diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index d58154861..77a45cbc9 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -1369,7 +1369,8 @@ class BulkEditSerializer(
             return bulk_edit.delete_pages
         elif method == "edit_pdf":
             return bulk_edit.edit_pdf
-        else:
+        else:  # pragma: no cover
+            # This will never happen as it is handled by the ChoiceField
             raise serializers.ValidationError("Unsupported method.")
 
     def _validate_parameters_tags(self, parameters):
diff --git a/src/documents/tests/test_api_bulk_edit.py b/src/documents/tests/test_api_bulk_edit.py
index 33f1e9bec..7e636b0c7 100644
--- a/src/documents/tests/test_api_bulk_edit.py
+++ b/src/documents/tests/test_api_bulk_edit.py
@@ -1393,6 +1393,7 @@ class TestBulkEditAPI(DirectoriesMixin, APITestCase):
         self.assertEqual(kwargs["user"], self.user)
 
     def test_edit_pdf_invalid_params(self):
+        # multiple documents
         response = self.client.post(
             "/api/documents/bulk_edit/",
             json.dumps(
@@ -1404,10 +1405,10 @@ class TestBulkEditAPI(DirectoriesMixin, APITestCase):
             ),
             content_type="application/json",
         )
-
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
         self.assertIn(b"Edit PDF method only supports one document", response.content)
 
+        # no operations specified
         response = self.client.post(
             "/api/documents/bulk_edit/",
             json.dumps(
@@ -1419,10 +1420,141 @@ class TestBulkEditAPI(DirectoriesMixin, APITestCase):
             ),
             content_type="application/json",
         )
-
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
         self.assertIn(b"operations not specified", response.content)
 
+        # operations not a list
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {"operations": "not_a_list"},
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"operations must be a list", response.content)
+
+        # invalid operation
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {"operations": ["invalid_operation"]},
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"invalid operation entry", response.content)
+
+        # page not an int
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {"operations": [{"page": "not_an_int"}]},
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"page must be an integer", response.content)
+
+        # rotate not an int
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {"operations": [{"page": 1, "rotate": "not_an_int"}]},
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"rotate must be an integer", response.content)
+
+        # doc not an int
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {"operations": [{"page": 1, "doc": "not_an_int"}]},
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"doc must be an integer", response.content)
+
+        # update_document not a boolean
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {
+                        "update_document": "not_a_bool",
+                        "operations": [{"page": 1}],
+                    },
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"update_document must be a boolean", response.content)
+
+        # include_metadata not a boolean
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {
+                        "include_metadata": "not_a_bool",
+                        "operations": [{"page": 1}],
+                    },
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(b"include_metadata must be a boolean", response.content)
+
+        # update_document True but output would be multiple documents
+        response = self.client.post(
+            "/api/documents/bulk_edit/",
+            json.dumps(
+                {
+                    "documents": [self.doc2.id],
+                    "method": "edit_pdf",
+                    "parameters": {
+                        "update_document": True,
+                        "operations": [{"page": 1, "doc": 1}, {"page": 2, "doc": 2}],
+                    },
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(
+            b"update_document only allowed with a single output document",
+            response.content,
+        )
+
     @override_settings(AUDIT_LOG_ENABLED=True)
     def test_bulk_edit_audit_log_enabled_simple_field(self):
         """