Building AI Agents in Kotlin • Anton Arhipov • YOW! 2025

This presentation was recorded at YOW! Australia 2025. #GOTOcon #YOW https://yowcon.com Anton Arhipov - Developer Advocate at JetBrains @AntonArhipov RESOURCES https://bsky.app/profile/antonarhipov.bsky.social https://twitter.com/antonarhipov https://github.com/antonarhipov https://www.linkedin.com/in/antonarhipov Links https://www.jetbrains.com/koog https://github.com/JetBrains/koog https://github.com/antonarhipov/koding-agent https://speakerdeck.com/antonarhipov ABSTRACT In this session, we’ll walk step-by-step through the process of building AI agents in Kotlin using Koog — a lightweight framework for constructing tool-using LLM agents. Starting from first principles, we’ll examine how an agent interacts with a language model, how tools are registered and invoked, and how to structure reliable interactions whether you're working with local models or remote APIs from OpenAI and Google. Along the way, we’ll explore integrations with Model Control Protocol (MCP) and demonstrate how they enable structured coordination between components. Using Koog's DSL, we'll describe agent workflows as graphs, making the logic of the agent both readable and reproducible. The session will culminate in building a simple coding agent — capable of generating and testing small programs — showing how to integrate tools like test runners, linters, and file systems into a coherent agent behavior. Koog is the result of our internal efforts at JetBrains to build a practical, Kotlin-native agent framework, and is already at the core of the coding agent inside the AI Assistant plugin. This talk will be useful for engineers interested in understanding and building LLM-based automation, from scratch to working prototypes, with full control over the process. [...] TIMECODES 00:00 Intro 00:53 Agenda 02:05 Why build AI agents? 04:20 Why Kotlin for AI? 07:12 Architecture 10:39 Demo 45:04 Outro Read the full abstract here: https://yowcon.com/brisbane-2025/sessions/3953 RECOMMENDED BOOKS Venkat Subramaniam • Programming Kotlin • https://amzn.to/2MIC8D1 Marcin Moskala • Functional Kotlin • https://amzn.to/40TVJ6M Marcin Moskala • Kotlin Coroutines • https://amzn.to/3EcdTYT Marcin Moskala • Advanced Kotlin • https://amzn.to/4aDzJR2 Ken Kousen • Kotlin Cookbook • https://amzn.to/3TaCGBM https://bsky.app/profile/gotocon.com https://twitter.com/GOTOcon https://www.linkedin.com/company/goto- https://www.instagram.com/goto_con https://www.facebook.com/GOTOConferences #Kotlin #KotlinAI #AIAgents #Koog #JetBrains #LocalLLM #ModelControlProtocol #MCP #Programming #SoftwareEngineering #TodayInTech #AntonArhipov #YOWcon CHANNEL MEMBERSHIP BONUS Join this channel to get early access to videos & other perks: https://www.youtube.com/channel/UCs_tLP3AiwYKwdUHpltJPuA/join Looking for a unique learning experience? Attend the next GOTO conference near you! Get your ticket at https://gotopia.tech Sign up for updates and specials at https://gotopia.tech/newsletter SUBSCRIBE TO OUR CHANNEL - new videos posted almost daily. https://www.youtube.com/user/GotoConferences/?sub_confirmation=1