inflearn logo
inflearn logo

Building Claude Code with Kotlin from Scratch

This course is a practical program where you will master Kotlin-based AI agent development by building your own coding agents. Using Koog, an AI framework built with Kotlin, you will learn step-by-step how to implement coding agents similar to Claude Code, Cursor, and Junie. Koog is more than just a simple server-side framework; it integrates seamlessly with Spring and offers the scalability to connect with various environments—including Android, iOS, Desktop, and Web—through Kotlin Multiplatform (KMP). By building intelligent agents that can read, analyze, modify, and generate code, you will gain hands-on experience in AI agent architecture, strategy, context handling, and tool integration.

(4.9) 9 reviews

112 learners

Level Basic

Course period Unlimited

Spring
Spring
Android
Android
Kotlin
Kotlin
AI
AI
AI Agent
AI Agent
Spring
Spring
Android
Android
Kotlin
Kotlin
AI
AI
AI Agent
AI Agent

What you will gain after the course

  • How to implement an Agent in a Spring Boot / Android project

  • Core operating principles of AI Agents, such as Tool Calling and Agent Loops

  • How to build a coding agent like Claude Code

  • Optimization techniques for maximizing performance within Context Window limits

  • Creating an Agent that remembers context using Sessions and Memory

⚠️ In the era of AI coding, what is your point of differentiation as a developer?

In today's world

  • Non-developers are also building apps using Cursor or Claude Code.

  • Designers can also easily create landing pages using Claude Code.

It is a great era. The barrier to entry for technology has been lowered.

Anyone can create code using natural language. If you have an idea, AI will implement it for you.

But what if we, as developers, also just use Cursor or Claude Code in the same way?

The same tools, the same prompts, and the same $20 monthly subscription. What makes us any different from non-developers?

Where will the differentiation come from?



😰 The Uncomfortable Truth

The title of "developer" alone is no longer enough to differentiate yourself.

With the rise of "vibe coding" using AI, many people are jumping into development regardless of their job roles. Claude Code, Cursor, Copilot... we are in an era where code is written using only natural language.

Nevertheless, many developers still believe they are safe.

  • "Because the limitations of AI tools seem clear"

  • "Because developers are still needed"

  • "Because what I do isn't just simple coding"

However, this is like a frog feeling comfortable in water that is slowly heating up.



🚀 Vibe coding is just the beginning; now it's time to take it one step further.

Now is the time to stop and think.

Right now, many people are focusing only on vibe coding and AI coding. However, that is only the beginning of the change.

We must go one step further than others.



💡 The answer is clear: from AI consumer to provider

An era where everyone uses the same AI tools.

Where does a developer's true differentiation come from?

The answer is simple:

  • AI tool user → AI tool builder

  • AI Consumer → AI Provider

Non-developers use Cursor.

Developers create Cursor.

This is the decisive difference.

You can create these results after taking the course


With Tool Calling and Agent Loops

A Coding Agent that works on its own

reading and analyzing the project structure

Code Analyzer

Create a coding agent that solves complex problems by connecting tools for reading, writing, and modifying files, as well as executing Bash commands.

Explore directories and read files to understand the project architecture. Create an analysis agent that quickly understands even unfamiliar codebases.

Generating code with natural language commands

Code Generator

Operating in the terminal

CLI Coding Agent

Generate HTML/CSS and save them as files with a single command like "Make me a landing page." Create a generation agent that turns ideas into code instantly.

Complete your own CLI tool that allows you to code through conversation in the terminal, just like Claude Code. It is a practical Agent equipped with an ASCII UI.

Here is what you can learn!

How LLMs and AI Agents Work

How do Cursor and Claude Code work? Understand the core concepts of LLMs and the architecture of AI Agents. We will dive deep into the key mechanisms of AI Agents, such as Agent Loops and Tool Routing.

Implementing Core Elements of AI Agents with Kotlin

You will create five tools, including ReadFile, EditFile, and Bash, and implement an agent that operates autonomously through an agent loop. You will learn how to solve complex tasks step-by-step using tool calling.

Implementing Memory for Agents with Sessions and Memory

Implement Session to manage conversation history and Memory to store project information. By providing context to a stateless LLM, you will create an Agent that remembers and utilizes previous conversations like a human.

Context Window Optimization Techniques
Learn how to extract maximum performance within token limits. Master practical techniques to reduce costs and increase accuracy through unnecessary context cleanup, summarization strategies, and dynamic prompt configuration.


Why Koog?

Works anywhere with Kotlin Multiplatform

Integrated with KMP, a single Agent logic can be utilized across various platforms, including Android, iOS, Desktop, and Web.

Seamless Integration with Spring

Since it is based on Kotlin, it can be applied directly to existing Spring projects. There is no need to create a separate Python server for AI logic.

From Domain Server to Agent All at Once

The majority of servers in Korea use Spring. By using Koog, you can implement Agent logic cohesively within each domain server instead of separating it into a distinct service. This reduces infrastructure complexity and increases development speed.



Practice Environment

  • Operating System and Version (OS): macOS, Java 24, Kotlin


  • Tools used: IntelliJ

  • API Key : Claude API Key


  • Library used: Koog

Learning Materials

  • PDF Handbook summarizing key theories

  • Video lectures structured so that anyone can follow along step-by-step


Recommended Audience

  • Job seekers preparing for a career transition to AI Engineer

  • Java / Spring-based backend developer

  • Kotlin-based Android developers

Recommended for
these people

Who is this course right for?

  • Those who want to implement AI Agents in Spring Boot or Android

  • Those who have wanted to build their own Cursor or Claude Code

  • Those who want to create a clear competitive advantage as a developer in the AI era

  • Those who want to master Koog, the Kotlin Agent framework, ahead of everyone else.

  • A developer who wants to become an AI engineer

Need to know before starting?

  • Understanding basic Kotlin syntax

Hello
This is Hiro Son

126

Learners

9

Reviews

4.9

Rating

2

Courses

Hello, I'm Hiro, helping you transition to AI.

The journey from a working engineer to an AI engineer is not difficult.

I also started as a backend/frontend developer and transitioned into the field of AI.

This course is for:

  • Engineers with development experience who are new to AI

  • Those who want to learn through a practical approach without math or statistics

  • Those who want to apply AI to real-world projects

What we will learn together:

✓ AI Literacy
✓ AI Agent Development

More

Curriculum

All

25 lectures ∙ (4hr 43min)

Course Materials:

Lecture resources
Published: 
Last updated: 

Reviews

All

9 reviews

4.9

9 reviews

  • codemaru님의 프로필 이미지
    codemaru

    Reviews 9

    Average Rating 4.0

    4

    31% enrolled

    • hiroson
      Instructor

      Thank you for the course review! 😍

  • jmchoi13423님의 프로필 이미지
    jmchoi13423

    Reviews 1

    Average Rating 5.0

    5

    32% enrolled

    • hiroson
      Instructor

      Thank you for the course review! 😍

  • sangmoo님의 프로필 이미지
    sangmoo

    Reviews 4

    Average Rating 5.0

    5

    32% enrolled

    • hiroson
      Instructor

      Thank you for your review!

  • jhl22953352님의 프로필 이미지
    jhl22953352

    Reviews 6

    Average Rating 5.0

    5

    31% enrolled

    • hiroson
      Instructor

      Thank you! 😍 I'll do my best to be even more helpful!

  • nar998614님의 프로필 이미지
    nar998614

    Reviews 12

    Average Rating 4.8

    5

    31% enrolled

    • hiroson
      Instructor

      Thank you so much for the review! 😍

Similar courses

Explore other courses in the same field!

Limited time deal ends in 8 days

$33,000.00

25%

$34.10