Safe Change Decision Examples¶

Positive example — compatible seam migration¶

Context: a long-lived contract needs a replacement and consumers migrate independently.
Mode: compatibility-first.
Decision: introduce the new contract additively, observe adoption, migrate consumers, then remove the old path under explicit criteria.
Why it fits: intermediate states remain operable and rollback is possible.
Rejected alternative: replace the contract in one deployment because the new shape is cleaner.

Context: a production defect is isolated to one unfamiliar subsystem.
Mode: local-safe-change.
Bad decision: reorganize the subsystem and replace its abstractions before applying the fix.
Why it fails: behavior, review, and rollback risks expand without being required by the outcome.
Better decision: characterize the failing behavior, apply a bounded fix, and propose broader work separately.