aicoolies logo
Koog logo
Koog logo

Koog

Kotlin-native AI agent framework by JetBrains with MCP support

open sourceupdated Jul 11, 2026

Koog is JetBrains official Kotlin-native framework for building predictable, fault-tolerant AI agents. It provides structured agent workflows with MCP protocol support, type-safe tool definitions, and deterministic execution patterns designed for JVM production environments. As the first production-grade Kotlin agent framework, it fills the gap in a JVM ecosystem dominated by Python-based alternatives and integrates naturally with existing Kotlin and Java backend infrastructure.

Koog brings AI agent development to the Kotlin ecosystem with a framework that emphasizes predictability and fault tolerance over the flexible but sometimes unpredictable patterns common in Python agent libraries. Agent workflows are defined using Kotlin DSL constructs with type-safe tool definitions, structured output parsing, and deterministic execution paths that make agent behavior easier to test and debug. The framework integrates with the Model Context Protocol for standardized tool integration across different LLM providers.

The architecture targets JVM production environments where teams already operate Kotlin or Java backend services. Rather than requiring a separate Python runtime for agent logic, Koog lets teams build agents using the same language, build tools, and deployment pipelines as their existing backend infrastructure. Coroutine-based concurrency handles parallel tool execution efficiently, and the structured error handling patterns provide clear recovery paths when individual tool calls fail during complex agent workflows.

Developed as an official JetBrains project, Koog benefits from the engineering rigor and long-term support commitment that characterize JetBrains open-source efforts. With over 3,600 GitHub stars and rapid growth following its announcement at KotlinConf, the framework is gaining traction among teams that want agent capabilities without adding Python to their technology stack. The Apache 2.0 license enables commercial use, and JetBrains internal usage provides real-world validation of the framework reliability and performance characteristics.

Pricing

Free and open source under Apache 2.0

Platforms

JVM (Kotlin/Java) on any platform

Categories

Tags

Use Cases

Related Tools

computed discovery: shared active categories · kept separate from editor-verified Alternatives

Agent Skills logo

Agent Skills

Open standard for portable skills across AI agents

Agent Skills is the open SKILL.md folder specification for packaging reusable instructions, scripts, references, and assets that compatible AI agents load through progressive disclosure. Originally developed by Anthropic and released as an open standard, it defines the portable format itself—not an example library, marketplace, or hosted agent product.

Open Source
hyperagent

HyperAgent

Open-source natural-language browser automation framework for AI agents

An AGPL-3.0 TypeScript framework that drives a real browser from natural-language tasks — the self-hostable OSS framework from Hyperbrowser, distinct from the vendor's paid cloud browser product.

freeOpen Source
KaibanJS logo

KaibanJS

JavaScript framework for building and visualizing multi-agent workflows on a Kanban board

KaibanJS is an MIT-licensed JavaScript framework for defining AI agents, tasks, tools, and teams, then orchestrating their work through a Kanban-inspired runtime and visual board. It can run inside Node.js, React, or Next.js projects, supports custom UIs and headless workflows, and provides real-time task-state visibility for multi-agent applications.

Open SourceTelemetry
Sakana Fugu logo

Sakana Fugu

Multi-agent model API that orchestrates frontier models behind one OpenAI-compatible endpoint

Sakana Fugu is a hosted model-provider API that exposes a learned multi-agent system as one OpenAI-compatible model. It dynamically routes coding, code review, research, and reasoning tasks across a frontier-model pool, with Fugu for lower-latency work and Fugu Ultra for harder workloads where answer quality matters more than cost or speed.

paidTelemetry
LangChain logo

OpenWiki

LangChain CLI for maintaining agent-friendly codebase documentation

OpenWiki is LangChain’s open-source CLI for generating and maintaining an agent-focused wiki inside a codebase. It can create an openwiki/ documentation folder, update it from repository changes, add guidance to AGENTS.md or CLAUDE.md, and run via an interactive CLI or daily GitHub Action so coding agents have durable context without stuffing every detail into prompts.

Open SourceTelemetry
Accomplish Coworker logo

Accomplish Coworker

Open-source desktop AI coworker for browsing and code execution.

Accomplish Coworker is an MIT-licensed open-source AI coworker that runs on the desktop, combining computer-use style browsing with code execution so agents can research, implement, run, and debug workflows in one local environment.

Open SourceTelemetry

FAQ

What is Koog?

Koog is JetBrains official Kotlin-native framework for building predictable, fault-tolerant AI agents. It provides structured agent workflows with MCP protocol support, type-safe tool definitions, and deterministic execution patterns designed for JVM production environments. As the first production-grade Kotlin agent framework, it fills the gap in a JVM ecosystem dominated by Python-based alternatives and integrates naturally with existing Kotlin and Java backend infrastructure.

Is Koog free?

Yes — Koog is open source and free to use. Free and open source under Apache 2.0

Is Koog open source?

Yes — Koog is open source.

What are the best Koog alternatives?

The top editor-verified Koog alternatives are OpenManus, Agent Zero, Parlant.