diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 32210d7..e9bf063 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,19 +1,19 @@
 name: Build CI
 
-on: [pull_request, push]
+on: [pull_request, push, workflow_dispatch]
 
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
     - name: Set up Python 3
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: 3.x
     - name: Versions
       run: |
         python3 --version
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
       with:
         submodules: true
     - name: Fetch correct submodule shas
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 008f440..bb833aa 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -10,20 +10,18 @@ jobs:
     steps:
     - name: Translate Repo Name For Build Tools filename_prefix
       id: repo-name
+      env:
+        REPO: ${{ github.repository }}
       run: |
-        echo "repo-name=$(
-        echo ${{ github.repository }} |
-        awk -F '\/' '{ print tolower($2) }' |
-        tr '_' '-'
-        )" >> $GITHUB_OUTPUT
+        echo "repo-name=$(echo "$REPO" | awk -F '/' '{ print tolower($2) }' | tr '_' '-')" >> "$GITHUB_OUTPUT"
     - name: Set up Python 3
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: 3.x
     - name: Versions
       run: |
         python3 --version
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
       with:
         submodules: true
     - name: Fetch correct submodule shas
@@ -32,16 +30,29 @@ jobs:
       run: |
         sudo apt-get install -y gettext gawk
         pip install -r requirements.txt
-    - name: Package Folder Prefix For circuitpython-build-tools (Community Bundle Specific)
-      id: pkg-folder
+    - name: Build assets
+      env:
+        # Passed as environment, not spliced into the script by the expression.
+        FILENAME_PREFIX: ${{ steps.repo-name.outputs.repo-name }}
       run: |
-        echo prefix=$(
+        # Computed in the step that consumes it. Going via $GITHUB_OUTPUT and an
+        # expression would put a directory name into the next step as script text:
+        # a newline in it writes extra variables to $GITHUB_OUTPUT, and a quote or
+        # backtick escapes whatever quoting that step uses. Held in a shell
+        # variable it stays exactly one argument.
+        prefix=$(
         ls -RUx |
         gawk -F '\n' '{ match($1, /(drivers|helpers)\/(.+)\/(.+)\:/, arr) ; if (length(arr[0]) > 0 && match(arr[3], arr[2]) > 0) printf "%s, ", arr[3] }' |
-        gawk '{ trimmed = substr($0, 1, length($0) - 2) ; print "\"" trimmed "\"" }'
-        ) >> $GITHUB_OUTPUT
-    - name: Build assets
-      run: circuitpython-build-bundles --filename_prefix ${{ steps.repo-name.outputs.repo-name }} --library_location libraries --library_depth 2 --package_folder_prefix ${{ steps.pkg-folder.outputs.prefix }}
+        gawk '{ print substr($0, 1, length($0) - 2) }'
+        )
+        # An empty list is never correct: build-tools splits on ", " and matches
+        # with startswith(), and "".startswith("") is True, so an empty prefix
+        # would silently make every folder -- docs/, tests/, ci/ -- a package.
+        if [ -z "$prefix" ]; then
+          echo "::error::no package folders matched under libraries/; refusing to build an empty bundle"
+          exit 1
+        fi
+        circuitpython-build-bundles --filename_prefix "$FILENAME_PREFIX" --library_location libraries --library_depth 2 --package_folder_prefix "$prefix"
     - name: Upload Release Assets
       uses: shogo82148/actions-upload-release-asset@v1
       with:
diff --git a/build.sh b/build.sh
index 94ed85f..1da0e1c 100755
--- a/build.sh
+++ b/build.sh
@@ -29,7 +29,12 @@ set -e
 P=$(
 ls -RUx |
 gawk -F '\n' '{ match($1, /(drivers|helpers)\/(.+)\/(.+)\:/, arr) ; if (length(arr[0]) > 0 && match(arr[3], arr[2]) > 0) printf "%s, ", arr[3] }' |
-gawk '{ trimmed = substr($0, 1, length($0) - 2) ; print "\"" trimmed "\"" }'
+gawk '{ print substr($0, 1, length($0) - 2) }'
 )
 
+if [ -z "$P" ]; then
+    echo "error: no package folders matched under libraries/; refusing to build an empty bundle" >&2
+    exit 1
+fi
+
 circuitpython-build-bundles --filename_prefix circuitpython-community-bundle --library_location libraries --library_depth 2 --package_folder_prefix "$P"