developers but also marketers, data analysts, students, and non-developers, are joining us.

I am a complete beginner who knows nothing about development. At first, I started developing with ChatGPT without watching any lectures or having any information. Then, I moved on to Cursor and realized the Claude model is excellent, so I am currently about to start developing with Claude.
I happened to learn about Gym Coding's lectures through someone nearby, and after listening to them, I thought, "I've really been doing this without any plan at all." I feel that after completing this course, I will be able to develop in a more systematic way with a higher level of understanding. Also, the continuous lecture updates!!! I think they will be a huge help. Thank you!^^
— Original Link

You can now enroll at a special discount price at gymcoding.co/vip. Please make sure to check it out before the discount ends!

👉Enroll now at a special discount (gymcoding.co/vip)

Thank you! 🙇‍♂

Hello, I'm GymCoding!

I'm sure everyone has experienced a time when the same AI model works well once but performs poorly another time. Those moments when you wonder why the results are so different even though you used a similar prompt, whether the model is the problem, or if you're missing something.

I feel like many people have been having these concerns lately. So, I've properly organized everything in this additional lecture!

This lecture is not just about prompt tips. I will systematically explain, along with the latest research cases, how the results change completely depending on how you design the environment in which the AI works, even when using the same AI model.

What is covered in this lecture

• Exactly what harness engineering is and why it is gaining attention now

• Anthropic's actual experimental cases — a ruined app for $9 vs. a completed app for$200 with the same model, and what the difference was.

• 3 causes of AI agent errors (Memory loss between sessions, Context Anxiety, Self-Evaluation)

• CLAUDE.md, Permissions, Hooks, MCP, to Subagents — 6 components for designing a harness in Claude Code

• How to re-evaluate harness rules as models evolve

The core of this lecture is not to blame the AI, but to create an environment where the AI can work effectively!

👉Go to the lecture!

😊 To those currently enrolled

Those who are taking the Claude Code Perfect Master course can watch the new lecture immediately at no additional cost. It has been added to the end of the existing curriculum, so please check it out.

And if the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would appreciate it if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now, we are in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Since its release, over 5,500 people have taken the course, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are participating.

"I am a complete beginner who knows nothing about development.At first, I started developing with ChatGPT without watching any lectures or having any information. Then I moved to Cursor and felt that the Claude model was great, so I am currently at the stage of starting development with Claude. I happened to find out about Gym Coding's lectures through someone nearby, and after listening to them, I thought, 'I have really been doing this without any plan at all.' I feel that after completing this course, I will be able to develop in a more systematic way with a higher level of understanding. Also, the continuous lecture updates!!! I think they will be a huge help. Thank you!^^ " — LExxxx

You can now enroll at a special discount price at gymcoding.co/vip. Please make sure to check it out before the discount ends!

👉Enroll now at a special discount price

Thank you! 🙇‍♂

Hello, I'm GymCoding!

Harness Engineering is becoming a hot topic, and many people are curious about what exactly it is!

I am currently planning this as an additional lecture.

Harness Engineering is not a new technology. It is a method for systematically designing things you are already using, such as CLAUDE.md, Hooks, and Permissions.

The core point is "change the environment before you change the model." Even with the same Claude, the results vary completely depending on the environment design.

I will be uploading it as an additional lecture soon.

😊 To those currently taking the course

The additional lectures will be provided to existing students at no extra cost.

And if the lecture was helpful, a one-line review would be a huge source of strength. If you haven't left a review yet, I would be grateful if you could leave a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now, we are in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Within just 4 months of its release, more than 5,000 people have taken the course, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are participating.

Recent Reviews

I've taken dozens of courses on Inflearn, but this course was on another level. It's absolutely insane!!
I've watched a few Claude Code-related lectures on YouTube and Inflearn, but this is the first time I've seen a course that covers everything so systematically, from the basics to the latest updates. It was really impressive how it didn't just stop at introducing features but also pointed out why things are used this way. I am confident that it will be of practical help to everyone, from those who know nothing about Vibe Coding to those who already have experience.
...
Even though I only applied a part of this course, my development speed and depth have completely changed. It's not just about coding fast; I feel like the level of design itself has improved. I truly felt like I had grown wings.

...
To be honest, it's so good that I almost want to keep it to myself, but I still highly recommend it. I will definitely buy Gym Coding's new lectures as soon as they are released. I've already purchased the Next.js and React courses as well. I would be grateful if you continue to create more lectures like this in the future!

View original review

And right now, we are having a 25% discount on all courses to celebrate reaching 5,000 students! This discount is only valid until midnight tonight. Many people contacted me saying they missed the previous discount, so I'm making sure to let you know this time.

👉Enroll now at the discounted price

Thank you! 🙇‍♂

Hello, I'm GymCoding!

As the project grows, CLAUDE.md grows with it, causing Claude to follow the wrong rules... I'm feeling the limits of trying to manage everything with a single CLAUDE.md in a monorepo...

I've noticed many people have been sharing these concerns lately. So, I've put together a proper explanation in this additional lecture!

This lecture is not just a tip for splitting CLAUDE.md into multiple files. It is a proven strategy that allows Claude to automatically read manuals only when working on a specific folder by dividing them accordingly.

What is covered in this lecture

• The core principle of sub-CLAUDE.md — a structure that automatically loads only when working in that specific folder

• Umbraco CMS Real-world Case Study — How to manage large-scale projects with 23 CLAUDE.md files

• Braintree/PayPal Real-world Case Study — 26 CLAUDE.md Operation Patterns by Payment Feature

• .claude/rules/ vs sub-directory CLAUDE.md — Comparison table on when to use which

• File Size Guidelines — The 30-line root CLAUDE.md case study from CopilotKit (29K ⭐)

The core of this lecture is not about reducing rules, but how to make only the rules of the folder you are currently working in visible to Claude!

👉Go to the lecture!

😊 To those currently taking the course

Existing students can take this additional lecture immediately at no extra cost!

If the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would appreciate it if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

We are now in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Within just 4 months of its release, more than 4,500 people are taking the course, including not only developers but also a wide range of individuals such as marketers, data analysts, students, and non-developers.

Recent Reviews

This is just insaneThere are so many things I didn't know. Honestly, there's a lot to study, but the instructor explains it so easily and it's very useful. Highly recommended, for real.

To celebrate surpassing 4,000 students within just 4 months of launch, all Gym Coding courses are currently 25% off. This is the maximum discount rate a knowledge sharer can set. It runs only until 4/6 (Mon), so don't miss out!

👉Enroll now at a discounted price

Thank you! 🙇‍♂~~!!

Hello, this is Gym Coding!

The Claude Code Master course has surpassed 4,000 students within just 4 months of its release.

A truly diverse range of people, including not only developers but also marketers, planners, and non-majors, have joined us.

I feel with every course review that these numbers didn't just accumulate on their own. I am truly grateful 🙏

I prepared this because I wanted to convey my gratitude in the most direct way possible.

📌 Gym Coding All Courses 25% Discount Event

📌Running for exactly 2 weeks, from 3/23 (Mon) to 4/6 (Mon) at midnight

👉Enroll now at a discounted price

✅ If you haven't taken the Claude Code course yet

There's a reason why 4,000 people chose it.

• Lifetime Free Updates — AI changes every week, and the lectures keep up with it.

• Complete 4 Real-world Projects — By the end of the course, you'll have 4 services built with your own hands

• Learning Based on Official Documentation — Based on Anthropic's official documentation, ensuring information reliability

Recent Course Reviews

In the first session, I couldn't understand what was being said at all, nor could I grasp the purpose or meaning behind why things had to be done that way.

From the second session, I gradually became more familiar with it, became able to carry out projects on my own, and could proceed by finding the necessary parts as needed.

By the 3rd round, I was watching with a full understanding, so unlike the difficult 1st round, I was able to enjoy the lectures.

It's okay even if you've never used Claude Code before. We will go through it step-by-step from the very beginning.

👉View Course Reviews

✅ For those already taking the Claude Code course

I recommend taking this opportunity to watch the React / Vue / Next.js lectures together.

The more you understand frameworks, the more you can utilize AI coding tools to their full potential.

The synergy is different when viewed together.

👉View all Gym Coding courses

I am always grateful 🙇‍♂

Best regards, Gym Coding

Hello, this is Gym Coding.

The lecture uses Cursor, but do I have to use it?
Can I use VSCode?
I'm using Anti-Gravity; is that okay?

I have received this question many times in the Q&A and the community. That's why I've updated the lecture to clear everything up!

To start with the conclusion, everything works. Since Claude Code is a tool that runs in the terminal, it doesn't matter which editor you use as long as you have a terminal.

However, you need to understand "why everything works" and "why Cursor was used in the lectures" so you can start without any lingering doubts. In this lesson, I will clearly explain those parts, starting from the core principles.

Updated Lecture (Section 5)

• Lecture 25. Installing Cursor AI: The Relationship Between VSCode, Cursor, and Antigravity

• Lecture 26. Code Editor Explanation: cursor command, extension installation

Go see it now → Cursor AI Installation: Relationship between VSCode, Cursor, and Antigravity

To those currently taking the course

If the lecture was helpful, a single line of review would be a great help. Each of your reviews is the driving force behind creating better lectures. If you haven't left a review yet, I would be truly grateful if you could leave even a short one! 🙏

👉Write a Course Review

For those who haven't taken the course yet

Now, it is no longer a question of whether you use AI coding tools or not, but an era where how well you use them determines the difference in skill. Within just three months of its release, 4,000 people have enrolled, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are joining us.

Recent Reviews

During the first round, I couldn't understand what was being said at all, nor could I grasp the purpose or meaning behind why things had to be done that way. From the second round, I gradually became more familiar and was able to proceed with projects on my own, and I could move forward while looking up the parts I needed. By the third round, since I watched it with a sufficient level of understanding, I was able to enjoy the lectures, unlike the difficult first round. It's a great help that you update new lectures quickly according to trends and answer questions well. Thank you for the great lectures.

👉Enroll now at a discounted price

Thank you! 🙇‍♂

Hello, I'm Gym Coding!

The Claude Code PPT Creation Lecture that many of you have been curious about has finally been added! 🎉

A new lesson has been uploaded to Section 30. Creating Your Own Workflow, and in this lecture, it doesn't just stop at simply creating a PPT.

What is covered in this lecture

• Directly creating a web PPT skill that fits the official document structure using skill-creator

• Research collection method using sub-agents in parallel

• A practical course for reviewing and editing AI-generated results

• The entire pipeline of packaging completed skills into plugins and registering them on the marketplace

You can learn everything at once—from creating skills and bundling them into plugins to uploading them to the marketplace and sharing them with other projects or team members.

👉Go to the lecture!

😊 To those currently taking the course

Whenever a new lecture is added, you can take it immediately at no additional cost. Check it out right now!

And if the course was helpful, a one-line review would be a huge help. If you haven't left a review yet, I would appreciate it if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

The skill systems, sub-agents, and plugin marketplaces covered in this lecture are the core features of Claude Code. This course allows you to systematically learn these functions from the basics to practical application, so if you've been interested, please take this opportunity to check it out!

👉Before the discount ends

Thank you! 👏

Hello, I'm GymCoding.

What is the difference between skills and plugins? How did you make the PPT?

Since these questions have been coming up often lately, I'm preparing a proper video about it!

So, I am preparing a proper additional video!

I won't just be showing you how to make a PPT; I will cover everything from creating your own skills, packaging them as plugins for reuse across multiple projects, and registering them on the marketplace to share with your team. I'm going to properly show you how to utilize Claude Code in practical work beyond just development.

What we cover in this video

• The entire process of creating a Web PPT skill directly from scratch

• Create a skill that fits the official documentation structure with skill-creator

• Research collection utilizing sub-agents in parallel

• How to share completed skills through the Plugin + Marketplace

I plan to upload this as an additional lecture within this week. Also, I will be providing the skill files created in the video to all students.

😊 To those currently taking the course

If the lecture was helpful, a one-line review would be a great help. Each of your reviews is the driving force behind creating better lectures. If you haven't left a review yet, I would be very grateful if you could leave even a short one! 🙏

👉Write a review

🎯 To those who haven't taken the course yet

Development using AI has now become a necessity, not an option.

Recent Reviews

Even as a non-developer in the AI era, I took this course while looking for a way to create my own service. As a result, I am extremely satisfied, to the point where I have absolutely no regrets about choosing this course. The content was substantial, but above all, the instructor's delivery was so excellent that I could understand and follow along despite the difficult subject matter. Although I still have a long way to go, I plan to study steadily through review. Thank you for providing such a great lecture!

This is a course where you can systematically learn the skills, sub-agents, and plugin systems covered in this video, from the basics to practical application. If you are interested, please check it out!

👉Enroll now at a discounted price

Thank you! 👏