Pattern
Negative know-how ledger
This note gives a ledger of failed approaches, so the cost of a failure is not paid again when a person or project leaves. It records the conditions that make each approach fail and what design decision the lesson changes, and it keeps evidence and uncertainty attached rather than folklore. Preserve failed approaches and the conditions that make them fail before the lesson leaves with a person or project.
Record
Name the failed approach, setting, evidence, cause, boundary conditions, cost, risk, and later design decision it changes.
Value
Estimate time, money, harm, or regulatory trouble avoided by knowing not to repeat the path.
Control
Decide whether the lesson is public, patent material, confidential know-how, or a restricted operating record.
Stop
Do not preserve folklore. Keep evidence and uncertainty attached to the failure claim.