Quarkus MCP Server

This Quarkus extension provides both declarative and programmatic APIs that enable developers to easily implement MCP[^1] server features.

[^1]: "Model Context Protocol (MCP) is an open protocol that enables seamless integration between LLM applications and external data sources and tools."

[!NOTE]
The LangChain4j project provides the MCP client functionality, either as a low-level programmatic API or as a full-fledged integration into AI-infused applications.

Get Started

Step #1

Add the following dependency to your POM file:

<dependency>
    <groupId>io.quarkiverse.mcp</groupId>
    <!-- use 'quarkus-mcp-server-stdio' if you want to use the STDIO transport instead of the HTTP/SSE transport -->
    <artifactId>quarkus-mcp-server-sse</artifactId>
    <version>${project-version}</version>
</dependency>

Step #2

Add server features (prompts, resources and tools) represented by annotated business methods of CDI beans.

import jakarta.inject.Inject;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;

import io.quarkiverse.mcp.server.BlobResourceContents;
import io.quarkiverse.mcp.server.Prompt;
import io.quarkiverse.mcp.server.PromptArg;
import io.quarkiverse.mcp.server.PromptMessage;

import io.quarkiverse.mcp.server.Tool;
import io.quarkiverse.mcp.server.Resource;
import io.quarkiverse.mcp.server.TextContent;

// This class is automatically registered as a @Singleton CDI bean
public class ServerFeatures {

    @Inject
    CodeService codeService;

    @Tool(description = "Converts the string value to lower case")
    String toLowerCase(String value) {
        return value.toLowerCase();
    }

    @Prompt(name = "code_assist")
    PromptMessage codeAssist(@PromptArg(name = "lang") String language) {
        return PromptMessage.withUserRole(new TextContent(codeService.assist(language)));
    }

    @Resource(uri = "file:///project/alpha")
    BlobResourceContents alpha(RequestUri uri) throws IOException{
        return BlobResourceContents.create(uri.value(), Files.readAllBytes(Path.of("alpha.txt")));
    }

}

Step #3

Run your Quarkus app and have fun!

Documentation

The full documentation is available at https://quarkiverse.github.io/quarkiverse-docs/quarkus-mcp-server/dev/index.html.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

_{Martin Kouba} 💻 🚧	_{Georgios Andrianakis} 💻	_{Max Rydahl Andersen} 💡	_{Rostislav Svoboda} 💻	_{George Gastaldi} 🚇	_{Jan Martiska} 📖	_{Ioannis Canellos} 💻
_{Sergey Beryozkin} 💡	_{Konstantin Pavlov} ⚠️ 🚇	_{Martijn van Duijnhoven} 💻 ⚠️ 📖