SKILL.md
Invoice Template Skill
Overview
This skill generates professional PDF invoices from structured data and templates. Create invoices with company branding, itemized lists, tax calculations, and payment details.
How to Use
- Describe what you want to accomplish
- Provide any required input data or files
- I'll execute the appropriate operations
Example prompts:
- "Generate invoices from order data"
- "Create recurring invoices"
- "Batch generate monthly invoices"
- "Customize invoice templates per client"
Domain Knowledge
Invoice Data Structure
invoice_data = {
"invoice_number": "INV-2026-001",
"date": "2026-01-30",
"due_date": "2026-02-28",
"from": {
"name": "Your Company",
"address": "123 Business St",
"email": "[email protected]"
},
"to": {
"name": "Client Name",
"address": "456 Client Ave",
"email": "[email protected]"
},
"items": [
{"description": "Consulting", "quantity": 10, "rate": 150.00},
{"description": "Development", "quantity": 20, "rate": 100.00}
],
"tax_rate": 0.08,
"notes": "Payment due within 30 days"
}PDF Generation with ReportLab
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas
from reportlab.lib.units import inch
def create_invoice(data: dict, output_path: str):
c = canvas.Canvas(output_path, pagesize=letter)
width, height = letter
# Header
c.setFont("Helvetica-Bold", 24)
c.drawString(1*inch, height - 1*inch, "INVOICE")
# Invoice details
c.setFont("Helvetica", 12)
c.drawString(1*inch, height - 1.5*inch, f"Invoice #: {data['invoice_number']}")
c.drawString(1*inch, height - 1.75*inch, f"Date: {data['date']}")
# From/To
y = height - 2.5*inch
c.drawString(1*inch, y, f"From: {data['from']['name']}")
c.drawString(4*inch, y, f"To: {data['to']['name']}")
# Items table
y = height - 4*inch
c.setFont("Helvetica-Bold", 10)
c.drawString(1*inch, y, "Description")
c.drawString(4*inch, y, "Qty")
c.drawString(5*inch, y, "Rate")
c.drawString(6*inch, y, "Amount")
c.setFont("Helvetica", 10)
subtotal = 0
for item in data['items']:
y -= 0.3*inch
amount = item['quantity'] * item['rate']
subtotal += amount
c.drawString(1*inch, y, item['description'])
c.drawString(4*inch, y, str(item['quantity']))
c.drawString(5*inch, y, f"${item['rate']:.2f}")
c.drawString(6*inch, y, f"${amount:.2f}")
# Totals
tax = subtotal * data['tax_rate']
total = subtotal + tax
y -= 0.5*inch
c.drawString(5*inch, y, f"Subtotal: ${subtotal:.2f}")
y -= 0.25*inch
c.drawString(5*inch, y, f"Tax ({data['tax_rate']*100}%): ${tax:.2f}")
y -= 0.25*inch
c.setFont("Helvetica-Bold", 12)
c.drawString(5*inch, y, f"Total: ${total:.2f}")
c.save()
return output_pathHTML Template Approach
from weasyprint import HTML
from jinja2 import Template
invoice_template = """
<!DOCTYPE html>
<html>
<head>
<style>
body { font-family: Arial; margin: 40px; }
.header { display: flex; justify-content: space-between; }
table { width: 100%; border-collapse: collapse; margin: 20px 0; }
th, td { border: 1px solid #ddd; padding: 10px; text-align: left; }
.total { font-weight: bold; font-size: 18px; }
</style>
</head>
<body>
<div class="header">
<h1>INVOICE</h1>
<div>
<p>Invoice #: {{ invoice_number }}</p>
<p>Date: {{ date }}</p>
</div>
</div>
<table>
<tr><th>Description</th><th>Qty</th><th>Rate</th><th>Amount</th></tr>
{% for item in items %}
<tr>
<td>{{ item.description }}</td>
<td>{{ item.quantity }}</td>
<td>${{ "%.2f"|format(item.rate) }}</td>
<td>${{ "%.2f"|format(item.quantity * item.rate) }}</td>
</tr>
{% endfor %}
</table>
<p class="total">Total: ${{ "%.2f"|format(total) }}</p>
</body>
</html>
"""
def create_invoice_html(data: dict, output_path: str):
template = Template(invoice_template)
# Calculate total
total = sum(i['quantity'] * i['rate'] for i in data['items'])
total *= (1 + data.get('tax_rate', 0))
data['total'] = total
html = template.render(**data)
HTML(string=html).write_pdf(output_path)
return output_pathBest Practices
- Validate required fields before generation
- Use templates for consistent branding
- Auto-calculate totals (don't trust input)
- Include payment instructions and terms
Installation
# Install required dependencies
pip install python-docx openpyxl python-pptx reportlab jinja2