📄 claude/resources/prompt-library/cosmic-keystrokes
File: cosmic-keystrokes.md | Updated: 11/15/2025
Source: https://docs.claude.com/en/resources/prompt-library/cosmic-keystrokes
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Cosmic Keystrokes
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| | Content | | --- | --- | | User | Write me a fully complete web app as a single HTML file. The app should contain a simple side-scrolling game where I use WASD to move around. When moving around the world, occasionally the character/sprite will encounter words. When a word is encountered, the player must correctly type the word as fast as possible.The faster the word is successfully typed, the more point the player gets. We should have a counter in the top-right to keep track of points. Words should be random and highly variable to keep the game interesting. <br> <br>You should make the website very aesthetic and use Tailwind. |
Example Output
Copy
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<script src="https://cdn.tailwindcss.com"></script>
<title>Side-Scrolling Typing Game</title>
</head>
<body class="bg-gray-900 text-white">
<div class="fixed top-4 right-4 text-2xl">
Score: <span id="score">0</span>
</div>
<div id="game" class="h-screen w-screen overflow-hidden relative">
<div
id="player"
class="absolute bottom-10 left-10 w-8 h-8 bg-blue-500"
></div>
</div>
<div
id="word-input"
class="fixed top-1/2 left-1/2 transform -translate-x-1/2 -translate-y-1/2 bg-white text-black p-4 rounded hidden"
>
<input
type="text"
id="typed-word"
class="border border-gray-300 rounded px-2 py-1 mb-2 w-full"
/>
<button id="submit-word" class="bg-blue-500 text-white px-4 py-2 rounded">
Submit
</button>
</div>
<script>
const words = [\
'ability',\
'able',\
'about',\
'above',\
'accept',\
'according',\
'account',\
'across',\
'action',\
'activity',\
'actually',\
'address',\
'administration',\
'admit',\
'adult',\
'affect',\
'after',\
'again',\
'against',\
'agency',\
'agent',\
'ago',\
'agree',\
'agreement',\
'ahead',\
'air',\
'all',\
'allow',\
'almost',\
'alone',\
'along',\
'already',\
'also',\
'although',\
'always',\
'American',\
'among',\
'amount',\
'analysis',\
'and',\
'animal',\
'another',\
'answer',\
'any',\
'anyone',\
'anything',\
'appear',\
'apply',\
'approach',\
'area',\
'argue',\
'arm',\
'around',\
'arrive',\
'art',\
'article',\
'artist',\
'as',\
'ask',\
'assume',\
'at',\
'attack',\
'attention',\
'attorney',\
'audience',\
'author',\
'authority',\
'available',\
'avoid',\
'away',\
'baby',\
'back',\
'bad',\
'bag',\
'ball',\
'bank',\
'bar',\
'base',\
'be',\
'beat',\
'beautiful',\
'because',\
'become',\
'bed',\
'before',\
'begin',\
'behavior',\
'behind',\
'believe',\
'benefit',\
'best',\
'better',\
'between',\
'beyond',\
'big',\
'bill',\
'billion',\
'bit',\
'black',\
'blood',\
'blue',\
'board',\
'body',\
'book',\
'born',\
'both',\
'box',\
'boy',\
'break',\
'bring',\
'brother',\
'budget',\
'build',\
'building',\
'business',\
'but',\
'buy',\
'by',\
'call',\
'camera',\
'campaign',\
];
let score = 0;
let currentWord;
let startTime;
const game = document.getElementById('game');
const player = document.getElementById('player');
const wordInput = document.getElementById('word-input');
const typedWord = document.getElementById('typed-word');
const submitWord = document.getElementById('submit-word');
const scoreDisplay = document.getElementById('score');
let playerX = 10;
let playerY = game.offsetHeight - 50;
const speed = 5;
function placeWord() {
const word = document.createElement('div');
word.textContent = words[Math.floor(Math.random() * words.length)];
word.className = 'absolute text-2xl';
word.style.left = `${game.offsetWidth + 10}px`;
word.style.top = `${Math.random() * (game.offsetHeight - 50)}px`;
game.appendChild(word);
return word;
}
function checkCollision(word) {
const playerRect = player.getBoundingClientRect();
const wordRect = word.getBoundingClientRect();
return !(
playerRect.right < wordRect.left ||
playerRect.left > wordRect.right ||
playerRect.bottom < wordRect.top ||
playerRect.top > wordRect.bottom
);
}
function startInput(word) {
currentWord = word.textContent;
wordInput.style.display = 'block';
typedWord.value = '';
typedWord.focus();
startTime = Date.now();
}
function endInput() {
wordInput.style.display = 'none';
const endTime = Date.now();
const elapsedTime = endTime - startTime;
const timeBonus = Math.max(2000 - elapsedTime, 0);
score += Math.round(1000 + timeBonus);
scoreDisplay.textContent = score;
}
function checkInput() {
if (typedWord.value === currentWord) {
endInput();
}
}
function gameLoop() {
playerY = Math.max(
0,
Math.min(playerY, game.offsetHeight - player.offsetHeight)
);
playerX = Math.max(
0,
Math.min(playerX, game.offsetWidth - player.offsetWidth)
);
player.style.top = `${playerY}px`;
player.style.left = `${playerX}px`;
const words = Array.from(
document.querySelectorAll('#game > div:not(#player)')
);
words.forEach((word) => {
const currentLeft = parseInt(word.style.left);
word.style.left = `${currentLeft - speed}px`;
if (checkCollision(word)) {
startInput(word);
}
if (currentLeft < -word.offsetWidth) {
word.remove();
}
});
if (Math.random() < 0.01) {
placeWord();
}
requestAnimationFrame(gameLoop);
}
document.addEventListener('keydown', (e) => {
if (e.key === 'w') playerY -= speed;
if (e.key === 'a') playerX -= speed;
if (e.key === 's') playerY += speed;
if (e.key === 'd') playerX += speed;
});
typedWord.addEventListener('input', checkInput);
submitWord.addEventListener('click', checkInput);
gameLoop();
</script>
</body>
</html>
API Request
Python
TypeScript
AWS Bedrock Python
AWS Bedrock TypeScript
Copy
import anthropic
client = anthropic.Anthropic(
# defaults to os.environ.get("ANTHROPIC_API_KEY")
api_key="my_api_key",
)
message = client.messages.create(
model="claude-sonnet-4-5",
max_tokens=2000,
temperature=0,
messages=[\
{\
"role": "user",\
"content": [\
{\
"type": "text",\
"text": "Write me a fully complete web app as a single HTML file. The app should contain a simple side-scrolling game where I use WASD to move around. When moving around the world, occasionally the character/sprite will encounter words. When a word is encountered, the player must correctly type the word as fast as possible.The faster the word is successfully typed, the more point the player gets. We should have a counter in the top-right to keep track of points. Words should be random and highly variable to keep the game interesting. \n \nYou should make the website very aesthetic and use Tailwind."\
}\
]\
}\
]
)
print(message.content)
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