Pre-submission Checklist

• I have checked that this question would not be more appropriate as an issue in a specific repository
• I have searched existing discussions and documentation for answers

Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
• Documentation
• Other

Your Question

Sorry if this was already explained but I haven't found anything that explains it (e.g. here).

I was expecting to find Project Reactor in Webflux related modules or even in non-webflux but asynchronous components. But I was surprised to find it here in the McpSyncServer class. That class seems to be a mere "adapter" when you want to use non-reactive components, but under the hood it calls to the McpAsyncServer (reactive) class by calling .block() in each reactive operation.

I understand this was done this way in order to centralize all behavior in one of the "flavors" and to adapt the other one without the need of a generalized abstraction.

I'm aware that the current implementation will work as well with Java 21+ and that implementing a pure non reactive option for McpSyncServer will be a potential architectural change but I'm curious about the reasons to include Project Reactor so core-inside the SDK. And if to have a non reactive implementation for "blocking" servers was ever considered.

Thanks in advance for any answer.

P.D. I found #192 but the discussion was not answered nor explained.