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Documentation Index

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Installation

The MCP C# SDK is distributed as three NuGet packages. Choose the package that best matches your scenario.

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Choosing the Right Package

The SDK provides three packages with different capabilities and dependencies:
PackageUse WhenDependencies
ModelContextProtocol.CoreYou only need the client or low-level server APIs and want the minimum set of dependenciesMicrosoft.Extensions.AI.Abstractions, Microsoft.Extensions.Logging.Abstractions
ModelContextProtocolYou’re building a client or a stdio-based server and want hosting, dependency injection, and attribute-based discoveryIncludes ModelContextProtocol.Core + Microsoft.Extensions.Hosting.Abstractions
ModelContextProtocol.AspNetCoreYou’re building an HTTP-based MCP server hosted in ASP.NET CoreIncludes ModelContextProtocol + ASP.NET Core framework
If you’re unsure which package to choose, start with ModelContextProtocol. This is the right starting point for most projects. You can always add ModelContextProtocol.AspNetCore later if you need HTTP transport support.

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Core Package

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When to Use

Choose ModelContextProtocol.Core when you:
  • Only need to build an MCP client
  • Want to use low-level server APIs with minimal dependencies
  • Need the smallest possible package footprint
  • Don’t require hosting or dependency injection features

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Installation

dotnet add package ModelContextProtocol.Core

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What’s Included

  • McpClient - Connect to any MCP server
  • Low-level server types and interfaces
  • Protocol types and message structures
  • Transport implementations (stdio, HTTP, SSE)
  • Minimal external dependencies

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Framework Support

  • .NET 10.0, 9.0, 8.0
  • .NET Standard 2.0
  • Native AOT compatible (except .NET Standard 2.0)

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Main Package

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When to Use

Choose ModelContextProtocol when you:
  • Are building most client or server applications
  • Want attribute-based tool/prompt/resource discovery
  • Need dependency injection support
  • Want to use Microsoft.Extensions.Hosting for server lifecycle management
  • Are building a stdio-based MCP server

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Installation

dotnet add package ModelContextProtocol

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What’s Included

Everything from ModelContextProtocol.Core, plus:
  • AddMcpServer() - Service collection extensions for dependency injection
  • WithStdioServerTransport() - stdio transport for process-based servers
  • WithToolsFromAssembly() - Automatic tool discovery from attributes
  • WithResources<T>() and WithPrompts<T>() - Resource and prompt registration
  • Hosting integration with IHostedService
  • Caching and background service support

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Framework Support

  • .NET 10.0, 9.0, 8.0
  • .NET Standard 2.0
  • Native AOT compatible (except .NET Standard 2.0)

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Additional Dependencies

For hosting support, you’ll typically also install: 
dotnet add package Microsoft.Extensions.Hosting

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AspNetCore Package

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When to Use

Choose ModelContextProtocol.AspNetCore when you:
  • Are building an HTTP-based MCP server
  • Want to host your MCP server in ASP.NET Core
  • Need to expose MCP over HTTP/HTTPS endpoints
  • Want to integrate MCP with existing ASP.NET Core applications
  • Need features like authentication, authorization, or CORS

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Installation

dotnet add package ModelContextProtocol.AspNetCore

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What’s Included

Everything from ModelContextProtocol, plus:
  • WithHttpTransport() - HTTP transport for ASP.NET Core servers
  • MapMcp() - Endpoint routing extensions
  • ASP.NET Core middleware integration
  • HttpContext access from tools and resources
  • Support for SSE (Server-Sent Events) streaming

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Framework Support

  • .NET 10.0, 9.0, 8.0
  • Native AOT compatible
The AspNetCore package does not support .NET Standard 2.0 because it requires ASP.NET Core framework features.

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Verification

After installation, verify the package is correctly installed by checking your project file: 
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="ModelContextProtocol" Version="1.0.0" />
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="9.0.0" />
  </ItemGroup>
</Project>

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Package Versions

All three packages follow the same versioning scheme. Check NuGet for the latest stable version:

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Next Steps

Quick Start Guide

Build your first MCP client and server with step-by-step examples