1 Hour to Claude Code

By the end of this hour, you'll have built a functional CLI tool with Claude's help and learned the core patterns of AI pair programming.

🎯 What You'll Build

A weather CLI tool that fetches current conditions for any city. Claude will help you design the architecture, write the code, and debug issues.

$ weather-cli "San Francisco"
🌤️  San Francisco, CA
Temperature: 68°F (20°C)
Conditions: Partly Cloudy
Humidity: 72%
Wind: 8 mph SW

⏱️ Time Breakdown

📋 Prerequisites

• Node.js 18+ installed
• Basic command line familiarity
• Claude account (free tier works)
• Text editor or IDE
• OpenWeatherMap API key (free)

Step 1: Start Your AI Pair Programming Session (0–10 min)

Open Claude and establish your coding partnership with this prompt:

I want to build a CLI weather tool in Node.js in the next hour. I'm a [your skill level] developer.

Requirements:
- Takes city name as argument
- Shows current weather with nice formatting
- Handles errors gracefully
- Uses a free weather API

Help me plan the architecture, then we'll build it step by step. What's the best approach?

Claude will suggest an architecture. Follow up with:

Perfect! Let's use the OpenWeatherMap API. Can you help me:
1. Set up the project structure
2. Choose the right npm packages
3. Plan the main functions we'll need

Show me the initial file structure and package.json.

Create your project directory:

mkdir weather-cli
cd weather-cli
npm init -y

Step 2: Scaffold with Claude's Guidance (10–25 min)

Install the packages Claude recommended:

npm install axios commander chalk dotenv
npm install -D nodemon

Ask Claude to generate your initial file structure:

Now create the basic file structure. I need:
- Main CLI entry point
- Weather service module  
- Configuration handling
- Error handling utilities

Show me the code for each file, starting with package.json scripts and the main index.js.

Create the files Claude suggests. Typically this includes:

touch index.js lib/weather-service.js lib/config.js lib/utils.js

Add Claude's suggested package.json scripts:

{
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js"
  },
  "bin": {
    "weather-cli": "./index.js"
  }
}

Set up your .env file:

echo "OPENWEATHER_API_KEY=your_api_key_here" > .env

Get your free API key from OpenWeatherMap and replace the placeholder.

Step 3: Implement Core Weather Fetching (25–40 min)

Now build the weather service with Claude's help:

Let's implement the weather service. I need a function that:
- Takes a city name
- Calls OpenWeatherMap API  
- Returns formatted weather data
- Handles API errors

Show me the complete weather-service.js code with error handling.

Implement Claude's suggested code. The weather service should look similar to:

// lib/weather-service.js
const axios = require('axios');
require('dotenv').config();

class WeatherService {
  constructor() {
    this.apiKey = process.env.OPENWEATHER_API_KEY;
    this.baseUrl = 'https://api.openweathermap.org/data/2.5/weather';
  }

  async getCurrentWeather(city) {
    // Claude will provide the implementation
  }
}

module.exports = WeatherService;

Test your API connection:

node -e "
const WeatherService = require('./lib/weather-service');
const ws = new WeatherService();
ws.getCurrentWeather('London').then(console.log);
"

Ask Claude to help debug any issues:

I'm getting [specific error]. Here's my code: [paste code]
What's wrong and how do I fix it?

Step 4: Add Polish and Error Handling (40–55 min)

Enhance your CLI with Claude's help:

Now let's make this production-ready:
1. Add colorful output with chalk
2. Handle all error cases (no API key, invalid city, network issues)  
3. Add a help command
4. Format the output beautifully

Show me the updated index.js with proper error handling and formatting.

Implement Claude's suggestions for error handling:

// Example error handling Claude might suggest
try {
  const weather = await weatherService.getCurrentWeather(city);
  console.log(formatWeatherOutput(weather));
} catch (error) {
  if (error.response?.status === 404) {
    console.error(chalk.red(`City "${city}" not found`));
  } else if (error.code === 'ENOTFOUND') {
    console.error(chalk.red('Network error - check your connection'));
  } else {
    console.error(chalk.red(`Error: ${error.message}`));
  }
  process.exit(1);
}

Test edge cases Claude suggests:

npm start "InvalidCityName123"
npm start ""
npm start "London,UK"

Step 5: Ship It (55–60 min)

Make your CLI globally installable:

npm link

Test the global command:

weather-cli "Tokyo"
weather-cli "New York"

Ask Claude for final improvements:

What finishing touches would make this CLI tool more professional?
Should I add features like:
- Multiple cities at once
- Different unit systems  
- Colored output based on conditions
- Configuration file support

Implement one quick enhancement Claude suggests.

🎉 Your weather CLI is complete! You've successfully used Claude as a pair programmer to build a real tool from scratch.

🎁 Bonus

• Add weather icons using Unicode symbols based on conditions
• Implement a 5-day forecast option with --forecast flag
• Create a config file system for default cities and units

📚 Next Steps

🔗 Resources

• OpenWeatherMap API Documentation
• Commander.js CLI Framework
• Chalk for Terminal Colors
• Claude AI Best Practices
• Node.js CLI Best Practices