Building efficient MCP servers efficiently, with Quarkus

Speakers:

Martin Kouba (https://x.com/martunek) - Quarkus core engineer at IBM

Slides & code - https://github.com/mkouba/brnojug2025

Abstract:

“Model Context Protocol (MCP) is an open protocol that enables seamless integration between LLM applications and external data sources and tools.”

It's time to create your first MCP server with Quarkus!

In this talk, we will showcase the quarkus-mcp-server project - a Quarkus extension that provides declarative and programmatic APIs that enable developers to implement the MCP server features easily.

First, we'll describe the basics of the specification. Then, we'll explain the building blocks and APIs of the extension, execution model, configuration, and also why and how it follows the idiomatic approach used in fundamental Quarkus extensions (such as quarkus-rest). Finally, we will develop a simple MCP server to extend an AI agent.

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00:00 Introduction - Martin Stefanko
00:30 Introduction - Martin Kouba
01:03 What's the plan for today?
02:31 MCP - tl;dr
04:37 MCP - big picture
09:06 MCP - Model Context Protocol
10:49 MCP missing pieces
15:25 MCP concepts
18:24 MCP transports
21:10 What's quarkus-mcp-server?
22:20 Goals & design
23:32 Supported transports
24:27 Declarative API in action (demo 1)
33:35 Execution model
35:03 Programmatic API in action
36:09 Traffic logging (demo 2)
39:16 Client logging
41:28 Tools - optional arguments and default values
42:02 Tools - hibernate validator integration (demo 3)
49:25 Testing! (demo 4)
54:18 Initial checks
55:22 Sampling (demo 5)
01:05:54 Progress API (demo 6)
01:07:36 Questions/Answers/Demos