The Change Budget Prompt: Stop Scope Creep in AI-Assisted Coding

If you’ve used an assistant to help with a “quick fix,” you’ve probably seen this pattern: You ask for a small change. It proposes a “better structure.” Suddenly you have a refactor, renamed files, new abstractions, and a broken build. That’s not because the model is malicious. It’s because scope is underspecified . A simple way to prevent this is to add a change budget : a hard constraint on how much code is allowed to move. I call it The Change Budget Prompt . The idea Before you ask for the solution, define a budget in terms the model can respect: Max files touched (e.g. 2) Max lines changed (e.g. 30) No new dependencies No renames / no new modules Keep the public API stable The budget forces the assistant to search for the smallest viable patch instead of the “cleanest” architecture. Think of it like WIP limits for AI-assisted coding: fewer moving parts means fewer hidden failures. A copy/paste template Here’s a template I keep around: Task: <what you want> Change budget: - Touch a