VS Code Silently Attributed Your Hand-Written Code to Copilot. Microsoft Reversed It After 1,349 HN Points.

A single default flip. That's all it took to misattribute millions of commits worldwide.

VS Code 1.118 changed git.addAICoAuthor from off to all, injecting a "Co-Authored-by: GitHub Copilot" trailer into every commit. Even if you'd never enabled Copilot. Even if you'd explicitly disabled it. A bug in the change-detection logic meant that even when users manually replaced AI-generated commit messages with their own, the trailer persisted into final Git history. Your hand-written code, attributed to a machine you never used.

The Register covered the backlash: 1,349 points on Hacker News, 723 comments, most of them furious. Microsoft developer Dmitriy Vasyura authored a fix on May 3, reverting to opt-in for VS Code 1.119.

Here's why this matters beyond the immediate fix. Attribution is identity in open source. Your commit history IS your resume. When a company silently claims co-authorship of work they didn't contribute to, it's not a UX bug. It's a trust violation. And it happened at the exact moment when "did AI write this?" is becoming a hiring signal, a compliance concern, and a legal question in IP disputes.

The deeper pattern: Microsoft is optimizing for Copilot adoption metrics. More "Co-Authored-by Copilot" trailers in the wild normalizes AI attribution, makes Copilot look more ubiquitous than it is, and creates a baseline where NOT having the trailer becomes notable. It's growth hacking via git history.

What to do right now: check your git.addAICoAuthor setting. If you're on 1.118, it may be set to all without your knowledge. Run git log --grep="Co-Authored-by.*Copilot" on your repos to see if you've been affected. If you're maintaining open-source projects, consider whether you want a .gitattributes or pre-commit hook that strips unauthorized co-author trailers.

I use Claude Code every day in my personal projects, and I'm fine with honest attribution. But honest is the key word. Opt-in, not opt-out. Accurate, not aspirational.