diff --git a/demos/askem-var.py b/demos/askem-var.py
index 59255004..97a68bc3 100644
--- a/demos/askem-var.py
+++ b/demos/askem-var.py
@@ -36,10 +36,11 @@ class Variable(Schema):
 if __name__ == "__main__":
     run_pz = True
     dataset = "askem"
+    file_path = "testdata/askem-tiny"
 
     if run_pz:
         # reference, plan, stats = run_workload()
-        excerpts = Dataset(dataset, schema=TextFile)
+        excerpts = Dataset(file_path, schema=TextFile)
         output = excerpts.convert(
             Variable, desc="A variable used or introduced in the paper snippet", cardinality=pz.Cardinality.ONE_TO_MANY
         )
diff --git a/src/palimpzest/datamanager/datamanager.py b/src/palimpzest/datamanager/datamanager.py
index f1006ef7..f5eda67e 100644
--- a/src/palimpzest/datamanager/datamanager.py
+++ b/src/palimpzest/datamanager/datamanager.py
@@ -140,6 +140,19 @@ def register_user_source(self, src: UserSource, dataset_id: str):
         # user sources are always ephemeral
         self._registry[dataset_id] = ("user", src)
 
+    def get_or_register_source(self, dataset_id_or_path):
+        """Return a dataset from the registry."""
+        if dataset_id_or_path in self._registry:
+            return self.get_registered_dataset(dataset_id_or_path)
+        else:
+            if os.path.isfile(dataset_id_or_path):
+                self.register_local_file(dataset_id_or_path, dataset_id_or_path)
+            elif os.path.isdir(dataset_id_or_path):
+                self.register_local_directory(dataset_id_or_path, dataset_id_or_path)
+            else:
+                raise Exception(f"Path {dataset_id_or_path} is invalid. Does not point to a file or directory.")
+            return self.get_registered_dataset(dataset_id_or_path)
+
     def get_registered_dataset(self, dataset_id):
         """Return a dataset from the registry."""
         if dataset_id not in self._registry:
diff --git a/src/palimpzest/sets.py b/src/palimpzest/sets.py
index 2ec73b68..92eeed69 100644
--- a/src/palimpzest/sets.py
+++ b/src/palimpzest/sets.py
@@ -135,7 +135,13 @@ class Dataset(Set):
 
     def __init__(self, source: str | DataSource, *args, **kwargs):
         # convert source (str) -> source (DataSource) if need be
-        source = DataDirectory().get_registered_dataset(source) if isinstance(source, str) else source
+        if isinstance(source, str):
+            try:
+                source = DataDirectory().get_or_register_source(source)
+            except Exception as e:
+                raise Exception(f"Invalid source path: {source}") from e
+        elif not isinstance(source, (DataSource, Set)):
+            raise Exception(f"Invalid source type: {type(source)}")
 
         # intialize class
         super().__init__(source, *args, **kwargs)