diff --git a/tests/definitions_test.py b/tests/definitions_test.py
index dce19f84a..c8430123b 100644
--- a/tests/definitions_test.py
+++ b/tests/definitions_test.py
@@ -63,6 +63,10 @@ def _get_diff_from_upstream():
         for file in changes:
             # Ensure the files are modified or added, this will disclude deleted files
             if file.change_type in CHANGE_TYPE_LIST:
+                # Check if the file is a .pickle file
+                if 'known-slugs.pickle' in file.__str__():
+                    file_list.append(('tests/known-slugs.pickle', 'pickle'))
+
                 # If the file is renamed, ensure we are picking the right schema
                 if 'R' in file.change_type and path in file.rename_to:
                     file_list.append((file.rename_to, schema))
@@ -120,6 +124,9 @@ def test_definitions(file_path, schema):
     """
     Validate each definition file using the provided JSON schema and check for duplicate entries.
     """
+    if schema == 'pickle':
+        pytest.fail(f'Pickle file modification detected: {file_path}\nPlease revert and remove the pickle file from your commit.', False)
+
     # Check file extension. Only .yml or .yaml files are supported.
     assert file_path.split('.')[-1] in ('yaml', 'yml'), f"Invalid file extension: {file_path}"