IntelliJ IDEA
IntelliJ IDEA – the Leading IDE for Professional Development in Java and Kotlin
Agent Skills in IntelliJ IDEA
Agent Skills have become a key building block of the Agent Harness for AI-driven agentic development. They give AI agents additional capabilities and knowledge, enabling them to complete tasks in a way that aligns with your preferences.
If you are new to Agent Skills, I recommend reading AI-Assisted Java Application Development with Agent Skills first.
IntelliJ IDEA and other JetBrains IDEs include AI Assistant, which helps developers with AI agentic development. AI Assistant provides an elegant and secure way to use and manage Agent Skills.
If you missed the announcement, see Introducing the Skill Manager and Skill Repository.
In this article, we will explore:
- How to install Agent Skills via the Skills Manager.
- Managing skills with the Skill Repository.
- Installing skills globally, per project, or per agent.
- Adding your own Skill Repository.
Skills Manager
AI Assistant supports a wide range of AI agents through ACP (Agent Client Protocol).
The Skills Manager in AI Assistant lets you view the list of available skills and install them.
If you have already installed Agent Skills globally, the Skills Manager detects them and helps you install them as IntelliJ IDEA agent skills.
You can install a skill globally, at the project level, or per agent.
Skill Repositories
The Skill Repository lets you manage a list of locations where your verified skills are stored.
By default, JetBrains provides a Skill Repository hosted at https://github.com/JetBrains/skills.
These skills are verified by JetBrains for security vulnerabilities.
It is essential to check for security issues before using agent skills downloaded from the internet. A better approach is to maintain an organization-wide Skill Repository, verified by your team, and add it to the Skill Repository list.
Agent Skills in action
Based on the prompt description, the AI agent automatically detects and uses relevant agent skills.
For example, I installed spring-boot-skill, and when I asked the AI agent to write tests for Spring Boot REST API endpoints, it used the spring-boot-skill.
You can also explicitly invoke an agent skill using $skill-name [prompt] with Codex or `/skill-name [prompt]` with Claude.
Agentic Debugging using Debugger Skill
IntelliJ IDEA also includes the bundled ij-debugger skill, which teaches AI agents such as Junie, Claude, and Codex how to use the IDE’s debugger. It is particularly useful when source code analysis and logs are not enough. For example, when an incorrect value appears only at runtime, execution follows an unexpected branch, or you need to inspect variables, expressions, threads, and call stacks. The agent can start and control a debugging session, manage breakpoints, step through the code, and collect runtime evidence to identify the root cause. See Install the debugger skill to make it available to your agent.
To debug your code, describe the problem in natural language and provide any useful details, such as how to reproduce it or where you suspect the issue occurs.
For example, “A pet whose name differs only by case is not detected as a duplicate. Start a debug session, set a breakpoint in Owner.getPet(), and find out why.”
The agent sets the necessary breakpoints, runs the application, inspects the call stack and runtime values, evaluates its hypotheses, and reports its findings. Because it controls the standard IntelliJ IDEA debugger, you can follow the investigation in the Debug tool window and take over at any time.
For more details, see Agentic debugging.
Summary
AI Assistant’s Skills Manager makes agent skills part of your regular IDE workflow. You can discover, install, and manage skills without leaving IntelliJ IDEA, then make them available globally, for a specific project, or only to a particular AI agent. The AI agent can automatically select a relevant skill from your prompt, while explicit invocation gives you control when you need it.
Just as importantly, the Skill Repository provides access to skills verified by JetBrains for security vulnerabilities. Teams can also add their own repositories containing internally reviewed skills. This makes it easier to benefit from reusable agent capabilities while maintaining control over which skills developers use in their projects.
