diff --git a/packages/deepctl-telemetry/src/deepctl_telemetry/client.py b/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
index 5602854..516c173 100644
--- a/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
+++ b/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import atexit
 import os
 import platform
 import sys
@@ -62,6 +63,7 @@ def init_telemetry(config: Config) -> bool:
         release=f"deepctl@{cli_version}",
         environment="production",
         send_default_pii=False,
+        auto_session_tracking=True,
         traces_sample_rate=0.0,
         profiles_sample_rate=0.0,
         max_breadcrumbs=20,
@@ -76,10 +78,22 @@ def init_telemetry(config: Config) -> bool:
     )
     sentry_sdk.set_tag("cli.version", cli_version)
 
+    atexit.register(_flush_on_exit)
+
     _initialized = True
     return True
 
 
+def _flush_on_exit() -> None:
+    """Flush queued envelopes before process exit (best-effort, 2s budget)."""
+    try:
+        import sentry_sdk
+
+        sentry_sdk.flush(timeout=2.0)
+    except Exception:
+        pass
+
+
 def _read_cli_version() -> str:
     import importlib.metadata
 
diff --git a/packages/deepctl-telemetry/tests/unit/test_telemetry.py b/packages/deepctl-telemetry/tests/unit/test_telemetry.py
index 15941a9..0f50e26 100644
--- a/packages/deepctl-telemetry/tests/unit/test_telemetry.py
+++ b/packages/deepctl-telemetry/tests/unit/test_telemetry.py
@@ -2,9 +2,11 @@
 
 from __future__ import annotations
 
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
-from deepctl_telemetry import is_enabled, render_notice
+import pytest
+
+from deepctl_telemetry import init_telemetry, is_enabled, render_notice
 from deepctl_telemetry.client import DISABLE_ENV_VAR
 
 
@@ -35,3 +37,60 @@ def test_on_message(self) -> None:
     def test_off_message(self) -> None:
         notice = render_notice(_config(False))
         assert "Telemetry is off" in notice
+
+
+class TestSessionFlush:
+    """Verify init_telemetry enables session tracking and registers atexit flush."""
+
+    @pytest.fixture(autouse=True)
+    def reset_initialized(self) -> None:
+        from deepctl_telemetry import client
+
+        client._initialized = False
+        yield
+        client._initialized = False
+
+    def test_init_enables_auto_session_tracking(self) -> None:
+        with patch("deepctl_telemetry.client.atexit.register"), patch(
+            "sentry_sdk.init"
+        ) as mock_init, patch("sentry_sdk.set_tag"):
+            init_telemetry(_config(True))
+
+        assert mock_init.called
+        kwargs = mock_init.call_args.kwargs
+        assert kwargs["auto_session_tracking"] is True
+        assert kwargs["traces_sample_rate"] == 0.0
+        assert kwargs["profiles_sample_rate"] == 0.0
+
+    def test_init_registers_atexit_flush(self) -> None:
+        from deepctl_telemetry.client import _flush_on_exit
+
+        with patch(
+            "deepctl_telemetry.client.atexit.register"
+        ) as mock_register, patch("sentry_sdk.init"), patch("sentry_sdk.set_tag"):
+            init_telemetry(_config(True))
+
+        mock_register.assert_called_once_with(_flush_on_exit)
+
+    def test_disabled_does_not_register_atexit(self) -> None:
+        with patch(
+            "deepctl_telemetry.client.atexit.register"
+        ) as mock_register, patch("sentry_sdk.init") as mock_init:
+            init_telemetry(_config(False))
+
+        assert not mock_init.called
+        assert not mock_register.called
+
+    def test_flush_on_exit_calls_sentry_flush_with_2s_budget(self) -> None:
+        from deepctl_telemetry.client import _flush_on_exit
+
+        with patch("sentry_sdk.flush") as mock_flush:
+            _flush_on_exit()
+
+        mock_flush.assert_called_once_with(timeout=2.0)
+
+    def test_flush_on_exit_swallows_exceptions(self) -> None:
+        from deepctl_telemetry.client import _flush_on_exit
+
+        with patch("sentry_sdk.flush", side_effect=RuntimeError("boom")):
+            _flush_on_exit()