trial → active → past_due → canceled
              → paused → resumed

from billing import BillingEngine, Subscription

# Initialize billing engine
billing = BillingEngine()

# Create subscription
subscription = billing.create_subscription(
    customer_id="cus_123",
    plan_id="plan_pro_monthly",
    billing_cycle_anchor=datetime.now(),
    trial_days=14
)

# Process billing cycle
billing.process_billing_cycle(subscription.id)

f

...(truncated)

</details>

### paypal-integration

> Integrate PayPal payment processing with support for express checkout, subscriptions, and refund management. Use when implementing PayPal payments, processing online transactions, or building e-commerce checkout flows.

<details>
<summary>View skill definition</summary>

# PayPal Integration

Master PayPal payment integration including Express Checkout, IPN handling, recurring billing, and refund workflows.

## When to Use This Skill

- Integrating PayPal as a payment option
- Implementing express checkout flows
- Setting up recurring billing with PayPal
- Processing refunds and payment disputes
- Handling PayPal webhooks (IPN)
- Supporting international payments
- Implementing PayPal subscriptions

## Core Concepts

### 1. Payment Products

**PayPal Checkout**

- One-time payments
- Express checkout experience
- Guest and PayPal account payments

**PayPal Subscriptions**

- Recurring billing
- Subscription plans
- Automatic renewals

**PayPal Payouts**

- Send money to multiple recipients
- Marketplace and platform payments

### 2. Integration Methods

**Client-Side (JavaScript SDK)**

- Smart Payment Buttons
- Hosted payment flow
- Minimal backend code

**Server-Side (REST API)**

- Full control over payment flow
- Custom checkout UI
- Advanced features

### 3. IPN (Instant Payment Notification)

- Webhook-like payment notifications
- Asynchronous payment updates
- Verification required

## Quick Start

```javascript
// Frontend - PayPal Smart Buttons
<div id="paypal-button-container"></div>

<script src="https://www.paypal.com/sdk/js?client-id=YOUR_CLIENT_ID&currency=USD"></script>
<script>
  paypal.Buttons({
    createOrder: function(data, actions) {
      return actions.order.create({
        purchase_units: [{
          amount: {
      

...(truncated)

</details>

### pci-compliance

> Implement PCI DSS compliance requirements for secure handling of payment card data and payment systems. Use when securing payment processing, achieving PCI compliance, or implementing payment card security measures.

<details>
<summary>View skill definition</summary>

# PCI Compliance

Master PCI DSS (Payment Card Industry Data Security Standard) compliance for secure payment processing and handling of cardholder data.

## When to Use This Skill

- Building payment processing systems
- Handling credit card information
- Implementing secure payment flows
- Conducting PCI compliance audits
- Reducing PCI compliance scope
- Implementing tokenization and encryption
- Preparing for PCI DSS assessments

## PCI DSS Requirements (12 Core Requirements)

### Build and Maintain Secure Network

1. Install and maintain firewall configuration
2. Don't use vendor-supplied defaults for passwords

### Protect Cardholder Data

3. Protect stored cardholder data
4. Encrypt transmission of cardholder data across public networks

### Maintain Vulnerability Management

5. Protect systems against malware
6. Develop and maintain secure systems and applications

### Implement Strong Access Control

7. Restrict access to cardholder data by business need-to-know
8. Identify and authenticate access to system components
9. Restrict physical access to cardholder data

### Monitor and Test Networks

10. Track and monitor all access to network resources and cardholder data
11. Regularly test security systems and processes

### Maintain Information Security Policy

12. Maintain a policy that addresses information security

## Compliance Levels

**Level 1**: > 6 million transactions/year (annual ROC required)
**Level 2**: 1-6 million transactions/year (annual SAQ)
**Level 3

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</details>

### stripe-integration

> Implement Stripe payment processing for robust, PCI-compliant payment flows including checkout, subscriptions, and webhooks. Use when integrating Stripe payments, building subscription systems, or implementing secure checkout flows.

<details>
<summary>View skill definition</summary>

# Stripe Integration

Master Stripe payment processing integration for robust, PCI-compliant payment flows including checkout, subscriptions, webhooks, and refunds.

## When to Use This Skill

- Implementing payment processing in web/mobile applications
- Setting up subscription billing systems
- Handling one-time payments and recurring charges
- Processing refunds and disputes
- Managing customer payment methods
- Implementing SCA (Strong Customer Authentication) for European payments
- Building marketplace payment flows with Stripe Connect

## Core Concepts

### 1. Payment Flows

**Checkout Session (Hosted)**

- Stripe-hosted payment page
- Minimal PCI compliance burden
- Fastest implementation
- Supports one-time and recurring payments

**Payment Intents (Custom UI)**

- Full control over payment UI
- Requires Stripe.js for PCI compliance
- More complex implementation
- Better customization options

**Setup Intents (Save Payment Methods)**

- Collect payment method without charging
- Used for subscriptions and future payments
- Requires customer confirmation

### 2. Webhooks

**Critical Events:**

- `payment_intent.succeeded`: Payment completed
- `payment_intent.payment_failed`: Payment failed
- `customer.subscription.updated`: Subscription changed
- `customer.subscription.deleted`: Subscription canceled
- `charge.refunded`: Refund processed
- `invoice.payment_succeeded`: Subscription payment successful

### 3. Subscriptions

**Components:**

- **Product**: What you're sel

...(truncated)

</details>

## Source

[View on GitHub](https://github.com/wshobson/agents)