RSCG_MCP2OpenAPI by Ignat Andrei

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NuGet / site data

Details

Info

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Name: RSCG_MCP2OpenAPI

Generating Swagger/OpenAPI function from MCP tool.

Author: Ignat Andrei

NuGet: https://www.nuget.org/packages/RSCG_MCP2OpenAPI/

You can find more details at https://github.com/ignatandrei/RSCG_OpenApi2MCP

Source: https://github.com/ignatandrei/RSCG_OpenApi2MCP

Author

note

Ignat Andrei

Original Readme

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This is a place holder

About

note

Generating OpenAPI based on MCP source code.

How to use

Example (source csproj, source files)

CSharp Project

This is the CSharp Project that references RSCG_MCP2OpenAPI

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
	<ItemGroup>
		<PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="10.0.0" />

		<PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.0" />
		<PackageReference Include="ModelContextProtocol" Version="0.5.0-preview.1" />
		<PackageReference Include="ModelContextProtocol.AspNetCore" Version="0.5.0-preview.1" />
		<PackageReference Include="RSCG_MCP2OpenAPI" Version="9.2025.1202.1952" />
		<PackageReference Include="OpenAPISwaggerUI" Version="9.2024.1215.2209" />
		<PackageReference Include="Serilog.AspNetCore" Version="10.0.0" />

	</ItemGroup>
	<PropertyGroup>
		<EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
		<CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)\GX</CompilerGeneratedFilesOutputPath>
	</PropertyGroup>
</Project>

Program.cs

This is the use of RSCG_MCP2OpenAPI in Program.cs

// See https://aka.ms/new-console-template for more information
global using Microsoft.AspNetCore.Builder;
using MCPDemo;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using OpenAPISwaggerUI;


Console.WriteLine("Hello, World!");
var    builderApp = Host.CreateApplicationBuilder(args);

var    builderWeb = WebApplication.CreateBuilder();

// Configure all logs to go to stderr (stdout is used for the MCP protocol messages).
//builder.Logging.AddConsole(o => o.LogToStandardErrorThreshold = LogLevel.Trace);

var serverApp = builderApp.Services
    .AddMcpServer();
serverApp = serverApp.WithStdioServerTransport();
serverApp.WithTools<MyTools>();


var serverWeb = builderWeb.Services.AddMcpServer();
serverWeb = serverWeb.WithHttpTransport();
serverWeb.WithTools<MyTools>();


builderWeb.Services.AddOpenApi();
builderWeb.Services.AddTransient<MyTools>();
    
var app = builderApp.Build();
var web = builderWeb.Build();
    web.MapOpenApi();
    web.MapOpenApi("/openapi/{documentName}.yaml");
    web.MapMcp();
    web.UseOpenAPISwaggerUI();
web.AddAll_MyTools();

var t1 = web.RunAsync();
var t2 = app.RunAsync();

await Task.WhenAll(t1, t2);

MyTools.cs

This is the use of RSCG_MCP2OpenAPI in MyTools.cs

using ModelContextProtocol.Server;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;

namespace MCPDemo;
[MCP2OpenAPI.AddMCP2OpenApi()]
partial class MyTools
{
    [McpServerTool]
    [Description("Echo demo")]
    public async Task<string> SendEcho([Description("echo")] string echoData)
    {
        await Task.Delay(10);
        return echoData;
    }

}

Generated Files

Those are taken from $(BaseIntermediateOutputPath)\GX

MCP2OpenAPI.g.cs

                namespace MCP2OpenAPI
                {
                    [global::Microsoft.CodeAnalysis.EmbeddedAttribute]
                    [global::System.AttributeUsage(global::System.AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
                    internal class AddMCP2OpenApi: global::System.Attribute {} 
                }

Microsoft.CodeAnalysis.EmbeddedAttribute.cs

// <auto-generated/>
namespace Microsoft.CodeAnalysis
{
    internal sealed partial class EmbeddedAttribute : global::System.Attribute
    {
    }
}

MyTools_ExportToFile.g.cs

namespace MCPDemo;


///Number methods : 1
internal static partial class MyTools_OpenAPI
{
    public static void AddAll_MyTools(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder builder){
Add_SendEcho(builder);
    }



    public record rec_SendEcho ( string? echoData );
    
public static void Add_SendEcho (Microsoft.AspNetCore.Routing.IEndpointRouteBuilder builder){
    
        builder.MapPost("/api/mcp/MyTools/SendEcho",([Microsoft.AspNetCore.Mvc.FromServices]MCPDemo.MyTools toolClass,[Microsoft.AspNetCore.Mvc.FromBody]rec_SendEcho  value)=>
        toolClass.SendEcho(value.echoData)
        );

}



}

Useful

Download Example (.NET C#)

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Download Example project RSCG_MCP2OpenAPI

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https://ignatandrei.github.io/RSCG_Examples/v2/docs/RSCG_MCP2OpenAPI

Category "MCP" has the following generators:

1 RSCG_MCP2File 2025-11-15

2 RSCG_MCP2OpenAPI 2025-11-11

See category

MCP