const client = new CastariClient({ apiKey: '...' });
const usage = client.usage;

const summary = await client.usage.summary(options?);

const summary = await client.usage.summary({ days: 7 });
console.log(`Invocations: ${summary.total_invocations}`);
console.log(`Input tokens: ${summary.total_input_tokens}`);
console.log(`Output tokens: ${summary.total_output_tokens}`);
console.log(`Total cost: $${summary.total_cost_usd}`);

interface UsageSummary {
  total_invocations: number;
  total_input_tokens: number;
  total_output_tokens: number;
  total_cost_usd: number;
  period_start: string;
  period_end: string;
}

const days = await client.usage.daily(options?);

const days = await client.usage.daily({ days: 7 });
for (const day of days) {
  console.log(`${day.date}: ${day.invocation_count} invocations, $${day.cost_usd}`);
}

interface DailyUsage {
  date: string;
  invocation_count: number;
  input_tokens: number;
  output_tokens: number;
  cost_usd: number;
}