diff --git a/src/fontra_compile/workflow_action.py b/src/fontra_compile/workflow_action.py
index d53983e..249687f 100644
--- a/src/fontra_compile/workflow_action.py
+++ b/src/fontra_compile/workflow_action.py
@@ -27,6 +27,7 @@ async def connect(
             self.input = None
 
     async def process(self, outputDir: os.PathLike = pathlib.Path()) -> None:
+        outputDir = pathlib.Path(outputDir)
         outputFontPath = outputDir / self.destination
         builder = Builder(self.input)
         await builder.setup()