Fix tool error causing double event scope pop (#4373)

When a tool raises an error, both ToolUsageErrorEvent and
ToolUsageFinishedEvent were being emitted. Since both events pop the
event scope stack, this caused the agent scope to be incorrectly popped
along with the tool scope.

Author: vinibrsl

lib/crewai/src/crewai/agents/crew_agent_executor.py

@@ -814,6 +814,7 @@ def _handle_native_tool_calls(
                 agent_key=agent_key,
             ),
         )
+        error_event_emitted = False
 
         track_delegation_if_needed(func_name, args_dict, self.task)
 
@@ -896,6 +897,7 @@ def _handle_native_tool_calls(
                             error=e,
                         ),
                     )
+                    error_event_emitted = True
         elif max_usage_reached and original_tool:
             # Return error message when max usage limit is reached
             result = f"Tool '{func_name}' has reached its usage limit of {original_tool.max_usage_count} times and cannot be used anymore."
@@ -923,20 +925,20 @@ def _handle_native_tool_calls(
                     color="red",
                 )
 
-        # Emit tool usage finished event
-        crewai_event_bus.emit(
-            self,
-            event=ToolUsageFinishedEvent(
-                output=result,
-                tool_name=func_name,
-                tool_args=args_dict,
-                from_agent=self.agent,
-                from_task=self.task,
-                agent_key=agent_key,
-                started_at=started_at,
-                finished_at=datetime.now(),
-            ),
-        )
+        if not error_event_emitted:
+            crewai_event_bus.emit(
+                self,
+                event=ToolUsageFinishedEvent(
+                    output=result,
+                    tool_name=func_name,
+                    tool_args=args_dict,
+                    from_agent=self.agent,
+                    from_task=self.task,
+                    agent_key=agent_key,
+                    started_at=started_at,
+                    finished_at=datetime.now(),
+                ),
+            )
 
         # Append tool result message
         tool_message: LLMMessage = {

lib/crewai/src/crewai/experimental/agent_executor.py

@@ -689,6 +689,7 @@ def execute_native_tool(
                     agent_key=agent_key,
                 ),
             )
+            error_event_emitted = False
 
             track_delegation_if_needed(func_name, args_dict, self.task)
 
@@ -764,6 +765,7 @@ def execute_native_tool(
                                 error=e,
                             ),
                         )
+                        error_event_emitted = True
             elif max_usage_reached and original_tool:
                 # Return error message when max usage limit is reached
                 result = f"Tool '{func_name}' has reached its usage limit of {original_tool.max_usage_count} times and cannot be used anymore."
@@ -792,20 +794,20 @@ def execute_native_tool(
                         color="red",
                     )
 
-            # Emit tool usage finished event
-            crewai_event_bus.emit(
-                self,
-                event=ToolUsageFinishedEvent(
-                    output=result,
-                    tool_name=func_name,
-                    tool_args=args_dict,
-                    from_agent=self.agent,
-                    from_task=self.task,
-                    agent_key=agent_key,
-                    started_at=started_at,
-                    finished_at=datetime.now(),
-                ),
-            )
+            if not error_event_emitted:
+                crewai_event_bus.emit(
+                    self,
+                    event=ToolUsageFinishedEvent(
+                        output=result,
+                        tool_name=func_name,
+                        tool_args=args_dict,
+                        from_agent=self.agent,
+                        from_task=self.task,
+                        agent_key=agent_key,
+                        started_at=started_at,
+                        finished_at=datetime.now(),
+                    ),
+                )
 
             # Append tool result message
             tool_message: LLMMessage = {

lib/crewai/src/crewai/tools/tool_usage.py

@@ -270,6 +270,7 @@ async def _ause(
         result = None  # type: ignore
         should_retry = False
         available_tool = None
+        error_event_emitted = False
 
         try:
             if self.tools_handler and self.tools_handler.cache:
@@ -408,6 +409,7 @@ async def _ause(
 
                 except Exception as e:
                     self.on_tool_error(tool=tool, tool_calling=calling, e=e)
+                    error_event_emitted = True
                     self._run_attempts += 1
                     if self._run_attempts > self._max_parsing_attempts:
                         self._telemetry.tool_usage_error(llm=self.function_calling_llm)
@@ -435,7 +437,7 @@ async def _ause(
                 result = self._format_result(result=result)
 
         finally:
-            if started_event_emitted:
+            if started_event_emitted and not error_event_emitted:
                 self.on_tool_use_finished(
                     tool=tool,
                     tool_calling=calling,
@@ -500,6 +502,7 @@ def _use(
         result = None  # type: ignore
         should_retry = False
         available_tool = None
+        error_event_emitted = False
 
         try:
             if self.tools_handler and self.tools_handler.cache:
@@ -638,6 +641,7 @@ def _use(
 
                 except Exception as e:
                     self.on_tool_error(tool=tool, tool_calling=calling, e=e)
+                    error_event_emitted = True
                     self._run_attempts += 1
                     if self._run_attempts > self._max_parsing_attempts:
                         self._telemetry.tool_usage_error(llm=self.function_calling_llm)
@@ -665,7 +669,7 @@ def _use(
                 result = self._format_result(result=result)
 
         finally:
-            if started_event_emitted:
+            if started_event_emitted and not error_event_emitted:
                 self.on_tool_use_finished(
                     tool=tool,
                     tool_calling=calling,

lib/crewai/tests/events/test_event_context.py

@@ -177,4 +177,40 @@ def test_scope_restores_on_exception(self) -> None:
                 raise ValueError("test error")
         except ValueError:
             pass
-        assert get_triggering_event_id() is None
+        assert get_triggering_event_id() is None
+
+
+def test_agent_scope_preserved_after_tool_error_event() -> None:
+    from crewai.events import crewai_event_bus
+    from crewai.events.types.tool_usage_events import (
+        ToolUsageErrorEvent,
+        ToolUsageStartedEvent,
+    )
+
+    push_event_scope("crew-1", "crew_kickoff_started")
+    push_event_scope("task-1", "task_started")
+    push_event_scope("agent-1", "agent_execution_started")
+
+    crewai_event_bus.emit(
+        None,
+        ToolUsageStartedEvent(
+            tool_name="test_tool",
+            tool_args={},
+            agent_key="test_agent",
+        )
+    )
+
+    crewai_event_bus.emit(
+        None,
+        ToolUsageErrorEvent(
+            tool_name="test_tool",
+            tool_args={},
+            agent_key="test_agent",
+            error=ValueError("test error"),
+        )
+    )
+
+    crewai_event_bus.flush()
+
+    assert get_current_parent_id() == "agent-1"
+

lib/crewai/tests/tools/test_tool_usage.py

@@ -10,7 +10,9 @@
 from crewai.events.event_bus import crewai_event_bus
 from crewai.events.types.tool_usage_events import (
     ToolSelectionErrorEvent,
+    ToolUsageErrorEvent,
     ToolUsageFinishedEvent,
+    ToolUsageStartedEvent,
     ToolValidateInputErrorEvent,
 )
 from crewai.tools import BaseTool
@@ -744,3 +746,78 @@ def event_handler(source, event):
     assert isinstance(event.started_at, datetime.datetime)
     assert isinstance(event.finished_at, datetime.datetime)
     assert event.type == "tool_usage_finished"
+
+
+def test_tool_error_does_not_emit_finished_event():
+    from crewai.tools.tool_calling import ToolCalling
+
+    class FailingTool(BaseTool):
+        name: str = "Failing Tool"
+        description: str = "A tool that always fails"
+
+        def _run(self, **kwargs) -> str:
+            raise ValueError("Intentional failure")
+
+    failing_tool = FailingTool().to_structured_tool()
+
+    mock_agent = MagicMock()
+    mock_agent.key = "test_agent_key"
+    mock_agent.role = "test_agent_role"
+    mock_agent._original_role = "test_agent_role"
+    mock_agent.verbose = False
+    mock_agent.fingerprint = None
+    mock_agent.i18n.tools.return_value = {"name": "Add Image"}
+    mock_agent.i18n.errors.return_value = "Error: {error}"
+    mock_agent.i18n.slice.return_value = "Available tools: {tool_names}"
+
+    mock_task = MagicMock()
+    mock_task.delegations = 0
+    mock_task.name = "Test Task"
+    mock_task.description = "A test task"
+    mock_task.id = "test-task-id"
+
+    mock_action = MagicMock()
+    mock_action.tool = "failing_tool"
+    mock_action.tool_input = "{}"
+
+    tool_usage = ToolUsage(
+        tools_handler=MagicMock(cache=None, last_used_tool=None),
+        tools=[failing_tool],
+        task=mock_task,
+        function_calling_llm=None,
+        agent=mock_agent,
+        action=mock_action,
+    )
+
+    started_events = []
+    error_events = []
+    finished_events = []
+    error_received = threading.Event()
+
+    @crewai_event_bus.on(ToolUsageStartedEvent)
+    def on_started(source, event):
+        if event.tool_name == "failing_tool":
+            started_events.append(event)
+
+    @crewai_event_bus.on(ToolUsageErrorEvent)
+    def on_error(source, event):
+        if event.tool_name == "failing_tool":
+            error_events.append(event)
+            error_received.set()
+
+    @crewai_event_bus.on(ToolUsageFinishedEvent)
+    def on_finished(source, event):
+        if event.tool_name == "failing_tool":
+            finished_events.append(event)
+
+    tool_calling = ToolCalling(tool_name="failing_tool", arguments={})
+    tool_usage.use(calling=tool_calling, tool_string="Action: failing_tool")
+
+    assert error_received.wait(timeout=5), "Timeout waiting for error event"
+    crewai_event_bus.flush()
+
+    assert len(started_events) >= 1, "Expected at least one ToolUsageStartedEvent"
+    assert len(error_events) >= 1, "Expected at least one ToolUsageErrorEvent"
+    assert len(finished_events) == 0, (
+        "ToolUsageFinishedEvent should NOT be emitted after ToolUsageErrorEvent"
+    )