Skills

Agent Skills is an open specification for reusable, model-agnostic skill definitions that can be loaded from the filesystem and exposed to an LLM as tools. For general information about skills, see the LangChain4j Skills documentation.

The quarkus-langchain4j-skills extension provides integration with the LangChain4j Skills module. When configured, it automatically loads skills from specified directories and registers a SkillsToolProvider CDI bean that exposes them to your AI services.

Only the tool mode is supported for skills at the moment. Shell skills don’t have Quarkus integration (yet), but you may use the dev.langchain4j:langchain4j-experimental-skills-shell module directly if you want.

Dependency

<dependency>
    <groupId>io.quarkiverse.langchain4j</groupId>
    <artifactId>quarkus-langchain4j-skills</artifactId>
</dependency>

Configuration

The extension is configured via the quarkus.langchain4j.skills.directories property, which accepts a list of directories from which to load skills. Each directory is in the list is a relative or absolute filesystem path.

quarkus.langchain4j.skills.directories=skills

Each listed directory is expected to contain subdirectories, where each subdirectory represents a single skill and must contain a SKILL.md file with YAML front matter defining the skill’s name and description. The body of the file becomes the skill’s instructions. See the Agent Skills specification for details on the SKILL.md format.

Example

Given the following directory structure on the classpath:

skills/
  poem-writing/
    SKILL.md

With skills/poem-writing/SKILL.md containing:

---
name: poem-writing
description: Instructions for writing a poem
---

When asked to write a poem, follow these rules strictly:

1. The poem MUST have exactly 12 lines.
2. The poem MUST be about a sad mushroom.

And application.properties:

quarkus.langchain4j.skills.directories=skills

The skills ToolProvider is automatically registered as a CDI bean of type SkillsToolProvider. Any @RegisterAiService that uses a ToolProvider will pick it up:

@RegisterAiService
public interface PoemAiService {

    String chat(String message);
}

@Path("/poem")
public class PoemResource {

    @Inject
    PoemAiService poemAiService;

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String poem() {
        return poemAiService.chat(
                "Activate the poem-writing skill and write a poem following its instructions.");
    }
}

A complete working example is available in the skills sample.