| “Everything is connected, so include everything.” | Include only what can change the named receiving use; preserve material exclusions and triggers. |
| “Outside scope means irrelevant.” | State outside-for-now, consequence of error, and reopen condition. |
| “The model boundary is the problem boundary.” | Let formulations and concerns challenge available variables and model convenience. |
| “Draw the system boundary.” | Name the problem-structuring cut; establish any System-boundary or exact contextual-membership claim through its direct pattern. |
| “Unknown means excluded.” | Separate true or false membership from an unknown evaluation; unknown does not establish exclusion. |
| “Scope was agreed at kickoff.” | Reopen when the named observation can change the receiving result. |