# Thinking Guides

Use a guide only when its trigger applies and its relevant context is not
already loaded. Stable implementation contracts remain in the domain specs;
these guides help locate the questions that matter.

| Guide | Trigger |
| --- | --- |
| [Code reuse](./code-reuse-thinking-guide.md) | A new helper/component, repeated behavior, or a shared constant/contract change |
| [Cross-layer behavior](./cross-layer-thinking-guide.md) | Data, authority or state crosses a boundary; multiple consumers depend on a change |

Search affected consumers for a shared-contract change. A local wording or
literal correction does not require a full-repository search. Add a reusable
insight at its existing owner; keep one-off findings in the task.