calvyntwh/karu-custom-skills/occams-razor

Occam's Razor (The Subtraction Method)

"Entities should not be multiplied without necessity." - William of Ockham

When to Use

• Before adding a new library or dependency.
• When refactoring legacy code.
• When a solution feels "heavy", "boilerplate-y", or hard to explain.
• During Code Review to challenge over-engineering.

When NOT to Use

• Performance-critical paths where the "simpler" solution has worse algorithmic complexity.
• Security boundaries where simplicity traded for readability may introduce vulnerabilities.
• Multi-team APIs where your simplicity creates complexity for consumers.
• Stable, well-tested code with low bug rates — pruning risk exceeds benefit.
• During active incidents — focus on recovery, not refactoring.
• Novel architectures — you don't yet know which complexity is load-bearing.

The Protocol: The Subtraction Method

Do not ask "What can I add?". Ask "What can I remove?". Follow these 4 steps explicitly.

0. Problem Verification

Before pruning, verify the problem statement is correct. Ask: "What problem does this solve for the user?" If you can't answer, do not prune.

1. The Hypothesis

Assume the current solution is over-engineered. State: "This solution is too complex. It can be simpler."

2. The "Why" Test (Safety Check)

Iterate through every component. Prune ruthlessly, but verify safety.

• Grep Test: Search for the string/symbol in the entire codebase. Is it referenced dynamically?
• Test Suite: Run the project's tests. Do they pass?
• Chesterton Check: If uncertain about purpose, invoke `chestertons-fence` protocol first. Mandatory for non-trivial components.
• Rubber Duck Test: Can you explain in one sentence why this component exists? If not, invoke chestertons-fence.

3. The Prune

Actively remove the unnecessary components.

• Replace heavy libraries with native language features (e.g., lodash -> Array.map).
• Collapse "Passthrough" classes (Manager/Service/impl/Interface) into a single function if they don't add logic.
• Delete unused config/boilerplate.

4. Verification

Does the bare metal system still solve the user's Core Problem?

• If YES: You are done.
• If NO: Restore only the minimum necessary piece.

Stop Conditions

Stop pruning when:

• Tests fail and you don't understand why
• You cannot explain the component's purpose in plain English
• The component is referenced by code you don't own
• You've reached the "Core Problem" boundary — removing further breaks user value

Second-Order Check

Before pruning, anticipate workarounds:

Ask: "If I remove this, what will developers likely do instead?"

• Over-pruning pattern: Removed abstraction → developers add inline duplication across 10 callers → more complexity than removed
• Contract breach: Removing validation layer → callers must add checks → distributed complexity
• Knowledge loss: Removing documentation → tribal knowledge only → fragility

If workaround complexity > removed complexity, do not prune.

Skill Integration Matrix

Rule: If systems-thinking identifies a reinforcing loop involving this component, do not prune without tracing the full loop.

Self-Improvement Protocol

After applying Occam's Razor, log only failures:

Log to `.learnings/CORRECTIONS.md`:

-[YYYY-MM-DD] {what was removed} → {outcome}

Log if:

• Pruning caused a bug
• Over-pruning required restoration
• Second-order workaround created more complexity

Do NOT log routine successful prunes — this overhead exceeds value.

Pattern Categories (Prioritized)

High-Impact (Prune First):

• Unused exports / dead code
• Passthrough classes with no logic
• Wrapper libraries around native features

Medium-Impact (Verify Before):

• Abstraction layers over stable internals
• Configuration that could be hardcoded
• Boilerplate that exceeds code it wraps

Low-Impact (Leave Alone):

• Code referenced by unknown callers
• Security-sensitive validation
• Multi-team API boundaries

Resources

• Detailed Research Notes
• Complexity Indicators Reference

Evaluations

Eval 1: Problem Verification Before Pruning

Scenario: User says "this library does X, we should remove it." You cannot explain what X solves for the user. Expected: Stops, verifies problem statement. If no clear user problem exists, does NOT prune. Pass criteria: MUST identify missing problem statement before any pruning action.

Eval 2: Over-Pruning Cascade Prevention

Scenario: Removing a shared utility function would require 10 callers to add inline code. Expected: Identifies that workaround complexity > removed complexity, does NOT prune. Pass criteria: Calculates second-order cost, refuses prune that creates net-more complexity.

Eval 3: Security Boundary Respect

Scenario: User wants to remove "redundant" input validation in a public API endpoint. Expected: Identifies as security boundary, does NOT prune without chestertons-fence investigation. Pass criteria: Correctly identifies validation as potentially load-bearing security fence.