simplify-code

name	simplify-code
description	Reduce complexity of over-engineered code. Identify unnecessary abstractions, remove dead code, flatten deep nesting, and simplify logic while preserving behavior.
when_to_use	When code is over-engineered, overly abstract, deeply nested, or more complex than needed. When user asks to 'simplify', 'clean up', 'reduce complexity', or 'make this simpler'. NOT for adding new features.
allowed-tools	Read, Write, Edit, Grep, Glob
effort	medium

Simplify Code — Reduce Unnecessary Complexity

The best code is the code you don't have to write. The second best is the code anyone can read.

Core Principle

Complexity is a cost. Every abstraction, every indirection, every clever pattern
adds cognitive load. Simplify ruthlessly unless complexity serves a clear purpose.

---

Simplification Checklist

1. Unnecessary Abstractions

Smell	Simplification
Wrapper class that just delegates	Remove wrapper, use the inner class directly
Factory that creates only one type	Replace with direct constructor
Strategy pattern with one strategy	Replace with simple function
Interface with one implementation	Remove interface, use the class
Abstract class with one child	Merge into the child class
Config object for 2 values	Use function parameters

2. Dead Code

Smell	Action
Unused imports	Remove
Unreachable branches	Remove (check tests first)
Commented-out code	Remove (it's in git history)
Unused variables/functions	Remove
TODO comments older than 6 months	Remove or create issue
Feature flags for launched features	Remove flag, keep the code

3. Deep Nesting

// ❌ Before: 4 levels deep
function process(data) {
  if (data) {
    if (data.items) {
      for (const item of data.items) {
        if (item.active) {
          doSomething(item)
        }
      }
    }
  }
}

// ✅ After: Early returns + filter
function process(data) {
  if (!data?.items) return

  data.items
    .filter(item => item.active)
    .forEach(doSomething)
}

4. Over-Parameterized Functions

// ❌ Before: 8 parameters
function createUser(name, email, age, role, dept, active, verified, avatar) { }

// ✅ After: Object parameter
function createUser(opts: CreateUserOpts) { }

5. Premature Optimization

Smell	Simplification
Custom cache for <100 items	Remove cache, measure first
Memoization on cheap functions	Remove memo
Lazy loading for small modules	Use direct import
Complex state machine for 3 states	Use simple if/else or switch

---

Simplification Protocol

Step 1: Identify Complexity

- Count nesting levels (target: ≤3)
- Count function parameters (target: ≤4)
- Count lines per function (target: ≤30)
- Count abstractions per feature (target: ≤2)
- Check for dead code (target: 0)

Step 2: Verify Understanding

Before simplifying, ensure you understand:

• What the code does (not what it looks like it does)
• Why it was written this way (maybe there's a reason)
• What tests cover it (simplification must not break tests)

Step 3: Simplify Incrementally

1. Remove dead code first (safest)
2. Flatten nesting with early returns
3. Inline trivial abstractions
4. Merge related functions
5. Simplify data structures

Step 4: Verify Behavior Preserved

npm run test    # All existing tests still pass
npm run build   # Still compiles

---

When NOT to Simplify

Situation	Why Keep Complexity
Performance-critical hot path	Optimization may look complex but is necessary
Required by framework/library	External constraints
Explicitly requested pattern	User chose this architecture
Will need extension soon	Abstraction prepares for known growth

Ask first: "This pattern seems over-engineered. Should I simplify it, or is there a reason for the abstraction?"