fix(noma): prevent falsy-coercion of streaming_sampling_rate=0

Replace `or 5`/`or False` with `is not None` check so that explicit
0 and False values are not silently replaced with defaults.
Add test for the rate=0 edge case and a comment clarifying that
streaming knobs are consumed by UnifiedLLMGuardrails framework.

litellm/proxy/guardrails/guardrail_hooks/noma/__init__.py

@@ -46,12 +46,18 @@ def initialize_guardrail_v2(litellm_params: "LitellmParams", guardrail: "Guardra
         application_id=litellm_params.application_id,
         monitor_mode=litellm_params.monitor_mode,
         block_failures=litellm_params.block_failures,
-        streaming_end_of_stream_only=getattr(
-            litellm_params, "streaming_end_of_stream_only", None
-        )
-        or False,
-        streaming_sampling_rate=getattr(litellm_params, "streaming_sampling_rate", None)
-        or 5,
+        streaming_end_of_stream_only=(
+            _v
+            if (_v := getattr(litellm_params, "streaming_end_of_stream_only", None))
+            is not None
+            else False
+        ),
+        streaming_sampling_rate=(
+            _r
+            if (_r := getattr(litellm_params, "streaming_sampling_rate", None))
+            is not None
+            else 5
+        ),
         event_hook=litellm_params.mode,
         default_on=litellm_params.default_on,
     )

litellm/proxy/guardrails/guardrail_hooks/noma/noma_v2.py

@@ -55,6 +55,7 @@ class NomaV2Guardrail(CustomGuardrail):
         streaming_sampling_rate: int = 5,
         **kwargs: Any,
     ) -> None:
+        # Read by UnifiedLLMGuardrails streaming hook
         self.streaming_end_of_stream_only = streaming_end_of_stream_only
         self.streaming_sampling_rate = streaming_sampling_rate
         self.async_handler = get_async_httpx_client(

tests/test_litellm/proxy/guardrails/guardrail_hooks/test_noma_v2.py

@@ -693,6 +693,32 @@ class TestNomaV2StreamingKnobs:
         assert model.streaming_end_of_stream_only is None
         assert model.streaming_sampling_rate is None
 
+    def test_streaming_sampling_rate_zero_is_not_coerced(self):
+        """streaming_sampling_rate=0 must not be silently replaced with default 5."""
+        from litellm.proxy.guardrails.guardrail_hooks.noma import (
+            initialize_guardrail_v2,
+        )
+
+        class FakeLitellmParams:
+            api_key = "test-key"
+            api_base = "https://self-managed.local"
+            application_id = "app-1"
+            monitor_mode = False
+            block_failures = False
+            streaming_end_of_stream_only = False
+            streaming_sampling_rate = 0
+            mode = "pre_call"
+            default_on = True
+
+        guardrail = {"guardrail_name": "test-guardrail"}
+
+        with patch("litellm.logging_callback_manager.add_litellm_callback"):
+            result = initialize_guardrail_v2(
+                litellm_params=FakeLitellmParams(), guardrail=guardrail
+            )
+
+        assert result.streaming_sampling_rate == 0
+
     def test_initialize_guardrail_v2_passes_streaming_knobs(self):
         from unittest.mock import patch as _patch