fix: status code in error message in RestApiTool

Merge https://github.com/google/adk-python/pull/2819

add status code to http error to make it more verbose

issue: https://github.com/google/adk-python/issues/2820

# testing plan
run new tests that have beed added in PR

Co-authored-by: Hangfei Lin <hangfei@google.com>
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/2819 from milkisbad:rest_api_tool_verbose_error 79ac6d96174d414e7ca958379102cfa7ede0e883
PiperOrigin-RevId: 832367374

src/google/adk/tools/openapi_tool/openapi_spec_parser/rest_api_tool.py

@@ -428,7 +428,7 @@ class RestApiTool(BaseTool):
               f"Tool {self.name} execution failed. Analyze this execution error"
               " and your inputs. Retry with adjustments if applicable. But"
               " make sure don't retry more than 3 times. Execution Error:"
-              f" {error_details}"
+              f" Status Code: {response.status_code}, {error_details}"
           )
       }
     except ValueError:

tests/unittests/tools/openapi_tool/openapi_spec_parser/test_rest_api_tool.py

@@ -34,6 +34,7 @@ from google.adk.tools.tool_context import ToolContext
 from google.genai.types import FunctionDeclaration
 from google.genai.types import Schema
 import pytest
+import requests
 
 
 class TestRestApiTool:
@@ -224,6 +225,49 @@ class TestRestApiTool:
     # Check the result
     assert result == {"result": "success"}
 
+  @patch(
+      "google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool.requests.request"
+  )
+  @pytest.mark.asyncio
+  async def test_call_http_failure(
+      self,
+      mock_request,
+      mock_tool_context,
+      sample_endpoint,
+      sample_operation,
+      sample_auth_scheme,
+      sample_auth_credential,
+  ):
+    mock_response = MagicMock()
+    mock_response.status_code = 500
+    mock_response.content = b"Internal Server Error"
+    mock_response.raise_for_status.side_effect = requests.exceptions.HTTPError(
+        "500 Server Error"
+    )
+    mock_request.return_value = mock_response
+
+    tool = RestApiTool(
+        name="test_tool",
+        description="Test Tool",
+        endpoint=sample_endpoint,
+        operation=sample_operation,
+        auth_scheme=sample_auth_scheme,
+        auth_credential=sample_auth_credential,
+    )
+
+    # Call the method
+    result = await tool.call(args={}, tool_context=mock_tool_context)
+
+    # Check the result
+    assert result == {
+        "error": (
+            "Tool test_tool execution failed. Analyze this execution error"
+            " and your inputs. Retry with adjustments if applicable. But"
+            " make sure don't retry more than 3 times. Execution Error:"
+            " Status Code: 500, Internal Server Error"
+        )
+    }
+
   @patch(
       "google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool.requests.request"
   )