diff --git a/packages/deepctl-telemetry/src/deepctl_telemetry/client.py b/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
index 516c173..ecfb8d5 100644
--- a/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
+++ b/packages/deepctl-telemetry/src/deepctl_telemetry/client.py
@@ -78,6 +78,7 @@ def init_telemetry(config: Config) -> bool:
     )
     sentry_sdk.set_tag("cli.version", cli_version)
 
+    sentry_sdk.start_session()
     atexit.register(_flush_on_exit)
 
     _initialized = True
diff --git a/packages/deepctl-telemetry/tests/unit/test_telemetry.py b/packages/deepctl-telemetry/tests/unit/test_telemetry.py
index 0f50e26..01c2915 100644
--- a/packages/deepctl-telemetry/tests/unit/test_telemetry.py
+++ b/packages/deepctl-telemetry/tests/unit/test_telemetry.py
@@ -53,7 +53,9 @@ def reset_initialized(self) -> None:
     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"):
+        ) as mock_init, patch("sentry_sdk.set_tag"), patch(
+            "sentry_sdk.start_session"
+        ):
             init_telemetry(_config(True))
 
         assert mock_init.called
@@ -61,17 +63,28 @@ def test_init_enables_auto_session_tracking(self) -> None:
         assert kwargs["auto_session_tracking"] is True
         assert kwargs["traces_sample_rate"] == 0.0
         assert kwargs["profiles_sample_rate"] == 0.0
+        assert "session_mode" not in kwargs
 
     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"):
+        ) as mock_register, patch("sentry_sdk.init"), patch(
+            "sentry_sdk.set_tag"
+        ), patch("sentry_sdk.start_session"):
             init_telemetry(_config(True))
 
         mock_register.assert_called_once_with(_flush_on_exit)
 
+    def test_init_starts_session(self) -> None:
+        with patch("sentry_sdk.init"), patch("sentry_sdk.set_tag"), patch(
+            "deepctl_telemetry.client.atexit.register"
+        ), patch("sentry_sdk.start_session") as mock_start:
+            init_telemetry(_config(True))
+
+        mock_start.assert_called_once_with()
+
     def test_disabled_does_not_register_atexit(self) -> None:
         with patch(
             "deepctl_telemetry.client.atexit.register"