Ca Refactor Agent Skill

$ca-refactor — behavior-preserving restructure

The only permitted entry to refactor work. A refactor that cannot prove parity through unmodified pre-existing tests is a feature change in disguise and routes to $ca-feature. Two required parts: the surface (exact files, functions, classes, or methods — vague surfaces like "the auth module" are rejected) and the motivation (why the restructure is worth doing).

Flow

Routes to the refactor skill — six phases:

• Surface identification — lock the exact files, symbols, and public signatures.
• Parity coverage proof — demonstrate pre-existing tests already cover the named surface, with at

least one direct test per public method.

• Red parity tests (conditional) — if the refactor exposes a new test seam, route to tdd

Phase 1 to write failing tests pinning the seam's contract first.

• Implementation — apply the restructure mechanically within the surface table; no new behavior,

branches, error paths, or side effects.

• Parity verification — the full pre-existing suite passes with zero edits to any pre-existing

test file.

• Lint / coverage gate — lint, type-check, and coverage clear; surface coverage MUST NOT regress.

Routes to

refactor (${CLAUDE_PLUGIN_ROOT}/routines/refactor/SKILL.md) — all six phases.

When NOT to use

• New behavior — a new branch, error path, side effect, public method beyond a Phase 3 seam, or a

change to what any input maps to → $ca-feature.

• A change motivated by "the current behavior is wrong" → $ca-fix.
• Questions or discussion → $ca-btw.
• Persisting an already-completed refactor → $ca-commit.

Hard gate

No refactor proceeds without behavioral-parity coverage proof in Phase 2; if the surface is

under-covered, the skill halts and routes to tdd Phase 1 to backfill before resuming. A Phase 4 diff

that would classify as feat, or a Phase 5 verification that depends on edits to a pre-existing test,

terminates the refactor and re-routes to $ca-feature or $ca-fix.