diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 9cedd955e..fa99fe576 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -121,7 +121,17 @@ jobs:
         with:
           node-version: '22'
           cache: npm
-          cache-dependency-path: frontend/package-lock.json
+          cache-dependency-path: |
+            frontend/package-lock.json
+            aether-vscodex/web/package-lock.json
+
+      # The frontend prebuild synchronizes the embedded VSCodex UI by running
+      # its build from a separate package. Install that package explicitly so
+      # vue-tsc can resolve vite/client, vitest/globals, and node types in a
+      # clean runner.
+      - name: Install VSCodex web dependencies
+        working-directory: aether-vscodex/web
+        run: npm ci
 
       - name: Install dependencies
         working-directory: frontend