fix(tool_permission): log expected skip and deny events below WARNING (#40208)

The no-tools skip path in async_pre_call_hook now logs at DEBUG and the
denied-by-rule messages in async_pre_call_hook and _evaluate_tool_calls
log at INFO. The malformed tool arguments warning is unchanged. Adds
regression tests pinning each level

Co-authored-by: yucheng <yucheng@berri.ai>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/proxy/guardrails/guardrail_hooks/tool_permission.py

@@ -547,7 +547,7 @@ class ToolPermissionGuardrail(CustomGuardrail):
 
         for _tool_call, is_allowed, _rule_id, message in checked:
             if not is_allowed and message is not None:
-                verbose_proxy_logger.warning("Tool Permission Guardrail: %s", message)
+                verbose_proxy_logger.info("Tool Permission Guardrail: %s", message)
                 if self.on_disallowed_action == "block":
                     raise GuardrailRaisedException(
                         guardrail_name=self.guardrail_name, message=message, blocked_content=True
@@ -809,7 +809,7 @@ class ToolPermissionGuardrail(CustomGuardrail):
 
         new_tools: Final = self._collect_request_tools(data)
         if not new_tools:
-            verbose_proxy_logger.warning(
+            verbose_proxy_logger.debug(
                 "Tool Permission Guardrail: not running guardrail. No tools or functions in data"
             )
             return data
@@ -820,7 +820,7 @@ class ToolPermissionGuardrail(CustomGuardrail):
             is_allowed, _, message = self._check_tool_permission(tool_name, tool_type)
 
             if not is_allowed and message is not None:
-                verbose_proxy_logger.warning("Tool Permission Guardrail: %s", message)
+                verbose_proxy_logger.info("Tool Permission Guardrail: %s", message)
                 if self.on_disallowed_action == "block":
                     raise HTTPException(
                         status_code=400,

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

@@ -3,6 +3,7 @@ Unit tests for Tool Permission Guardrail (OpenAI tool_calls semantics)
 """
 
 import json
+import logging
 import re
 from unittest.mock import patch
 
@@ -520,6 +521,80 @@ class TestToolPermissionGuardrail:
                 )
         assert excinfo.value.status_code == 400
 
+    @pytest.mark.asyncio
+    async def test_async_pre_call_hook_without_tools_logs_skip_at_debug(self, caplog):
+        data = {"model": "gpt-4", "messages": [{"role": "user", "content": "hi"}]}
+
+        with caplog.at_level(logging.DEBUG, logger="LiteLLM Proxy"):
+            with patch.object(self.guardrail, "should_run_guardrail", return_value=True):
+                result = await self.guardrail.async_pre_call_hook(
+                    user_api_key_dict=UserAPIKeyAuth(),
+                    cache=DualCache(default_in_memory_ttl=1),
+                    data=data,
+                    call_type="completion",
+                )
+
+        assert result is data
+        skip_levels = [r.levelno for r in caplog.records if "No tools or functions in data" in r.getMessage()]
+        assert skip_levels == [logging.DEBUG]
+        assert [r.getMessage() for r in caplog.records if r.levelno >= logging.WARNING] == []
+
+    @pytest.mark.asyncio
+    async def test_async_pre_call_hook_denied_tool_logs_at_info(self, caplog):
+        data = {"tools": [{"type": "function", "function": {"name": "Read"}}]}
+
+        with caplog.at_level(logging.DEBUG, logger="LiteLLM Proxy"):
+            with patch.object(self.guardrail, "should_run_guardrail", return_value=True):
+                with pytest.raises(HTTPException):
+                    await self.guardrail.async_pre_call_hook(
+                        user_api_key_dict=UserAPIKeyAuth(),
+                        cache=DualCache(default_in_memory_ttl=1),
+                        data=data,
+                        call_type="completion",
+                    )
+
+        denied_levels = [
+            r.levelno
+            for r in caplog.records
+            if r.getMessage() == "Tool Permission Guardrail: Tool 'Read' denied by rule 'deny_read'"
+        ]
+        assert denied_levels == [logging.INFO]
+        assert [r.getMessage() for r in caplog.records if r.levelno >= logging.WARNING] == []
+
+    @pytest.mark.asyncio
+    async def test_async_post_call_success_hook_denied_tool_logs_at_info(self, caplog):
+        tool_call = {"function": {"name": "Read", "arguments": "{}"}, "type": "function"}
+        response = ModelResponse(choices=[Choices(message={"tool_calls": [tool_call]})])
+
+        with caplog.at_level(logging.DEBUG, logger="LiteLLM Proxy"):
+            with patch.object(self.guardrail, "should_run_guardrail", return_value=True):
+                with pytest.raises(GuardrailRaisedException):
+                    await self.guardrail.async_post_call_success_hook(
+                        data={"guardrails": ["test-tool-permission"]},
+                        user_api_key_dict=UserAPIKeyAuth(),
+                        response=response,
+                    )
+
+        denied_levels = [
+            r.levelno
+            for r in caplog.records
+            if r.getMessage() == "Tool Permission Guardrail: Tool 'Read' denied by rule 'deny_read'"
+        ]
+        assert denied_levels == [logging.INFO]
+        assert [r.getMessage() for r in caplog.records if r.levelno >= logging.WARNING] == []
+
+    def test_parse_tool_call_arguments_malformed_json_logs_warning(self, caplog):
+        tool_call = ChatCompletionMessageToolCall(function={"name": "Bash", "arguments": "{not json"}, id="call_1")
+
+        with caplog.at_level(logging.DEBUG, logger="LiteLLM Proxy"):
+            parsed, error = self.guardrail._parse_tool_call_arguments(tool_call)
+
+        assert parsed is None
+        assert error == "arguments could not be parsed"
+        warning_messages = [r.getMessage() for r in caplog.records if r.levelno == logging.WARNING]
+        assert len(warning_messages) == 1
+        assert warning_messages[0].startswith("Tool Permission Guardrail: Failed to decode arguments for tool Bash")
+
     @pytest.mark.asyncio
     async def test_async_pre_call_hook_blocks_legacy_functions(self):
         data = {