fix(ptu): coerce naive datetimes on reservation requests to UTC

Pydantic accepted naive datetimes on effective_from and effective_to;
comparing those against Prisma's UTC-aware row values raised TypeError,
turning /ptu_reservation/close into a 500 on inputs like
'2026-08-15T00:00:00'. Adds a field validator on both the request types
and the domain model that stamps missing tzinfo as UTC and converts
tz-aware values into UTC. Three regression tests pin the new contract
(create with naive input, close with naive input, close with naive
input before effective_from).

litellm/models/ptu_reservation.py

@@ -4,10 +4,10 @@ PTU Reservation table model.
 Canonical definition for ``litellm_ptureservation``.
 """
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Literal
 
-from pydantic import ConfigDict, model_validator
+from pydantic import ConfigDict, field_validator, model_validator
 
 from litellm.types.llms.base import LiteLLMPydanticObjectBase
 
@@ -32,6 +32,15 @@ class LiteLLM_PTUReservation(LiteLLMPydanticObjectBase):
 
     model_config = ConfigDict(protected_namespaces=())
 
+    @field_validator("effective_from", "effective_to", mode="after")
+    @classmethod
+    def _coerce_utc(cls, value: datetime | None) -> datetime | None:
+        if value is None:
+            return None
+        if value.tzinfo is None:
+            return value.replace(tzinfo=timezone.utc)
+        return value.astimezone(timezone.utc)
+
     @model_validator(mode="after")
     def _enforce_cost_source_fields(self) -> "LiteLLM_PTUReservation":
         if self.cost_source == "manual":

litellm/types/proxy/management_endpoints/ptu_reservation.py

@@ -1,13 +1,21 @@
 """Request/response types for /ptu_reservation/* endpoints."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Literal
 
-from pydantic import ConfigDict, Field
+from pydantic import ConfigDict, Field, field_validator
 
 from litellm.types.llms.base import LiteLLMPydanticObjectBase
 
 
+def _to_utc(value: datetime | None) -> datetime | None:
+    if value is None:
+        return None
+    if value.tzinfo is None:
+        return value.replace(tzinfo=timezone.utc)
+    return value.astimezone(timezone.utc)
+
+
 class PTUReservationNewRequest(LiteLLMPydanticObjectBase):
     """Body accepted by POST /ptu_reservation/new."""
 
@@ -37,6 +45,11 @@ class PTUReservationNewRequest(LiteLLMPydanticObjectBase):
 
     model_config = ConfigDict(protected_namespaces=())
 
+    @field_validator("effective_from", "effective_to", mode="after")
+    @classmethod
+    def _coerce_utc(cls, value: datetime | None) -> datetime | None:
+        return _to_utc(value)
+
 
 class PTUReservationListRequest(LiteLLMPydanticObjectBase):
     """Query params for GET /ptu_reservation/list."""
@@ -54,3 +67,8 @@ class PTUReservationCloseRequest(LiteLLMPydanticObjectBase):
         default=None,
         description="Timestamp to set as effective_to. Defaults to now (UTC) if omitted.",
     )
+
+    @field_validator("effective_to", mode="after")
+    @classmethod
+    def _coerce_utc(cls, value: datetime | None) -> datetime | None:
+        return _to_utc(value)

tests/test_litellm/proxy/management_endpoints/test_ptu_reservation_endpoints.py

@@ -413,3 +413,48 @@ async def test_create_after_close_of_same_team_model(client_and_mocks):
     )
     assert resp.status_code == 200, resp.text
     mock_table.create.assert_awaited_once()
+
+
+@pytest.mark.asyncio
+async def test_new_reservation_accepts_naive_datetime_and_coerces_to_utc(client_and_mocks):
+    client, _, mock_table = client_and_mocks
+
+    resp = client.post(
+        "/ptu_reservation/new",
+        json=_valid_new_payload(effective_from="2026-08-01T00:00:00"),
+    )
+    assert resp.status_code == 200, resp.text
+    mock_table.create.assert_awaited_once()
+    created = mock_table.create.await_args.kwargs["data"]["effective_from"]
+    assert created.tzinfo is not None
+    assert created.utcoffset() == timedelta(0)
+
+
+@pytest.mark.asyncio
+async def test_close_with_naive_datetime_does_not_500(client_and_mocks):
+    client, _, mock_table = client_and_mocks
+    existing = _row(id="res_1", effective_from=_dt(), effective_to=None)
+    mock_table.find_unique = AsyncMock(return_value=existing)
+
+    resp = client.post(
+        "/ptu_reservation/close",
+        json={"id": "res_1", "effective_to": "2026-07-16T00:00:00"},
+    )
+    assert resp.status_code == 200, resp.text
+    stored = mock_table.update.await_args.kwargs["data"]["effective_to"]
+    assert stored.tzinfo is not None
+    assert stored.utcoffset() == timedelta(0)
+
+
+@pytest.mark.asyncio
+async def test_close_rejects_naive_effective_to_before_from(client_and_mocks):
+    client, _, mock_table = client_and_mocks
+    existing = _row(id="res_1", effective_from=_dt(days=10), effective_to=None)
+    mock_table.find_unique = AsyncMock(return_value=existing)
+
+    resp = client.post(
+        "/ptu_reservation/close",
+        json={"id": "res_1", "effective_to": "2026-07-05T00:00:00"},
+    )
+    assert resp.status_code == 400, resp.text
+    mock_table.update.assert_not_awaited()