diff --git a/.github/workflows/build-book.yaml b/.github/workflows/build-book.yaml
index 15d93ea..31a583f 100644
--- a/.github/workflows/build-book.yaml
+++ b/.github/workflows/build-book.yaml
@@ -26,7 +26,7 @@ on:
       build_command:
         description: 'The linux command to build the book or site.'
         required: false
-        default: 'myst build --execute --html'
+        default: 'myst build --execute --html --strict'
         type: string
       output_path:
         description: 'Path to the built html content relative to `path_to_notebooks`'