MCP Server Starter

A minimal MCP (Model Context Protocol) server with 2 working tools, ready to use with Claude Desktop and Claude Code.

Built and maintained by Darren Betney.

What's Included

• Calculator tool

• Memory (key-value store) tool

• Claude Desktop config

• Claude Code integration

• Automated tests

Related MCP server: demo-mcp-01

Quick Start

1. Clone the repo

git clone https://github.com/Quartalis/mcp-server-starter.git
cd mcp-server-starter

2. Run the tests

pip install pytest
python -m pytest -v tests

tests/test_tools.py covers the two tool implementations; tests/test_protocol.py covers the JSON-RPC layer (initialize, tools/list, tools/call, error codes, Content-Length framing). The same suite runs in GitHub Actions on Python 3.10, 3.11 and 3.12 on every push and pull request (.github/workflows/ci.yml).

3. Configure Claude Desktop

Copy the snippet from claude_desktop_config.json into your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Update the cwd path to point to your cloned directory.

4. Configure Claude Code

Add to your .claude/settings.json:

{
  "mcpServers": {
    "mcp-server-starter": {
      "command": "python",
      "args": ["src/server.py"],
      "cwd": "/path/to/mcp-server-starter"
    }
  }
}

5. Restart Claude and use the tools

Ask Claude to:

• "Calculate 2 ** 10 + 15 * 3"

• "Store my project name as 'My App' in memory"

• "List everything in memory"

Tools

Calculator

Evaluates mathematical expressions safely. Supports +, -, *, /, **, and parentheses.

Input:  {"expression": "(2 + 3) * 4"}
Output: "(2 + 3) * 4 = 20"

Memory Store

A session-scoped key-value store. Data persists for the duration of the server process.

Input:  {"action": "set", "key": "project", "value": "My SaaS"}
Output: "Stored: project = My SaaS"

Project Structure

mcp-server-starter/
├── .github/
│   └── workflows/
│       └── ci.yml         # GitHub Actions: pytest on Python 3.10–3.12
├── src/
│   ├── __init__.py
│   └── server.py          # MCP server with tool handlers
├── tests/
│   ├── test_tools.py      # Unit tests for both tools
│   └── test_protocol.py   # JSON-RPC handshake, tools/list, tools/call, framing
├── claude_desktop_config.json
├── pyproject.toml
└── LICENSE

Requirements

• Python 3.10+

• No external dependencies (stdlib only)

How MCP Works

The Model Context Protocol allows AI assistants like Claude to call tools hosted on your machine. The server communicates over stdin/stdout using JSON-RPC, following the MCP specification.

This starter implements the core protocol:

• initialize / notifications/initialized handshake

• tools/list to advertise available tools

• tools/call to execute a tool and return results

License

MIT License. See LICENSE for details.

Links

• MCP Specification — Official protocol docs