fix: prevent zeroed data in local trace message and ensure cleanup on all paths

- Read execution start time non-destructively before _finalize_backend_batch
    consumes it, so the server receives the real duration and the local
    fallback message also shows the correct value
  - Pass pre-captured events_count, duration_ms, and batch_id to
    _show_local_trace_message instead of reading from batch_manager
    (buffer cleared by send, duration consumed by finalize)
  - Extract _reset_batch_state to reset all singleton state (current_batch,
    event_buffer, trace_batch_id, is_current_batch_ephemeral,
    backend_initialized, batch_owner_type/id) and call it in every exit
    path: success, init failure, send failure, and exception handler

lib/crewai/src/crewai/events/listeners/tracing/first_time_trace_handler.py

@@ -1,6 +1,7 @@
 import logging
 import uuid
 import webbrowser
+from datetime import datetime, timezone
 
 from rich.console import Console
 from rich.panel import Panel
@@ -105,11 +106,22 @@ class FirstTimeTraceHandler:
 
                 if not self.batch_manager.trace_batch_id:
                     self._gracefully_fail("Backend batch creation failed, cannot send events.")
+                    self._reset_batch_state()
                     return
 
                 self.batch_manager.backend_initialized = True
 
+            # Capture values before send/finalize consume them
             events_count = len(self.batch_manager.event_buffer)
+            batch_id = self.batch_manager.trace_batch_id
+            # Read duration non-destructively — _finalize_backend_batch will consume it
+            start_time = self.batch_manager.execution_start_times.get("execution")
+            duration_ms = (
+                int((datetime.now(timezone.utc) - start_time).total_seconds() * 1000)
+                if start_time
+                else 0
+            )
+
             if self.batch_manager.event_buffer:
                 send_status = self.batch_manager._send_events_to_backend()
                 if send_status == 500 and self.batch_manager.trace_batch_id:
@@ -117,25 +129,20 @@ class FirstTimeTraceHandler:
                         self.batch_manager.trace_batch_id,
                         "Error sending events to backend",
                     )
+                    self._reset_batch_state()
                     return
 
             self.batch_manager._finalize_backend_batch(events_count)
             self.ephemeral_url = self.batch_manager.ephemeral_trace_url
 
-            # Clean up batch state (mirrors finalize_batch cleanup)
-            self.batch_manager.batch_owner_type = None
-            self.batch_manager.batch_owner_id = None
-            self.batch_manager.current_batch = None
-            self.batch_manager.event_buffer.clear()
-            self.batch_manager.trace_batch_id = None
-            self.batch_manager.is_current_batch_ephemeral = False
-            self.batch_manager._cleanup_batch_data()
-
             if not self.ephemeral_url:
-                self._show_local_trace_message()
+                self._show_local_trace_message(events_count, duration_ms, batch_id)
+
+            self._reset_batch_state()
 
         except Exception as e:
             self._gracefully_fail(f"Backend initialization failed: {e}")
+            self._reset_batch_state()
 
     def _display_ephemeral_trace_link(self):
         """Display the ephemeral trace link to the user and automatically open browser."""
@@ -206,6 +213,19 @@ To enable tracing later, do any one of these:
         console.print(panel)
         console.print()
 
+    def _reset_batch_state(self):
+        """Reset batch manager state to allow future executions to re-initialize."""
+        if not self.batch_manager:
+            return
+        self.batch_manager.batch_owner_type = None
+        self.batch_manager.batch_owner_id = None
+        self.batch_manager.current_batch = None
+        self.batch_manager.event_buffer.clear()
+        self.batch_manager.trace_batch_id = None
+        self.batch_manager.is_current_batch_ephemeral = False
+        self.batch_manager.backend_initialized = False
+        self.batch_manager._cleanup_batch_data()
+
     def _gracefully_fail(self, error_message: str):
         """Handle errors gracefully without disrupting user experience."""
         console = Console()
@@ -213,7 +233,7 @@ To enable tracing later, do any one of these:
 
         logger.debug(f"First-time trace error: {error_message}")
 
-    def _show_local_trace_message(self):
+    def _show_local_trace_message(self, events_count: int = 0, duration_ms: int = 0, batch_id: str | None = None):
         """Show message when traces were collected locally but couldn't be uploaded."""
         console = Console()
 
@@ -221,9 +241,9 @@ To enable tracing later, do any one of these:
 📊 Your execution traces were collected locally!
 
 Unfortunately, we couldn't upload them to the server right now, but here's what we captured:
-• {len(self.batch_manager.event_buffer)} trace events
-• Execution duration: {self.batch_manager.calculate_duration("execution")}ms
-• Batch ID: {self.batch_manager.trace_batch_id}
+• {events_count} trace events
+• Execution duration: {duration_ms}ms
+• Batch ID: {batch_id}
 
 ✅ Tracing has been enabled for future runs!
 Your preference has been saved. Future Crew/Flow executions will automatically collect traces.

lib/crewai/tests/tracing/test_tracing.py

@@ -1242,7 +1242,7 @@ class TestFirstTimeHandlerBackendInitGuard:
         return handler, bm
 
     def test_backend_initialized_true_on_success(self):
-        """backend_initialized is True and events are sent when batch creation succeeds."""
+        """Events are sent when batch creation succeeds, then state is cleaned up."""
         handler, bm = self._make_handler_with_manager()
         server_id = "server-id-abc"
 
@@ -1252,11 +1252,11 @@ class TestFirstTimeHandlerBackendInitGuard:
         )
         mock_send_response = MagicMock(status_code=200)
 
-        trace_batch_id_after_init = None
+        trace_batch_id_during_send = None
 
         def capture_send(*args, **kwargs):
-            nonlocal trace_batch_id_after_init
-            trace_batch_id_after_init = bm.trace_batch_id
+            nonlocal trace_batch_id_during_send
+            trace_batch_id_during_send = bm.trace_batch_id
             return mock_send_response
 
         with (
@@ -1279,8 +1279,12 @@ class TestFirstTimeHandlerBackendInitGuard:
             bm.event_buffer = [MagicMock(to_dict=MagicMock(return_value={}))]
             handler._initialize_backend_and_send_events()
 
-        assert bm.backend_initialized is True
-        assert trace_batch_id_after_init == server_id
+        # trace_batch_id was set correctly during send
+        assert trace_batch_id_during_send == server_id
+        # State cleaned up after completion (singleton reuse)
+        assert bm.backend_initialized is False
+        assert bm.trace_batch_id is None
+        assert bm.current_batch is None
 
     def test_backend_initialized_false_on_failure(self):
         """backend_initialized stays False and events are NOT sent when batch creation fails."""