fix: Avoid error when we have just the tool_calls in input (#17753)

* fix: Avoid error when we have just the tool_calls in input

* fix: Remove the tool call validation

* feat: Add unit test

litellm/proxy/guardrails/guardrail_hooks/bedrock_guardrails.py

@@ -1287,36 +1287,38 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
             )
             filtered_messages = filter_result.payload_messages or mock_messages
 
-            bedrock_response = await self.make_bedrock_api_request(
-                source="INPUT",
-                messages=filtered_messages,
-                request_data=request_data,
-            )
-
-            if bedrock_response.get("action") == "BLOCKED":
-                raise Exception(
-                    f"Content blocked by Bedrock guardrail: {bedrock_response.get('reason', 'Unknown reason')}"
+            # Bedrock will throw an error if there is no text to process
+            if filtered_messages:
+                bedrock_response = await self.make_bedrock_api_request(
+                    source="INPUT",
+                    messages=filtered_messages,
+                    request_data=request_data,
                 )
 
-            # Apply any masking that was applied by the guardrail
+                if bedrock_response.get("action") == "BLOCKED":
+                    raise Exception(
+                        f"Content blocked by Bedrock guardrail: {bedrock_response.get('reason', 'Unknown reason')}"
+                    )
 
-            output_list = bedrock_response.get("output")
-            if output_list:
-                # If the guardrail returned modified content, use that
-                for output_item in output_list:
-                    text_content = output_item.get("text")
-                    if text_content:
-                        masked_text = str(text_content)
-                        masked_texts.append(masked_text)
-            else:
-                outputs_list = bedrock_response.get("outputs")
-                if outputs_list:
-                    # Fallback to outputs field if output is not available
-                    for output_item in outputs_list:
+                # Apply any masking that was applied by the guardrail
+
+                output_list = bedrock_response.get("output")
+                if output_list:
+                    # If the guardrail returned modified content, use that
+                    for output_item in output_list:
                         text_content = output_item.get("text")
                         if text_content:
                             masked_text = str(text_content)
                             masked_texts.append(masked_text)
+                else:
+                    outputs_list = bedrock_response.get("outputs")
+                    if outputs_list:
+                        # Fallback to outputs field if output is not available
+                        for output_item in outputs_list:
+                            text_content = output_item.get("text")
+                            if text_content:
+                                masked_text = str(text_content)
+                                masked_texts.append(masked_text)
 
             # If no output/outputs were provided, use the original texts
             # This happens when the guardrail allows content without modification

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

@@ -1049,3 +1049,55 @@ async def test_bedrock_guardrail_parameter_takes_precedence_over_env(monkeypatch
         ), f"Expected parameter endpoint to take precedence. Got: {prepped_request.url}"
 
         print(f"Parameter precedence test passed. URL: {prepped_request.url}")
+
+
+@pytest.mark.asyncio
+async def test_bedrock_apply_guardrail_with_only_tool_calls_response():
+    """Test that apply_guardrail handles response with tool_calls (no text content) without calling Bedrock API"""
+    # Create a BedrockGuardrail instance
+    guardrail = BedrockGuardrail(
+        guardrailIdentifier="test-guardrail", guardrailVersion="DRAFT"
+    )
+
+    # Mock the make_bedrock_api_request method
+    with patch.object(
+        guardrail, "make_bedrock_api_request", new_callable=AsyncMock
+    ) as mock_api_request:
+        # Test the apply_guardrail method with tool_calls in response
+        inputs = {
+            "texts": [],
+            "tool_calls": [
+                {
+                    "id": "call_eFSCWFsyL7MclHYnzKrcQnMK",
+                    "type": "function",
+                    "function": {
+                        "name": "get_weather",
+                        "arguments": '{"location":"São Paulo"}',
+                    },
+                }
+            ],
+        }
+
+        guardrailed_inputs = await guardrail.apply_guardrail(
+            inputs=inputs,
+            request_data={},
+            input_type="response",
+            logging_obj=None,
+        )
+
+        # Verify the result - should succeed without errors
+        assert guardrailed_inputs is not None
+        assert "tool_calls" in guardrailed_inputs
+        assert len(guardrailed_inputs["tool_calls"]) == 1
+        assert (
+            guardrailed_inputs["tool_calls"][0]["id"]
+            == "call_eFSCWFsyL7MclHYnzKrcQnMK"
+        )
+        assert guardrailed_inputs["tool_calls"][0]["function"]["name"] == "get_weather"
+        assert (
+            guardrailed_inputs["tool_calls"][0]["function"]["arguments"]
+            == '{"location":"São Paulo"}'
+        )
+        # Verify that the Bedrock API was NOT called since there's no text to process
+        mock_api_request.assert_not_called()
+        print("✅ apply_guardrail with tool_calls test passed - no API call made")