Why Claude Code Over-Simplifies Your Code and How to Stop It

Mar 15, 2026

I spent two days debugging a Swift build that Claude Code had “simplified” for me. The build succeeded, but the app crashed at runtime. Claude had removed what it thought were “unnecessary” compiler flags - flags that enabled full-text search and thread safety.

Me: "Update the Package.swift dependencies"
Claude: "I've simplified the build configuration by removing redundant flags"
Me: "Those weren't redundant. The app crashes now."
Claude: "I apologize. I was following the 'avoid over-engineering' directive."

The fix? I had to prefix critical sections with “THIS IS NOT OVER-ENGINEERING” - which is absurd, but it actually works.

The Problem: Claude’s Hidden Directive

Claude Code operates with built-in directives that prioritize simplicity. Two of them cause the most trouble:

1. "Avoid over-engineering. Only make changes that are directly
   requested or clearly necessary"

2. "Don't add features, refactor code, or make 'improvements'
   beyond what was asked"

These sound reasonable. But they create a fundamental conflict when working with intentional complexity.

What Claude Sees vs. What Exists

┌─────────────────────────────────────────────────────────────┐
│  What Claude sees:                                          │
│  - Extra layers in the architecture                         │
│  - "Redundant" validation checks                            │
│  - "Unnecessary" build flags                                │
│  - "Overly complex" patterns                                │
├─────────────────────────────────────────────────────────────┤
│  What actually exists:                                      │
│  - Cross-platform build requirements                         │
│  - Security layers preventing injection attacks             │
│  - Compiler flags for runtime features                       │
│  - Patterns enabling testability and maintenance            │
└─────────────────────────────────────────────────────────────┘

Claude lacks context about WHY complexity exists. It only sees the complexity itself.

Real Examples from the Trenches

Example 1: Build Flags Get Stripped

I had a Swift package with conditional compilation flags:

let package = Package(
    name: "DocumentIndexer",
    targets: [
        .target(
            name: "DocumentIndexer",
            swiftSettings: [
                .define("SQLITE_ENABLE_FTS5"),      // Full-text search
                .define("SQLITE_THREADSAFE", to: "1") // Thread safety
            ]
        )
    ]
)

Claude “simplified” it to:

let package = Package(
    name: "DocumentIndexer",
    targets: [
        .target(name: "DocumentIndexer")
    ]
)

The build succeeded. The app crashed the moment anyone tried to search documents.

Example 2: Repository Pattern Removed

I had a clean architecture with repositories:

// Repository pattern for testability and multi-tenant support
export class UserRepository {
  constructor(private db: Database) {}

  async findById(id: string): Promise<User | null> {
    return this.db.users.find({ id })
  }

  async create(data: CreateUserDTO): Promise<User> {
    return this.db.users.create(data)
  }
}

Claude “simplified” it to direct database calls everywhere, removing the repository layer entirely. This broke:

Unit tests (no more mocking)
Multi-tenant architecture (tenant context lost)
Audit logging (no central point)

Example 3: Validation Layer Deleted

# Input validation layer
def validate_user_input(data: dict) -> ValidatedInput:
    if not data.get('email'):
        raise ValidationError("Email required")
    if not is_valid_email(data['email']):
        raise ValidationError("Invalid email format")
    if contains_sql_injection(data):
        raise ValidationError("Invalid characters detected")
    return ValidatedInput(**data)

Claude removed this as “redundant” because the database also validates. But the database validation doesn’t check for SQL injection patterns - it just escapes them. The security layer was gone.

The Solution: Explicit Purpose Labels

The Reddit community found a workaround that sounds ridiculous but works:

<!-- THIS IS NOT OVER-ENGINEERING: Required for cross-platform builds -->
<!-- Context: Windows requires different linking flags, macOS needs .framework -->

I now prefix every critical section with this pattern:

# THIS IS NOT OVER-ENGINEERING
# Purpose: This validation layer prevents injection attacks
# Context: User input flows through 3 different endpoints
# Do NOT remove - required by security policy

def validate_user_input(data: dict) -> ValidatedInput:
    if not data.get('email'):
        raise ValidationError("Email required")
    if not is_valid_email(data['email']):
        raise ValidationError("Invalid email format")
    if contains_sql_injection(data):
        raise ValidationError("Invalid characters detected")
    return ValidatedInput(**data)

The key is explaining WHY, not just WHAT.

Solution 2: Strategic CLAUDE.md Documentation

A vague CLAUDE.md gets ignored:

# Coding Style
- Keep architecture patterns
- Don't simplify build configs
- Maintain existing structure

A specific CLAUDE.md with rationale works:

# Build Configuration

## Swift Build Flags
CRITICAL: Do NOT simplify these flags. This is not over-engineering.

```swift
// These conditional flags are REQUIRED:
// - SQLITE_ENABLE_FTS5: Full-text search for document indexing
// - SQLITE_THREADSAFE=1: Thread safety for concurrent requests
// Without these, the app will CRASH on document search.

let package = Package(
    name: "MyApp",
    targets: [
        .target(
            name: "MyApp",
            swiftSettings: [
                .define("SQLITE_ENABLE_FTS5"),
                .define("SQLITE_THREADSAFE", to: "1")
            ]
        )
    ]
)

If you remove these thinking they’re “unnecessary complexity,” the build will succeed but the app will crash at runtime.

Repository Pattern

This is NOT over-engineering. We use repositories because:

Enables unit testing with mock data
Decouples business logic from database
Required for multi-tenant architecture

DO NOT simplify to direct database calls. This will break:

All unit tests (no mocking capability)
Tenant isolation (context lost)
Audit logging (no central point)

## The Pattern: Context + Consequence

I've found a formula that works:

```text title="The anti-simplification formula"
┌─────────────────────────────────────────────────────────────┐
│  1. Label: "THIS IS NOT OVER-ENGINEERING"                   │
│  2. Purpose: What this code does                            │
│  3. Context: Why it exists in this architecture              │
│  4. Consequence: What breaks if removed                      │
└─────────────────────────────────────────────────────────────┘

Example:

// THIS IS NOT OVER-ENGINEERING
// Purpose: Caching layer for API responses
// Context: We make 10,000+ API calls per hour
// Consequence: Without this, API costs increase 90% and response times triple

export class CacheLayer {
  private cache = new Map<string, CachedResponse>()

  async get<T>(key: string, fetcher: () => Promise<T>): Promise<T> {
    const cached = this.cache.get(key)
    if (cached && !this.isExpired(cached)) {
      return cached.data as T
    }
    const data = await fetcher()
    this.cache.set(key, { data, timestamp: Date.now() })
    return data
  }
}

Common Mistakes I Made

Mistake 1: Fighting Claude After the Fact

I used to let Claude simplify, then try to re-explain. This is inefficient:

1. Claude simplifies code
2. I notice something broke
3. I explain why the original was needed
4. Claude restores it
5. Repeat for next section

Now I prevent with proactive documentation:

1. Document WHY complexity exists in CLAUDE.md
2. Label critical sections with purpose
3. Claude reads context before making changes
4. Complexity is preserved

Mistake 2: Vague Rules

“Maintain architecture” means nothing to Claude. Be specific:

# Rules
- Maintain existing patterns
- Don't over-simplify

# Architecture Patterns

## CQRS Pattern
This is NOT over-engineering. We use Command Query Responsibility Segregation because:
- Read and write workloads have different scaling needs
- Enables separate optimization for queries vs commands
- Required for eventual consistency with event sourcing

DO NOT merge read and write models. This will break the event replay mechanism.

Mistake 3: Assuming Claude Remembers Context

Claude starts fresh each session. I used to assume it remembered previous conversations:

Session 1: "This caching layer is critical for performance"
Session 2: Claude remembers and preserves caching layer

Session 1: "This caching layer is critical for performance"
Session 2: Claude has no memory, sees "extra layer", removes it

Now I put critical context in CLAUDE.md, which is read every session.

What I Actually Do Now

My current workflow:

Before any Claude session, I ensure CLAUDE.md has:
- Purpose explanations for all architectural decisions
- Consequence descriptions for removing each pattern
- Explicit “NOT OVER-ENGINEERING” labels
In code, I label critical sections:

// THIS IS NOT OVER-ENGINEERING
// Purpose: Enable full-text search and thread safety
// Context: Document indexing runs on background threads
// Consequence: App crashes on search without SQLITE_ENABLE_FTS5

let package = Package(
    name: "DocumentIndexer",
    targets: [
        .target(
            name: "DocumentIndexer",
            swiftSettings: [
                .define("SQLITE_ENABLE_FTS5"),
                .define("SQLITE_THREADSAFE", to: "1")
            ]
        )
    ]
)

After Claude makes changes, I verify critical sections weren’t touched.

Decision Tree: When to Add Labels

Does this code look like it could be "simplified"?
│
├─ YES → Would simplification break something?
│        │
│        ├─ YES → Add "THIS IS NOT OVER-ENGINEERING" label
│        │         with purpose, context, and consequence
│        │
│        └─ NO → No label needed
│
└─ NO → No label needed

Signs that code needs a label:

Multiple layers of abstraction
Configuration that seems “redundant”
Validation that duplicates other checks
Patterns that add indirection
Build flags or conditional compilation

Key Takeaways

Claude lacks context about WHY - It sees complexity, not the reason for it
“THIS IS NOT OVER-ENGINEERING” works - It’s absurd but effective
Explain purpose + context + consequence - Give Claude the “why”
CLAUDE.md needs specifics - Vague rules get deprioritized
Proactive beats reactive - Document before Claude touches code
Each session is fresh - Claude doesn’t remember previous conversations

The “avoid over-engineering” directive is well-intentioned. It prevents Claude from adding unnecessary complexity. But it misfires when applied to intentional complexity - the kind that exists for good reasons.

Treat Claude like a junior developer who needs the “why,” not just the “what.” The absurd solution of prefixing sections with “THIS IS NOT OVER-ENGINEERING” actually works because it gives Claude the context it needs to distinguish between accidental and intentional complexity.

Final Words + More Resources

My intention with this article was to help others share my knowledge and experience. If you want to contact me, you can contact by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!