diff --git a/.github/workflows/pkgdown.yaml b/.github/workflows/pkgdown.yaml
index c90bb00b8..c0b63195c 100644
--- a/.github/workflows/pkgdown.yaml
+++ b/.github/workflows/pkgdown.yaml
@@ -34,7 +34,7 @@ jobs:
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
-          extra-packages: any::pkgdown, local::., stan-dev/pkgdown-config
+          extra-packages: any::pkgdown, local::., stan-dev/pkgdown-config, qs2=?source, stringfish=?source
 
       - name: Install CmdStan
         run: Rscript -e "cmdstanr::install_cmdstan()"
@@ -53,4 +53,4 @@ jobs:
         with:
           clean: false
           branch: gh-pages
-          folder: docs
\ No newline at end of file
+          folder: docs