mcp-csharp-publish

C# MCP Server Publishing

Publish and deploy MCP servers to their target platforms. stdio servers are distributed as NuGet tool packages. HTTP servers are containerized and deployed to Azure or other container hosts. Both can optionally be listed in the official MCP Registry.

When to Use

• Packaging a stdio MCP server for NuGet distribution
• Creating a Docker container for an HTTP MCP server
• Deploying to Azure Container Apps or App Service
• Publishing to the official MCP Registry for discoverability
• Setting up server.json metadata for the MCP Registry

Stop Signals

• Server not tested yet? → Use mcp-csharp-test first
• Server not working locally? → Use mcp-csharp-debug
• No server project yet? → Use mcp-csharp-create
• Publishing a non-MCP NuGet package? → Use nuget-trusted-publishing instead

Inputs

Input	Required	Description
Transport type	Yes	stdio → NuGet path, http → Docker/Azure path
Target destination	Yes	NuGet.org, Docker registry, Azure Container Apps, Azure App Service, MCP Registry
Project path	Yes	Path to the .csproj file
Package ID / server name	Required for publishing	NuGet PackageId or MCP Registry name

Workflow

Step 1: Choose the publishing path

Transport	Primary Destination	Users Run With
stdio	NuGet.org	dnx YourPackage@version
HTTP	Docker → Azure	Container URL

Both paths can optionally publish to the MCP Registry for discoverability.

Step 2a: NuGet publishing (stdio servers)

1. Configure .csproj with package properties:

<PropertyGroup>
  <PackAsTool>true</PackAsTool>
  <ToolCommandName>mymcpserver</ToolCommandName>
  <PackageId>YourUsername.MyMcpServer</PackageId>
  <Version>1.0.0</Version>
  <Authors>Your Name</Authors>
  <Description>MCP server for interacting with MyService</Description>
  <PackageLicenseExpression>MIT</PackageLicenseExpression>
  <PackageTags>mcp;modelcontextprotocol;ai;llm</PackageTags>
  <PackageReadmeFile>README.md</PackageReadmeFile>
</PropertyGroup>

<ItemGroup>
  <None Include="README.md" Pack="true" PackagePath="\" />
</ItemGroup>

2. Build and pack:

dotnet build -c Release
dotnet pack -c Release

3. Test locally before publishing:

dotnet tool install --global --add-source bin/Release/ YourUsername.MyMcpServer
mymcpserver --help          # verify it runs
dotnet tool uninstall --global YourUsername.MyMcpServer

4. Push to NuGet.org:

dotnet nuget push bin/Release/*.nupkg \
  --api-key YOUR_NUGET_API_KEY \
  --source https://api.nuget.org/v3/index.json

5. Verify — users configure in mcp.json:

{
  "servers": {
    "MyMcpServer": {
      "type": "stdio",
      "command": "dnx",
      "args": ["YourUsername.MyMcpServer@1.0.0", "--yes"]
    }
  }
}

For detailed NuGet packaging and trusted publishing setup, see references/nuget-packaging.md.

Step 2b: Docker containerization (HTTP servers)

1. Create Dockerfile:

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src
COPY *.csproj ./
RUN dotnet restore
COPY . ./
RUN dotnet publish -c Release -o /app

FROM mcr.microsoft.com/dotnet/aspnet:10.0
WORKDIR /app
COPY --from=build /app .

# Non-root user for security
RUN adduser --disabled-password --gecos '' appuser
USER appuser

ENV ASPNETCORE_URLS=http://+:8080
EXPOSE 8080
HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1
ENTRYPOINT ["dotnet", "MyMcpServer.dll"]

2. Build and test locally:

docker build -t mymcpserver:latest .
docker run -d -p 3001:8080 -e API_KEY=test-key --name mymcpserver mymcpserver:latest
curl http://localhost:3001/health

3. Push to container registry:

# Docker Hub
docker tag mymcpserver:latest <yourusername>/<mymcpserver>:1.0.0
docker push <yourusername>/<mymcpserver>:1.0.0

# Azure Container Registry
az acr login --name yourregistry
docker tag mymcpserver:latest <yourregistry>.azurecr.io/<mymcpserver>:1.0.0
docker push <yourregistry>.azurecr.io/<mymcpserver>:1.0.0

Step 3: Deploy to Azure (HTTP servers)

Azure Container Apps (recommended — serverless with auto-scaling):

az containerapp create \
  --name mymcpserver \
  --resource-group mygroup \
  --environment myenvironment \
  --image <yourregistry>.azurecr.io/<mymcpserver>:1.0.0 \
  --target-port 8080 \
  --ingress external \
  --min-replicas 0 \
  --max-replicas 10 \
  --secrets api-key=my-actual-api-key \
  --env-vars API_KEY=secretref:api-key

Azure App Service (traditional web hosting):

az webapp create \
  --name mymcpserver \
  --resource-group mygroup \
  --plan myplan \
  --deployment-container-image-name <yourregistry>.azurecr.io/<mymcpserver>:1.0.0

For detailed Azure deployment, see references/docker-azure.md.

Step 4: Publish to MCP Registry (optional)

List your server in the official MCP Registry for discoverability.

1. Install mcp-publisher:

# macOS/Linux
brew install mcp-publisher

# Or download from https://github.com/modelcontextprotocol/registry/releases

2. Create .mcp/server.json (or run mcp-publisher init to generate interactively):

{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
  "name": "io.github.username/servername",
  "description": "Your server description",
  "version": "1.0.0",
  "packages": [{
    "registryType": "nuget",
    "registryBaseUrl": "https://api.nuget.org",
    "identifier": "YourUsername.MyMcpServer",
    "version": "1.0.0",
    "transport": { "type": "stdio" }
  }],
  "repository": {
    "url": "https://github.com/username/repo",
    "source": "github"
  }
}

Version consistency (critical): The root version, packages[].version, and <Version> in .csproj must all match. A mismatch causes registry validation failures or users downloading the wrong version.

3. Authenticate and publish:

mcp-publisher login github      # name must be io.github.<username>/... for GitHub auth
mcp-publisher publish

4. Verify:

curl "https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.<username>/<servername>"

For Registry details (namespace conventions, environment variables, CI/CD automation), see references/mcp-registry.md.

Step 5: Security checklist

• No hardcoded secrets — use environment variables or Key Vault
• HTTPS enabled for HTTP transport in production
• Health check endpoint implemented
• Input validation on all tool parameters
• Rate limiting considered for HTTP servers

Validation

• NuGet: Package installs and runs via dnx PackageId@version
• Docker: Container starts and health check passes
• Azure: Server is reachable and tools respond
• MCP Registry: Server appears at registry.modelcontextprotocol.io
• MCP client can connect and call tools on the deployed server

Common Pitfalls

Pitfall	Solution
NuGet package doesn't run as a tool	Missing <PackAsTool>true</PackAsTool> in .csproj
Version mismatch between .csproj and server.json	Keep <Version>, server.json root version, and packages[].version in sync
Docker container exits immediately	Check entrypoint DLL name matches project output. Run docker logs mymcpserver for errors
Azure Container App returns 502	Target port mismatch. Ensure --target-port matches ASPNETCORE_URLS port in the container
MCP Registry rejects publish	Name must follow namespace convention: io.github.<username>/<name> for GitHub auth
API keys leaked in Docker image	Use multi-stage builds. Never COPY .env files. Pass secrets via --env-vars at runtime

Related Skills

• mcp-csharp-create — Create a new MCP server project
• mcp-csharp-debug — Running and interactive debugging
• mcp-csharp-test — Automated tests and evaluations

Reference Files

• references/nuget-packaging.md — Complete NuGet .csproj configuration, server.json for MCP, NuGet.org push, testing with dnx, version management. Load when: publishing a stdio server to NuGet.
• references/docker-azure.md — Production Dockerfile patterns, ACR setup, Azure Container Apps full configuration, App Service with Key Vault, secrets management. Load when: deploying an HTTP server to Docker or Azure.
• references/mcp-registry.md — mcp-publisher CLI installation, server.json schema, namespace conventions (GitHub vs DNS auth), CI/CD automation. Load when: publishing to the official MCP Registry.

More Info

• NuGet publishing — NuGet.org publishing guide
• Azure Container Apps — Serverless container hosting
• MCP Registry — Official MCP server registry