Fix lint errors: Remove unused variable and fix whitespace

Co-Authored-By: João <joao@crewai.com>

src/crewai/events/event_listener.py

@@ -378,12 +378,8 @@ class EventListener(BaseEventListener):
         @crewai_event_bus.on(LLMStreamChunkEvent)
         def on_llm_stream_chunk(source, event: LLMStreamChunkEvent):
             self.text_stream.write(event.chunk)
-
             self.text_stream.seek(self.next_chunk)
-
-            # Read from the in-memory stream
-            content = self.text_stream.read()
-            print(content, end="", flush=True)
+            self.text_stream.read()
             self.next_chunk = self.text_stream.tell()
 
         # ----------- LLM GUARDRAIL EVENTS -----------

tests/utilities/test_events.py

@@ -7,10 +7,8 @@ from pydantic import Field
 from crewai.agent import Agent
 from crewai.agents.crew_agent_executor import CrewAgentExecutor
 from crewai.crew import Crew
-from crewai.flow.flow import Flow, listen, start
-from crewai.llm import LLM
-from crewai.task import Task
-from crewai.tools.base_tool import BaseTool
+from crewai.events.event_bus import crewai_event_bus
+from crewai.events.event_listener import EventListener
 from crewai.events.types.agent_events import (
     AgentExecutionCompletedEvent,
     AgentExecutionErrorEvent,
@@ -24,9 +22,6 @@ from crewai.events.types.crew_events import (
     CrewTestResultEvent,
     CrewTestStartedEvent,
 )
-from crewai.events.event_bus import crewai_event_bus
-from crewai.events.event_listener import EventListener
-from crewai.events.types.tool_usage_events import ToolUsageFinishedEvent
 from crewai.events.types.flow_events import (
     FlowCreatedEvent,
     FlowFinishedEvent,
@@ -47,7 +42,12 @@ from crewai.events.types.task_events import (
 )
 from crewai.events.types.tool_usage_events import (
     ToolUsageErrorEvent,
+    ToolUsageFinishedEvent,
 )
+from crewai.flow.flow import Flow, listen, start
+from crewai.llm import LLM
+from crewai.task import Task
+from crewai.tools.base_tool import BaseTool
 
 
 @pytest.fixture(scope="module")
@@ -991,3 +991,39 @@ def test_llm_emits_event_with_lite_agent():
 
     assert set(all_agent_roles) == {agent.role}
     assert set(all_agent_id) == {agent.id}
+
+def test_llm_stream_chunks_do_not_print_to_stdout(capsys):
+    """Test that LLM streaming chunks are not printed to stdout.
+
+    This test verifies the fix for issue #3715 where LLM stream chunks
+    were being printed directly to stdout via print() statement.
+    """
+    received_chunks = []
+
+    with crewai_event_bus.scoped_handlers():
+
+        @crewai_event_bus.on(LLMStreamChunkEvent)
+        def handle_stream_chunk(source, event):
+            received_chunks.append(event.chunk)
+
+        # Manually emit stream chunk events to simulate streaming
+        llm = LLM(model="gpt-4o", stream=True)
+
+        test_chunks = ["Hello", " ", "world", "!"]
+        for chunk in test_chunks:
+            crewai_event_bus.emit(llm, event=LLMStreamChunkEvent(chunk=chunk))
+
+        # Capture stdout
+        captured = capsys.readouterr()
+
+        # Verify that we received chunks
+        assert len(received_chunks) == len(test_chunks), "Should receive all streaming chunks"
+        assert received_chunks == test_chunks, "Chunks should match what was emitted"
+
+        # Verify that chunks were NOT printed to stdout
+        # The bug was that all chunks were being printed via print()
+        for chunk in test_chunks:
+            assert chunk not in captured.out, (
+                f"Chunk '{chunk}' should not be printed to stdout. "
+                "This indicates the bug in event_listener.py is not fixed."
+            )