diff --git a/ui/src/components/Layout.tsx b/ui/src/components/Layout.tsx
index 67faee65..76db3391 100644
--- a/ui/src/components/Layout.tsx
+++ b/ui/src/components/Layout.tsx
@@ -14,6 +14,7 @@ import { DevRestartBanner } from "./DevRestartBanner";
 import { IconRail } from "./frame/IconRail";
 import { MobileTabBar } from "./frame/MobileTabBar";
 import { TopStrip } from "./frame/TopStrip";
+import { useCommandPalette } from "../context/CommandPaletteContext";
 import { useDialog } from "../context/DialogContext";
 import { GeneralSettingsProvider } from "../context/GeneralSettingsContext";
 import { useCompany } from "../context/CompanyContext";
@@ -30,6 +31,7 @@ import { NotFoundPage } from "../pages/NotFound";
 export function Layout() {
   const { isMobile } = useSidebar();
   const { openNewIssue, openOnboarding } = useDialog();
+  const commandPalette = useCommandPalette();
   const {
     companies,
     loading: companiesLoading,
@@ -129,9 +131,10 @@ export function Layout() {
     enabled: keyboardShortcutsEnabled,
     onNewIssue: () => openNewIssue(),
     onSearch: () => {
-      // Phase 8: open the command palette via synthetic keydown, mirroring
-      // the CmdKButton shim. Phase 14 replaces with a real palette context.
-      document.dispatchEvent(new KeyboardEvent("keydown", { key: "k", metaKey: true, bubbles: true }));
+      // Phase 14: the CommandPalette is state-managed via a real context
+      // now, so we can open it directly instead of dispatching a synthetic
+      // Cmd+K keydown. The old shim is gone.
+      commandPalette.setOpen(true);
     },
   });
 
diff --git a/ui/src/components/assistant/PromoteTransition.tsx b/ui/src/components/assistant/PromoteTransition.tsx
index 7da81132..5e462a50 100644
--- a/ui/src/components/assistant/PromoteTransition.tsx
+++ b/ui/src/components/assistant/PromoteTransition.tsx
@@ -79,6 +79,22 @@ const TRANSITION_STYLE = `
     transition: none !important;
   }
 }
+/* Phase 15: on mobile the brainstormer completely covers the chat
+   instead of rendering a 30/70 split. The ribbon and source label are
+   hidden; the panel takes the full viewport height. Single 768px
+   breakpoint matches the rest of the Nexus frame. */
+@media (max-width: 767px) {
+  .nx-promote-ribbon[data-pstate="prompting"],
+  .nx-promote-ribbon[data-pstate="creating"] {
+    max-height: 0;
+    box-shadow: none;
+    overflow: hidden;
+  }
+  .nx-promote-label[data-pstate="prompting"],
+  .nx-promote-label[data-pstate="creating"] {
+    display: none;
+  }
+}
 `;
 
 export function PromoteTransition({
diff --git a/ui/src/components/frame/TopStrip.test.tsx b/ui/src/components/frame/TopStrip.test.tsx
index 3c6d06dd..a24e41e6 100644
--- a/ui/src/components/frame/TopStrip.test.tsx
+++ b/ui/src/components/frame/TopStrip.test.tsx
@@ -22,6 +22,32 @@ vi.mock("@/context/CompanyContext", () => ({
   }),
 }));
 
+// Phase 14 wired CmdKButton to CommandPaletteContext. Without a provider
+// the hook throws at render time. Stub both of the Phase 14 contexts at
+// module scope so the TopStrip renders in isolation.
+vi.mock("@/context/CommandPaletteContext", () => ({
+  useCommandPalette: () => ({
+    open: false,
+    setOpen: () => {},
+    toggle: () => {},
+  }),
+  CommandPaletteProvider: ({ children }: { children: React.ReactNode }) => children,
+}));
+
+vi.mock("@/context/VoiceContext", () => ({
+  useVoice: () => ({
+    state: "idle" as const,
+    mediaStream: null,
+    hasQueuedVoice: false,
+    queueCount: 0,
+    startListening: () => {},
+    stopListening: () => {},
+    toggleListening: () => {},
+    drainQueue: () => [],
+  }),
+  VoiceProvider: ({ children }: { children: React.ReactNode }) => children,
+}));
+
 describe("TopStrip", () => {
   let container: HTMLDivElement;
   let root: ReturnType<typeof createRoot> | null = null;