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Microsoft.Extensions.AI–Part VII–MCP integration

Our journey continues, as we keep finding new features to explore in the Microsoft.Extensions.AI library. Today we have a look at the support for MCP.

This post is part of a blog series. Other posts so far:

What is MCP?

I know, I know, you should have been hiding under a rock if you have never heard about MCP before. But just in case; MCP (Model Context Protocol) is an open protocol developed by Anthropic that provides a standardized way to connect AI models to different data sources and tools.

This allows us to use tool calling without having to build our own plugins (as I demonstrated in Part III of this blog series).

Using MCP with Microsoft.Extensions.AI

The first thing you need is an MCP server. Today there are typically 2 ways that an MCP server can exchange information:

  • Standard Input Output (STDIO)
  • Streamable HTTP

Remark: The Streamable HTTP option replaces the HTTP+SSE transport from protocol version 2024-11-05. You can optionally still use Server-Sent Events (SSE) to stream multiple server messages.

I will be using Streamable HTTP in this example with the Playwright MCP server.

  • Start the server by executing the following command:

npx @playwright/mcp@latest --port 8931

  • Now open your project and add the following NuGet package:

dotnet add ModelContextProtocol

  • Next step is to instantiate an MCP client and get the tools provided by the MCP server:
  • As these tools are instances of McpClientTool, which inherits from AIFunction, we can pass them directly in as ‘plugins’ to our ChatOptions:

That’s all that we need to do!

More information

Tool calling using MCP with Semantic Kernel

Overview | MCP C# SDK

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