Use the official Java SDK to implement Micronaut MCP

[sdelamo]

Official Java SDK:
https://modelcontextprotocol.io/sdk/java/mcp-overview#dependencies
https://github.com/modelcontextprotocol/java-sdk

[sdelamo]

@graemerocher

Why aren't we implemented the official MCP Java SDK? https://github.com/modelcontextprotocol/java-sdk/

[sdelamo]

I am checking it. Not sure about the api. There is a sync server specification and an async server specification which models the Spring boot duality of either using mvc or webflux.

Moreover, It is coupled to Jackson.

We would need also to create a McpServerTransportProvider implementation for HTTP transport.

[graemerocher]

those don't seem like insurmountable issues. Also we can upstream a PR to them. It seems logical to me to implement the official SDK rather than invent our own.

[melix]

As far as I understand, there isn't much in the SDK I would also have considered implementing something as our own implementation to avoid coupling to Jackson, servlet API, etc. The alternative is indeed to contribute upstream to decouple things and potentially add a mcp-micronaut module upstream. At this stage I don't know what's best.

[graemerocher]

yeah I mean ideally we don't want to couple to Jackson, but having links directly from the official SDK to our implementation will increase visibility. My preference is definitely to support the official SDK if we can

[sdelamo]

I was able to write a MCP server with Picocli and STDIO transport today. See draft PR. Still a work in progress but it is working for a simple tools scenario. We will need to provide a HTTP transport layer bridge though.

Moreover, I am writing tests with a JDK SDK agonstic way using the Langchain4J MCP client. Thus, we could eventually swap implementations.

[graemerocher]

the RawHttpClient impl that @yawkat did might be useful here

[sdelamo]

they need to catchup the release pace modelcontextprotocol/java-sdk#381