# cs-mic-mcp

`cs-mic-mcp` is a small [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) server that gives an MCP client a deterministic calculator. It evaluates expressions with the [CSMic](https://git.jordanwages.com/wagesj45/cs-mic) expression parser instead of asking a language model to do the arithmetic itself.

It provides:

- `calculate(expression)`: evaluate an expression.
- `search(expression)`: find supported CSMic functions and their arguments. Use an empty search to list them all.
- A function-reference resource for clients that support MCP resources.

For example, a client can call `calculate` with an expression such as `sqrt(144)` or use `search` to discover the exact syntax of a function.

## Requirements

- The .NET 10 SDK to build or run from source.

## Run locally with stdio

Use this mode when the MCP client starts the server as a local subprocess. The server communicates only through standard input and output, so it does not listen on a network port.

From the repository root:

```bash
dotnet run --project src/cs-mic-mcp -- --stdio
```

Configure your MCP client to launch that command. A typical command-based configuration looks like this (adjust the working directory or use an absolute project path if your client starts elsewhere):

```json
{
  "command": "dotnet",
  "args": ["run", "--project", "src/cs-mic-mcp", "--", "--stdio"],
  "cwd": "/path/to/cs-mic-mcp"
}
```

Do not write ordinary output to the terminal while using stdio mode: stdout is reserved for MCP messages.

## Serve over HTTP

Run without `--stdio` to host the MCP endpoint over HTTP:

```bash
dotnet run --project src/cs-mic-mcp
```

By default, the development profile listens on `http://localhost:5000`. Connect an HTTP-capable MCP client to:

```
http://localhost:5000/mcp
```

To use a different address or port, set ASP.NET Core's URL setting when starting the server:

```bash
ASPNETCORE_URLS=http://localhost:8080 dotnet run --project src/cs-mic-mcp
```

The MCP endpoint would then be `http://localhost:8080/mcp`.

## Build and publish

Build the project:

```bash
dotnet build src/cs-mic-mcp/cs-mic-mcp.csproj
```

Publish self-contained, single-file builds for the project's supported platforms:

```bash
dotnet msbuild src/cs-mic-mcp/cs-mic-mcp.csproj -t:PublishAll
```

The output is placed under `src/cs-mic-mcp/bin/Publish/`, with one folder per platform. Run the published executable with `--stdio` for local-process use, or without it for HTTP serving.

## Notes

This server enables permissive CORS for its HTTP endpoint so browser-based MCP clients can connect. If you expose it beyond your own machine, put it behind the authentication and network controls appropriate for your environment.