@@ -656,7 +656,7 @@
           "./locales/shell-copy.js": 1
         },
         "importSpecifiers": 2,
-        "nonTriviaTokens": 302
+        "nonTriviaTokens": 301
       },
       "src/renderer/app-shell-turn-actions.ts": {
         "importDeclarations": 4,
@@ -887,8 +887,8 @@
           "@maka/ui/icons": 1,
           "react": 1
         },
-        "importSpecifiers": 148,
-        "nonTriviaTokens": 15601
+        "importSpecifiers": 147,
+        "nonTriviaTokens": 15600
       },
       "src/renderer/use-app-shell-composer-quotes.ts": {
         "importDeclarations": 2,
 
@@ -44,8 +44,7 @@ test('removes exactly the transient messages the Host retracts while stopping',
       toastApi: { error() {} },
     });
 
-    await stop();
-
+    assert.equal(await stop(), true);
     assert.deepEqual(removed, [
       { sessionId: 'session-1', messageId: 'message-1' },
       { sessionId: 'session-1', messageId: 'message-2' },
@@ -54,3 +53,36 @@ test('removes exactly the transient messages the Host retracts while stopping',
     target.window = previousWindow;
   }
 });
+
+test('returns undefined when stop fails so plain-Enter send can abort', async () => {
+  const target = globalThis as unknown as { window?: unknown };
+  const previousWindow = target.window;
+  const errors: string[] = [];
+  target.window = {
+    maka: {
+      sessions: {
+        stop: async () => {
+          throw new Error('stop failed');
+        },
+      },
+    },
+  };
+  try {
+    const stop = createAppShellStopAction({
+      uiLocale: 'en',
+      activeIdRef: { current: 'session-1' },
+      stopPending: { claim: () => true, release: () => undefined },
+      removeTransientMessage: () => undefined,
+      toastApi: {
+        error(title) {
+          errors.push(title);
+        },
+      },
+    });
+
+    assert.equal(await stop(), undefined);
+    assert.equal(errors.length, 1);
+  } finally {
+    target.window = previousWindow;
+  }
+});
@@ -39,7 +39,7 @@ export function createAppShellStopAction(deps: {
   stopPending: SessionPendingClaim;
   removeTransientMessage: (sessionId: string, messageId: string) => void;
   toastApi: ToastApi;
-}): () => Promise<void> {
+}): () => Promise<boolean | void> {
   const {
     uiLocale,
     activeIdRef,
@@ -58,13 +58,8 @@ export function createAppShellStopAction(deps: {
           removeTransientMessage(sessionId, messageId);
         }
       }
+      return true;
     } catch (error) {
-      // The Composer wires this through both the Stop button onClick
-      // and the Escape key. Both invoke `onStop` without awaiting, so
-      // a rejected IPC would otherwise surface as an
-      // UnhandledPromiseRejection and the user would see nothing.
-      // Surface it as a toast so the user knows the model wasn't
-      // actually interrupted and can retry.
       if (activeIdRef.current === sessionId) {
         const copy = getDesktopConversationCopy(uiLocale).actions;
         toastApi.error(
 
@@ -392,14 +392,14 @@ function AppShellContent({
     reportError: reportTaskEntryError,
     manageProjects: openProjectSettings,
   });
-  // Named on its own because the rail depends on it: `taskEntry.commands` is a
-  // fresh object every render, so depending on the bag rather than the command
-  // would rebuild the rail's Project rows on every AppShell commit (#4109).
+  /* Named on its own because the rail depends on it: `taskEntry.commands` is a
+   * fresh object every render, so depending on the bag rather than the command
+   * would rebuild the rail's Project rows on every AppShell commit (#4109). */
   const { selectLocalProject } = taskEntry.commands;
   const currentNewTaskDraftKey = taskEntry.selectors.draftKey;
-  // Staged files and quotes do NOT take the target-scoped key: they belong to
-  // the composer the user is looking at, and an in-flight send needs an owner
-  // that cannot move under it. See NEW_TASK_PENDING_KEY.
+  /* Staged files and quotes do NOT take the target-scoped key: they belong to
+   * the composer the user is looking at, and an in-flight send needs an owner
+   * that cannot move under it. See NEW_TASK_PENDING_KEY. */
   const attachmentDraftKey = activeId ?? NEW_TASK_PENDING_KEY;
   const directoryHostId = activeId
     ? (activeCatalogSession?.profileKind === 'local'
@@ -437,19 +437,19 @@ function AppShellContent({
     clearQuotes,
     restoreQuotes,
   } = useAppShellComposerQuotes({ draftKey: attachmentDraftKey });
-  // Held for the whole of sendOwningItsTarget; see ChatComposerRegion.
+  /* Held for the whole of sendOwningItsTarget; see ChatComposerRegion. */
   const [newTaskSendPending, setNewTaskSendPending] = useState(false);
-  // What a new chat will start with, held the way the Session holds it: a
-  // Plan toggle and one orchestration value, not one fused choice.
+  /* What a new chat will start with, held the way the Session holds it: a
+   * Plan toggle and one orchestration value, not one fused choice. */
   const [newChatPlanModeActive, setNewChatPlanModeActive] = useState(false);
   const [newChatOrchestrationMode, setNewChatOrchestrationMode] = useState<OrchestrationMode>('default');
   const [newTaskPermissionChoice, setNewTaskPermissionChoice, clearNewTaskPermissionChoice] =
     useNewTaskChoice<ChatDefaultPermissionMode>(currentNewTaskDraftKey);
   const [historyLoadPendingSessionId, setHistoryLoadPendingSessionId] = useState<string>();
-  // The state above is what the transcript renders; this is what the guard
-  // reads. A scroller can ask twice in one task — two scroll events before
-  // React has re-rendered anything — and a state read is still the old value
-  // for both of them.
+  /* The state above is what the transcript renders; this is what the guard
+   * reads. A scroller can ask twice in one task — two scroll events before
+   * React has re-rendered anything — and a state read is still the old value
+   * for both of them. */
   const historyLoadPendingRef = useRef(false);
   const [transcriptTurnIndex, setTranscriptTurnIndex] = useState<{
     sessionId: string;
@@ -536,8 +536,8 @@ function AppShellContent({
       unsubscribe();
     };
   }, [setNavSelection]);
-  // #1985: the shell's complete read of session UI state. See the hook for why
-  // the two token-rate maps are absent.
+  /* #1985: the shell's complete read of session UI state. See the hook for why
+   * the two token-rate maps are absent. */
   const {
     messageLoadErrorBySession,
     messageRetryPendingBySession,
@@ -548,8 +548,8 @@ function AppShellContent({
     streamingSessionIds,
     activeLiveTurnSnapshot,
   } = useAppShellSessionUiReads(sessionUiController, activeId);
-  // The chat surface follows the active Session's Host. Settings and global
-  // commands remain owned by the default Host.
+  /* The chat surface follows the active Session's Host. Settings and global
+   * commands remain owned by the default Host. */
   const { memoryActive, refreshMemoryActive } = useShellMemoryPill({
     toastApi,
     uiLocale,
@@ -712,10 +712,10 @@ function AppShellContent({
   }, []);
 
   const updateReminder = updateReminderFromStatus(appUpdateStatus);
-  // Dispatches on the task, not on the raw status: the footer is this
-  // callback's only caller and it only renders for the two states above, so
-  // reading the status again here would be the same "who needs the user" list
-  // maintained twice.
+  /* Dispatches on the task, not on the raw status: the footer is this
+   * callback's only caller and it only renders for the two states above, so
+   * reading the status again here would be the same "who needs the user" list
+   * maintained twice. */
   const openUpdateDownload = useCallback(() => {
     if (updateReminder?.state === 'downloaded') {
       if (updateInstallInFlightRef.current) return;
@@ -766,9 +766,9 @@ function AppShellContent({
         );
       });
   }, [updateReminder, shellCopy, toastApi, uiLocale]);
-  // Persisted composer defaults seed the empty-state model, project path, and
-  // recent workspace history so the home view is populated before the async
-  // `app:info` round-trip completes on mount.
+  /* Persisted composer defaults seed the empty-state model, project path, and
+   * recent workspace history so the home view is populated before the async
+   * `app:info` round-trip completes on mount. */
   const persistedComposerDefaults = loadComposerDefaults();
   const [helpOpen, closeHelp, openHelp] = useKeyboardHelp();
   const [paletteOpen, openPalette, closePalette] = useCommandPalette();
@@ -1829,6 +1829,14 @@ function AppShellContent({
     });
   }
 
+  const stop = createAppShellStopAction({
+    uiLocale,
+    activeIdRef,
+    stopPending: sessionUiController.stopPending,
+    removeTransientMessage,
+    toastApi,
+  });
+
   /**
    * The send the composer calls, wrapped so the new-task target cannot move
    * out from under it (#3408). `sendCurrent` captures the draft key it
@@ -1920,8 +1928,6 @@ function AppShellContent({
       ? sessionsRef.current.find((session) => session.id === sessionId)?.runningTurnIds
       : undefined;
     const hasActiveTurn = hasActiveTurnAtSubmit({ liveTurn, runningTurnIds });
-    // Slash commands are not follow-up text for a live turn — dispatch them.
-    // Explicit Shift+Enter steer / queue still uses metadata.followUpMode.
     const followUpAtSubmit = !slashCommand ? metadata?.followUpMode : undefined;
     if (sessionId && followUpAtSubmit) {
       const queued = await enqueueFollowUp(sessionId, text, followUpAtSubmit, {
@@ -1931,32 +1937,7 @@ function AppShellContent({
       if (queued) delete retractedWorkspaceReferencesRef.current[sessionId];
       return queued;
     }
-    // Plain Enter during a live turn: interrupt first, then fall through to a
-    // new root send so the typed message stops the runaway loop (#4083).
-    // Interrupt retracts any prior queue entries, so this must precede send.
-    // Host `turn.interrupt` awaits the cancelled turn's terminal fact before
-    // resolving, so the Session lane is free for the root send below — not
-    // merely "usually fast enough" relative to settlement.
-    if (sessionId && hasActiveTurn && !slashCommand) {
-      try {
-        const stopped = await window.maka.sessions.stop(sessionId, { source: 'stop_button' });
-        if (stopped?.kind === 'interrupted') {
-          for (const messageId of stopped.retractedMessageIds) {
-            removeTransientMessage(sessionId, messageId);
-          }
-        }
-      } catch (error) {
-        if (activeIdRef.current === sessionId) {
-          const copy = getDesktopConversationCopy(uiLocale).actions;
-          showSessionError(
-            sessionId,
-            copy.operationFailedTitle,
-            localizedShellErrorMessage(error, copy.operationFailedFallback, uiLocale),
-          );
-        }
-        return false;
-      }
-    }
+    if (sessionId && hasActiveTurn && !slashCommand && !(await stop())) return false;
     if (
       revisionSend &&
       revision &&
@@ -2208,14 +2189,6 @@ function AppShellContent({
     );
   }
 
-  const stop = createAppShellStopAction({
-    uiLocale,
-    activeIdRef,
-    stopPending: sessionUiController.stopPending,
-    removeTransientMessage,
-    toastApi,
-  });
-
   const [sessionDisplayBatch] = useState(createAppShellSessionDisplayBatch);
   const {
     handleEvent,