diff --git a/action.yml b/action.yml
index 746853d..5fd168c 100644
--- a/action.yml
+++ b/action.yml
@@ -86,7 +86,7 @@ runs:
   using: "composite"
   steps:
     - name: Setup python
-      if: ${{ ! inputs.use-external-python }}
+      if: ${{ ! fromJSON(inputs.use-external-python) }}
       uses: actions/setup-python@v5
       with:
         python-version: ${{ inputs.python-version }}