DotNetCampus.ModelContextProtocol

A lightweight, zero-dependency yet full-featured MCP protocol implementation built with .NET. It can be easily integrated into your application, regardless of its architecture.

Features

• 🚀 Lightweight and high-performance
• 📦 Zero external dependencies
• 🔌 Easy to integrate
• 🎯 Full MCP protocol support

Getting Started

Installation

dotnet add package DotNetCampus.ModelContextProtocol

Quick Start

A typical MCP server program looks like this:

internal class Program
{
    private static async Task Main(string[] args)
    {
        // The server name and version will be sent to clients via the MCP protocol
        var mcpServer = new McpServerBuilder("Sample Server", "1.0.0")
            // If your MCP tool parameters and return values use custom types, you need to provide a JSON serialization context
            .WithJsonSerializer(McpToolJsonContext.Default)
            .WithTools(t => t
                // Register various MCP tools
                .WithTool(() => new SampleTools())
                .WithTool(() => new SampleTools2())
            )
            // Use Streamable HTTP transport, listening on http://localhost:5943/mcp
            // Also compatible with SSE, listening on http://localhost:5943/mcp/sse
            .WithLocalHostHttp(5943, "mcp")
            // You can also use stdio (standard input/output) transport, which is recommended by the MCP protocol for all MCP servers
            // However, it's generally not recommended to enable both http and stdio simultaneously,
            // as the former typically requires singleton execution while the latter must support multiple instances
            // .WithStdio()
            .Build();
#if DEBUG
        // Enable debug mode so that when the MCP server encounters exceptions, it returns exception information to clients for easier debugging
        // It's generally not recommended to enable this mode in production, as it would expose internal implementation details of the server
        mcpServer.EnableDebugMode();
#endif
        // Run the MCP server
        await mcpServer.RunAsync();
    }
}

[JsonSerializable(typeof(Foo))]
[JsonSerializable(typeof(Bar))]
[JsonSourceGenerationOptions(
    // Recommended: Most MCP protocol implementations use camelCase naming
    PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
    // Recommended: Most MCP protocol implementations use string enums
    UseStringEnumConverter = true,
    // Recommended: Cannot guarantee AI will always put metadata properties first
    AllowOutOfOrderMetadataProperties = true
    // If you plan to use less capable models, you can also enable the following options
    // PropertyNameCaseInsensitive = true,
    // NumberHandling = JsonNumberHandling.AllowReadingFromString
    )]
internal partial class McpToolJsonContext : JsonSerializerContext;

Declaring MCP Tool Methods

public class SampleTools
{
    /// <summary>
    /// A tool for AI debugging that echoes back information as-is
    /// </summary>
    /// <param name="text">The string to echo back</param>
    /// <returns>The echoed string</returns>
    [McpServerTool(ReadOnly = true)]
    public string Echo(string text)
    {
        return text;
    }
}

Advanced Usage

For advanced usage including supported types for parameters and return values, type polymorphism, and more, please refer to the Quick Start Guide

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

About dotnet-campus

dotnet-campus（.NET 职业技术学院）