diff --git a/.github/actions/docs/entrypoint.sh b/.github/actions/docs/entrypoint.sh
deleted file mode 100755
index 7ac74e427..000000000
--- a/.github/actions/docs/entrypoint.sh
+++ /dev/null
@@ -1,21 +0,0 @@
-#!/bin/sh -l
-
-set -e
-
-apt-get update
-apt-get install -y git wget
-
-# Fix github "detected dubious ownership" error
-git config --global --add safe.directory /github/workspace
-
-git reset --hard HEAD
-
-# Create the directories
-mkdir .docs
-mkdir .cache
-
-wget https://github.com/jdpedrie/Sami/releases/download/v4.3.0/sami.phar
-
-# Run the docs generation command
-php sami.phar update .github/actions/docs/sami.php
-chmod -R 0777 .
diff --git a/.github/actions/docs/sami.php b/.github/actions/docs/sami.php
deleted file mode 100644
index b3d3da8f7..000000000
--- a/.github/actions/docs/sami.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php
-
-use Sami\RemoteRepository\GitHubRemoteRepository;
-use Sami\Sami;
-use Sami\Version\GitVersionCollection;
-use Symfony\Component\Finder\Finder;
-
-$projectRoot = realpath(__DIR__ . '/../../..');
-
-$iterator = Finder::create()
-    ->files()
-    ->name('*.php')
-    ->exclude('vendor')
-    ->exclude('tests')
-    ->in($projectRoot);
-
-$versions = GitVersionCollection::create($projectRoot)
-    ->addFromTags(function($tag) {
-        return 0 === strpos($tag, 'v2.') && false === strpos($tag, 'RC');
-    })
-    ->add('main', 'main branch');
-
-return new Sami($iterator, [
-    'title' => 'Google APIs Client Library for PHP API Reference',
-    'build_dir' => $projectRoot . '/.docs/%version%',
-    'cache_dir' => $projectRoot . '/.cache/%version%',
-    'remote_repository' => new GitHubRemoteRepository('googleapis/google-api-php-client', $projectRoot),
-    'versions' => $versions
-]);
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index ae9bf2ed0..b9de0cfb9 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -1,31 +1,26 @@
 name: Generate Documentation
 on:
     push:
-        branches: [main]
+        tags:
+            - "*"
+    workflow_dispatch:
+        inputs:
+            tag:
+                description: 'Tag to generate documentation for'
+                required: false
+    pull_request:
+
+permissions:
+  contents: write
 
 jobs:
     docs:
-        name: "Generate Project Documentation"
-        runs-on: ubuntu-latest
-        steps:
-        - name: Checkout
-          uses: actions/checkout@v2
-        - run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
-        - name: Install Dependencies
-          uses: nick-invision/retry@v1
-          with:
-            timeout_minutes: 10
-            max_attempts: 3
-            command: composer install
-        - name: Generate and Push Documentation
-          uses: docker://php:8.1-cli
-          env:
-            GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
-          with:
-            entrypoint: ./.github/actions/docs/entrypoint.sh
-        - name: Deploy 🚀
-          uses: JamesIves/github-pages-deploy-action@releases/v3
-          with:
-            ACCESS_TOKEN: ${{ secrets.ACCESS_TOKEN }}
-            BRANCH: gh-pages
-            FOLDER: .docs
+        name: "Generate and Deploy Documentation"
+        uses: GoogleCloudPlatform/php-tools/.github/workflows/doctum.yml@main
+        with:
+          title: "Google Cloud PHP Client"
+          default_version: ${{ inputs.tag || github.ref_name }}
+          exclude_file: aliases.php
+          tag_pattern: "v2.*"
+          dry_run: ${{ github.event_name == 'pull_request' }}
+
diff --git a/README.md b/README.md
index 95150d9f1..93b52cacb 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ list of [Google cloud packages](https://cloud.google.com/php/docs/reference) fir
 these are the recommended libraries.
 
 <dl>
-  <dt>Reference Docs</dt><dd><a href="https://googleapis.github.io/google-api-php-client/main/">https://googleapis.github.io/google-api-php-client/main/</a></dd>
+  <dt>Reference Docs</dt><dd><a href="https://googleapis.github.io/google-api-php-client/">https://googleapis.github.io/google-api-php-client/</a></dd>
   <dt>License</dt><dd>Apache 2.0</dd>
 </dl>
 
diff --git a/src/Client.php b/src/Client.php
index 330e8ac6b..1285c49a7 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -1043,7 +1043,8 @@ public function setAuthConfig($config)
 
         $key = isset($config['installed']) ? 'installed' : 'web';
         if (isset($config['type']) && $config['type'] == 'service_account') {
-            // application default credentials
+            // @TODO(v3): Remove this, as it isn't accurate. ADC applies only to determining
+            // credentials based on the user's environment.
             $this->useApplicationDefaultCredentials();
 
             // set the information from the config
diff --git a/tests/Google/ClientTest.php b/tests/Google/ClientTest.php
index 7aea7e9ef..4e53e34b4 100644
--- a/tests/Google/ClientTest.php
+++ b/tests/Google/ClientTest.php
@@ -714,8 +714,10 @@ public function testOnGceCacheAndCacheOptions()
         $mockCache->getItem($prefix . GCECache::GCE_CACHE_KEY)
             ->shouldBeCalledTimes(1)
             ->willReturn($mockCacheItem->reveal());
-        $mockCache->getItem(GCECredentials::cacheKey . 'universe_domain')
-            ->shouldBeCalledTimes(1)
+        // cache key from GCECredentials::getTokenUri() . 'universe_domain'
+        $mockCache->getItem('cc685e3a0717258b6a4cefcb020e96de6bcf904e76fd9fc1647669f42deff9bf') // google/auth < 1.41.0
+            ->willReturn($mockUniverseDomainCacheItem->reveal());
+        $mockCache->getItem(GCECredentials::cacheKey . 'universe_domain') // google/auth >= 1.41.0
             ->willReturn($mockUniverseDomainCacheItem->reveal());
 
         $client = new Client(['cache_config' => $cacheConfig]);