diff --git a/config/clients/python/template/src/client/client.py.mustache b/config/clients/python/template/src/client/client.py.mustache
index faedf31f..9b569f5d 100644
--- a/config/clients/python/template/src/client/client.py.mustache
+++ b/config/clients/python/template/src/client/client.py.mustache
@@ -643,17 +643,17 @@ class OpenFgaClient:
             elif isinstance(options["max_batch_size"], int):
                 max_batch_size = options["max_batch_size"]
 
-        check_to_id: dict[str, ClientBatchCheckItem]= {}
+        id_to_check: dict[str, ClientBatchCheckItem]= {}
         def track_and_transform(checks):
             transformed = []
             for check in checks:
                 if check.correlation_id is None:
                     check.correlation_id = str(uuid.uuid4())
 
-                if check.correlation_id in check_to_id:
-                    raise FgaValidationException("Duplicate correlation_id provided")
+                if check.correlation_id in id_to_check:
+                    raise FgaValidationException(f"Duplicate correlation_id ({check.correlation_id}) provided")
 
-                check_to_id[check.correlation_id] = check
+                id_to_check[check.correlation_id] = check
 
                 transformed.append(construct_batch_item(check))
             return transformed
@@ -666,7 +666,7 @@ class OpenFgaClient:
         result = []
         sem = asyncio.Semaphore(max_parallel_requests)
         def map_response(id, result):
-            check = check_to_id[id]
+            check = id_to_check[id]
             return ClientBatchCheckSingleResponse(
                 allowed=result.allowed,
                 request=check,
diff --git a/config/clients/python/template/src/sync/client/client.py.mustache b/config/clients/python/template/src/sync/client/client.py.mustache
index 5436f24d..a96a321e 100644
--- a/config/clients/python/template/src/sync/client/client.py.mustache
+++ b/config/clients/python/template/src/sync/client/client.py.mustache
@@ -615,7 +615,7 @@ class OpenFgaClient:
             elif isinstance(options["max_batch_size"], int):
                 max_batch_size = options["max_batch_size"]
 
-        check_to_id: dict[str, ClientBatchCheckItem] = {}
+        id_to_check: dict[str, ClientBatchCheckItem] = {}
 
         def track_and_transform(checks):
             transformed = []
@@ -623,10 +623,10 @@ class OpenFgaClient:
                 if check.correlation_id is None:
                     check.correlation_id = str(uuid.uuid4())
 
-                if check.correlation_id in check_to_id:
-                    raise FgaValidationException("Duplicate correlation_id provided")
+                if check.correlation_id in id_to_check:
+                    raise FgaValidationException(f"Duplicate correlation_id ({check.correlation_id}) provided")
 
-                check_to_id[check.correlation_id] = check
+                id_to_check[check.correlation_id] = check
 
                 transformed.append(construct_batch_item(check))
             return transformed
@@ -639,7 +639,7 @@ class OpenFgaClient:
         ]
 
         def map_response(id, result):
-            check = check_to_id[id]
+            check = id_to_check[id]
             return ClientBatchCheckSingleResponse(
                 allowed=result.allowed,
                 request=check,
diff --git a/config/clients/python/template/test/client/client_test.py.mustache b/config/clients/python/template/test/client/client_test.py.mustache
index bcdaacd4..06c8d56f 100644
--- a/config/clients/python/template/test/client/client_test.py.mustache
+++ b/config/clients/python/template/test/client/client_test.py.mustache
@@ -1902,7 +1902,7 @@ class TestOpenFgaClient(IsolatedAsyncioTestCase):
     "result": {
         "fake-uuid": {
             "error": {
-                "inputError": "validation_error",
+                "input_error": "validation_error",
                 "message": "type 'doc' not found"
             }
         }
@@ -2046,11 +2046,15 @@ class TestOpenFgaClient(IsolatedAsyncioTestCase):
         configuration = self.configuration
         configuration.store_id = store_id
         async with OpenFgaClient(configuration) as api_client:
-            with self.assertRaises(FgaValidationException):
+            with self.assertRaises(FgaValidationException) as error:
                 await api_client.batch_check(
                     body=body,
                     options={"authorization_model_id": "01GXSA8YR785C4FYS3C0RTG7B1"},
                 )
+            self.assertEqual(
+                "Duplicate correlation_id (1) provided",
+                str(error.exception)
+            )
             await api_client.close()
 
     @patch.object(rest.RESTClientObject, "request")
diff --git a/config/clients/python/template/test/sync/client/client_test.py.mustache b/config/clients/python/template/test/sync/client/client_test.py.mustache
index b012b17b..9d6e934a 100644
--- a/config/clients/python/template/test/sync/client/client_test.py.mustache
+++ b/config/clients/python/template/test/sync/client/client_test.py.mustache
@@ -1954,7 +1954,7 @@ class TestOpenFgaClient(IsolatedAsyncioTestCase):
     "result": {
         "fake-uuid": {
             "error": {
-                "inputError": "validation_error",
+                "input_error": "validation_error",
                 "message": "type 'doc' not found"
             }
         }
@@ -2092,11 +2092,15 @@ class TestOpenFgaClient(IsolatedAsyncioTestCase):
         configuration = self.configuration
         configuration.store_id = store_id
         with OpenFgaClient(configuration) as api_client:
-            with self.assertRaises(FgaValidationException):
+            with self.assertRaises(FgaValidationException) as error:
                 api_client.batch_check(
                     body=body,
                     options={"authorization_model_id": "01GXSA8YR785C4FYS3C0RTG7B1"},
                 )
+            self.assertEqual(
+                "Duplicate correlation_id (1) provided",
+                str(error.exception)
+            )
             api_client.close()
 
     @patch.object(rest.RESTClientObject, "request")