diff --git a/ui/src/lib/utils.test.ts b/ui/src/lib/utils.test.ts
index dd6cf96..34b1161 100644
--- a/ui/src/lib/utils.test.ts
+++ b/ui/src/lib/utils.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { statusTone, toneClasses } from './utils';
+import { statusTone, toneClasses, formatActivityMeta } from './utils';
 
 describe('statusTone', () => {
   it('returns theme-adaptive light-dark() colors', () => {
@@ -24,3 +24,19 @@ describe('toneClasses', () => {
     expect(toneClasses('neutral')).toBe('bg-surface-2 text-slate-700 border-hairline');
   });
 });
+
+describe('formatActivityMeta (backend-primary labels)', () => {
+  it('shows the physical backend as the worker with a via-proxy suffix', () => {
+    expect(formatActivityMeta('aao-gateway', 'quality', 'gpu-rtx-a'))
+      .toBe('worker: gpu-rtx-a (via aao-gateway) · mode: quality');
+  });
+
+  it('falls back to the plain worker name when no backend tag exists', () => {
+    expect(formatActivityMeta('my-worker', null, null)).toBe('worker: my-worker');
+  });
+
+  it('ignores a backend equal to the worker id (direct worker echo)', () => {
+    expect(formatActivityMeta('gpu-a', 'auto', 'gpu-a'))
+      .toBe('worker: gpu-a · mode: auto');
+  });
+});
diff --git a/ui/src/lib/utils.ts b/ui/src/lib/utils.ts
index 4a7b390..c04c3a5 100644
--- a/ui/src/lib/utils.ts
+++ b/ui/src/lib/utils.ts
@@ -120,12 +120,16 @@ export interface ActivityEvent {
 }
 
 export function formatActivityMeta(workerId: string | null, mode: string | null, backendId?: string | null): string {
-  return [
-    workerId ? `worker: ${workerPill(workerId)}` : '',
-    // Show the physical backend when it differs from the (proxy) worker name.
-    backendId && backendId !== workerId ? `backend: ${workerPill(backendId)}` : '',
-    mode ? `mode: ${mode}` : '',
-  ].filter(Boolean).join(' · ');
+  // For proxy workers (AAO gateway) the interesting name is the PHYSICAL
+  // backend behind the gateway — show it as the worker, with the proxy
+  // relegated to a "via" suffix. Lines without a backend tag (direct
+  // workers, or logs written before the backend tag existed) keep the
+  // plain worker name.
+  const hasBackend = !!backendId && backendId !== workerId;
+  const workerLabel = hasBackend
+    ? `worker: ${workerPill(backendId!)}${workerId ? ` (via ${workerId})` : ''}`
+    : workerId ? `worker: ${workerPill(workerId)}` : '';
+  return [workerLabel, mode ? `mode: ${mode}` : ''].filter(Boolean).join(' · ');
 }
 
 export function parseActivityLog(logText: string): ActivityEvent[] {
@@ -215,7 +219,7 @@ export function buildActivitySteps(events: ActivityEvent[]): Array<{ label: stri
   let currentMovement: string | null = null;
 
   for (const event of events) {
-    const meta = formatActivityMeta(event.workerId, event.mode);
+    const meta = formatActivityMeta(event.workerId, event.mode, event.backendId);
     const suffix = meta ? ` · ${meta}` : '';
 
     if (event.kind === 'movement_start') {