diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fab0776c2..b8630fd32 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -42,7 +42,9 @@ repository, and we're happy to link to it.
 
 Node `^22 || ^24`, a working `tmux` and `rsync` are required. macOS includes `rsync`; many Linux
 installs don't (`sudo apt-get install rsync` on Debian or Ubuntu). `npm test` and `npm run mirror-skills`
-use it. Then:
+use it. Use the npm that comes with your Node, which is npm 10 or newer (`npm --version` shows which you
+have). A separately packaged npm 9, such as Debian or Ubuntu's `npm` package, fails a fresh `npm ci` with
+`ENOENT` on `chmod` of `node_modules/@openrig/tui/dist/main.js`. Then:
 
 ```bash
 git clone https://github.com/mvschwarz/openrig.git