| name | asc-refactor |
| description | Structured refactoring workflow. Preserves existing behavior while improving structure. Use this skill when user asks to refactor code, clean up code, improve code structure, rewrite legacy code, extract components, reduce technical debt, apply SOLID/DRY principles, or migrate codebases.
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Refactor Skill
Structured refactoring workflow. Preserves existing behavior while improving structure.
Grounded in: Fowler's Refactoring (read-understand-smallest scope-preserve behavior), Rule of Three (abstraction threshold), YAGNI principle (XP/Kent Beck). Empirical evidence: agents dominate low-level refactors (rename, extract, type changes) but struggle with multi-file architectural changes (arXiv, 15k+ instance study).
YAGNI Scan (Before Any Restructuring)
Before changing structure, scan for speculative code to remove:
- "Just in case" logic, unused feature flags, dead branches behind config toggles.
- Abstractions wrapping a single implementation with no second consumer.
- Premature extension points (plugin hooks, strategy patterns) with one concrete path.
Removing speculative code is the highest-value, lowest-risk refactor type.
Classify Before Proceeding
After reading the target code, classify the refactor:
- Low-level (rename, extract method, type safety, dead code removal): proceed after explaining the change. No approval gate needed.
- High-level (move module, change architecture, redesign abstractions, multi-file structural changes): output a plan with specific files and rationale, then stop and wait for user approval before implementing.
Known limitation: The high-level refactor gate is a skill-text instruction — the agent self-classifies and self-stops. Unlike /asc-add-feature and /asc-new-project, this gate is not backed by the PostToolUse hook or workflow-gate.json. If the agent bypasses the gate, there is no automated nudge.
Before Editing
- Read the target code and understand existing patterns.
- Identify the smallest relevant scope for the refactor.
- Classify the refactor (see above). If high-level, stop and present a plan.
- If the change touches UI, check accessibility and responsive behavior.
- If the change touches dependencies, verify current official docs.
Refactor Rules
- Improve clarity, boundaries, naming, validation, error handling, and tests.
- Prioritize maintainability over compressed one-liners.
- Keep the main flow traceable. Use early returns where they reduce nesting.
- Introduce abstractions only when the repeated pattern is real and visible.
- Split large files when the split makes the flow easier to understand.
- Remove code that does not carry behavior, safety, clarity, maintainability, or test value.
- Prefer the shorter implementation only when it keeps the same guarantees.
- Run a final simplification pass before completion.
- Update tests and docs whenever behavior contracts, public APIs, data shape, or UI contracts change.
For Every Change, Explain
- What risk or friction existed.
- What changed.
- Why the new shape is safer or easier to maintain.
Validation
- Existing behavior is preserved unless the user approved a change.
- Edge cases, empty states, error paths, and rollback paths are handled.
- Public contracts remain stable or are versioned.
- Tests pass.
