diff --git a/lib/crewai/src/crewai/events/event_context.py b/lib/crewai/src/crewai/events/event_context.py
index 96db485df..b097e0141 100644
--- a/lib/crewai/src/crewai/events/event_context.py
+++ b/lib/crewai/src/crewai/events/event_context.py
@@ -68,7 +68,7 @@ def push_event_scope(event_id: str, event_type: str = "") -> None:
     config = _event_context_config.get() or _default_config
     stack = _event_id_stack.get()
 
-    if config.max_stack_depth > 0 and len(stack) >= config.max_stack_depth:
+    if 0 < config.max_stack_depth <= len(stack):
         raise StackDepthExceededError(
             f"Event stack depth limit ({config.max_stack_depth}) exceeded. "
             f"This usually indicates missing ending events."
@@ -137,21 +137,24 @@ SCOPE_STARTING_EVENTS: frozenset[str] = frozenset(
         "flow_started",
         "method_execution_started",
         "crew_kickoff_started",
+        "crew_train_started",
+        "crew_test_started",
         "agent_execution_started",
+        "agent_evaluation_started",
         "lite_agent_execution_started",
         "task_started",
         "llm_call_started",
         "llm_guardrail_started",
         "tool_usage_started",
+        "mcp_connection_started",
+        "mcp_tool_execution_started",
         "memory_retrieval_started",
         "memory_save_started",
         "memory_query_started",
-        "knowledge_retrieval_started",
         "knowledge_query_started",
+        "knowledge_search_query_started",
         "a2a_delegation_started",
         "a2a_conversation_started",
-        "a2a_polling_started",
-        "a2a_streaming_started",
         "a2a_server_task_started",
         "a2a_parallel_delegation_started",
         "agent_reasoning_started",
@@ -166,8 +169,14 @@ SCOPE_ENDING_EVENTS: frozenset[str] = frozenset(
         "method_execution_failed",
         "crew_kickoff_completed",
         "crew_kickoff_failed",
+        "crew_train_completed",
+        "crew_train_failed",
+        "crew_test_completed",
+        "crew_test_failed",
         "agent_execution_completed",
         "agent_execution_error",
+        "agent_evaluation_completed",
+        "agent_evaluation_failed",
         "lite_agent_execution_completed",
         "lite_agent_execution_error",
         "task_completed",
@@ -175,20 +184,24 @@ SCOPE_ENDING_EVENTS: frozenset[str] = frozenset(
         "llm_call_completed",
         "llm_call_failed",
         "llm_guardrail_completed",
+        "llm_guardrail_failed",
         "tool_usage_finished",
         "tool_usage_error",
+        "mcp_connection_completed",
+        "mcp_connection_failed",
+        "mcp_tool_execution_completed",
+        "mcp_tool_execution_failed",
         "memory_retrieval_completed",
         "memory_save_completed",
         "memory_save_failed",
         "memory_query_completed",
         "memory_query_failed",
-        "knowledge_retrieval_completed",
         "knowledge_query_completed",
         "knowledge_query_failed",
+        "knowledge_search_query_completed",
+        "knowledge_search_query_failed",
         "a2a_delegation_completed",
         "a2a_conversation_completed",
-        "a2a_polling_completed",
-        "a2a_streaming_completed",
         "a2a_server_task_completed",
         "a2a_server_task_canceled",
         "a2a_server_task_failed",
@@ -205,8 +218,14 @@ VALID_EVENT_PAIRS: dict[str, str] = {
     "method_execution_failed": "method_execution_started",
     "crew_kickoff_completed": "crew_kickoff_started",
     "crew_kickoff_failed": "crew_kickoff_started",
+    "crew_train_completed": "crew_train_started",
+    "crew_train_failed": "crew_train_started",
+    "crew_test_completed": "crew_test_started",
+    "crew_test_failed": "crew_test_started",
     "agent_execution_completed": "agent_execution_started",
     "agent_execution_error": "agent_execution_started",
+    "agent_evaluation_completed": "agent_evaluation_started",
+    "agent_evaluation_failed": "agent_evaluation_started",
     "lite_agent_execution_completed": "lite_agent_execution_started",
     "lite_agent_execution_error": "lite_agent_execution_started",
     "task_completed": "task_started",
@@ -214,20 +233,24 @@ VALID_EVENT_PAIRS: dict[str, str] = {
     "llm_call_completed": "llm_call_started",
     "llm_call_failed": "llm_call_started",
     "llm_guardrail_completed": "llm_guardrail_started",
+    "llm_guardrail_failed": "llm_guardrail_started",
     "tool_usage_finished": "tool_usage_started",
     "tool_usage_error": "tool_usage_started",
+    "mcp_connection_completed": "mcp_connection_started",
+    "mcp_connection_failed": "mcp_connection_started",
+    "mcp_tool_execution_completed": "mcp_tool_execution_started",
+    "mcp_tool_execution_failed": "mcp_tool_execution_started",
     "memory_retrieval_completed": "memory_retrieval_started",
     "memory_save_completed": "memory_save_started",
     "memory_save_failed": "memory_save_started",
     "memory_query_completed": "memory_query_started",
     "memory_query_failed": "memory_query_started",
-    "knowledge_retrieval_completed": "knowledge_retrieval_started",
     "knowledge_query_completed": "knowledge_query_started",
     "knowledge_query_failed": "knowledge_query_started",
+    "knowledge_search_query_completed": "knowledge_search_query_started",
+    "knowledge_search_query_failed": "knowledge_search_query_started",
     "a2a_delegation_completed": "a2a_delegation_started",
     "a2a_conversation_completed": "a2a_conversation_started",
-    "a2a_polling_completed": "a2a_polling_started",
-    "a2a_streaming_completed": "a2a_streaming_started",
     "a2a_server_task_completed": "a2a_server_task_started",
     "a2a_server_task_canceled": "a2a_server_task_started",
     "a2a_server_task_failed": "a2a_server_task_started",
diff --git a/lib/crewai/src/crewai/tools/tool_usage.py b/lib/crewai/src/crewai/tools/tool_usage.py
index dc46267bc..780cce32d 100644
--- a/lib/crewai/src/crewai/tools/tool_usage.py
+++ b/lib/crewai/src/crewai/tools/tool_usage.py
@@ -401,6 +401,8 @@ class ToolUsage:
                         if self.task:
                             self.task.increment_tools_errors()
                         should_retry = True
+            else:
+                result = self._format_result(result=result)
 
         finally:
             if started_event_emitted:
@@ -602,6 +604,8 @@ class ToolUsage:
                         if self.task:
                             self.task.increment_tools_errors()
                         should_retry = True
+            else:
+                result = self._format_result(result=result)
 
         finally:
             if started_event_emitted: