Refactor Safely Examples

Use these examples when the main SKILL.md flow is clear and you need concrete execution patterns.

Example 1: Extract Service from Controller

Stable behavior to preserve:
"Creating an order validates line items, applies pricing, persists the order, and enqueues NotifyWarehouseJob."

Smallest safe sequence:

1. Add a characterization test (request or service spec) that covers current OrdersController#create.
2. Extract Orders::CreateOrder with identical behavior and call it from the controller.
3. Keep response/redirect logic unchanged while migrating internals.
4. Remove duplication from controller once the new path is proven.
5. Run full tests after each step.

Example 2: Rename in Small Batches

Goal: Rename Order to Purchase safely.

Safe sequence:

1. Introduce compatibility alias/wrapper (temporary).
2. Rename a small set of call sites (one boundary at a time).
3. Run full suite after each batch.
4. Remove alias only when all call sites are migrated and tests are green.

Anti-Pattern Example

Avoid: "Rename Order to Purchase and update all 50 call sites in one PR."

Why unsafe: Too many touchpoints in one step, high rollback cost, poor reviewability, and no isolation when tests fail.