feat(mobile): add steer and queue messaging modes (port #2663)

Adds a per-task messaging mode toggle — Steer vs Queue — controlling what
happens when the user sends a message while a session turn is still running.

- Queue (default): messages are held locally while a turn is running and
  flushed as a single combined prompt (in order) when the turn ends.
- Steer: interrupts the running turn and resends immediately. Mobile is
  cloud-only with no native mid-turn inject, so steer maps to
  interrupt-and-resend via the existing cloud cancel command.

New state:
- messagingModeStore: persisted per-task override + global default (Queue).
- messageQueueStore: in-memory buffer with combine/drain/prepend primitives.

The composer gains a touch-friendly toggle pill showing the current mode and
the queued count; settings gains a global default. Sends emit a "Prompt sent"
analytics event carrying is_steer.

Generated-By: PostHog Code
Task-Id: 148dc71c-a24a-4b9a-a9e6-04586e782678

Author: Gilbert09

apps/mobile/src/app/settings/index.tsx

@@ -19,6 +19,10 @@ import { FloatingSettingsHeader } from "@/features/settings/components/FloatingS
 import { SettingsRow } from "@/features/settings/components/SettingsRow";
 import { SettingsSection } from "@/features/settings/components/SettingsSection";
 import { SelectSheet } from "@/features/tasks/composer/SelectSheet";
+import {
+  type MessagingMode,
+  useMessagingModeStore,
+} from "@/features/tasks/stores/messagingModeStore";
 import { playCompletionSound } from "@/features/tasks/utils/sounds";
 import { useScreenInsets } from "@/hooks/useScreenInsets";
 import { logger } from "@/lib/logger";
@@ -71,6 +75,23 @@ const TASK_MODE_OPTIONS = [
   },
 ] as const;
 
+const MESSAGING_MODE_OPTIONS: ReadonlyArray<{
+  value: MessagingMode;
+  label: string;
+  description: string;
+}> = [
+  {
+    value: "queue",
+    label: "Queue",
+    description: "Hold messages until the current turn finishes",
+  },
+  {
+    value: "steer",
+    label: "Steer",
+    description: "Interrupt the current turn and send right away",
+  },
+];
+
 const REASONING_EFFORT_OPTIONS: ReadonlyArray<{
   value: DefaultReasoningEffort;
   label: string;
@@ -111,6 +132,10 @@ function taskModeLabel(mode: InitialTaskMode): string {
   return TASK_MODE_OPTIONS.find((o) => o.value === mode)?.label ?? "Plan";
 }
 
+function messagingModeLabel(mode: MessagingMode): string {
+  return MESSAGING_MODE_OPTIONS.find((o) => o.value === mode)?.label ?? "Queue";
+}
+
 function reasoningEffortLabel(effort: DefaultReasoningEffort): string {
   return (
     REASONING_EFFORT_OPTIONS.find((o) => o.value === effort)?.label ??
@@ -161,6 +186,10 @@ export default function SettingsScreen() {
   const setDefaultReasoningEffort = usePreferencesStore(
     (s) => s.setDefaultReasoningEffort,
   );
+  const defaultMessagingMode = useMessagingModeStore((s) => s.defaultMode);
+  const setDefaultMessagingMode = useMessagingModeStore(
+    (s) => s.setDefaultMode,
+  );
   const decidedCount = useDismissedReportsStore(
     (s) => s.dismissedIds.length + s.acceptedIds.length,
   );
@@ -173,6 +202,7 @@ export default function SettingsScreen() {
   const [taskModeSheetOpen, setTaskModeSheetOpen] = useState(false);
   const [reasoningEffortSheetOpen, setReasoningEffortSheetOpen] =
     useState(false);
+  const [messagingModeSheetOpen, setMessagingModeSheetOpen] = useState(false);
   const [projectSheetOpen, setProjectSheetOpen] = useState(false);
 
   // The selected project's name. Prefer the names fetched for the scoped teams
@@ -349,7 +379,6 @@ export default function SettingsScreen() {
             label="Default effort level"
             description="Reasoning effort to pre-fill on new tasks"
             onPress={() => setReasoningEffortSheetOpen(true)}
-            showDivider={false}
             rightSlot={
               <>
                 <Text className="text-[14px] text-gray-11">
@@ -359,6 +388,20 @@ export default function SettingsScreen() {
               </>
             }
           />
+          <SettingsRow
+            label="Messaging mode"
+            description="What happens when you send while a turn is running"
+            onPress={() => setMessagingModeSheetOpen(true)}
+            showDivider={false}
+            rightSlot={
+              <>
+                <Text className="text-[14px] text-gray-11">
+                  {messagingModeLabel(defaultMessagingMode)}
+                </Text>
+                <CaretRight size={14} color={themeColors.gray[10]} />
+              </>
+            }
+          />
         </SettingsSection>
 
         {/* Integrations */}
@@ -612,6 +655,19 @@ export default function SettingsScreen() {
         }))}
       />
 
+      <SelectSheet
+        open={messagingModeSheetOpen}
+        title="Messaging mode"
+        value={defaultMessagingMode}
+        onChange={(value) => setDefaultMessagingMode(value as MessagingMode)}
+        onClose={() => setMessagingModeSheetOpen(false)}
+        options={MESSAGING_MODE_OPTIONS.map((option) => ({
+          value: option.value,
+          label: option.label,
+          description: option.description,
+        }))}
+      />
+
       <SelectSheet
         open={projectSheetOpen}
         title="Active project"

apps/mobile/src/app/task/[id].tsx

@@ -31,7 +31,13 @@ import {
   type ReasoningEffort,
 } from "@/features/tasks/composer/options";
 import { TaskChatComposer } from "@/features/tasks/composer/TaskChatComposer";
+import {
+  useMessagingMode,
+  useQueuedCount,
+  useToggleMessagingMode,
+} from "@/features/tasks/hooks/useMessagingMode";
 import { taskKeys } from "@/features/tasks/hooks/useTasks";
+import { useMessageQueueStore } from "@/features/tasks/stores/messageQueueStore";
 import {
   pendingTaskPromptStoreApi,
   usePendingTaskPrompt,
@@ -41,7 +47,11 @@ import { useTaskStore } from "@/features/tasks/stores/taskStore";
 import type { Task } from "@/features/tasks/types";
 import { getSessionActivityPhase } from "@/features/tasks/utils/sessionActivity";
 import { useScreenInsets } from "@/hooks/useScreenInsets";
-import { useActiveTaskAnalyticsContext } from "@/lib/analytics";
+import {
+  ANALYTICS_EVENTS,
+  useActiveTaskAnalyticsContext,
+  useAnalytics,
+} from "@/lib/analytics";
 import { logger } from "@/lib/logger";
 import { useThemeColors } from "@/lib/theme";
 
@@ -81,6 +91,7 @@ export default function TaskDetailScreen() {
     disconnectFromTask,
     sendPrompt,
     cancelPrompt,
+    sendInterrupting,
     sendPermissionResponse,
     setConfigOption,
     getSessionForTask,
@@ -147,6 +158,11 @@ export default function TaskDetailScreen() {
   const composerReasoning: ReasoningEffort =
     composerConfig?.reasoning ?? DEFAULT_REASONING;
 
+  const messagingMode = useMessagingMode(taskId);
+  const queuedCount = useQueuedCount(taskId);
+  const toggleMessagingMode = useToggleMessagingMode(taskId);
+  const analytics = useAnalytics();
+
   const { height } = useReanimatedKeyboardAnimation();
 
   // useReanimatedKeyboardAnimation returns negative height values
@@ -309,6 +325,20 @@ export default function TaskDetailScreen() {
     ],
   );
 
+  const trackPromptSent = useCallback(
+    (text: string, isSteer: boolean) => {
+      if (!taskId) return;
+      analytics.track(ANALYTICS_EVENTS.PROMPT_SENT, {
+        task_id: taskId,
+        is_initial: false,
+        execution_type: "cloud",
+        prompt_length_chars: text.length,
+        is_steer: isSteer,
+      });
+    },
+    [taskId, analytics],
+  );
+
   const handleSendPrompt = useCallback(
     (text: string, attachments: PendingAttachment[]) => {
       if (!taskId) return;
@@ -319,15 +349,41 @@ export default function TaskDetailScreen() {
         return;
       }
 
-      sendPrompt(taskId, text, attachments).catch((err) => {
+      const onSendFailed = (err: unknown) => {
         log.error("Failed to send prompt", err);
         Alert.alert(
           "Failed to send",
           "Your message could not be delivered. Please try again.",
         );
-      });
+      };
+
+      // A turn is running. Queue holds the message locally until it ends;
+      // Steer interrupts the turn and resends right away.
+      if (session?.isPromptPending) {
+        if (messagingMode === "queue") {
+          useMessageQueueStore.getState().enqueue(taskId, text, attachments);
+          return;
+        }
+        sendInterrupting(taskId, text, attachments)
+          .then(() => trackPromptSent(text, true))
+          .catch(onSendFailed);
+        return;
+      }
+
+      sendPrompt(taskId, text, attachments)
+        .then(() => trackPromptSent(text, false))
+        .catch(onSendFailed);
     },
-    [taskId, sendPrompt, session?.terminalStatus, handleSendAfterTerminal],
+    [
+      taskId,
+      sendPrompt,
+      sendInterrupting,
+      session?.terminalStatus,
+      session?.isPromptPending,
+      messagingMode,
+      handleSendAfterTerminal,
+      trackPromptSent,
+    ],
   );
 
   const handleModeChange = useCallback(
@@ -577,6 +633,9 @@ export default function TaskDetailScreen() {
             onModeChange={handleModeChange}
             onModelChange={handleModelChange}
             onReasoningChange={handleReasoningChange}
+            messagingMode={messagingMode}
+            queuedCount={queuedCount}
+            onToggleMessagingMode={toggleMessagingMode}
           />
         </Animated.View>
       </Animated.View>

apps/mobile/src/features/tasks/composer/TaskChatComposer.tsx

@@ -2,13 +2,15 @@ import * as Haptics from "expo-haptics";
 import {
   ArrowUp,
   BrainIcon,
+  Lightning,
   Microphone,
   PaperclipIcon,
   PauseIcon,
   PencilIcon,
   Robot,
   ShieldCheck,
   Sparkle,
+  Stack,
   Stop,
 } from "phosphor-react-native";
 import {
@@ -31,6 +33,7 @@ import {
 import { useVoiceRecording } from "@/features/chat";
 import { logger } from "@/lib/logger";
 import { useThemeColors } from "@/lib/theme";
+import type { MessagingMode } from "../stores/messagingModeStore";
 import { AttachmentSheet } from "./attachments/AttachmentSheet";
 import { AttachmentsBar } from "./attachments/AttachmentsBar";
 import {
@@ -72,6 +75,10 @@ interface TaskChatComposerProps {
   onModeChange: (mode: ExecutionMode) => void;
   onModelChange: (model: string) => void;
   onReasoningChange: (reasoning: ReasoningEffort) => void;
+  /** Steer vs Queue behaviour for messages sent while a turn is running. */
+  messagingMode: MessagingMode;
+  queuedCount: number;
+  onToggleMessagingMode: () => void;
 }
 
 function modeIcon(mode: ExecutionMode, color: string, size = 14): ReactNode {
@@ -154,6 +161,9 @@ export function TaskChatComposer({
   onModeChange,
   onModelChange,
   onReasoningChange,
+  messagingMode,
+  queuedCount,
+  onToggleMessagingMode,
 }: TaskChatComposerProps) {
   const themeColors = useThemeColors();
   const [message, setMessage] = useState(() => initialMessage ?? "");
@@ -229,6 +239,18 @@ export function TaskChatComposer({
     onStop?.();
   };
 
+  const isSteer = messagingMode === "steer";
+  const messagingModeLabel = isSteer
+    ? "Steer"
+    : queuedCount > 0
+      ? `Queue (${queuedCount})`
+      : "Queue";
+
+  const handleToggleMessagingMode = () => {
+    Haptics.selectionAsync();
+    onToggleMessagingMode();
+  };
+
   return (
     <>
       <View className="px-3">
@@ -288,6 +310,23 @@ export function TaskChatComposer({
                   paddingRight: 4,
                 }}
               >
+                <Pill
+                  icon={
+                    isSteer ? (
+                      <Lightning
+                        size={14}
+                        color={themeColors.accent[11]}
+                        weight="fill"
+                      />
+                    ) : (
+                      <Stack size={14} color={themeColors.gray[11]} />
+                    )
+                  }
+                  label={messagingModeLabel}
+                  accent={isSteer}
+                  onPress={handleToggleMessagingMode}
+                />
+
                 <Pill
                   icon={modeIcon(
                     mode,

apps/mobile/src/features/tasks/hooks/useMessagingMode.ts

@@ -0,0 +1,33 @@
+import { useCallback } from "react";
+import { useMessageQueueStore } from "../stores/messageQueueStore";
+import {
+  type MessagingMode,
+  useMessagingModeStore,
+} from "../stores/messagingModeStore";
+import { useTaskSessionStore } from "../stores/taskSessionStore";
+
+/** Effective mode for a task: per-task override, else the global default. */
+export function useMessagingMode(taskId: string | undefined): MessagingMode {
+  return useMessagingModeStore((s) => s.getEffectiveMode(taskId));
+}
+
+export function useQueuedCount(taskId: string | undefined): number {
+  return useMessageQueueStore((s) => (taskId ? s.getQueue(taskId).length : 0));
+}
+
+/**
+ * Toggle the per-task messaging mode. Switching to Steer flushes any buffered
+ * messages into the current turn so nothing stays stuck in a queue the user
+ * just turned off.
+ */
+export function useToggleMessagingMode(taskId: string | undefined): () => void {
+  const mode = useMessagingMode(taskId);
+  return useCallback(() => {
+    if (!taskId) return;
+    const next: MessagingMode = mode === "steer" ? "queue" : "steer";
+    useMessagingModeStore.getState().setMode(taskId, next);
+    if (next === "steer") {
+      void useTaskSessionStore.getState().flushQueuedMessages(taskId);
+    }
+  }, [taskId, mode]);
+}