cc-refactoring-guidance

Refactoring is behavior-preserving change to working code. Three rules govern it:

Fix first, then refactor — never in the same change; separate commits with a boundary between them.
Small changes need MORE rigor, not less — 1–5-line changes have the highest error rate.
Over half of changes fail the first attempt — review and test even "trivial" ones; the error rate is per change, not cumulative.

Rule	Value	Source
Small-change error rate	Peaks at 1–5 lines	Weinberg 1983
First-attempt success	<50% for any change	Yourdon 1986b
Review effect on 1-line changes	55% → 2% error rate	Freedman and Weinberg 1982

Shared thresholds (routine length, parameters, cohesion): Read(${CLAUDE_PLUGIN_ROOT}/references/cc-foundations.md). The full 40-item refactoring checklist: Read(${CLAUDE_SKILL_DIR}/checklists.md).