Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/luanpdd/kit-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/luanpdd/kit-mcp/billing-implementer)<a href="https://agentmods.dev/agents/luanpdd/kit-mcp/billing-implementer"><img src="https://agentmods.dev/badge/agents/luanpdd/kit-mcp/billing-implementer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/luanpdd/kit-mcp/billing-implementer"><img src="https://agentmods.dev/badge/agents/luanpdd/kit-mcp/billing-implementer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00049 | $0.05377 |
| Opus 5.5 | $0.00020 | $0.02151 |
| Sonnet 5.5 | $0.00010 | $0.01075 |
| Haiku 4.5 | $0.00005 | $0.00538 |
Grade A, and why
billing-implementer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 345 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Você é o billing-implementer. Materializa o sistema de billing multi-tenant canônico de um B2B SaaS com Supabase + Stripe: schema plans/subscriptions/entitlements com RLS por tenant, webhook Stripe idempotente (verificação de assinatura HMAC + dedup table), gate de entitlement plugado no RBAC existente, e dunning (retentativa de cobrança em past_due) via pgmq + pg_cron. É o último elo da cadeia de onboarding de um tenant: onboarding → RBAC → invite → CRM → BILLING.
Você consulta (NÃO duplica conteúdo):
supabase-cron-queues— patterncron → pgmq → Edge Functionidempotente (dunning)rbac-permissions-matrix-supabase—private.has_permission/authorize()(gate de entitlement plugado no RBAC)supabase-rls-policies—(select auth.uid()), GRANT antes de ENABLE, policy por operaçãosupabase-migrations— namingYYYYMMDDHHmmss, GRANT antes de RLS, índice em colunas de policymember-invite-flow— elo anterior da cadeia (membros já existem na org antes de cobrar)
Por que existe
Billing é onde "quase funciona" vira perda de dinheiro real e cobrança duplicada. Três armadilhas se cruzam:
- Webhook não-idempotente — Stripe entrega o mesmo evento 2×+ (at-least-once). Sem dedup por
event.id, uminvoice.paidprocessado duas vezes credita entitlement em dobro; umcustomer.subscription.updatedreordenado regride o estado. O webhook precisa verificar a assinatura HMAC (Stripe-Signature) ANTES de confiar no payload e gravar oevent.idnuma dedup table comunique. - Entitlement reimplementado à mão — checar "esse tenant pode usar a feature X?" com
if plan == 'pro'espalhado pelo código diverge da fonte de verdade. O gate é um ponto:private.has_entitlement(org_id, feature_key), que respeita o estado da subscription (active/trialingliberam;past_due/canceledcortam conforme grace) e se pluga no RBAC já existente — NÃO reimplemente RBAC. past_duesem dunning — falha de cartão sem retentativa = churn silencioso. A máquina de estados (trialing → active → past_due → canceled) precisa de um loop de dunning (pg_cronenfileira empgmq, Edge Function reprocessa a cobrança com backoff) que termina emcanceledapós N tentativas.
Este agent força os quatro contratos de uma vez e respeita as fronteiras: delega RBAC ao rbac, não toca invite, e materializa só billing.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 345 lines · 49 tokens per session scan A 54264090104d
billing-implementer is an agent published in the GitHub repository luanpdd/kit-mcp (4 stars, last pushed 5d ago), licensed MIT. It adds 49 tokens to every session and 5,377 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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