I kept pushing changes and finding out 20 minutes later in CI that I broke a bunch of stuff downstream. Last week I added one field to a shared struct and it turned out 417 files depended on it.

I wanted to see that before pushing, so I built this. It's a VS Code extension (works in Cursor too) that shows you which files are affected every time you save. The sidebar fills up with a tree of everything downstream, and the files get color coded by how far away they are from your change.

The part I actually use the most is the CodeLens — it shows caller counts above functions. If something shows zero callers, you know you can change it without worrying. Saves me from grep -r.

It's a Rust CLI underneath that uses tree-sitter to parse your code and build a dependency graph. Supports Rust, TypeScript, Python, Go, Java, and a few others (10 languages total). The CLI watches your repo and streams updates to the extension, usually under a second.

There's also a GitHub Action if you want blast radius comments on PRs automatically: https://github.com/codelayers-ai/codelayers-action

And you can try it without installing anything — paste a public GitHub URL here and it'll build a 3D dependency graph in the browser: https://codelayers.ai/explore