diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 695cad7..2d6528d 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -1,6 +1,7 @@
 name: CI
 on:
   push:
+    branches: [main]
   pull_request:
   workflow_dispatch:
 permissions:
diff --git a/.github/workflows/release-android.yml b/.github/workflows/release-android.yml
index 3d80a1d..de7c0a6 100644
--- a/.github/workflows/release-android.yml
+++ b/.github/workflows/release-android.yml
@@ -58,6 +58,8 @@ jobs:
       - uses: actions/setup-node@a0853c24544627f65ddf259abe73b1d18a591444 # v5
         with:
           node-version-file: .nvmrc
+          # Signing uses Node built-ins only; no package manager is installed.
+          package-manager-cache: false
       - uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961 # v5
         with:
           distribution: temurin