Methodologygeneric

invoice-template

Generate professional PDF invoices from templates

claude-office-skills/skills

Install

npx skills add https://github.com/claude-office-skills/skills --skill invoice-template

Use with your agent

Install the invoice-template skill, then use it as build context. Run: npx skills add https://github.com/claude-office-skills/skills --skill invoice-template. Then read the installed skill.md and follow its guidance to build or refactor my project.

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_path

HTML 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_path

Best 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