Understand your costs

const token = await createToken({
  userId: 'user-123',
  projectId: process.env.CHUCKY_PROJECT_ID,
  secret: process.env.CHUCKY_HMAC_SECRET,
  budget: createBudget({
    aiDollars: 5.00,        // Max AI spend
    computeHours: 1,        // Max compute time
    window: 'day',          // Reset period
  }),
});

import { BudgetExceededError } from '@chucky.cloud/sdk';

try {
  await session.send(message);
} catch (err) {
  if (err instanceof BudgetExceededError) {
    // Handle gracefully
    console.log('User budget exceeded');
    // Show upgrade prompt
  }
}

for await (const msg of session.stream()) {
  if (msg.type === 'result') {
    console.log('Cost:', msg.total_cost_usd);
    console.log('Tokens:', msg.usage);
    // {
    //   input_tokens: 1500,
    //   output_tokens: 800,
    //   total_tokens: 2300
    // }
  }
}

// Use Haiku for simple tasks
const session = client.createSession({
  model: 'claude-3-5-haiku-20241022',
});

// Use Opus only when needed
const session = client.createSession({
  model: 'claude-opus-4-5-20251101',
});

// Start conservative
budget: createBudget({
  aiDollars: 0.50,  // 50 cents
  computeHours: 0.5, // 30 minutes
  window: 'hour',
})

const session = client.createSession({
  maxTurns: 5,  // Prevent runaway conversations
});

// Bad: Sends entire file every time
await session.send(`Here's my code:\n${entireFile}\n\nFix the bug.`);

// Good: Be specific
await session.send('Fix the null pointer exception on line 42 of api.ts');

const cacheKey = hash(prompt);
const cached = await cache.get(cacheKey);

if (cached) {
  return cached;
}

const result = await client.prompt(prompt);
await cache.set(cacheKey, result, { ttl: 3600 });
return result;

const plans = {
  free: { aiDollars: 0.50, computeHours: 0.5 },
  pro: { aiDollars: 10, computeHours: 5 },
  enterprise: { aiDollars: 100, computeHours: 50 },
};

const userPlan = plans[user.plan];

const token = await createToken({
  userId: user.id,
  budget: createBudget({
    aiDollars: userPlan.aiDollars,
    computeHours: userPlan.computeHours,
    window: 'month',
    windowStart: user.billingCycleStart,
  }),
});

// Track usage
const usage = await getMonthlyUsage(user.id);

// Calculate overage
const overage = Math.max(0, usage - plan.includedAmount);
const overageCharge = overage * 1.2; // 20% markup

// Add to invoice
await billing.addCharge(user.id, {
  description: 'AI Usage Overage',
  amount: overageCharge,
});

const usage = await getUsage(user.id);
const percentUsed = (usage / budget) * 100;

if (percentUsed > 80) {
  await sendEmail(user, {
    subject: 'AI Budget Alert',
    body: `You've used ${percentUsed}% of your monthly AI budget.`,
  });
}