The musl release build plus the gate is most of the wall clock, and a commit that touches only `web/` cannot change a byte of it. A `what changed` step diffs against the previous head and sets one output; the gate, the build, the ts-rs drift check and the whole `deploy-api` job hang off it. Not `on.push.paths`, which would skip the entire workflow — the site still has to build and ship. Anything unrecognised counts as Rust. A false positive costs a slow deploy; a false negative leaves a binary on bob that does not match the commit, and nothing would report it. Two entries in the path list are less obvious than they look: `asset/`, because deploy-api ships the systemd units, the firewalld service and the rendered config from it; and `web/src/api/generated/`, because the drift gate only runs once `cargo test` has regenerated those files, so a hand-edit of them must not be able to arrive labelled frontend-only — that is exactly the change the gate exists to catch. Checked against this session's five commits: the two pure-UI ones classify as frontend, the three touching crates or .sqlx classify as Rust, and a hand-edited generated type classifies as Rust. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Jp6a8EDar9ueEhAxzep4V5