A dotnet new template for a Model Context Protocol server using the MCP C# SDK in .NET 10, built with a streamlined Clean Architecture. All the layers you need, none of the ceremony you don't.
It's one of five Lean Mean Clean Apps templates. They share the same Application and Infrastructure layers and differ only in how they face the world. Same genes, different haircuts.
The guides, the reference and the reasoning behind every opinion live at leanmeancleanapps.github.io/mcp. This is the version for people who skim. We see you.
You need the .NET 10 SDK. Docker is optional, but it's the quickest way to see it running.
# Install the template
dotnet new install CleanModelContextProtocol.Template
# Create a solution
dotnet new cleanmodelcontextprotocol --name Acme.Reviews --authorName "Your Name"
cd Acme.Reviews| Option | What it does |
|---|---|
--name |
Names the solution and its root namespace |
--authorName |
Puts your name on the assembly instead of ours |
--authority |
Your OAuth authorization server. Leave it out and the server runs without authentication |
--audience |
The audience tokens must be issued for, usually the server's own URL |
That's three layers, four test projects, a Dockerfile and a CI pipeline. Go and tell your team you've been working on it all week.
# Build the image and start it with sample data, plus the MCP Inspector and Seq
docker compose up -d --build
# Ask the movies_search tool for a page of movies
curl http://localhost:8080/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "movies_search",
"arguments": { "query": "global", "limit": 2 }
}
}'The answer comes back as an event stream, and its result carries the movies as structured content:
{
"items": [
{
"id": "30fca414-247a-779e-105a-d81aa2506f58",
"title": "Assimilated global infrastructure",
"reviewCount": 1,
"averageStars": 1
},
{
"id": "c27d6600-79a6-9346-2595-a52b7f07dc3e",
"title": "Automated global alliance",
"reviewCount": 3,
"averageStars": 3.3
}
],
"totalCount": 2
}Yes, the sample movies are named by a corporate buzzword generator, and the critics are harsh.
Curl is a fine way to prove it works and a terrible way to spend an afternoon. Open the MCP Inspector at http://localhost:6274 instead. It's already pointed at the server, so flip the switch to connect and open Tools.
There are six tools shaped around jobs rather than tables: movies_search, movies_get, authors_search, reviews_list, reviews_write and reviews_delete. Each has a description written for agents and hints that say what's read-only and what's destructive. Lists come back ten at a time, with a totalCount and a nextOffset when there's more to come, so an agent doesn't drown in its own context window. There are resources for every movie, author and review, and prompts for jobs like comparing two movies. The logs land in Seq at http://localhost:5341.
No Docker? dotnet run --project src/Presentation works too. Every other way to run it, from plain docker run to stamping a version into the image, is in docs/RUN.md.
The server is open until you give it an authorization server. Pass --authority and --audience when you create the solution, or set Authentication:Authority later. /mcp then asks for a bearer token, and the server publishes protected resource metadata so MCP clients can find your authorization server and sign in by themselves. Securing the server has the details.
Three layers, loosely based on Clean Architecture. Fewer layers than an onion, more than a sandwich.
- Presentation is the MCP server, stateless Streamable HTTP at
/mcp. Its tools, resources and prompts send each request through Mediator, and Application errors become tool errors that tell the agent how to recover. - Application owns the rules. Commands and queries are validated by FluentValidation and mapped by Mapperly.
- Infrastructure owns the data, with Entity Framework Core on SQLite. Everything in it is
internal, so Presentation can wire it up but can't move in.
There's a little CQRS in how commands and queries are shaped, but reads and writes share one database underneath. CQRS-curious, not CQRS-committed.
And around the edges:
- Tests use xUnit, Shouldly and NSubstitute, with coverage from Coverlet. Each test gets its own throwaway in-memory database, so no test can spoil another one's data.
- Sample data comes from Bogus, and only when
Database:SeedSampleDatais on. A real deployment never starts with fake reviews. - Logs go through Serilog, to the console and to Seq when you run it with Docker Compose. Health checks answer at
/health/liveand/health/ready. - Build rules live in
Directory.Build.props. Code style and the recommended analyzers run on every build, warnings fail it, and package versions sit in one place with Central Package Management. - The container runs as a non-root user and has its own health check.
- The pipeline builds, checks formatting, tests with a 95% coverage bar, makes sure the packed template still works, runs CodeQL, reviews new dependencies and their licences, starts the image to check it actually answers, and scans the container and Dockerfile with Trivy. Then it sums the lot up in one comment on your pull request, so you know exactly who to blame. It needs no accounts, tokens or secrets, so your copy works the moment you push it. Trust is earned.
- Dependabot bundles the month's dependency updates into one pull request on the 15th.
The architecture page has the long version, with full credit to Jason Taylor's template and Uncle Bob for the ideas.
A new version lands on the 1st of each month, as long as something changed, with notes for every pull request in the GitHub release. No changes, no release. We're not here to pad the download stats. Each release also carries an SPDX bill of materials listing every package the server ships with, for anyone whose security team asks nicely (or not so nicely).
dotnet new update| Template | Presentation |
|---|---|
| Clean Minimal API | ASP.NET Core Minimal APIs |
| Clean Model Context Protocol | Model Context Protocol server, you are here |
| Clean GraphQL API | GraphQL with Hot Chocolate |
| Clean Web API | ASP.NET Core controllers |
| Clean Lambda Function | AWS Lambda |
Bug reports, ideas and pull requests are all welcome, and typo fixes doubly so. Start with the contributing guide and the code of conduct. Security problems go through the security policy, not an issue.
Built by Stephen Walsh in spare time, with strong coffee and a healthy disregard for pomp and ceremony. Say hello on GitHub, LinkedIn, Medium or at stphnwlsh.github.io.
If this template saves you some time, sponsoring the work keeps all five templates current and the coffee flowing, which is the real dependency here.
MIT. Take it, change it, ship it. Just don't blame us for what your agent does with it.