diff --git a/check-code-style/action.yml b/check-code-style/action.yml
index b42c032..8769df7 100644
--- a/check-code-style/action.yml
+++ b/check-code-style/action.yml
@@ -5,14 +5,16 @@ name: "Check Code Style"
 desciption: "Check files for correct code style"
 
 inputs:
-  os:
-    description: "Specify operating system on which this action will run"
+  buildifier-version:
+    description: "Version of 'buildifier' to install"
+    required: false
+    default: '5.1.0'
 
 runs:
   using: "composite"
   steps:
     - name: Install clang-format-13 if Ubuntu
-      if: inputs.os == 'ubuntu-latest'
+      if: ${{ runner.os == 'Linux' }}
       run: |
         # Install Clang 13 (including clang-format-13) through LLVM's preferred mechanism:
         #   https://apt.llvm.org/
@@ -29,8 +31,11 @@ runs:
 
     # On macOS we should install clang-format.
     - name: Install clang-format-13 if macOS
-      if: inputs.os == 'macos-latest'
+      if: ${{ runner.os == 'macOS' }}
       run: |
+        # TODO(benh): is 'brew' not in PATH on macOS like it is not in
+        # the PATH for Linux? If so, where does GitHub install 'brew'
+        # on a macOS runner?
         brew install clang-format@13
       shell: bash
 
@@ -40,8 +45,14 @@ runs:
         ${{ github.action_path }}/check_style_of_all_files.sh
       shell: bash
 
-    - name: Install buildifier for .bzl files
-      run: brew install buildifier
+    - name: Install buildifier for .bzl files (macOS)
+      if: ${{ runner.os == 'macOS' }}
+      run: brew install buildifier@${{ inputs.buildifier-version }}
+      shell: bash
+
+    - name: Install buildifier for .bzl files (Linux)
+      if: ${{ runner.os == 'Linux' }}
+      run: /home/linuxbrew/.linuxbrew/bin/brew install buildifier@${{ inputs.buildifier-version }}
       shell: bash
 
     - name: Check all .bzl, .bazel files for correct code style