Your First Production Server

Prerequisites: Make sure you've completed the Development Environment Setup before continuing. You'll need Rust, cargo-pmcp, and Claude Code installed.

Let's build your first MCP server. We'll get it running and connected to Claude in under 5 minutes—then we'll explore how it works.

Quick Start: From Zero to Working Server

Step 1: Create the Workspace

cargo pmcp new my-mcp-servers
cd my-mcp-servers

This creates a workspace structure for building MCP servers.

Step 2: Add a Calculator Server

cargo pmcp add server calculator --template calculator

This generates a complete, working MCP server with example tools.

Step 3: Build and Run

cargo pmcp dev calculator

You should see:

INFO Starting MCP server "calculator" v1.0.0
INFO Listening on http://0.0.0.0:3000

Your server is running.

Step 4: Connect to Claude Code

In a new terminal, add the server to Claude Code:

claude mcp add calculator -t http http://0.0.0.0:3000

That's it—Claude Code now knows about your server.

Step 5: Try It!

Start Claude Code and ask:

"What is 1234 + 5678?"

Claude will call your add tool and respond with the result. You just built an MCP server!

Try a few more:

  • "Calculate 100 divided by 7"
  • "What's 15 times 23?"
  • "Divide 10 by 0" (watch the error handling)

What Just Happened?

In those 5 steps, you created a production-ready MCP server that:

FeatureWhat It Does
Type-safe inputsInvalid inputs are rejected automatically
Structured outputsResults include both values and descriptions
Error handlingDivision by zero returns a proper error, not a crash
JSON SchemaClaude knows exactly what parameters each tool accepts
HTTP transportReady for cloud deployment

This isn't a toy example—it's the same foundation you'll use for enterprise servers.

Testing with MCP Inspector

Before connecting to Claude, you can test your server interactively using MCP Inspector:

npx @modelcontextprotocol/inspector http://localhost:3000/mcp

This opens a web UI where you can:

  • Browse available tools and their schemas
  • Call tools with test inputs
  • See the raw JSON-RPC messages

Try the divide tool with divisor: 0 to see how errors are handled.

Project Structure

Let's look at what cargo pmcp generated:

my-mcp-servers/
├── Cargo.toml              # Workspace manifest
├── pmcp.toml               # PMCP configuration
├── server-common/          # Shared HTTP bootstrap code
│   ├── Cargo.toml
│   └── src/lib.rs
└── servers/
    └── calculator/         # Your calculator server
        ├── Cargo.toml
        └── src/
            ├── main.rs     # Entry point
            └── tools/
                ├── mod.rs
                └── calculator.rs

Why a workspace? As you build more servers, they'll share the server-common code for HTTP handling, authentication, and other infrastructure. This keeps each server focused on business logic.

Your Turn: Build Your First Server

You've seen the calculator server in action. Now build your own MCP server from scratch.

Chapter 2 Exercises - Start with Exercise 1: Your First MCP Server

Next Steps

Now that you have a working server, the following sections will cover:

  1. Building and Running - Understanding the workspace structure
  2. The Calculator Server - Deep dive into the generated code
  3. Understanding the Code - Rust patterns and PMCP conventions
  4. Testing with MCP Inspector - Advanced debugging techniques

Continue to Building and Running →