cs-mic-mcp

cs-mic-mcp is a small Model Context Protocol (MCP) server that gives an MCP client a deterministic calculator. It evaluates expressions with the CSMic 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:

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):

{
  "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:

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:

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:

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

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

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.

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