modify-feature

You MUST use this skill before changing, enhancing, or refactoring any existing functionality. Use when the code already exists and you are altering its behavior, performance, or structure — not fixing a bug. Stronger signals: "modify", "refactor", "optimize", "improve", "change how X works", "enhance", "update the logic". Use sextant:add-feature instead when the thing being built does not yet exist. Use…