From Prompt to Play: Building a Chess Game with Amazon Q CLI

When you're married to another developer, date nights can look a bit different. We've competed with each other on LeetCode, built apps together, and learned new technology. Last weekend, we decided to use Amazon Q CLI to build a Chess game. Amazon Q CLI transforms your terminal into an AI-powered coding companion, helping you to build applications faster by converting natural language prompts into working code.

Why just play when you can build and play? Here's how we did it, step by step.

Step #1 - The setup

Q CLI doesn't support Windows yet, so we decided to set up WSL to install and run it. See this link for Operating systems supported. The steps in the video are covered in the official Amazon Q Developer CLI installation documentation for windows.

Step #2 - Let's Build

The initial implementation generated by Q CLI comprised of three core files:

index.html: Structured the 8*8 chessboard using HTML elements
chess.js: Implemented custom game logic, including piece movements, turn management and basic move validation
style.css: Styled the board and pieces for visual clarity with plain CSS

We were able to play the game straightaway by opening the index.html file in the browser. Here's what it looked like without any changes to Q CLI's output.

Step #3 - Inspect the Code

Taking a closer look, it's clear that the Q CLI's implementation incorporates the fundamental rules of chess. chess.js establishes an 8x8 board representation, proper piece placement with Unicode characters for the pieces themselves. All six chess piece types have the correct movement patterns, turn-based play is enforced, piece selections are highlighted, and validation stops illegal moves.

However advanced features like castling, en passant captures, and checkmate detection were missing. It's time to ask Q CLI to improve our code.

Step #4 - Improve the Code

Rather than asking Q CLI to implement the missing movement patterns and checkmate detection directly, let's use an existing open source library. Chess rules are complex and require detailed rule based logic. Open source libraries like Chess.js offer battle-tested solution. They come with built-in edge case handling and comprehensive test coverage. This approach eliminates the need to write, test and debug numerous scenario ourselves, resulting in a simpler codebase.

Let's get Q CLI to refactor the codebase to use chess.js.

Let's test checkmate detection, using the Fool's Mate pattern.

Step #5 - Improve the user experience

Now that we have all the missing movement patterns and checkmate detection, the user experience could use an improvement. Instead of managing DOM elements manually, lets use the open source library Chessboard.js to update the design. This syncs seamlessly with chess.js and includes drag and drop piece movements, automatic position syncing on valid moves and responsive layout for mobile and desktop.

Step #6 - Let's play!

That looked good enough for us. With the build part of date night complete, it was time to move on to playing. (I was a school chess champion in my 2nd grade, so it will be tough competition for my husband!)

TL;DR 40 minutes 59 seconds later, it was a stalemate!

Lessons Learned

From Prompt to Playable: For anyone who loves building things, Amazon Q CLI offers a fun way to bring your ideas to life. We started with a basic chess implementation and gradually transformed it into a fully functional game – all while having a great time!
Build, Inspect and Improve: As we inspected the Q CLI output, we replaced the custom-built game logic with established open-source libraries, saving time and improving maintainability. This ensured that we were happy with the code that was generated
Prompt Engineering is a skill: Our prompts evolved as we built, inspected and improved the codebase. Being more specific like "Improve the game by using open source library - chess.js" yielded better results.

Finally, 2nd Grade school champion skills are only good enough for a stalemate ;)

Looking Ahead: Taking Our Chess Game to the Next Level

Now that we've successfully built our working chess game (and had a blast doing it on our date nights!), here's what we're planning to explore:

Deploy the Game with AWS Amplify
Add an AI opponent by integrating Stockfish
Add a AI assistant to help players improve their game through move suggestions
Enable Multiplayer with WebSockets
Track Scores and Create Leaderboard to make the game competitive
Voice Commands with Amazon Lex or Alexa to introduce hands-free play
Turn it into a Progressive Web App (PWA) for mobile play

Stay Tuned!

Your Turn to Make a Move

Join the AWS Challenge and Build Games with Amazon Q CLI.

We're excited to announce a special AWS Challenge that puts your creativity and coding skills to the test. From May 20th to June 20th, 2025, we're inviting developers to explore the power of Amazon Q CLI through game development and score a T-shirt.

Who knows? You might just turn your next coding session into an entertaining gaming night like we did!

Happy coding (and chess playing)! ♟

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