diff --git a/openfga_sdk/client/client.py b/openfga_sdk/client/client.py
index 40d8fa9..38b7aae 100644
--- a/openfga_sdk/client/client.py
+++ b/openfga_sdk/client/client.py
@@ -706,7 +706,7 @@ async def batch_check(self, body: ClientBatchCheckRequest, options=None):
             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 = []
@@ -714,10 +714,12 @@ def track_and_transform(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
@@ -733,7 +735,7 @@ def track_and_transform(checks):
         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/openfga_sdk/sync/client/client.py b/openfga_sdk/sync/client/client.py
index f4bd3f4..07bddcc 100644
--- a/openfga_sdk/sync/client/client.py
+++ b/openfga_sdk/sync/client/client.py
@@ -692,7 +692,7 @@ def batch_check(self, body: ClientBatchCheckRequest, options=None):
             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 = []
@@ -700,10 +700,12 @@ def track_and_transform(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
@@ -716,7 +718,7 @@ def track_and_transform(checks):
         ]
 
         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/test/client/client_test.py b/test/client/client_test.py
index fa16fe7..70f6850 100644
--- a/test/client/client_test.py
+++ b/test/client/client_test.py
@@ -2414,11 +2414,14 @@ async def test_batch_check_errors_dupe_cor_id(self):
         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/test/sync/client/client_test.py b/test/sync/client/client_test.py
index 5d7ca86..292e78b 100644
--- a/test/sync/client/client_test.py
+++ b/test/sync/client/client_test.py
@@ -2416,11 +2416,14 @@ def test_batch_check_errors_dupe_cor_id(self):
         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")