| name | usage-monitor |
| description | Track real-world usage and cost across LLM providers, hosting, DB, and email after a feature ships or a launch happens. Complements `cost-watchdog` (preventive). Triggers when the user says "tô gastando muito", "quanto custa", "quanto deu de fatura", or after launch. |
Usage Monitor
When to run this skill
- 24h after a public launch.
- Weekly during the first month after launch.
- Whenever the user asks "quanto tá custando" / "tô gastando muito" / "como tá a fatura".
- After a feature that calls a metered service ships.
- When a billing alert fires.
Dashboard format
📊 Usage & cost — last 7 days
🤖 LLM (Anthropic):
Input tokens: 1.2M (R$ 9.00)
Output tokens: 340K (R$ 17.00)
Cache reads: 800K (R$ 0.60)
Total: R$ 26.60
Per active user: R$ 0.27
⚠️ Up 340% vs prev week — investigate.
☁️ Hosting (Vercel):
Bandwidth: 4.2 GB / 100 GB free
Function invocations: 22K / 100K free
Status: 🟢 within free tier
🗄️ Database (Supabase):
DB size: 142 MB / 500 MB free
Active users (mau): 18 / 50K free
Status: 🟢 within free tier
✉️ Email (Resend):
Sent: 240 / 3000 free
Status: 🟢 within free tier
💰 Total billable this week: R$ 26.60
🔮 Projected month: R$ 114
Sources of truth
- Anthropic: Console → Billing → Usage. API:
/v1/organizations/usage_report.
- Vercel: Dashboard → Usage tab.
- Supabase: Dashboard → Project Settings → Usage.
- Resend: Dashboard → Logs.
- Stripe: Dashboard → Reports.
If the user hasn't connected a usage API: "para automatizar, preciso da chave read-only da [provider]. Sem ela, eu te lembro de checar manualmente toda segunda."
Triggers for action
| Sinal | Ação recomendada |
|---|
| LLM custo / usuário ativo > R$ 1 | Revisar prompts, considerar Haiku, ativar cache. |
| Bandwidth > 70% do free tier | Auditar imagens grandes, downloads. |
| DB > 70% do free tier | Auditar tabelas grandes, archive. |
| Spike > 200% week-over-week | Investigar imediatamente — provável loop / abuse. |
| Erro de cobrança / cartão recusado | Avisar usuário no chat. |
Vibe coder explanation
Imagina que cada serviço que você usa tem um relógio rodando. Toda semana eu olho os relógios pra você e falo: "tudo OK", "tá perto do limite", ou "tem algo estranho". Você não precisa entrar em 5 dashboards.
Output cadence
- Weekly: 5-line summary in chat.
- On spike: same-day alert with the cause.
- Monthly: file
session-log/YYYY-MM-cost-review.md with totals + top 3 levers to reduce.
Relationship to cost-watchdog
cost-watchdog = preventive (before code ships).usage-monitor = reactive (after code is in production).
