diff --git a/src/google/adk/flows/llm_flows/functions.py b/src/google/adk/flows/llm_flows/functions.py
index 664d0d6c..a619aac4 100644
--- a/src/google/adk/flows/llm_flows/functions.py
+++ b/src/google/adk/flows/llm_flows/functions.py
@@ -570,19 +570,16 @@ async def _execute_single_function_call_async(
     return function_response_event
 
   with tracer.start_as_current_span(f'execute_tool {tool.name}'):
+    function_response_event = None
     try:
       function_response_event = await _run_with_trace()
+      return function_response_event
+    finally:
       trace_tool_call(
           tool=tool,
           args=function_args,
           function_response_event=function_response_event,
       )
-      return function_response_event
-    except:
-      trace_tool_call(
-          tool=tool, args=function_args, function_response_event=None
-      )
-      raise
 
 
 async def handle_function_calls_live(
@@ -720,19 +717,16 @@ async def _execute_single_function_call_live(
     return function_response_event
 
   with tracer.start_as_current_span(f'execute_tool {tool.name}'):
+    function_response_event = None
     try:
       function_response_event = await _run_with_trace()
+      return function_response_event
+    finally:
       trace_tool_call(
           tool=tool,
           args=function_args,
           function_response_event=function_response_event,
       )
-      return function_response_event
-    except:
-      trace_tool_call(
-          tool=tool, args=function_args, function_response_event=None
-      )
-      raise
 
 
 async def _process_function_live_helper(
diff --git a/src/google/adk/tools/apihub_tool/clients/apihub_client.py b/src/google/adk/tools/apihub_tool/clients/apihub_client.py
index b9197350..ac566c84 100644
--- a/src/google/adk/tools/apihub_tool/clients/apihub_client.py
+++ b/src/google/adk/tools/apihub_tool/clients/apihub_client.py
@@ -27,6 +27,7 @@ from urllib.parse import parse_qs
 from urllib.parse import urlparse
 
 from google.auth import default as default_service_credential
+from google.auth.exceptions import DefaultCredentialsError
 from google.auth.transport.requests import Request
 from google.oauth2 import service_account
 import requests
@@ -329,7 +330,7 @@ class APIHubClient(BaseAPIHubClient):
         credentials, _ = default_service_credential(
             scopes=["https://www.googleapis.com/auth/cloud-platform"]
         )
-      except:
+      except DefaultCredentialsError:
         credentials = None
 
     if not credentials:
diff --git a/src/google/adk/tools/application_integration_tool/clients/connections_client.py b/src/google/adk/tools/application_integration_tool/clients/connections_client.py
index 1756d5b0..fdec2d22 100644
--- a/src/google/adk/tools/application_integration_tool/clients/connections_client.py
+++ b/src/google/adk/tools/application_integration_tool/clients/connections_client.py
@@ -815,7 +815,7 @@ class ConnectionsClient:
         credentials, _ = default_service_credential(
             scopes=["https://www.googleapis.com/auth/cloud-platform"]
         )
-      except:
+      except google.auth.exceptions.DefaultCredentialsError:
         credentials = None
 
     if not credentials:
diff --git a/src/google/adk/tools/application_integration_tool/clients/integration_client.py b/src/google/adk/tools/application_integration_tool/clients/integration_client.py
index a7b5e44c..bb704ee4 100644
--- a/src/google/adk/tools/application_integration_tool/clients/integration_client.py
+++ b/src/google/adk/tools/application_integration_tool/clients/integration_client.py
@@ -253,7 +253,7 @@ class IntegrationClient:
         credentials, project_id = default_service_credential(
             scopes=["https://www.googleapis.com/auth/cloud-platform"]
         )
-      except:
+      except google.auth.exceptions.DefaultCredentialsError:
         credentials = None
       if credentials:
         quota_project_id = getattr(credentials, "quota_project_id", None)
diff --git a/src/google/adk/tools/bigquery/query_tool.py b/src/google/adk/tools/bigquery/query_tool.py
index 66cfb26b..d5b1264f 100644
--- a/src/google/adk/tools/bigquery/query_tool.py
+++ b/src/google/adk/tools/bigquery/query_tool.py
@@ -176,7 +176,7 @@ def _execute_sql(
         try:
           # if the json serialization of the value succeeds, use it as is
           json.dumps(val)
-        except:
+        except (TypeError, ValueError, OverflowError):
           val = str(val)
         row_values[key] = val
       rows.append(row_values)
diff --git a/src/google/adk/tools/bigtable/query_tool.py b/src/google/adk/tools/bigtable/query_tool.py
index 34830cc6..a7a785a2 100644
--- a/src/google/adk/tools/bigtable/query_tool.py
+++ b/src/google/adk/tools/bigtable/query_tool.py
@@ -101,7 +101,7 @@ def execute_sql(
           try:
             # if the json serialization of the value succeeds, use it as is
             json.dumps(val)
-          except:
+          except (TypeError, ValueError, OverflowError):
             val = str(val)
           row_values[key] = val
         rows.append(row_values)
diff --git a/src/google/adk/tools/spanner/metadata_tool.py b/src/google/adk/tools/spanner/metadata_tool.py
index 4b71f40c..51d8ac1a 100644
--- a/src/google/adk/tools/spanner/metadata_tool.py
+++ b/src/google/adk/tools/spanner/metadata_tool.py
@@ -277,7 +277,7 @@ def get_table_schema(
 
     try:
       json.dumps(results)
-    except:
+    except (TypeError, ValueError, OverflowError):
       results = str(results)
 
     return {"status": "SUCCESS", "results": results}
@@ -375,7 +375,7 @@ def list_table_indexes(
 
         try:
           json.dumps(index_info)
-        except:
+        except (TypeError, ValueError, OverflowError):
           index_info = str(index_info)
 
         indexes.append(index_info)
@@ -479,7 +479,7 @@ def list_table_index_columns(
 
         try:
           json.dumps(index_column_info)
-        except:
+        except (TypeError, ValueError, OverflowError):
           index_column_info = str(index_column_info)
 
         index_columns.append(index_column_info)
diff --git a/src/google/adk/tools/spanner/search_tool.py b/src/google/adk/tools/spanner/search_tool.py
index 93944dec..03f695b8 100644
--- a/src/google/adk/tools/spanner/search_tool.py
+++ b/src/google/adk/tools/spanner/search_tool.py
@@ -515,7 +515,7 @@ def similarity_search(
         try:
           # if the json serialization of the row succeeds, use it as is
           json.dumps(row)
-        except:
+        except (TypeError, ValueError, OverflowError):
           row = str(row)
 
         rows.append(row)
diff --git a/src/google/adk/tools/spanner/utils.py b/src/google/adk/tools/spanner/utils.py
index e2c2ce14..9f5efdb7 100644
--- a/src/google/adk/tools/spanner/utils.py
+++ b/src/google/adk/tools/spanner/utils.py
@@ -107,7 +107,7 @@ def execute_sql(
         try:
           # if the json serialization of the row succeeds, use it as is
           json.dumps(row)
-        except:
+        except (TypeError, ValueError, OverflowError):
           row = str(row)
 
         rows.append(row)
diff --git a/tests/unittests/tools/apihub_tool/clients/test_apihub_client.py b/tests/unittests/tools/apihub_tool/clients/test_apihub_client.py
index 621ebc1b..06244671 100644
--- a/tests/unittests/tools/apihub_tool/clients/test_apihub_client.py
+++ b/tests/unittests/tools/apihub_tool/clients/test_apihub_client.py
@@ -18,6 +18,7 @@ from unittest.mock import MagicMock
 from unittest.mock import patch
 
 from google.adk.tools.apihub_tool.clients.apihub_client import APIHubClient
+from google.auth.exceptions import DefaultCredentialsError
 import pytest
 from requests.exceptions import HTTPError
 
@@ -398,6 +399,24 @@ class TestAPIHubClient:
       # no service account client
       APIHubClient()._get_access_token()
 
+  @patch(
+      "google.adk.tools.apihub_tool.clients.apihub_client.default_service_credential"
+  )
+  def test_get_access_token_default_credentials_error(
+      self, mock_default_service_credential
+  ):
+    mock_default_service_credential.side_effect = DefaultCredentialsError(
+        "ADC not found"
+    )
+    with pytest.raises(
+        ValueError,
+        match=(
+            "Please provide a service account or an access token to API Hub"
+            " client."
+        ),
+    ):
+      APIHubClient()._get_access_token()
+
   @patch("requests.get")
   def test_get_spec_content_api_level(self, mock_get, client):
     mock_get.side_effect = [
diff --git a/tests/unittests/tools/application_integration_tool/clients/test_connections_client.py b/tests/unittests/tools/application_integration_tool/clients/test_connections_client.py
index c2334973..5c94d5ba 100644
--- a/tests/unittests/tools/application_integration_tool/clients/test_connections_client.py
+++ b/tests/unittests/tools/application_integration_tool/clients/test_connections_client.py
@@ -631,6 +631,25 @@ class TestConnectionsClient:
       ):
         client._get_access_token()
 
+  def test_get_access_token_default_credentials_error(
+      self, project, location, connection_name
+  ):
+    client = ConnectionsClient(project, location, connection_name, None)
+    with mock.patch(
+        "google.adk.tools.application_integration_tool.clients.connections_client.default_service_credential",
+        side_effect=google.auth.exceptions.DefaultCredentialsError(
+            "ADC not found"
+        ),
+    ):
+      with pytest.raises(
+          ValueError,
+          match=(
+              "Please provide a service account that has the required"
+              " permissions"
+          ),
+      ):
+        client._get_access_token()
+
   def test_get_access_token_refreshes_expired_token(
       self, project, location, connection_name, mock_credentials
   ):
diff --git a/tests/unittests/tools/application_integration_tool/clients/test_integration_client.py b/tests/unittests/tools/application_integration_tool/clients/test_integration_client.py
index 77e74653..eea0cbc3 100644
--- a/tests/unittests/tools/application_integration_tool/clients/test_integration_client.py
+++ b/tests/unittests/tools/application_integration_tool/clients/test_integration_client.py
@@ -595,6 +595,34 @@ class TestIntegrationClient:
             in str(e)
         )
 
+  def test_get_access_token_default_credentials_error(
+      self, project, location, integration_name, triggers, connection_name
+  ):
+    with mock.patch(
+        "google.adk.tools.application_integration_tool.clients.integration_client.default_service_credential",
+        side_effect=google.auth.exceptions.DefaultCredentialsError(
+            "ADC not found"
+        ),
+    ):
+      client = IntegrationClient(
+          project=project,
+          location=location,
+          integration=integration_name,
+          triggers=triggers,
+          connection=connection_name,
+          entity_operations=None,
+          actions=None,
+          service_account_json=None,
+      )
+      with pytest.raises(
+          ValueError,
+          match=(
+              "Please provide a service account that has the required"
+              " permissions to access the connection."
+          ),
+      ):
+        client._get_access_token()
+
   def test_get_access_token_uses_cached_token(
       self,
       project,
diff --git a/tests/unittests/tools/bigquery/test_bigquery_query_tool.py b/tests/unittests/tools/bigquery/test_bigquery_query_tool.py
index 8c182c89..150cdb75 100644
--- a/tests/unittests/tools/bigquery/test_bigquery_query_tool.py
+++ b/tests/unittests/tools/bigquery/test_bigquery_query_tool.py
@@ -1136,6 +1136,33 @@ def test_execute_sql_result_dtype(
   assert result == {"status": "SUCCESS", "rows": tool_result_rows}
 
 
+@mock.patch.dict(os.environ, {}, clear=True)
+@mock.patch.object(bigquery.Client, "query_and_wait", autospec=True)
+@mock.patch.object(bigquery.Client, "query", autospec=True)
+def test_execute_sql_result_dtype_circular_reference(
+    mock_query, mock_query_and_wait
+):
+  """Test execute_sql converts circular values to strings."""
+  credentials = mock.create_autospec(Credentials, instance=True)
+  tool_settings = BigQueryToolConfig()
+  tool_context = mock.create_autospec(ToolContext, instance=True)
+  query_job = mock.create_autospec(bigquery.QueryJob)
+  query_job.statement_type = "SELECT"
+  mock_query.return_value = query_job
+  circular_value = []
+  circular_value.append(circular_value)
+  mock_query_and_wait.return_value = [{"x": circular_value}]
+
+  result = query_tool.execute_sql(
+      "my_project", "SELECT 1", credentials, tool_settings, tool_context
+  )
+
+  assert result == {
+      "status": "SUCCESS",
+      "rows": [{"x": str(circular_value)}],
+  }
+
+
 @mock.patch.object(bq_client_lib, "get_bigquery_client", autospec=True)
 def test_execute_sql_bq_client_creation(mock_get_bigquery_client):
   """Test BigQuery client creation params during execute_sql tool invocation."""
diff --git a/tests/unittests/tools/bigtable/test_bigtable_query_tool.py b/tests/unittests/tools/bigtable/test_bigtable_query_tool.py
index 01eaf8d1..0bd0fedc 100644
--- a/tests/unittests/tools/bigtable/test_bigtable_query_tool.py
+++ b/tests/unittests/tools/bigtable/test_bigtable_query_tool.py
@@ -135,3 +135,37 @@ def test_execute_sql_error():
         tool_context=tool_context,
     )
     assert result == {"status": "ERROR", "error_details": "Test error"}
+
+
+def test_execute_sql_row_value_circular_reference_fallback():
+  """Test execute_sql converts circular row values to strings."""
+  project = "my_project"
+  instance_id = "my_instance"
+  query = "SELECT * FROM my_table"
+  credentials = mock.create_autospec(Credentials, instance=True)
+  tool_context = mock.create_autospec(ToolContext, instance=True)
+
+  with mock.patch(
+      "google.adk.tools.bigtable.client.get_bigtable_data_client"
+  ) as mock_get_client:
+    mock_client = mock.MagicMock()
+    mock_get_client.return_value = mock_client
+    mock_iterator = mock.create_autospec(ExecuteQueryIterator, instance=True)
+    mock_client.execute_query.return_value = mock_iterator
+    circular_value = []
+    circular_value.append(circular_value)
+    mock_row = mock.MagicMock()
+    mock_row.fields = {"col1": circular_value}
+    mock_iterator.__iter__.return_value = [mock_row]
+
+    result = execute_sql(
+        project_id=project,
+        instance_id=instance_id,
+        credentials=credentials,
+        query=query,
+        settings=BigtableToolSettings(),
+        tool_context=tool_context,
+    )
+
+  assert result["status"] == "SUCCESS"
+  assert result["rows"][0]["col1"] == str(circular_value)
diff --git a/tests/unittests/tools/spanner/test_metadata_tool.py b/tests/unittests/tools/spanner/test_metadata_tool.py
index 6ea7dd16..fcfcd4bd 100644
--- a/tests/unittests/tools/spanner/test_metadata_tool.py
+++ b/tests/unittests/tools/spanner/test_metadata_tool.py
@@ -192,6 +192,45 @@ def test_list_table_indexes_success(
   assert result["results"][0]["INDEX_NAME"] == "PRIMARY_KEY"
 
 
+@patch("google.adk.tools.spanner.client.get_spanner_client")
+def test_list_table_indexes_circular_row_fallback_to_string(
+    mock_get_spanner_client, mock_spanner_ids, mock_credentials
+):
+  """Test list_table_indexes stringifies rows with circular references."""
+  mock_spanner_client = MagicMock()
+  mock_instance = MagicMock()
+  mock_database = MagicMock()
+  mock_snapshot = MagicMock()
+  circular_value = []
+  circular_value.append(circular_value)
+  mock_result_set = MagicMock()
+  mock_result_set.__iter__.return_value = iter([(
+      circular_value,
+      "",
+      "PRIMARY_KEY",
+      "",
+      True,
+      False,
+      None,
+  )])
+  mock_snapshot.execute_sql.return_value = mock_result_set
+  mock_database.snapshot.return_value.__enter__.return_value = mock_snapshot
+  mock_database.database_dialect = DatabaseDialect.GOOGLE_STANDARD_SQL
+  mock_instance.database.return_value = mock_database
+  mock_spanner_client.instance.return_value = mock_instance
+  mock_get_spanner_client.return_value = mock_spanner_client
+
+  result = metadata_tool.list_table_indexes(
+      mock_spanner_ids["project_id"],
+      mock_spanner_ids["instance_id"],
+      mock_spanner_ids["database_id"],
+      mock_spanner_ids["table_name"],
+      mock_credentials,
+  )
+  assert result["status"] == "SUCCESS"
+  assert isinstance(result["results"][0], str)
+
+
 @patch("google.adk.tools.spanner.client.get_spanner_client")
 def test_list_table_index_columns_success(
     mock_get_spanner_client, mock_spanner_ids, mock_credentials
diff --git a/tests/unittests/tools/spanner/test_search_tool.py b/tests/unittests/tools/spanner/test_search_tool.py
index 2f0976d0..4532dd56 100644
--- a/tests/unittests/tools/spanner/test_search_tool.py
+++ b/tests/unittests/tools/spanner/test_search_tool.py
@@ -187,6 +187,47 @@ def test_similarity_search_error(
   assert "Test Exception" in result["error_details"]
 
 
+@mock.patch.object(utils, "embed_contents")
+@mock.patch.object(client, "get_spanner_client")
+def test_similarity_search_circular_row_fallback_to_string(
+    mock_get_spanner_client,
+    mock_embed_contents,
+    mock_spanner_ids,
+    mock_credentials,
+):
+  """Test similarity_search stringifies rows with circular references."""
+  mock_spanner_client = MagicMock()
+  mock_instance = MagicMock()
+  mock_database = MagicMock()
+  mock_snapshot = MagicMock()
+  circular_row = []
+  circular_row.append(circular_row)
+  mock_embed_contents.return_value = [[0.1, 0.2, 0.3]]
+  mock_snapshot.execute_sql.return_value = iter([circular_row])
+  mock_database.snapshot.return_value.__enter__.return_value = mock_snapshot
+  mock_database.database_dialect = DatabaseDialect.GOOGLE_STANDARD_SQL
+  mock_instance.database.return_value = mock_database
+  mock_spanner_client.instance.return_value = mock_instance
+  mock_get_spanner_client.return_value = mock_spanner_client
+
+  result = search_tool.similarity_search(
+      project_id=mock_spanner_ids["project_id"],
+      instance_id=mock_spanner_ids["instance_id"],
+      database_id=mock_spanner_ids["database_id"],
+      table_name=mock_spanner_ids["table_name"],
+      query="test query",
+      embedding_column_to_search="embedding_col",
+      columns=["col1"],
+      embedding_options={
+          "vertex_ai_embedding_model_name": "text-embedding-005"
+      },
+      credentials=mock_credentials,
+  )
+
+  assert result["status"] == "SUCCESS", result
+  assert result["rows"] == [str(circular_row)]
+
+
 @mock.patch.object(client, "get_spanner_client")
 def test_similarity_search_postgresql_knn_success(
     mock_get_spanner_client, mock_spanner_ids, mock_credentials
diff --git a/tests/unittests/tools/spanner/test_utils.py b/tests/unittests/tools/spanner/test_utils.py
index 0dd58f24..fe8d7db4 100644
--- a/tests/unittests/tools/spanner/test_utils.py
+++ b/tests/unittests/tools/spanner/test_utils.py
@@ -178,6 +178,35 @@ def test_add_contents_empty_contents(
     mock_spanner_database.batch.assert_not_called()
 
 
+@mock.patch.object(spanner_utils.client, "get_spanner_client", autospec=True)
+def test_execute_sql_circular_row_fallback_to_string(mock_get_spanner_client):
+  """Test execute_sql stringifies rows with circular references."""
+  mock_spanner_client = mock.MagicMock()
+  mock_instance = mock.MagicMock()
+  mock_database = mock.MagicMock()
+  mock_snapshot = mock.MagicMock()
+  circular_row = []
+  circular_row.append(circular_row)
+  mock_snapshot.execute_sql.return_value = iter([circular_row])
+  mock_database.snapshot.return_value.__enter__.return_value = mock_snapshot
+  mock_database.database_dialect = DatabaseDialect.GOOGLE_STANDARD_SQL
+  mock_instance.database.return_value = mock_database
+  mock_spanner_client.instance.return_value = mock_instance
+  mock_get_spanner_client.return_value = mock_spanner_client
+
+  result = spanner_utils.execute_sql(
+      project_id="test-project",
+      instance_id="test-instance",
+      database_id="test-database",
+      query="SELECT 1",
+      credentials=mock.Mock(),
+      settings=SpannerToolSettings(),
+      tool_context=mock.Mock(),
+  )
+
+  assert result == {"status": "SUCCESS", "rows": [str(circular_row)]}
+
+
 @mock.patch.object(spanner_utils, "embed_contents", autospec=True)
 def test_add_contents_additional_columns_list_mismatch(
     mock_embed_contents, spanner_tool_settings, mock_spanner_client