mcp-intro

A minimal Model Context Protocol server built with the official Python SDK (mcp 2.x). It exposes two tools, one resource, and one prompt so you can see each MCP primitive working end to end.

Contents

Related MCP server: MCP Server Basic Example

What the server provides

• Tools

  • add(a: int, b: int) -> int — returns a + b.

  • greet(name: str) -> str — returns "Hello, {name}!".

• Resource

  • config://version — returns the server version string ("1.0.0").

• Prompt

  • summarize(text: str) — a reusable prompt template that asks the model to summarize text in one sentence.

Setup

Requires Python 3.13+ (the checked-in .venv uses 3.13).

cd /Users/amoghmadireddi/pl/mcp-intro

# Create the virtualenv if it does not already exist
python3 -m venv .venv

# Install dependencies
./.venv/bin/python -m pip install -r requirements.txt

Running the server

The server speaks the stdio transport, so it is normally launched by an MCP client rather than run by hand. To start it directly:

./.venv/bin/python server.py

It will sit waiting for MCP protocol messages on stdin/stdout — this is expected. Press Ctrl+C to stop.

Quick smoke test (pure Python)

./.venv/bin/python client_demo.py

Expected output:

tools: ['add', 'greet']
add(2, 3) -> 5
greet('Ada') -> Hello, Ada!
resources: ['config://version']
config://version -> 1.0.0
prompts: ['summarize']
summarize(...) -> Summarize the following text in one sentence:

MCP is a protocol.

Using it interactively (MCP Inspector)

The mcp CLI (installed via mcp[cli]) can launch the server with a web-based inspector for poking at tools, resources, and prompts:

./.venv/bin/mcp dev server.py

Requires Node.js — mcp dev shells out to npx to run the MCP Inspector. On macOS: brew install node.

Then open the URL it prints (it includes an auth token and usually opens your browser automatically). Click Connect, then from the inspector you can:

• call add with e.g. a = 2, b = 3 and see 5

• call greet with name = "Ada" and see Hello, Ada!

• read the config://version resource

• render the summarize prompt with some text

Using it from an MCP client

Register the server with any MCP-capable client (Claude Desktop, Claude Code, etc.) by pointing it at the virtualenv's Python and server.py.

Example client config entry:

{
  "mcpServers": {
    "mcp-intro": {
      "command": "/Users/amoghmadireddi/pl/mcp-intro/.venv/bin/python",
      "args": ["/Users/amoghmadireddi/pl/mcp-intro/server.py"]
    }
  }
}

For Claude Code specifically:

claude mcp add mcp-intro -- /Users/amoghmadireddi/pl/mcp-intro/.venv/bin/python /Users/amoghmadireddi/pl/mcp-intro/server.py

Once connected, the client can list and call the add / greet tools, read the config://version resource, and use the summarize prompt.

Extending it

Add a new tool by writing a function and decorating it:

@mcp.tool()
def multiply(a: int, b: int) -> int:
    """Multiply two numbers."""
    return a * b

The type hints define the input schema and the docstring becomes the tool description shown to clients.