The Patch Letter Pattern: Make Your Assistant Write a Cover Letter Before It Touches Your Code

If you use an assistant to help you code, you’ve probably seen this movie: You ask for a small fix. You get a lot of changes. Some of them are great. Some of them are… creative. And now you’re reviewing a surprise refactor you didn’t budget for. The fastest way I’ve found to prevent that isn’t a better model or a longer prompt. It’s a tiny workflow change: The Patch Letter Pattern Before the assistant edits code, make it write a patch letter — a short “cover letter” describing the proposed change as if it were a pull request description . You review the patch letter like a spec. Only after you approve it do you ask for implementation. This turns “please fix this” into a controlled two-step loop: Design the patch (patch letter). Apply the patch (code). It’s boring. It’s also ridiculously effective. Why it works A patch letter forces the assistant to commit to specifics in text : What exactly will change? Which files will be touched? What won’t change? What’s the risk surface? How will w