.NET MCP Server: Return supported tools based on query parameter

Authorised Territory demonstrates how to build an MCP server in .NET that returns different supported tools depending on a query parameter, plus a .NET Minimal API client with endpoints to list tools and invoke one of them.

Full summary based on transcript

What the video builds

• An MCP server implemented in .NET that returns its supported tools based on a query parameter in the client connection URL.
• An MCP client implemented as a .NET Minimal API with two endpoints:
  • One endpoint that returns a list of the server’s tools.
  • One endpoint that calls/uses one of the tools exposed by the server.

Returning supported tools based on a query parameter

• The server’s tool discovery/advertisement behavior is made conditional on a query string value.
• The intent is that different clients (or different client modes) can connect using different URLs and receive different tool sets.

Minimal API client endpoints

• The client is built with ASP.NET Core Minimal APIs.
• It exposes:
  • A tool-listing endpoint (to fetch and return the tools the server reports).
  • A tool-invocation endpoint (to select one of the tools and execute it via the MCP interaction).

Key idea

• Use the connection URL (specifically a query parameter) as a simple way to control which tools an MCP server reports as available to the connecting client.