fix(router): carry next_page_token through the batch list aggregation

litellm/router.py

@@ -6504,6 +6504,7 @@ class Router:
             "first_id": None,
             "last_id": None,
             "has_more": False,
+            "next_page_token": None,
         }
 
         for result in results:
@@ -6513,6 +6514,9 @@ class Router:
                     final_results["first_id"] = getattr(result, "first_id")
                 final_results["last_id"] = getattr(result, "last_id")
                 final_results["data"].extend(result.data)
+                page_token = getattr(result, "next_page_token", None)
+                if page_token is not None:
+                    final_results["next_page_token"] = page_token
 
                 ## check 'has_more'
                 if getattr(result, "has_more", False) is True:

tests/unit/test_router_batch_list_pagination.py

@@ -0,0 +1,35 @@
+from typing import Final
+
+import pytest
+
+import litellm
+from litellm import Router
+from litellm.types.utils import OpenAIBatchListResponse
+
+TOKEN_BY_KEY: Final = {"key-with-more-pages": "1", "key-on-last-page": None}
+
+
+def _deployment(api_key: str) -> dict:
+    return {
+        "model_name": "mistral-ocr",
+        "litellm_params": {"model": "mistral/mistral-ocr-latest", "api_key": api_key},
+        "model_info": {"id": api_key},
+    }
+
+
+async def _fake_alist_batches(**kwargs: object) -> OpenAIBatchListResponse:
+    token: Final = TOKEN_BY_KEY[str(kwargs["api_key"])]
+    return OpenAIBatchListResponse(
+        data=(), first_id=None, last_id=None, has_more=token is not None, next_page_token=token
+    )
+
+
+@pytest.mark.asyncio
+async def test_alist_batches_keeps_the_page_token_a_deployment_returned(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(litellm, "alist_batches", _fake_alist_batches)
+    router: Final = Router(model_list=[_deployment("key-with-more-pages"), _deployment("key-on-last-page")])
+
+    result: Final = await router.alist_batches(model="mistral-ocr", limit=3)
+
+    assert result["has_more"] is True
+    assert result["next_page_token"] == "1"