diff --git a/.github/workflows/rust-ci.yml b/.github/workflows/rust-ci.yml
index effb99d..3f42a5d 100644
--- a/.github/workflows/rust-ci.yml
+++ b/.github/workflows/rust-ci.yml
@@ -10,6 +10,9 @@ on:
 permissions:
   actions: read
   contents: read
+# Pin must be at or past the standards commit that passes `toolchain: stable`
+# to the SHA-pinned dtolnay/rust-toolchain. d135b05b predates that and fails
+# every run with "'toolchain' is a required input" (#105).
 jobs:
   rust-ci:
-    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@95de3dfc3fcf09a1cf3325ab42723e3d81682b45