Refactor Code

Use this skill for behavior-preserving structural improvement.

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Rules

• Preserve external behavior unless the user explicitly asks for a behavior change
• Define the refactor target before editing
• Prefer small, reviewable transformations over broad rewrites
• Keep validation tight throughout the work
• Stop and call out any case where cleanup exposes a real behavior bug

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Step 1 — Define the Refactor Goal

Identify the primary reason:

• Duplication
• Hard-to-follow control flow
• Poor separation of concerns
• Naming or structure that blocks future work
• Excessive coupling or repeated special cases

State what must remain behaviorally unchanged.

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Step 2 — Inspect the Current Shape

Trace:

• The existing call path
• Shared dependencies and invariants
• Current tests that protect the behavior
• The smallest safe edit boundary

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Step 3 — Perform the Refactor

Prefer transformations such as:

• Extracting coherent helpers
• Consolidating duplicate logic
• Simplifying branching
• Improving module boundaries
• Renaming for clarity where the codebase already supports it safely

Avoid mixing unrelated cleanup into the same change.

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Step 4 — Verify Behavior Preservation

Run the closest relevant tests or build command first:

<targeted test/build command>

Then widen if the refactor touched shared code.

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Output

Return:

• Refactor goal
• Files changed
• Validation run
• Any residual behavior risk

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Done Criteria

The refactor is complete only when:

• The structural goal was defined
• The affected code path was inspected
• The cleanup was implemented
• Behavior-preservation validation was attempted when feasible