diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000..d87c685
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,2 @@
+# Vendored, minified third-party bundles must never be reformatted.
+*.min.js
diff --git a/TODO.md b/TODO.md
index 2f051a0..a3d6bf5 100644
--- a/TODO.md
+++ b/TODO.md
@@ -20,6 +20,8 @@ main cannot regress.
 
 # Completed Steps
 
+- 2026-09-22: Added `.prettierignore` so `make fmt` no longer rewrites
+  the vendored `static/js/alpine.min.js` bundle (#185).
 - 2026-09-09: Fixed four deployability blockers found by QA: CSRF origin
   check over plain HTTP (`UPAAS_PLAINTEXT_HTTP`, #189), pulling the git
   image when absent (#190), the env-var editor CSRF token lookup (#191),