diff --git a/lib/dotcom_web/controllers/schedule/finder_api.ex b/lib/dotcom_web/controllers/schedule/finder_api.ex
index 30244e91d9..27cc2d4635 100644
--- a/lib/dotcom_web/controllers/schedule/finder_api.ex
+++ b/lib/dotcom_web/controllers/schedule/finder_api.ex
@@ -40,7 +40,16 @@ defmodule DotcomWeb.ScheduleController.FinderApi do
 
   # Leverage the JourneyList module to return a simplified set of trips
   @spec journeys(Plug.Conn.t(), map) :: Plug.Conn.t()
-  def journeys(conn, %{"stop" => stop_id, "date" => date} = params) do
+  def journeys(
+        conn,
+        %{
+          "stop" => stop_id,
+          "date" => date,
+          "is_current" => is_current,
+          "id" => _id,
+          "direction" => _direction
+        } = params
+      ) do
     {:ok, user_selected_date} = Date.from_iso8601(date)
     {schedules, predictions} = load_from_repos(conn, params)
 
@@ -52,7 +61,7 @@ defmodule DotcomWeb.ScheduleController.FinderApi do
     # matching the design spec architecturally better than the existing
     # Schedules-only and Predictions-only configuration for
     # ScheduleFinder.
-    today? = params["is_current"] == "true"
+    today? = is_current == "true"
     current_time = if today?, do: user_selected_date, else: nil
 
     journey_list_opts = [
@@ -68,6 +77,10 @@ defmodule DotcomWeb.ScheduleController.FinderApi do
     json(conn, journeys)
   end
 
+  def journeys(conn, _) do
+    return_invalid_arguments_error(conn)
+  end
+
   # Use alternative JourneyList constructor to only return trips with predictions
   @spec departures(Plug.Conn.t(), map) :: Plug.Conn.t()
   def departures(conn, %{"stop" => stop_id} = params) do
@@ -87,7 +100,7 @@ defmodule DotcomWeb.ScheduleController.FinderApi do
   end
 
   def departures(conn, _) do
-    ControllerHelpers.return_invalid_arguments_error(conn)
+    return_invalid_arguments_error(conn)
   end
 
   @spec get_trip_info(Plug.Conn.t(), Trip.id_t(), Route.t(), String.t(), String.t(), String.t()) ::
@@ -171,7 +184,7 @@ defmodule DotcomWeb.ScheduleController.FinderApi do
   end
 
   def trip(conn, _) do
-    ControllerHelpers.return_invalid_arguments_error(conn)
+    return_invalid_arguments_error(conn)
   end
 
   # Use internal API to generate list of relevant schedules and predictions