Fix bugs and small behavior changes at the narrowest responsible layer. Use when regression proof, preserved surrounding behavior, and task-relevant tests matter.

Surgical patch Reproduce failure first when economical; otherwise capture strongest available evidence. Trace symptom to responsible mechanism. Change narrowest layer that owns incorrect behavior. Preserve unrelated behavior and user changes. Avoid cleanup, renaming, and abstraction outside fix. Add only regression proof relevant to task. Run focused proof plus nearest affected gate. Stop when failure is fixed and regression proof passes.

surgical-patch