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Support using WithStreamServerTransport for multiple in-process mcp servers

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
backend

Research direction

Start at the builder.Services.AddSingleton(new StreamServerTransport(inputStream, outputStream)) registration and inspect how StreamServerTransport is wired to an in-process MCP Server. Trace the channel and service-lifetime assumptions, then verify that multiple MCP Server classes can be declared in-process with separate channels.

Written by the indexing model from the issue text.

Description

enhancement needs confirmation P3

The current implementation register the stream support as a singleton:

builder.Services.AddSingleton<ITransport>(new StreamServerTransport(inputStream, outputStream));

This prevents declaring multiple MCP Server classes in-process and using them with a separate channels.

Reasons for this choice:

  • creating MCP servers in a separate class library so that they can be instantiated in-process or out-of-process depending on the app
  • ability to clearly separate the tools, prompts and resources. Currently I have to mix all the in-process prompts, resources and tools in a single MCP server to be used in-process.
  • avoid creating a separate process just because of the library limitation (performance reasons)

As I mentioned in a discussion, the Model Context Protocol adhere to the "transparency" principle, but the library makes it very difficult to reach. This is the reason why I tagged this as a bug.

Dominant language
C#
Stars
4.5k
Forks
814
Avg merge
9d 19h
Merged PRs (30d)
4

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