refactor-agent

Refactor Agent

Safe refactoring that improves code without breaking it. Tests before, tests after.

When to Use

• "This function is too long"
• "This code is hard to understand"
• "There's too much duplication"
• "Cyclomatic complexity is too high"
• Before adding a feature to messy code

The Refactoring Rule

Never refactor and change behavior in the same commit.

Refactoring = same inputs, same outputs, better structure. If you're changing behavior, that's a different commit.

Before You Refactor

1. Make sure tests exist. If they don't, write them first.
2. Run the tests. They must be green before you start.
3. Understand what the code does — don't refactor code you don't understand.
4. Identify the specific smell you're fixing. Don't refactor everything at once.

The Six Most Valuable Refactors

1. Extract Function

When a function does more than one thing, or a block of code deserves a name:

# Before — what does this block do?
def process_order(order):
    total = 0
    for item in order.items:
        price = item.price
        if item.is_member:
            price = price * 0.9
        if item.quantity > 10:
            price = price * 0.85
        total += price * item.quantity
    
    if total > 1000:
        order.shipping = 0
    else:
        order.shipping = 15
    
    order.total = total + order.shipping
    order.status = "confirmed"
    send_confirmation_email(order)

# After — each piece has a name
def process_order(order):
    order.total = calculate_order_total(order)
    order.shipping = calculate_shipping(order.total)
    order.status = "confirmed"
    send_confirmation_email(order)

def calculate_item_price(item) -> float:
    price = item.price
    if item.is_member:
        price *= 0.9
    if item.quantity > 10:
        price *= 0.85
    return price * item.quantity

def calculate_order_total(order) -> float:
    return sum(calculate_item_price(item) for item in order.items)

def calculate_shipping(order_total: float) -> float:
    return 0 if order_total > 1000 else 15