fix: ensure flow execution start panel is not shown on plot

lib/crewai/src/crewai/events/event_listener.py

@@ -101,24 +101,25 @@ if TYPE_CHECKING:
 
 
 class EventListener(BaseEventListener):
-    _instance = None
+    _instance: EventListener | None = None
+    _initialized: bool = False
     _telemetry: Telemetry = PrivateAttr(default_factory=lambda: Telemetry())
-    logger = Logger(verbose=True, default_color=EMITTER_COLOR)
+    logger: Logger = Logger(verbose=True, default_color=EMITTER_COLOR)
     execution_spans: dict[Task, Any] = Field(default_factory=dict)
-    next_chunk = 0
+    next_chunk: int = 0
-    text_stream = StringIO()
+    text_stream: StringIO = StringIO()
-    knowledge_retrieval_in_progress = False
+    knowledge_retrieval_in_progress: bool = False
-    knowledge_query_in_progress = False
+    knowledge_query_in_progress: bool = False
     method_branches: dict[str, Any] = Field(default_factory=dict)
 
-    def __new__(cls):
+    def __new__(cls) -> EventListener:
         if cls._instance is None:
             cls._instance = super().__new__(cls)
             cls._instance._initialized = False
         return cls._instance
 
-    def __init__(self):
+    def __init__(self) -> None:
-        if not hasattr(self, "_initialized") or not self._initialized:
+        if not self._initialized:
             super().__init__()
             self._telemetry = Telemetry()
             self._telemetry.set_tracer()
@@ -136,14 +137,14 @@ class EventListener(BaseEventListener):
 
     def setup_listeners(self, crewai_event_bus: CrewAIEventsBus) -> None:
         @crewai_event_bus.on(CrewKickoffStartedEvent)
-        def on_crew_started(source, event: CrewKickoffStartedEvent) -> None:
+        def on_crew_started(source: Any, event: CrewKickoffStartedEvent) -> None:
             with self._crew_tree_lock:
                 self.formatter.create_crew_tree(event.crew_name or "Crew", source.id)
                 self._telemetry.crew_execution_span(source, event.inputs)
                 self._crew_tree_lock.notify_all()
 
         @crewai_event_bus.on(CrewKickoffCompletedEvent)
-        def on_crew_completed(source, event: CrewKickoffCompletedEvent) -> None:
+        def on_crew_completed(source: Any, event: CrewKickoffCompletedEvent) -> None:
             # Handle telemetry
             final_string_output = event.output.raw
             self._telemetry.end_crew(source, final_string_output)
@@ -157,7 +158,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(CrewKickoffFailedEvent)
-        def on_crew_failed(source, event: CrewKickoffFailedEvent) -> None:
+        def on_crew_failed(source: Any, event: CrewKickoffFailedEvent) -> None:
             self.formatter.update_crew_tree(
                 self.formatter.current_crew_tree,
                 event.crew_name or "Crew",
@@ -166,23 +167,23 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(CrewTrainStartedEvent)
-        def on_crew_train_started(source, event: CrewTrainStartedEvent) -> None:
+        def on_crew_train_started(_: Any, event: CrewTrainStartedEvent) -> None:
             self.formatter.handle_crew_train_started(
                 event.crew_name or "Crew", str(event.timestamp)
             )
 
         @crewai_event_bus.on(CrewTrainCompletedEvent)
-        def on_crew_train_completed(source, event: CrewTrainCompletedEvent) -> None:
+        def on_crew_train_completed(_: Any, event: CrewTrainCompletedEvent) -> None:
             self.formatter.handle_crew_train_completed(
                 event.crew_name or "Crew", str(event.timestamp)
             )
 
         @crewai_event_bus.on(CrewTrainFailedEvent)
-        def on_crew_train_failed(source, event: CrewTrainFailedEvent) -> None:
+        def on_crew_train_failed(_: Any, event: CrewTrainFailedEvent) -> None:
             self.formatter.handle_crew_train_failed(event.crew_name or "Crew")
 
         @crewai_event_bus.on(CrewTestResultEvent)
-        def on_crew_test_result(source, event: CrewTestResultEvent) -> None:
+        def on_crew_test_result(source: Any, event: CrewTestResultEvent) -> None:
             self._telemetry.individual_test_result_span(
                 source.crew,
                 event.quality,
@@ -193,7 +194,7 @@ class EventListener(BaseEventListener):
         # ----------- TASK EVENTS -----------
 
         @crewai_event_bus.on(TaskStartedEvent)
-        def on_task_started(source, event: TaskStartedEvent) -> None:
+        def on_task_started(source: Any, event: TaskStartedEvent) -> None:
             span = self._telemetry.task_started(crew=source.agent.crew, task=source)
             self.execution_spans[source] = span
 
@@ -211,7 +212,7 @@ class EventListener(BaseEventListener):
                 )
 
         @crewai_event_bus.on(TaskCompletedEvent)
-        def on_task_completed(source, event: TaskCompletedEvent):
+        def on_task_completed(source: Any, event: TaskCompletedEvent) -> None:
             # Handle telemetry
             span = self.execution_spans.get(source)
             if span:
@@ -229,7 +230,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(TaskFailedEvent)
-        def on_task_failed(source, event: TaskFailedEvent):
+        def on_task_failed(source: Any, event: TaskFailedEvent) -> None:
             span = self.execution_spans.get(source)
             if span:
                 if source.agent and source.agent.crew:
@@ -249,7 +250,9 @@ class EventListener(BaseEventListener):
         # ----------- AGENT EVENTS -----------
 
         @crewai_event_bus.on(AgentExecutionStartedEvent)
-        def on_agent_execution_started(source, event: AgentExecutionStartedEvent):
+        def on_agent_execution_started(
+            _: Any, event: AgentExecutionStartedEvent
+        ) -> None:
             self.formatter.create_agent_branch(
                 self.formatter.current_task_branch,
                 event.agent.role,
@@ -257,7 +260,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(AgentExecutionCompletedEvent)
-        def on_agent_execution_completed(source, event: AgentExecutionCompletedEvent):
+        def on_agent_execution_completed(
+            _: Any, event: AgentExecutionCompletedEvent
+        ) -> None:
             self.formatter.update_agent_status(
                 self.formatter.current_agent_branch,
                 event.agent.role,
@@ -268,8 +273,8 @@ class EventListener(BaseEventListener):
 
         @crewai_event_bus.on(LiteAgentExecutionStartedEvent)
         def on_lite_agent_execution_started(
-            source, event: LiteAgentExecutionStartedEvent
+            _: Any, event: LiteAgentExecutionStartedEvent
-        ):
+        ) -> None:
             """Handle LiteAgent execution started event."""
             self.formatter.handle_lite_agent_execution(
                 event.agent_info["role"], status="started", **event.agent_info
@@ -277,15 +282,17 @@ class EventListener(BaseEventListener):
 
         @crewai_event_bus.on(LiteAgentExecutionCompletedEvent)
         def on_lite_agent_execution_completed(
-            source, event: LiteAgentExecutionCompletedEvent
+            _: Any, event: LiteAgentExecutionCompletedEvent
-        ):
+        ) -> None:
             """Handle LiteAgent execution completed event."""
             self.formatter.handle_lite_agent_execution(
                 event.agent_info["role"], status="completed", **event.agent_info
             )
 
         @crewai_event_bus.on(LiteAgentExecutionErrorEvent)
-        def on_lite_agent_execution_error(source, event: LiteAgentExecutionErrorEvent):
+        def on_lite_agent_execution_error(
+            _: Any, event: LiteAgentExecutionErrorEvent
+        ) -> None:
             """Handle LiteAgent execution error event."""
             self.formatter.handle_lite_agent_execution(
                 event.agent_info["role"],
@@ -297,26 +304,28 @@ class EventListener(BaseEventListener):
         # ----------- FLOW EVENTS -----------
 
         @crewai_event_bus.on(FlowCreatedEvent)
-        def on_flow_created(source, event: FlowCreatedEvent):
+        def on_flow_created(_: Any, event: FlowCreatedEvent) -> None:
             self._telemetry.flow_creation_span(event.flow_name)
-            tree = self.formatter.create_flow_tree(event.flow_name, str(source.flow_id))
-            self.formatter.current_flow_tree = tree
 
         @crewai_event_bus.on(FlowStartedEvent)
-        def on_flow_started(source, event: FlowStartedEvent):
+        def on_flow_started(source: Any, event: FlowStartedEvent) -> None:
             self._telemetry.flow_execution_span(
                 event.flow_name, list(source._methods.keys())
             )
+            tree = self.formatter.create_flow_tree(event.flow_name, str(source.flow_id))
+            self.formatter.current_flow_tree = tree
             self.formatter.start_flow(event.flow_name, str(source.flow_id))
 
         @crewai_event_bus.on(FlowFinishedEvent)
-        def on_flow_finished(source, event: FlowFinishedEvent):
+        def on_flow_finished(source: Any, event: FlowFinishedEvent) -> None:
             self.formatter.update_flow_status(
                 self.formatter.current_flow_tree, event.flow_name, source.flow_id
             )
 
         @crewai_event_bus.on(MethodExecutionStartedEvent)
-        def on_method_execution_started(source, event: MethodExecutionStartedEvent):
+        def on_method_execution_started(
+            _: Any, event: MethodExecutionStartedEvent
+        ) -> None:
             method_branch = self.method_branches.get(event.method_name)
             updated_branch = self.formatter.update_method_status(
                 method_branch,
@@ -327,7 +336,9 @@ class EventListener(BaseEventListener):
             self.method_branches[event.method_name] = updated_branch
 
         @crewai_event_bus.on(MethodExecutionFinishedEvent)
-        def on_method_execution_finished(source, event: MethodExecutionFinishedEvent):
+        def on_method_execution_finished(
+            _: Any, event: MethodExecutionFinishedEvent
+        ) -> None:
             method_branch = self.method_branches.get(event.method_name)
             updated_branch = self.formatter.update_method_status(
                 method_branch,
@@ -338,7 +349,9 @@ class EventListener(BaseEventListener):
             self.method_branches[event.method_name] = updated_branch
 
         @crewai_event_bus.on(MethodExecutionFailedEvent)
-        def on_method_execution_failed(source, event: MethodExecutionFailedEvent):
+        def on_method_execution_failed(
+            _: Any, event: MethodExecutionFailedEvent
+        ) -> None:
             method_branch = self.method_branches.get(event.method_name)
             updated_branch = self.formatter.update_method_status(
                 method_branch,
@@ -351,7 +364,7 @@ class EventListener(BaseEventListener):
         # ----------- TOOL USAGE EVENTS -----------
 
         @crewai_event_bus.on(ToolUsageStartedEvent)
-        def on_tool_usage_started(source, event: ToolUsageStartedEvent):
+        def on_tool_usage_started(source: Any, event: ToolUsageStartedEvent) -> None:
             if isinstance(source, LLM):
                 self.formatter.handle_llm_tool_usage_started(
                     event.tool_name,
@@ -365,7 +378,7 @@ class EventListener(BaseEventListener):
                 )
 
         @crewai_event_bus.on(ToolUsageFinishedEvent)
-        def on_tool_usage_finished(source, event: ToolUsageFinishedEvent):
+        def on_tool_usage_finished(source: Any, event: ToolUsageFinishedEvent) -> None:
             if isinstance(source, LLM):
                 self.formatter.handle_llm_tool_usage_finished(
                     event.tool_name,
@@ -378,7 +391,7 @@ class EventListener(BaseEventListener):
                 )
 
         @crewai_event_bus.on(ToolUsageErrorEvent)
-        def on_tool_usage_error(source, event: ToolUsageErrorEvent):
+        def on_tool_usage_error(source: Any, event: ToolUsageErrorEvent) -> None:
             if isinstance(source, LLM):
                 self.formatter.handle_llm_tool_usage_error(
                     event.tool_name,
@@ -395,7 +408,7 @@ class EventListener(BaseEventListener):
         # ----------- LLM EVENTS -----------
 
         @crewai_event_bus.on(LLMCallStartedEvent)
-        def on_llm_call_started(source, event: LLMCallStartedEvent):
+        def on_llm_call_started(_: Any, event: LLMCallStartedEvent) -> None:
             # Capture the returned tool branch and update the current_tool_branch reference
             thinking_branch = self.formatter.handle_llm_call_started(
                 self.formatter.current_agent_branch,
@@ -406,7 +419,7 @@ class EventListener(BaseEventListener):
                 self.formatter.current_tool_branch = thinking_branch
 
         @crewai_event_bus.on(LLMCallCompletedEvent)
-        def on_llm_call_completed(source, event: LLMCallCompletedEvent):
+        def on_llm_call_completed(_: Any, event: LLMCallCompletedEvent) -> None:
             self.formatter.handle_llm_call_completed(
                 self.formatter.current_tool_branch,
                 self.formatter.current_agent_branch,
@@ -414,7 +427,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(LLMCallFailedEvent)
-        def on_llm_call_failed(source, event: LLMCallFailedEvent):
+        def on_llm_call_failed(_: Any, event: LLMCallFailedEvent) -> None:
             self.formatter.handle_llm_call_failed(
                 self.formatter.current_tool_branch,
                 event.error,
@@ -422,7 +435,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(LLMStreamChunkEvent)
-        def on_llm_stream_chunk(source, event: LLMStreamChunkEvent):
+        def on_llm_stream_chunk(_: Any, event: LLMStreamChunkEvent) -> None:
             self.text_stream.write(event.chunk)
             self.text_stream.seek(self.next_chunk)
             self.text_stream.read()
@@ -431,7 +444,7 @@ class EventListener(BaseEventListener):
         # ----------- LLM GUARDRAIL EVENTS -----------
 
         @crewai_event_bus.on(LLMGuardrailStartedEvent)
-        def on_llm_guardrail_started(source, event: LLMGuardrailStartedEvent):
+        def on_llm_guardrail_started(_: Any, event: LLMGuardrailStartedEvent) -> None:
             guardrail_str = str(event.guardrail)
             guardrail_name = (
                 guardrail_str[:50] + "..." if len(guardrail_str) > 50 else guardrail_str
@@ -440,13 +453,15 @@ class EventListener(BaseEventListener):
             self.formatter.handle_guardrail_started(guardrail_name, event.retry_count)
 
         @crewai_event_bus.on(LLMGuardrailCompletedEvent)
-        def on_llm_guardrail_completed(source, event: LLMGuardrailCompletedEvent):
+        def on_llm_guardrail_completed(
+            _: Any, event: LLMGuardrailCompletedEvent
+        ) -> None:
             self.formatter.handle_guardrail_completed(
                 event.success, event.error, event.retry_count
             )
 
         @crewai_event_bus.on(CrewTestStartedEvent)
-        def on_crew_test_started(source, event: CrewTestStartedEvent):
+        def on_crew_test_started(source: Any, event: CrewTestStartedEvent) -> None:
             cloned_crew = source.copy()
             self._telemetry.test_execution_span(
                 cloned_crew,
@@ -460,20 +475,20 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(CrewTestCompletedEvent)
-        def on_crew_test_completed(source, event: CrewTestCompletedEvent):
+        def on_crew_test_completed(_: Any, event: CrewTestCompletedEvent) -> None:
             self.formatter.handle_crew_test_completed(
                 self.formatter.current_flow_tree,
                 event.crew_name or "Crew",
             )
 
         @crewai_event_bus.on(CrewTestFailedEvent)
-        def on_crew_test_failed(source, event: CrewTestFailedEvent):
+        def on_crew_test_failed(_: Any, event: CrewTestFailedEvent) -> None:
             self.formatter.handle_crew_test_failed(event.crew_name or "Crew")
 
         @crewai_event_bus.on(KnowledgeRetrievalStartedEvent)
         def on_knowledge_retrieval_started(
-            source, event: KnowledgeRetrievalStartedEvent
+            _: Any, event: KnowledgeRetrievalStartedEvent
-        ):
+        ) -> None:
             if self.knowledge_retrieval_in_progress:
                 return
 
@@ -486,8 +501,8 @@ class EventListener(BaseEventListener):
 
         @crewai_event_bus.on(KnowledgeRetrievalCompletedEvent)
         def on_knowledge_retrieval_completed(
-            source, event: KnowledgeRetrievalCompletedEvent
+            _: Any, event: KnowledgeRetrievalCompletedEvent
-        ):
+        ) -> None:
             if not self.knowledge_retrieval_in_progress:
                 return
 
@@ -499,11 +514,13 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(KnowledgeQueryStartedEvent)
-        def on_knowledge_query_started(source, event: KnowledgeQueryStartedEvent):
+        def on_knowledge_query_started(
+            _: Any, event: KnowledgeQueryStartedEvent
+        ) -> None:
             pass
 
         @crewai_event_bus.on(KnowledgeQueryFailedEvent)
-        def on_knowledge_query_failed(source, event: KnowledgeQueryFailedEvent):
+        def on_knowledge_query_failed(_: Any, event: KnowledgeQueryFailedEvent) -> None:
             self.formatter.handle_knowledge_query_failed(
                 self.formatter.current_agent_branch,
                 event.error,
@@ -511,13 +528,15 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(KnowledgeQueryCompletedEvent)
-        def on_knowledge_query_completed(source, event: KnowledgeQueryCompletedEvent):
+        def on_knowledge_query_completed(
+            _: Any, event: KnowledgeQueryCompletedEvent
+        ) -> None:
             pass
 
         @crewai_event_bus.on(KnowledgeSearchQueryFailedEvent)
         def on_knowledge_search_query_failed(
-            source, event: KnowledgeSearchQueryFailedEvent
+            _: Any, event: KnowledgeSearchQueryFailedEvent
-        ):
+        ) -> None:
             self.formatter.handle_knowledge_search_query_failed(
                 self.formatter.current_agent_branch,
                 event.error,
@@ -527,7 +546,9 @@ class EventListener(BaseEventListener):
         # ----------- REASONING EVENTS -----------
 
         @crewai_event_bus.on(AgentReasoningStartedEvent)
-        def on_agent_reasoning_started(source, event: AgentReasoningStartedEvent):
+        def on_agent_reasoning_started(
+            _: Any, event: AgentReasoningStartedEvent
+        ) -> None:
             self.formatter.handle_reasoning_started(
                 self.formatter.current_agent_branch,
                 event.attempt,
@@ -535,7 +556,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(AgentReasoningCompletedEvent)
-        def on_agent_reasoning_completed(source, event: AgentReasoningCompletedEvent):
+        def on_agent_reasoning_completed(
+            _: Any, event: AgentReasoningCompletedEvent
+        ) -> None:
             self.formatter.handle_reasoning_completed(
                 event.plan,
                 event.ready,
@@ -543,7 +566,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(AgentReasoningFailedEvent)
-        def on_agent_reasoning_failed(source, event: AgentReasoningFailedEvent):
+        def on_agent_reasoning_failed(_: Any, event: AgentReasoningFailedEvent) -> None:
             self.formatter.handle_reasoning_failed(
                 event.error,
                 self.formatter.current_crew_tree,
@@ -552,7 +575,7 @@ class EventListener(BaseEventListener):
         # ----------- AGENT LOGGING EVENTS -----------
 
         @crewai_event_bus.on(AgentLogsStartedEvent)
-        def on_agent_logs_started(source, event: AgentLogsStartedEvent):
+        def on_agent_logs_started(_: Any, event: AgentLogsStartedEvent) -> None:
             self.formatter.handle_agent_logs_started(
                 event.agent_role,
                 event.task_description,
@@ -560,7 +583,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(AgentLogsExecutionEvent)
-        def on_agent_logs_execution(source, event: AgentLogsExecutionEvent):
+        def on_agent_logs_execution(_: Any, event: AgentLogsExecutionEvent) -> None:
             self.formatter.handle_agent_logs_execution(
                 event.agent_role,
                 event.formatted_answer,
@@ -568,7 +591,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2ADelegationStartedEvent)
-        def on_a2a_delegation_started(source, event: A2ADelegationStartedEvent):
+        def on_a2a_delegation_started(_: Any, event: A2ADelegationStartedEvent) -> None:
             self.formatter.handle_a2a_delegation_started(
                 event.endpoint,
                 event.task_description,
@@ -578,7 +601,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2ADelegationCompletedEvent)
-        def on_a2a_delegation_completed(source, event: A2ADelegationCompletedEvent):
+        def on_a2a_delegation_completed(
+            _: Any, event: A2ADelegationCompletedEvent
+        ) -> None:
             self.formatter.handle_a2a_delegation_completed(
                 event.status,
                 event.result,
@@ -587,7 +612,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2AConversationStartedEvent)
-        def on_a2a_conversation_started(source, event: A2AConversationStartedEvent):
+        def on_a2a_conversation_started(
+            _: Any, event: A2AConversationStartedEvent
+        ) -> None:
             # Store A2A agent name for display in conversation tree
             if event.a2a_agent_name:
                 self.formatter._current_a2a_agent_name = event.a2a_agent_name
@@ -598,7 +625,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2AMessageSentEvent)
-        def on_a2a_message_sent(source, event: A2AMessageSentEvent):
+        def on_a2a_message_sent(_: Any, event: A2AMessageSentEvent) -> None:
             self.formatter.handle_a2a_message_sent(
                 event.message,
                 event.turn_number,
@@ -606,7 +633,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2AResponseReceivedEvent)
-        def on_a2a_response_received(source, event: A2AResponseReceivedEvent):
+        def on_a2a_response_received(_: Any, event: A2AResponseReceivedEvent) -> None:
             self.formatter.handle_a2a_response_received(
                 event.response,
                 event.turn_number,
@@ -615,7 +642,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(A2AConversationCompletedEvent)
-        def on_a2a_conversation_completed(source, event: A2AConversationCompletedEvent):
+        def on_a2a_conversation_completed(
+            _: Any, event: A2AConversationCompletedEvent
+        ) -> None:
             self.formatter.handle_a2a_conversation_completed(
                 event.status,
                 event.final_result,
@@ -626,7 +655,7 @@ class EventListener(BaseEventListener):
         # ----------- MCP EVENTS -----------
 
         @crewai_event_bus.on(MCPConnectionStartedEvent)
-        def on_mcp_connection_started(source, event: MCPConnectionStartedEvent):
+        def on_mcp_connection_started(_: Any, event: MCPConnectionStartedEvent) -> None:
             self.formatter.handle_mcp_connection_started(
                 event.server_name,
                 event.server_url,
@@ -636,7 +665,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(MCPConnectionCompletedEvent)
-        def on_mcp_connection_completed(source, event: MCPConnectionCompletedEvent):
+        def on_mcp_connection_completed(
+            _: Any, event: MCPConnectionCompletedEvent
+        ) -> None:
             self.formatter.handle_mcp_connection_completed(
                 event.server_name,
                 event.server_url,
@@ -646,7 +677,7 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(MCPConnectionFailedEvent)
-        def on_mcp_connection_failed(source, event: MCPConnectionFailedEvent):
+        def on_mcp_connection_failed(_: Any, event: MCPConnectionFailedEvent) -> None:
             self.formatter.handle_mcp_connection_failed(
                 event.server_name,
                 event.server_url,
@@ -656,7 +687,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(MCPToolExecutionStartedEvent)
-        def on_mcp_tool_execution_started(source, event: MCPToolExecutionStartedEvent):
+        def on_mcp_tool_execution_started(
+            _: Any, event: MCPToolExecutionStartedEvent
+        ) -> None:
             self.formatter.handle_mcp_tool_execution_started(
                 event.server_name,
                 event.tool_name,
@@ -665,8 +698,8 @@ class EventListener(BaseEventListener):
 
         @crewai_event_bus.on(MCPToolExecutionCompletedEvent)
         def on_mcp_tool_execution_completed(
-            source, event: MCPToolExecutionCompletedEvent
+            _: Any, event: MCPToolExecutionCompletedEvent
-        ):
+        ) -> None:
             self.formatter.handle_mcp_tool_execution_completed(
                 event.server_name,
                 event.tool_name,
@@ -676,7 +709,9 @@ class EventListener(BaseEventListener):
             )
 
         @crewai_event_bus.on(MCPToolExecutionFailedEvent)
-        def on_mcp_tool_execution_failed(source, event: MCPToolExecutionFailedEvent):
+        def on_mcp_tool_execution_failed(
+            _: Any, event: MCPToolExecutionFailedEvent
+        ) -> None:
             self.formatter.handle_mcp_tool_execution_failed(
                 event.server_name,
                 event.tool_name,