fix: guard empty-dict team limits and malformed int in deployment default limits

- Change `if team_limit:` to `if team_limit is not None:` in both
  get_key_model_rpm_limit and get_key_model_tpm_limit so that an
  explicitly-empty team rate-limit map ({}) is returned as-is instead
  of silently falling through to deployment defaults (P1 fix).
- Replace the bare `int()` list comprehension in _get_deployment_default_limit
  with a loop that catches ValueError/TypeError so malformed config strings
  do not raise an unhandled exception during request handling (P2 fix).
- Add corresponding unit tests for both edge cases.

Co-Authored-By: Claude (claude-sonnet-4-6) <noreply@anthropic.com>

litellm/proxy/auth/auth_utils.py

@@ -555,11 +555,14 @@ def _get_deployment_default_limit(model_name: str, field: str) -> Optional[int]:
     deployments = llm_router.get_model_list(model_name=model_name)
     if not deployments:
         return None
-    limits = [
-        int(deployment.get("litellm_params", {}).get(field))
-        for deployment in deployments
-        if deployment.get("litellm_params", {}).get(field) is not None
-    ]
+    limits = []
+    for deployment in deployments:
+        raw = deployment.get("litellm_params", {}).get(field)
+        if raw is not None:
+            try:
+                limits.append(int(raw))
+            except (ValueError, TypeError):
+                pass
     return min(limits) if limits else None
 
 
@@ -602,7 +605,7 @@ def get_key_model_rpm_limit(
     # 3. Fallback to team metadata
     if user_api_key_dict.team_metadata:
         team_limit = user_api_key_dict.team_metadata.get("model_rpm_limit")
-        if team_limit:
+        if team_limit is not None:
             return team_limit
 
     # 4. Fallback to deployment default_api_key_rpm_limit
@@ -645,7 +648,7 @@ def get_key_model_tpm_limit(
     # 3. Fallback to team metadata
     if user_api_key_dict.team_metadata:
         team_limit = user_api_key_dict.team_metadata.get("model_tpm_limit")
-        if team_limit:
+        if team_limit is not None:
             return team_limit
 
     # 4. Fallback to deployment default_api_key_tpm_limit

tests/test_litellm/proxy/auth/test_auth_utils.py

@@ -71,6 +71,19 @@ class TestGetKeyModelRpmLimit:
         assert result is None
 
 
+    def test_team_metadata_empty_rpm_dict_falls_through_to_deployment_default(self):
+        """Explicitly empty team model_rpm_limit ({}) should be returned as-is, not fallen through."""
+        # An empty dict is a valid team limit map (no per-model limits configured).
+        # It should be returned directly rather than falling through to deployment defaults,
+        # so a team with an empty map is treated as unconstrained at the team level.
+        user_api_key_dict = UserAPIKeyAuth(
+            api_key="sk-123",
+            team_metadata={"model_rpm_limit": {}},
+        )
+        result = get_key_model_rpm_limit(user_api_key_dict)
+        assert result == {}
+
+
 class TestGetKeyModelTpmLimit:
     """Tests for get_key_model_tpm_limit function."""
 
@@ -137,6 +150,33 @@ class TestGetKeyModelTpmLimit:
         assert result == {"gpt-4": 10000}
 
 
+    def test_team_metadata_empty_tpm_dict_falls_through_to_deployment_default(self):
+        """Explicitly empty team model_tpm_limit ({}) should be returned as-is, not fallen through."""
+        # An empty dict is a valid team limit map (no per-model limits configured).
+        # It should be returned directly rather than falling through to deployment defaults,
+        # so a team with an empty map is treated as unconstrained at the team level.
+        user_api_key_dict = UserAPIKeyAuth(
+            api_key="sk-123",
+            team_metadata={"model_tpm_limit": {}},
+        )
+        result = get_key_model_tpm_limit(user_api_key_dict)
+        assert result == {}
+
+
+    def test_skips_deployments_with_malformed_limit_value(self):
+        """Deployments with non-integer-parseable limit values are skipped without raising."""
+        user_api_key_dict = UserAPIKeyAuth(api_key="sk-123")
+        mock_router = MagicMock()
+        mock_router.get_model_list.return_value = [
+            {"model_name": "model1", "litellm_params": {"default_api_key_tpm_limit": "not-a-number"}},
+            _make_deployment_dict("model1", tpm=500),
+        ]
+        with patch(_ROUTER_PATCH, mock_router):
+            result = get_key_model_tpm_limit(user_api_key_dict, model_name="model1")
+        # The malformed deployment is skipped; the valid one provides 500
+        assert result == {"model1": 500}
+
+
 class TestGetCustomerIdFromStandardHeaders:
     """Tests for _get_customer_id_from_standard_headers helper function."""
 
@@ -414,6 +454,20 @@ class TestDeploymentDefaultRpmLimit:
         assert result == {"model1": 75}
 
 
+    def test_skips_deployments_with_malformed_limit_value(self):
+        """Deployments with non-integer-parseable limit values are skipped without raising."""
+        user_api_key_dict = UserAPIKeyAuth(api_key="sk-123")
+        mock_router = MagicMock()
+        mock_router.get_model_list.return_value = [
+            {"model_name": "model1", "litellm_params": {"default_api_key_rpm_limit": "not-a-number"}},
+            _make_deployment_dict("model1", rpm=100),
+        ]
+        with patch(_ROUTER_PATCH, mock_router):
+            result = get_key_model_rpm_limit(user_api_key_dict, model_name="model1")
+        # The malformed deployment is skipped; the valid one provides 100
+        assert result == {"model1": 100}
+
+
 class TestDeploymentDefaultTpmLimit:
     """Tests for deployment default_api_key_tpm_limit fallback in get_key_model_tpm_limit."""