Mobile session cost + per-message model

apps/mobile/src/components/agents/active-now-section.test.ts

@@ -179,7 +179,7 @@ vi.mock('react-native-reanimated', () => ({
   LinearTransition: { duration: () => ({}) },
   useReducedMotion: () => true,
 }));
-vi.mock('@/components/agents/session-row', () => ({
+vi.mock('@/components/agents/remote-session-row', () => ({
   RemoteSessionRow: 'RemoteSessionRow',
 }));
 vi.mock('@/components/agents/session-list-section-header', () => ({

apps/mobile/src/components/agents/active-now-section.tsx

@@ -7,7 +7,7 @@ import Animated, {
   useReducedMotion,
 } from 'react-native-reanimated';
 
-import { RemoteSessionRow } from '@/components/agents/session-row';
+import { RemoteSessionRow } from '@/components/agents/remote-session-row';
 import { SessionListSectionHeader } from '@/components/agents/session-list-section-header';
 import { ACTIVE_NOW_TRAY_CAP, selectTrayWindow } from '@/components/agents/active-now-window';
 import { Text } from '@/components/ui/text';

apps/mobile/src/components/agents/context-usage-display.test.ts

@@ -230,7 +230,7 @@ describe('getContextSheetContent', () => {
     expect(content.percentage).toBe('125%');
     expect(content.remainingTokens).toBe('0');
     expect(content.remainingPercentage).toBe('0%');
-    expect(content.cost).toBeNull();
+    expect(content.cost).toBe('$0.0000');
     expect(content.tone).toBe('destructive');
   });
 
@@ -244,14 +244,14 @@ describe('getContextSheetContent', () => {
     expect(content.windowUnavailable).toBe(true);
     expect(content.percentage).toBeNull();
     expect(content.remainingTokens).toBeNull();
-    expect(content.cost).toBeNull();
+    expect(content.cost).toBe('$0.0000');
     expect(content.windowUnavailableLabel).toBe('Context-window size unavailable');
     expect(content.tone).toBe('neutral');
   });
 
-  it('omits the cost line when total cost is zero', () => {
+  it('shows the cost line as $0.0000 when total cost is zero', () => {
     const content = getContextSheetContent(info({ percentage: 20 }), 0);
-    expect(content.cost).toBeNull();
+    expect(content.cost).toBe('$0.0000');
   });
 });
 

apps/mobile/src/components/agents/context-usage-display.ts

@@ -114,7 +114,7 @@ type ContextSheetContent = {
   percentage: string | null;
   remainingTokens: string | null;
   remainingPercentage: string | null;
-  cost: string | null;
+  cost: string;
   tone: ContextTone;
 };
 
@@ -124,7 +124,7 @@ export function getContextSheetContent(
 ): ContextSheetContent {
   const tone = getContextTone(info.percentage);
   const usedTokens = formatExactTokens(info.contextTokens);
-  const cost = totalCost > 0 ? formatCost(totalCost) : null;
+  const cost = formatCost(totalCost);
   if (info.contextWindow === undefined) {
     return {
       usedTokens,

apps/mobile/src/components/agents/message-bubble.tsx

@@ -24,6 +24,13 @@ type MessageBubbleProps = {
   onOpenChildSession?: OpenChildSession;
   /** Per-user-message delivery state. v1 surfaces only a "Queued" badge. */
   deliveryState?: MessageDeliveryState;
+  /**
+   * Subtle model label for an assistant message, precomputed by the parent
+   * via `computeMessageModelLabels`. Only the assistant branch renders it
+   * (and only when truthy); the user branch and the unlabelled
+   * same-model follow-ups render nothing.
+   */
+  modelLabel?: string;
 };
 
 export function MessageBubble({
@@ -34,6 +41,7 @@ export function MessageBubble({
   defaultReasoningExpanded,
   onOpenChildSession,
   deliveryState,
+  modelLabel,
 }: Readonly<MessageBubbleProps>) {
   const isUser = message.info.role === 'user';
   const { copyMessage } = useMessageCopy();
@@ -131,6 +139,15 @@ export function MessageBubble({
             onOpenChildSession={onOpenChildSession}
           />
         ))}
+        {modelLabel ? (
+          <Text
+            className="text-xs text-muted-foreground"
+            accessibilityRole="text"
+            accessibilityLabel={`Model: ${modelLabel}`}
+          >
+            {modelLabel}
+          </Text>
+        ) : null}
       </View>
     </Pressable>
   );