diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 08c97bf6c..a73b4cf3c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -353,7 +353,13 @@ jobs:
     name: Antora Docs
     needs: [ runner-selection ]
     runs-on: ${{ fromJSON(needs.runner-selection.outputs.labelmatrix)['ubuntu-latest'] }}
+    container: ubuntu:23.10
     steps:
+      - name: Install packages
+        uses: alandefreitas/cpp-actions/package-install@v1.8.3
+        with:
+          apt-get: git cmake
+
       - name: Clone Boost.URL
         uses: actions/checkout@v4
 
@@ -366,12 +372,29 @@ jobs:
         id: setup-cpp
         with:
           compiler: clang
-          version: 17
+          version: 18
+
+      - name: Set environment variables
+        run: |
+          set -x
+          clangpp_path="$(which clang++-18)"
+          clang_path="$(which clang-18)"
+          echo "CXX_COMPILER=$clangpp_path" >> $GITHUB_ENV
+          echo "CXX=$clang_path" >> $GITHUB_ENV
+          echo "C_COMPILER=$clang_path" >> $GITHUB_ENV
+          echo "CC=$clang_path" >> $GITHUB_ENV
+          git config --global --add safe.directory "$(pwd)"
 
       - name: Build Antora Docs
         run: |
           cd doc
           bash ./build_antora.sh
+          
+          # Antora returns zero even if it fails, so we check if the site directory exists
+          if [ ! -d "build/site" ]; then
+              echo "Antora build failed"
+              exit 1
+          fi
 
       - name: Create Antora Docs Artifact
         uses: actions/upload-artifact@v4
diff --git a/doc/generate-files.mjs b/doc/generate-files.mjs
index 1f4a717a3..d434db8f6 100644
--- a/doc/generate-files.mjs
+++ b/doc/generate-files.mjs
@@ -100,12 +100,20 @@ if (cxxCompiler && process.platform === "win32") {
     // Replace "\" with "/" in CXX_COMPILER
     cxxCompiler = cxxCompiler.replace(/\\/g, '/')
 }
+if (cxxCompiler === undefined) {
+    console.error('Could not find a C++ compiler. Please set the CXX_COMPILER environment variable.')
+    process.exit(1)
+}
 const cxxCompilerName = path.basename(cxxCompiler).replace(/\.exe$/, '')
 let cCompiler = findExecutable(['clang', 'gcc', 'cl']) || process.env.C_COMPILER || process.env.CC
 if (cCompiler && process.platform === "win32") {
     // Replace "\" with "/" in CXX_COMPILER
     cCompiler = cCompiler.replace(/\\/g, '/')
 }
+if (cCompiler === undefined) {
+    console.error('Could not find a C compiler. Please set the C_COMPILER environment variable.')
+    process.exit(1)
+}
 const cCompilerName = path.basename(cCompiler).replace(/\.exe$/, '')
 
 console.log(`C++ compiler: ${cxxCompilerName} (${cxxCompiler})`)