# Payment Plans Service Implementation Summary
## Overview
Successfully implemented the `list_payment_plans` MCP service for retrieving payment plan information from the checkout API.
## Implementation Details
### 1. Service Layer (`src/services/paymentPlansService.ts`)
**Features:**
- ✅ Reads configuration from environment variables (`CHECKOUT_ID`, `PRODUCT_ID`)
- ✅ Makes single GET request with comma-separated product IDs
- ✅ Authenticates with Bearer token
- ✅ Processes API response to extract:
- Credit card installment options
- PIX single payment
- Bank slip single payment
- ✅ Ignores `fine`, `fine_tax`, and `late_interest` fields
- ✅ Generates human-friendly summary in Portuguese
- ✅ Comprehensive error handling
- ✅ Development logging support
**Key Methods:**
- `listPaymentPlans()`: Main method that calls the API and returns formatted data
- `formatCurrency()`: Formats numbers as Brazilian currency (R$)
- `generateSummary()`: Creates natural language payment summary
- `getConfig()`: Returns current configuration
### 2. MCP Server Integration (`src/index.ts`)
**Changes:**
- ✅ Imported `PaymentPlansService`
- ✅ Added `paymentPlansService` instance to server class
- ✅ Registered `list_payment_plans` tool in MCP tool list
- ✅ Added request handler for `list_payment_plans` calls
- ✅ No input parameters required (uses environment configuration)
### 3. Environment Configuration (`.env`)
**New Variables:**
```env
CHECKOUT_ID=your_checkout_id_here
PRODUCT_ID=36,42
```
### 4. Documentation Updates
**Updated Files:**
- ✅ `README.md` - Added complete tool documentation with examples
- ✅ `WARP.md` - Updated architecture and configuration sections
- ✅ Both documents include API behavior notes and example responses
## API Behavior
**Endpoint:**
```
GET {{host}}/api/v1/payment_plans?product_id=36,42&checkout_page_id={{checkout_id}}
```
**Key Points:**
- Single API call with comma-separated `product_id` string
- Backend processes multiple products and returns combined conditions
- Response includes credit card, PIX, and bank slip options
## Output Format
```json
{
"checkout_id": "<checkout_id>",
"product_id": "36,42",
"plans": {
"credit_card": [
{ "installments": 1, "value": 1096.00 },
{ "installments": 12, "value": 91.33 }
],
"pix": [
{ "value": 1096.00 }
],
"bank_slip": [
{ "value": 1096.00 }
]
},
"payment_summary": "Temos pagamentos em até 12x de R$ 91,33 no cartão de crédito, ou à vista no PIX por R$ 1.096,00 ou boleto por R$ 1.096,00."
}
```
## Testing
### Build Verification
```bash
cd /Users/rcslima/projects/mcpNova
yarn build
```
✅ **Result:** Successful compilation
### Generated Files
- ✅ `build/services/paymentPlansService.js`
- ✅ `build/services/paymentPlansService.d.ts`
- ✅ `build/index.js` (with integrated payment plans handler)
## Next Steps
1. **Configure Environment:**
- Update `.env` with actual `CHECKOUT_ID` value
- Verify `PRODUCT_ID` matches your requirements
2. **Test the Service:**
```bash
# Set actual CHECKOUT_ID in .env first
yarn dev
```
3. **MCP Client Integration:**
- Update your MCP client configuration (e.g., Claude Desktop)
- Add `CHECKOUT_ID` and `PRODUCT_ID` to environment variables
- Rebuild and restart: `yarn build`
4. **Verify API Response:**
- Call `list_payment_plans` tool from MCP client
- Verify payment options are returned correctly
- Check that summary is generated in Portuguese
## Architecture Patterns
This implementation follows the established patterns in the codebase:
1. **Service class pattern** - Similar to `CustomerService` and `ViaCepService`
2. **Environment configuration** - Uses `process.env` for API credentials
3. **Error handling** - Comprehensive axios error handling
4. **TypeScript interfaces** - Strongly typed request/response models
5. **Development logging** - Controlled by `NODE_ENV` variable
6. **MCP integration** - Follows existing tool registration pattern
## Files Modified
1. ✅ `src/services/paymentPlansService.ts` (new)
2. ✅ `src/index.ts` (updated)
3. ✅ `.env` (updated)
4. ✅ `README.md` (updated)
5. ✅ `WARP.md` (updated)
## Compliance
✅ Uses yarn (not npm) per project rules
✅ Follows existing TypeScript configuration (ES2022, Node16)
✅ Uses `.js` extensions in imports (ESM compatibility)
✅ Environment file not committed to git (security best practice)
✅ Bearer token authentication pattern maintained
✅ Comprehensive error handling implemented
✅ Development logging when `NODE_ENV=development`