diff --git a/simvue/api/objects/alert/base.py b/simvue/api/objects/alert/base.py
index f22c02d8..8d1258a0 100644
--- a/simvue/api/objects/alert/base.py
+++ b/simvue/api/objects/alert/base.py
@@ -29,7 +29,19 @@ class AlertBase(SimvueObject):
 
     @override
     @classmethod
-    def new(cls, *_, **__) -> Self:
+    def new(
+        cls,
+        *,
+        name: typing.Annotated[str, pydantic.Field(pattern=NAME_REGEX)],
+        description: str | None,
+        notification: typing.Literal["none", "email"],
+        enabled: bool,
+        allow_duplicates: bool,
+        offline: bool,
+        server_url: str | None,
+        server_token: pydantic.SecretStr | None,
+        **_,
+    ) -> Self:
         raise NotImplementedError
 
     @override
@@ -42,10 +54,14 @@ def __init__(
         **kwargs,
     ) -> None:
         """Retrieve an alert from the Simvue server by identifier"""
+        _params: dict[str, str | bool] = kwargs.pop("_params", {}) | {
+            "deduplicate": not kwargs.get("allow_duplicates", True)
+        }
         super().__init__(
             identifier=identifier,
             server_url=server_url,
             server_token=server_token,
+            _params=_params,
             **kwargs,
         )
         self._local_only_args += [
@@ -211,6 +227,8 @@ def set_status(self, run_id: str, status: typing.Literal["ok", "critical"]) -> N
 
     def get_status(self, run_id: str) -> typing.Literal["ok", "critical"]:
         """Retrieve the status of this alert for a given run"""
+        _offline_run: bool = run_id.startswith("offline")
+
         if not self._offline and run_id.startswith("offline"):
             raise ValueError(
                 f"Cannot retrieve status of online alert '{self.id}' for offline run '{run_id}'"
diff --git a/simvue/api/objects/alert/events.py b/simvue/api/objects/alert/events.py
index 2833b82c..f4a504d3 100644
--- a/simvue/api/objects/alert/events.py
+++ b/simvue/api/objects/alert/events.py
@@ -81,10 +81,10 @@ def new(
         notification: typing.Literal["none", "email"],
         pattern: str,
         frequency: pydantic.PositiveInt,
-        server_url: str | None = None,
-        server_token: pydantic.SecretStr | None = None,
         enabled: bool = True,
         offline: bool = False,
+        server_url: str | None = None,
+        server_token: pydantic.SecretStr | None = None,
         **_,
     ) -> Self:
         """Create a new event-based alert
diff --git a/simvue/api/objects/alert/user.py b/simvue/api/objects/alert/user.py
index 5461d40e..3e9dedac 100644
--- a/simvue/api/objects/alert/user.py
+++ b/simvue/api/objects/alert/user.py
@@ -101,10 +101,10 @@ def new(
             enabled=enabled,
             server_url=server_url,
             server_token=server_token,
+            _params={"deduplicate": True},
             _read_only=False,
             _offline=offline,
         )
-        _alert._params = {"deduplicate": True}
         return _alert
 
     @override
diff --git a/simvue/api/objects/base.py b/simvue/api/objects/base.py
index fb979103..b3a0970e 100644
--- a/simvue/api/objects/base.py
+++ b/simvue/api/objects/base.py
@@ -185,6 +185,7 @@ def __init__(
         *,
         server_url: str | None,
         server_token: pydantic.SecretStr | None,
+        _params: dict[str, str | bool] | None = None,
         _read_only: bool = True,
         _local: bool = False,
         _user_agent: str | None = None,
@@ -231,7 +232,7 @@ def __init__(
             self._user_config.headers if not self._offline else {}
         )
 
-        self._params: dict[str, str | bool] = {}
+        self._params: dict[str, str | bool] | None = _params
 
         self._staging: dict[str, typing.Any] = {}
 
@@ -655,7 +656,7 @@ def _post_batch(
         _response = sv_post(
             url=f"{self._base_url}",
             headers=self._headers | {"Content-Type": "application/msgpack"},
-            params=self._params,
+            params=self._params or {},
             data=batch_data,
             is_json=True,
         )
@@ -694,7 +695,7 @@ def _post_single(
         _response = sv_post(
             url=f"{self._base_url}",
             headers=self._headers | {"Content-Type": "application/msgpack"},
-            params=self._params,
+            params=self._params or {},
             data=data or kwargs,
             is_json=is_json,
         )
diff --git a/simvue/api/objects/run.py b/simvue/api/objects/run.py
index 79edd31a..b4d894f8 100644
--- a/simvue/api/objects/run.py
+++ b/simvue/api/objects/run.py
@@ -795,8 +795,12 @@ def on_reconnect(self, id_mapping: dict[str, str]) -> None:
         id_mapping: dict[str, str]
             A mapping from offline identifier to online identifier.
         """
-        online_alert_ids: list[str] = list(
-            set(id_mapping.get(_id) for _id in self._staging.get("alerts", []))
+        online_alert_ids: list[str | None] = list(
+            set(
+                id_mapping.get(_id)
+                for _id in self._staging.get("alerts", [])
+                if _id.startswith("offline")
+            )
         )
         if not all(online_alert_ids):
             raise KeyError("Could not find alert ID in offline to online ID mapping.")
diff --git a/simvue/executor.py b/simvue/executor.py
index 7b7f1a9a..ff8be2fc 100644
--- a/simvue/executor.py
+++ b/simvue/executor.py
@@ -420,7 +420,10 @@ def _update_alerts(self) -> None:
                 server_url=self._runner._user_config.server.url,
                 server_token=self._runner._user_config.server.token,
             )
-            _is_set = _alert.get_status(run_id=self._runner.id)
+            _is_set: bool = False
+
+            if self._runner.mode == "online":
+                _is_set = _alert.get_status(run_id=self._runner.id) is not None
 
             if process.returncode != 0:
                 # If the process fails then purge the dispatcher event queue
@@ -431,11 +434,8 @@ def _update_alerts(self) -> None:
                     self._runner.log_alert(
                         identifier=self._alert_ids[proc_id], state="critical"
                     )
-            else:
-                if not _is_set:
-                    self._runner.log_alert(
-                        identifier=self._alert_ids[proc_id], state="ok"
-                    )
+            elif self._runner.mode == "online" and not _is_set:
+                self._runner.log_alert(identifier=self._alert_ids[proc_id], state="ok")
 
             _current_time: float = 0
             while (
diff --git a/simvue/run.py b/simvue/run.py
index 6f73531f..d4c5b06f 100644
--- a/simvue/run.py
+++ b/simvue/run.py
@@ -285,9 +285,7 @@ def __exit__(
     ) -> None:
         logger.debug(
             "Automatically closing run '%s' in status %s",
-            self.id
-            if self._user_config.run.mode == "online" and self._sv_obj
-            else "unregistered",
+            self.id if self.mode == "online" and self._sv_obj else "unregistered",
             self._status,
         )
 
@@ -301,6 +299,11 @@ def duration(self) -> float:
         """Return current run duration"""
         return time.time() - self._start_time
 
+    @property
+    def mode(self) -> typing.Literal["offline", "online", "disabled"]:
+        """Return whether this run is offline."""
+        return self._user_config.run.mode
+
     @property
     def processes(self) -> list[psutil.Process]:
         """Create an array containing a list of processes"""
@@ -500,7 +503,7 @@ def _dispatch_callback(
             if category == "events":
                 _events = Events.new(
                     run=self.id,
-                    offline=self._user_config.run.mode == "offline",
+                    offline=self.mode == "offline",
                     server_url=self._user_config.server.url,
                     server_token=self._user_config.server.token,
                     events=buffer,
@@ -512,13 +515,13 @@ def _dispatch_callback(
                     data=buffer,
                     server_url=self._user_config.server.url,
                     server_token=self._user_config.server.token,
-                    offline=self._user_config.run.mode == "offline",
+                    offline=self.mode == "offline",
                 )
                 return _grid_metrics.commit()
             else:
                 _metrics = Metrics.new(
                     run=self.id,
-                    offline=self._user_config.run.mode == "offline",
+                    offline=self.mode == "offline",
                     server_url=self._user_config.server.url,
                     server_token=self._user_config.server.token,
                     metrics=buffer,
@@ -550,7 +553,7 @@ def _start(self) -> bool:
             if self._sv_obj.status != "running":
                 self._sv_obj.status = self._status
                 _changed = True
-            if self._user_config.run.mode == "offline":
+            if self.mode == "offline":
                 self._sv_obj.started = self._start_time
                 _changed = True
             if _changed:
@@ -721,7 +724,7 @@ def init(
 
         self._folder = Folder.new(
             path=folder,
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         )
@@ -742,7 +745,7 @@ def init(
         if name and not re.match(r"^[a-zA-Z0-9\-\_\s\/\.:]+$", name):
             self._error("specified name is invalid")
             return False
-        elif not name and self._user_config.run.mode == "offline":
+        elif not name and self.mode == "offline":
             name = randomname.get_name()
 
         self._status = "running" if running else "created"
@@ -1219,7 +1222,7 @@ def config(
                         "Emissions metrics require resource metrics collection - make sure resource metrics are enabled!"
                     )
                     return False
-                if self._user_config.run.mode == "offline":
+                if self.mode == "offline":
                     # Create an emissions monitor with no API calls
                     self._emissions_monitor = CO2Monitor(
                         intensity_refresh_interval=None,
@@ -1627,7 +1630,7 @@ def assign_metric_to_grid(
                 name=grid_name,
                 grid=axes_ticks,
                 labels=axes_labels,
-                offline=self._user_config.run.mode == "offline",
+                offline=self.mode == "offline",
                 server_url=self._user_config.server.url,
                 server_token=self._user_config.server.token,
             )
@@ -1650,7 +1653,7 @@ def assign_metric_to_grid(
         try:
             _grid_attach = Grid(
                 identifier=self._grids[grid_name]["id"],
-                offline=self._user_config.run.mode == "offline",
+                offline=self.mode == "offline",
                 server_url=self._user_config.server.url,
                 server_token=self._user_config.server.token,
             )
@@ -1859,7 +1862,7 @@ def save_object(
                 allow_pickling=allow_pickle,
                 storage=self._storage_id,
                 metadata=metadata,
-                offline=self._user_config.run.mode == "offline",
+                offline=self.mode == "offline",
                 server_url=self._user_config.server.url,
                 server_token=self._user_config.server.token,
             )
@@ -1931,7 +1934,7 @@ def save_file(
                 name=name or stored_file_name,
                 storage=self._storage_id,
                 file_path=file_path,
-                offline=self._user_config.run.mode == "offline",
+                offline=self.mode == "offline",
                 mime_type=file_type,
                 metadata=metadata,
                 snapshot=snapshot,
@@ -2096,11 +2099,7 @@ def _tidy_run(self) -> None:
             self._heartbeat_termination_trigger.set()
             self._heartbeat_thread.join()
 
-        if (
-            self._sv_obj
-            and self._user_config.run.mode == "offline"
-            and self._status != "created"
-        ):
+        if self._sv_obj and self.mode == "offline" and self._status != "created":
             self._user_config.offline.cache.joinpath(
                 "runs", f"{self.id}.closed"
             ).touch()
@@ -2231,14 +2230,14 @@ def add_alerts(
         names = names or []
 
         if names and not ids:
-            if self._user_config.run.mode == "offline":
+            if self.mode == "offline":
                 self._error(
                     "Cannot retrieve alerts based on names in offline mode - please use IDs instead."
                 )
                 return False
             try:
                 if alerts := Alert.get(
-                    offline=self._user_config.run.mode == "offline",
+                    offline=self.mode == "offline",
                     server_url=self._user_config.server.url,
                     server_token=self._user_config.server.token,
                 ):
@@ -2264,7 +2263,7 @@ def _check_if_alert_exists(self, alert: "AlertBase") -> str | None:
         """Check if an existing alert matches definition."""
         # If the alert already exists just add the existing one
         for _id, _existing_alert in Alert.get(
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         ):
@@ -2348,7 +2347,7 @@ def create_metric_range_alert(
             range_low=range_low,
             range_high=range_high,
             frequency=frequency or 60,
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         )
@@ -2438,7 +2437,7 @@ def create_metric_threshold_alert(
             frequency=frequency,
             aggregation=aggregation,
             notification=notification,
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         )
@@ -2501,7 +2500,7 @@ def create_event_alert(
             pattern=pattern,
             notification=notification,
             frequency=frequency,
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         )
@@ -2561,7 +2560,7 @@ def create_user_alert(
             name=name,
             notification=notification,
             description=description,
-            offline=self._user_config.run.mode == "offline",
+            offline=self.mode == "offline",
             server_url=self._user_config.server.url,
             server_token=self._user_config.server.token,
         )
@@ -2613,7 +2612,7 @@ def log_alert(
             self._error("Please specify alert to update either by ID or by name.")
             return False
 
-        if name and self._user_config.run.mode == "offline":
+        if name and self.mode == "offline":
             self._error(
                 "Cannot retrieve alerts based on names in offline mode - please use IDs instead."
             )
@@ -2621,7 +2620,7 @@ def log_alert(
 
         if name:
             try:
-                if alerts := Alert.get(offline=self._user_config.run.mode == "offline"):
+                if alerts := Alert.get(offline=self.mode == "offline"):
                     identifier = next(
                         (id for id, alert in alerts if alert.name == name), None
                     )
diff --git a/simvue/sender/actions.py b/simvue/sender/actions.py
index bc975f46..a01949b1 100644
--- a/simvue/sender/actions.py
+++ b/simvue/sender/actions.py
@@ -725,6 +725,10 @@ def initialise_object(cls, online_id: ObjectID | None, **data) -> AlertType:
         if not online_id:
             _source: str = data["source"]
 
+            # We need to make sure the ID of an existing alert is returned
+            # the server will return 409 with an ID if this is the case
+            data["allow_duplicates"] = False
+
             if _source == "events":
                 return EventsAlert.new(**data)
             elif _source == "metrics" and data.get("threshold"):
diff --git a/tests/functional/test_run_execute_process.py b/tests/functional/test_run_execute_process.py
index 66b8a4c9..11aed318 100644
--- a/tests/functional/test_run_execute_process.py
+++ b/tests/functional/test_run_execute_process.py
@@ -25,7 +25,7 @@ def test_monitor_processes(create_plain_run_offline: tuple[Run, dict]):
         _run.add_process(f"process_2_{os.environ.get('PYTEST_XDIST_WORKER', 0)}", Command="Get-ChildItem", executable="powershell")
         _run.add_process(f"process_3_{os.environ.get('PYTEST_XDIST_WORKER', 0)}", Command="exit 0", executable="powershell")
     _sender = Sender(_run._sv_obj._local_staging_file.parents[1], 1, 10, throw_exceptions=True)
-    _sender.upload(["folders", "runs", "alerts"], )
+    _sender.upload(["folders", "alerts", "runs"], )
 
 
 @pytest.mark.executor