diff --git a/mobile/lib/features/channels/default_agent_launcher.dart b/mobile/lib/features/channels/default_agent_launcher.dart
index 6461c2c482..00600a81eb 100644
--- a/mobile/lib/features/channels/default_agent_launcher.dart
+++ b/mobile/lib/features/channels/default_agent_launcher.dart
@@ -7,6 +7,8 @@ import 'package:flutter/services.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
+import '../../shared/agents/owned_agent_directory.dart';
+import '../../shared/agents/remote_agents.dart';
 import '../../shared/me/default_agent.dart';
 import '../../shared/animated_avatar.dart';
 import '../../shared/me/me_sync.dart';
@@ -17,6 +19,8 @@ import '../../shared/widgets/agent_navigation_icon.dart';
 import '../../shared/widgets/avatar_image.dart';
 import '../../shared/widgets/preset_agent_avatar.dart';
 import '../../shared/widgets/navigation_button_surface.dart';
+import '../../shared/widgets/buzz_callout.dart';
+import 'first_agent_callout.dart';
 import 'empty_bestie_avatar.dart';
 import 'channel.dart';
 import 'channel_detail_page.dart';
@@ -36,12 +40,33 @@ class DefaultAgentLauncher extends HookConsumerWidget {
     final profile = profiles[pubkey];
     final opening = useState(false);
     final resolving = useState(false);
+    final remoteAgents = ref.watch(remoteAgentsEnabledProvider);
+    // Only someone with no agents at all is invited to make a first one.
+    // Cheap checks come first, so the rest are watched only when relevant.
+    final showCallout =
+        remoteAgents &&
+        pubkey == null &&
+        !preference.isLoading &&
+        !preference.hasError &&
+        !ref.watch(firstAgentCalloutSeenProvider) &&
+        ref
+                .watch(ownedAgentDirectoryProvider)
+                .unwrapPrevious()
+                .value
+                ?.isEmpty ==
+            true;
     useEffect(() {
       if (pubkey != null) {
         ref.read(userCacheProvider.notifier).preload([pubkey]);
       }
+      // Having a Bestie, however it was chosen, retires the tip for good.
+      if (pubkey != null &&
+          remoteAgents &&
+          !ref.read(firstAgentCalloutSeenProvider)) {
+        dismissFirstAgentCallout(ref);
+      }
       return null;
-    }, [pubkey]);
+    }, [pubkey, remoteAgents]);
     final label = pubkey != null
         ? 'Chat with ${profile?.label ?? 'your Bestie'}'
         : preference.hasError
@@ -61,6 +86,7 @@ class DefaultAgentLauncher extends HookConsumerWidget {
         return;
       }
       if (pubkey == null) {
+        if (remoteAgents) dismissFirstAgentCallout(ref);
         onChooseAgent();
         return;
       }
@@ -118,36 +144,41 @@ class DefaultAgentLauncher extends HookConsumerWidget {
       }
     }
 
-    return NavigationButtonSurface(
-      child: SizedBox.square(
-        dimension: 56,
-        child: IconButton(
-          tooltip: label,
-          padding: EdgeInsets.zero,
-          onPressed: opening.value || preference.isLoading ? null : open,
-          icon: ExcludeSemantics(
-            child: resolving.value
-                ? const SizedBox.square(
-                    dimension: 22,
-                    child: CircularProgressIndicator(strokeWidth: 2),
-                  )
-                : pubkey == null
-                ? preference.isLoading || preference.hasError
-                      ? const AgentNavigationIcon(size: 24)
-                      : const EmptyBestieAvatar()
-                : usesInsetAgentArtwork(profile?.avatarUrl)
-                ? PresetAgentAvatar(
-                    imageUrl: profile!.avatarUrl!,
-                    size: 47.88,
-                    fallback: Center(child: Text(profile.initial)),
-                  )
-                : AvatarImage(
-                    imageUrl: profile?.avatarUrl,
-                    radius: 18,
-                    isAgent: true,
-                    backgroundColor: context.controlSurface,
-                    fallback: Center(child: Text(profile?.initial ?? 'A')),
-                  ),
+    return BuzzCallout(
+      message: 'Create your first agent',
+      visible: showCallout,
+      onDismiss: () => dismissFirstAgentCallout(ref),
+      child: NavigationButtonSurface(
+        child: SizedBox.square(
+          dimension: 56,
+          child: IconButton(
+            tooltip: label,
+            padding: EdgeInsets.zero,
+            onPressed: opening.value || preference.isLoading ? null : open,
+            icon: ExcludeSemantics(
+              child: resolving.value
+                  ? const SizedBox.square(
+                      dimension: 22,
+                      child: CircularProgressIndicator(strokeWidth: 2),
+                    )
+                  : pubkey == null
+                  ? preference.isLoading || preference.hasError
+                        ? const AgentNavigationIcon(size: 24)
+                        : const EmptyBestieAvatar()
+                  : usesInsetAgentArtwork(profile?.avatarUrl)
+                  ? PresetAgentAvatar(
+                      imageUrl: profile!.avatarUrl!,
+                      size: 47.88,
+                      fallback: Center(child: Text(profile.initial)),
+                    )
+                  : AvatarImage(
+                      imageUrl: profile?.avatarUrl,
+                      radius: 18,
+                      isAgent: true,
+                      backgroundColor: context.controlSurface,
+                      fallback: Center(child: Text(profile?.initial ?? 'A')),
+                    ),
+            ),
           ),
         ),
       ),
diff --git a/mobile/lib/features/channels/first_agent_callout.dart b/mobile/lib/features/channels/first_agent_callout.dart
new file mode 100644
index 0000000000..9d111d96f9
--- /dev/null
+++ b/mobile/lib/features/channels/first_agent_callout.dart
@@ -0,0 +1,34 @@
+import 'dart:async';
+
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/me/me_sync.dart';
+import '../../shared/theme/theme_provider.dart';
+
+/// The first-agent tip is dismissed once per account and community.
+String firstAgentCalloutKey(MeSync scope) =>
+    'buzz-first-agent-callout.v1:${Uri.encodeComponent(scope.community)}:'
+    '${scope.pubkey}';
+
+/// Whether this account has already dismissed the tip in this community.
+/// Without an identity there is nothing to scope it to, so it stays hidden.
+final firstAgentCalloutSeenProvider = Provider.autoDispose<bool>((ref) {
+  final scope = ref.watch(meSyncProvider);
+  if (scope.config.nsec == null) return true;
+  return ref.watch(savedPrefsProvider).getBool(firstAgentCalloutKey(scope)) ??
+      false;
+});
+
+/// Hides the tip for good. Preferences update in memory at once, so a failed
+/// disk write only means the tip may return on the next launch.
+void dismissFirstAgentCallout(WidgetRef ref) {
+  final scope = ref.read(meSyncProvider);
+  if (scope.config.nsec == null) return;
+  unawaited(
+    ref
+        .read(savedPrefsProvider)
+        .setBool(firstAgentCalloutKey(scope), true)
+        .catchError((Object _) => false),
+  );
+  ref.invalidate(firstAgentCalloutSeenProvider);
+}
diff --git a/mobile/lib/shared/widgets/buzz_callout.dart b/mobile/lib/shared/widgets/buzz_callout.dart
new file mode 100644
index 0000000000..3ba2e31e7a
--- /dev/null
+++ b/mobile/lib/shared/widgets/buzz_callout.dart
@@ -0,0 +1,229 @@
+import 'dart:math' as math;
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+import '../theme/theme.dart';
+import 'anchored_popover_menu.dart';
+
+const _arrowHeight = Grid.xxs;
+const _arrowWidth = Grid.xs;
+const _targetGap = Grid.half;
+
+/// A non-blocking tip that points down at [child] while [visible].
+///
+/// The tip floats above everything else on the current route without a scrim,
+/// so the screen underneath stays usable. Any tap, on the tip or elsewhere,
+/// calls [onDismiss]; so does a screen reader's dismiss action. The tip hides
+/// while another route covers this one.
+class BuzzCallout extends HookWidget {
+  const BuzzCallout({
+    required this.message,
+    required this.visible,
+    required this.onDismiss,
+    required this.child,
+    super.key,
+  });
+
+  final String message;
+  final bool visible;
+  final VoidCallback onDismiss;
+  final Widget child;
+
+  @override
+  Widget build(BuildContext context) {
+    final showing = visible && (ModalRoute.of(context)?.isCurrent ?? true);
+    final controller = useMemoized(OverlayPortalController.new);
+    useEffect(() {
+      // The controller can't change during a build, so it follows a frame
+      // behind; the builder below hides the tip in the meantime.
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (!context.mounted || showing == controller.isShowing) return;
+        showing ? controller.show() : controller.hide();
+      });
+      return null;
+    }, [showing]);
+    return OverlayPortal.overlayChildLayoutBuilder(
+      controller: controller,
+      overlayChildBuilder: (context, info) {
+        if (!showing) return const SizedBox.shrink();
+        final target = MatrixUtils.transformRect(
+          info.childPaintTransform,
+          Offset.zero & info.childSize,
+        );
+        final padding = MediaQuery.paddingOf(context);
+        return _CalloutPlacement(
+          target: target,
+          margin: EdgeInsets.only(
+            left: padding.left + Grid.xs,
+            right: padding.right + Grid.xs,
+            top: padding.top + Grid.xs,
+          ),
+          // Inverse colors set the tip apart from menus and the page.
+          color: context.colors.inverseSurface,
+          shadowColor: appPopoverShadowColor(context),
+          child: TapRegion(
+            onTapInside: (_) => onDismiss(),
+            onTapOutside: (_) => onDismiss(),
+            child: Semantics(
+              container: true,
+              liveRegion: true,
+              onDismiss: onDismiss,
+              onTap: onDismiss,
+              child: Padding(
+                padding: const EdgeInsets.symmetric(
+                  horizontal: Grid.xs,
+                  vertical: Grid.twelve,
+                ),
+                child: Text(
+                  message,
+                  textAlign: TextAlign.center,
+                  style: context.textTheme.bodyMedium?.copyWith(
+                    color: context.colors.onInverseSurface,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        );
+      },
+      child: child,
+    );
+  }
+}
+
+/// Fills the overlay, placing its child above [target] inside [margin] and
+/// painting one surface for the bubble and its arrow. Only the bubble is
+/// hit-testable, so the rest of the screen keeps receiving touches.
+class _CalloutPlacement extends SingleChildRenderObjectWidget {
+  const _CalloutPlacement({
+    required this.target,
+    required this.margin,
+    required this.color,
+    required this.shadowColor,
+    required super.child,
+  });
+
+  final Rect target;
+  final EdgeInsets margin;
+  final Color color;
+  final Color shadowColor;
+
+  @override
+  _RenderCalloutPlacement createRenderObject(BuildContext context) =>
+      _RenderCalloutPlacement(target, margin, color, shadowColor);
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    _RenderCalloutPlacement renderObject,
+  ) {
+    renderObject
+      ..target = target
+      ..margin = margin
+      ..color = color
+      ..shadowColor = shadowColor;
+  }
+}
+
+class _RenderCalloutPlacement extends RenderShiftedBox {
+  _RenderCalloutPlacement(
+    this._target,
+    this._margin,
+    this._color,
+    this._shadowColor,
+  ) : super(null);
+
+  Rect _target;
+  set target(Rect value) {
+    if (value == _target) return;
+    _target = value;
+    markNeedsLayout();
+  }
+
+  EdgeInsets _margin;
+  set margin(EdgeInsets value) {
+    if (value == _margin) return;
+    _margin = value;
+    markNeedsLayout();
+  }
+
+  Color _color;
+  set color(Color value) {
+    if (value == _color) return;
+    _color = value;
+    markNeedsPaint();
+  }
+
+  Color _shadowColor;
+  set shadowColor(Color value) {
+    if (value == _shadowColor) return;
+    _shadowColor = value;
+    markNeedsPaint();
+  }
+
+  Path _path = Path();
+
+  @override
+  void performLayout() {
+    size = constraints.biggest;
+    final child = this.child;
+    if (child == null) return;
+    final bottom = _target.top - _targetGap - _arrowHeight;
+    child.layout(
+      BoxConstraints(
+        maxWidth: math.max(0, size.width - _margin.horizontal),
+        maxHeight: math.max(0, bottom - _margin.top),
+      ),
+      parentUsesSize: true,
+    );
+    final left = (_target.center.dx - child.size.width / 2)
+        .clamp(
+          _margin.left,
+          math.max(_margin.left, size.width - _margin.right - child.size.width),
+        )
+        .toDouble();
+    final offset = Offset(left, bottom - child.size.height);
+    (child.parentData! as BoxParentData).offset = offset;
+
+    final bubble = offset & child.size;
+    final radius = math.min(Radii.popover, bubble.shortestSide / 2);
+    // Keep the arrow's base clear of the rounded corners.
+    final arrowX = _target.center.dx
+        .clamp(
+          bubble.left + radius + _arrowWidth / 2,
+          math.max(
+            bubble.left + radius + _arrowWidth / 2,
+            bubble.right - radius - _arrowWidth / 2,
+          ),
+        )
+        .toDouble();
+    // One outline, so the shadow doesn't cross where the arrow joins.
+    _path = Path.combine(
+      PathOperation.union,
+      Path()
+        ..addRRect(RRect.fromRectAndRadius(bubble, Radius.circular(radius))),
+      Path()..addPolygon([
+        Offset(arrowX - _arrowWidth / 2, bubble.bottom - 1),
+        Offset(arrowX, bubble.bottom + _arrowHeight),
+        Offset(arrowX + _arrowWidth / 2, bubble.bottom - 1),
+      ], true),
+    );
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    final child = this.child;
+    if (child == null) return;
+    final path = _path.shift(offset);
+    final canvas = context.canvas;
+    canvas.drawShadow(path, _shadowColor, appPopoverElevation, _color.a < 1);
+    canvas.drawPath(path, Paint()..color = _color);
+    super.paint(context, offset);
+  }
+
+  @override
+  bool hitTest(BoxHitTestResult result, {required Offset position}) =>
+      hitTestChildren(result, position: position);
+}
diff --git a/mobile/test/features/agents/agents_sheet_test.dart b/mobile/test/features/agents/agents_sheet_test.dart
index 521b99af4c..044ff982b1 100644
--- a/mobile/test/features/agents/agents_sheet_test.dart
+++ b/mobile/test/features/agents/agents_sheet_test.dart
@@ -3,6 +3,7 @@ import 'package:buzz/shared/widgets/app_list_card.dart';
 import 'package:buzz/shared/agents/remote_agents.dart';
 import 'package:buzz/shared/me/me_sync.dart';
 import 'package:buzz/shared/me/default_agent.dart';
+import 'package:buzz/shared/theme/theme_provider.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:buzz/features/channels/default_agent_launcher.dart';
 import 'package:buzz/features/agents/agents_page.dart';
@@ -11,6 +12,7 @@ import 'package:buzz/features/profile/user_profile_sheet.dart';
 import 'package:flutter/material.dart';
 import 'package:buzz/features/home/home_page.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 import 'agents_harness.dart';
 import '../../helpers/remote_agents_fixture.dart';
@@ -37,7 +39,12 @@ void main() {
     addTearDown(tester.view.resetDevicePixelRatio);
     addTearDown(tester.platformDispatcher.clearTextScaleFactorTestValue);
     final h = await AgentsHarness.create();
-    await h.open(tester, directory: [existing, otherAgentKeys.public]);
+    final prefs = await SharedPreferences.getInstance();
+    await h.open(
+      tester,
+      directory: [existing, otherAgentKeys.public],
+      overrides: [savedPrefsProvider.overrideWithValue(prefs)],
+    );
     expect(find.byKey(ValueKey(otherAgentKeys.public)), findsNothing);
     expect(find.byKey(ValueKey(oldAppAgentKeys.public)), findsNothing);
     if (!supportsRemoteAgents(h.community)) {
@@ -270,6 +277,7 @@ void main() {
     await h.open(
       tester,
       directory: [existing],
+      overrides: [savedPrefsProvider.overrideWithValue(prefs)],
       home: HomePage(
         onAgents: showAgents,
         defaultAgentBuilder: (context) => DefaultAgentLauncher(
diff --git a/mobile/test/features/channels/default_agent_launcher_test.dart b/mobile/test/features/channels/default_agent_launcher_test.dart
index bf5904f375..7c9d8be6f8 100644
--- a/mobile/test/features/channels/default_agent_launcher_test.dart
+++ b/mobile/test/features/channels/default_agent_launcher_test.dart
@@ -10,6 +10,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:nostr/nostr.dart' as nostr;
+import 'package:shared_preferences/shared_preferences.dart';
 
 import '../../shared/me/me_sync_test.dart' show FakeRelay;
 
@@ -37,8 +38,11 @@ void main() {
       final pending = Completer<List<NostrEvent>>();
       relayB.pendingRead = pending.future;
       var choices = 0;
+      SharedPreferences.setMockInitialValues({});
+      final prefs = await SharedPreferences.getInstance();
       Widget app(MeSync scope) => ProviderScope(
         overrides: [
+          savedPrefsProvider.overrideWithValue(prefs),
           meSyncProvider.overrideWithValue(scope),
           relaySessionProvider.overrideWith(() => relayA),
         ],
diff --git a/mobile/test/features/channels/first_agent_callout_test.dart b/mobile/test/features/channels/first_agent_callout_test.dart
new file mode 100644
index 0000000000..92eaa7b1d7
--- /dev/null
+++ b/mobile/test/features/channels/first_agent_callout_test.dart
@@ -0,0 +1,223 @@
+import 'dart:async';
+import 'dart:ui' show SemanticsAction;
+
+import 'package:buzz/features/channels/default_agent_launcher.dart';
+import 'package:buzz/features/channels/first_agent_callout.dart';
+import 'package:buzz/shared/agents/owned_agent_directory.dart';
+import 'package:buzz/shared/agents/remote_agents.dart';
+import 'package:buzz/shared/me/default_agent.dart';
+import 'package:buzz/shared/me/me_sync.dart';
+import 'package:buzz/shared/relay/relay.dart';
+import 'package:buzz/shared/theme/theme.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:nostr/nostr.dart' as nostr;
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../../shared/me/me_sync_test.dart' show FakeRelay;
+
+const _tip = 'Create your first agent';
+
+void main() {
+  final nsec = nostr.Nip19.encode(
+    prefix: nostr.Nip19Prefix.nsec,
+    data: '0' * 63 + '1',
+  );
+  late SharedPreferences prefs;
+  late StreamController<String?> bestie;
+  late int choices;
+  late int otherTaps;
+
+  setUp(() async {
+    SharedPreferences.setMockInitialValues({});
+    prefs = await SharedPreferences.getInstance();
+    bestie = StreamController<String?>.broadcast();
+    choices = 0;
+    otherTaps = 0;
+  });
+  tearDown(() => bestie.close());
+
+  Future<void> pumpHome(
+    WidgetTester tester, {
+    String community = 'https://a.test',
+    bool remoteAgents = true,
+    List<OwnedAgentDirectoryEntry> owned = const [],
+    String? initialBestie,
+  }) async {
+    final relay = FakeRelay();
+    final scope = MeSync(
+      relay,
+      RelayConfig(baseUrl: community, nsec: nsec),
+      prefs: prefs,
+    );
+    await tester.pumpWidget(
+      ProviderScope(
+        // A new key per call rebuilds the providers, like a fresh launch.
+        key: UniqueKey(),
+        overrides: [
+          savedPrefsProvider.overrideWithValue(prefs),
+          meSyncProvider.overrideWithValue(scope),
+          relaySessionProvider.overrideWith(() => relay),
+          remoteAgentsEnabledProvider.overrideWithValue(remoteAgents),
+          ownedAgentDirectoryProvider.overrideWith((ref) async => owned),
+          defaultAgentProvider.overrideWith((ref) async* {
+            yield initialBestie;
+            yield* bestie.stream;
+          }),
+        ],
+        child: MaterialApp(
+          theme: AppTheme.light(),
+          home: Scaffold(
+            body: Center(
+              child: TextButton(
+                onPressed: () => otherTaps++,
+                child: const Text('Channel'),
+              ),
+            ),
+            bottomNavigationBar: Align(
+              alignment: Alignment.centerRight,
+              heightFactor: 1,
+              child: DefaultAgentLauncher(onChooseAgent: () => choices++),
+            ),
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+  }
+
+  bool seen(String community) =>
+      prefs.getBool(
+        firstAgentCalloutKey(
+          MeSync(FakeRelay(), RelayConfig(baseUrl: community, nsec: nsec)),
+        ),
+      ) ==
+      true;
+
+  testWidgets('shows above the empty Bestie slot without blocking Home', (
+    tester,
+  ) async {
+    final semantics = tester.ensureSemantics();
+    await pumpHome(tester);
+    expect(find.text(_tip), findsOneWidget);
+    expect(
+      tester.getBottomLeft(find.text(_tip)).dy,
+      lessThan(tester.getTopLeft(find.byTooltip('Bestie')).dy),
+    );
+    expect(
+      tester.getSemantics(find.text(_tip)),
+      matchesSemantics(
+        label: _tip,
+        isLiveRegion: true,
+        hasDismissAction: true,
+        hasTapAction: true,
+      ),
+    );
+    // The screen underneath still takes the tap that dismisses the tip.
+    await tester.tap(find.text('Channel'));
+    await tester.pumpAndSettle();
+    expect(otherTaps, 1);
+    expect(find.text(_tip), findsNothing);
+    expect(seen('https://a.test'), isTrue);
+    semantics.dispose();
+  });
+
+  testWidgets('activating the slot dismisses it and starts creation', (
+    tester,
+  ) async {
+    await pumpHome(tester);
+    // Screen readers and keyboards activate the slot without a touch.
+    tester
+        .widget<IconButton>(
+          find.ancestor(
+            of: find.byTooltip('Bestie'),
+            matching: find.byType(IconButton),
+          ),
+        )
+        .onPressed!();
+    await tester.pumpAndSettle();
+    expect(choices, 1);
+    expect(find.text(_tip), findsNothing);
+    expect(seen('https://a.test'), isTrue);
+  });
+
+  testWidgets('tapping the tip itself dismisses it', (tester) async {
+    await pumpHome(tester);
+    await tester.tap(find.text(_tip));
+    await tester.pumpAndSettle();
+    expect(find.text(_tip), findsNothing);
+    expect(choices, 0);
+    expect(seen('https://a.test'), isTrue);
+  });
+
+  testWidgets('a screen reader can dismiss it', (tester) async {
+    final semantics = tester.ensureSemantics();
+    await pumpHome(tester);
+    tester.semantics.performAction(
+      find.semantics.byLabel(_tip),
+      SemanticsAction.dismiss,
+    );
+    await tester.pumpAndSettle();
+    expect(find.text(_tip), findsNothing);
+    expect(seen('https://a.test'), isTrue);
+    semantics.dispose();
+  });
+
+  testWidgets('a Bestie retires it, even if the Bestie is later cleared', (
+    tester,
+  ) async {
+    await pumpHome(tester);
+    expect(find.text(_tip), findsOneWidget);
+    bestie.add('a' * 64);
+    await tester.pumpAndSettle();
+    expect(find.text(_tip), findsNothing);
+    expect(seen('https://a.test'), isTrue);
+    bestie.add(null);
+    await tester.pumpAndSettle();
+    expect(find.text(_tip), findsNothing);
+  });
+
+  testWidgets('once dismissed it never returns in that community', (
+    tester,
+  ) async {
+    await pumpHome(tester);
+    await tester.tap(find.text('Channel'));
+    await tester.pumpAndSettle();
+    await pumpHome(tester);
+    expect(find.text(_tip), findsNothing);
+    // Another community is its own first run.
+    await pumpHome(tester, community: 'https://b.test');
+    expect(find.text(_tip), findsOneWidget);
+  });
+
+  testWidgets('stays hidden for anyone who already has agents', (tester) async {
+    await pumpHome(tester, owned: [OwnedAgentDirectoryEntry(pubkey: 'b' * 64)]);
+    expect(find.text(_tip), findsNothing);
+    await pumpHome(tester, remoteAgents: false);
+    expect(find.text(_tip), findsNothing);
+    // None of these count as dismissing it.
+    await pumpHome(tester);
+    expect(find.text(_tip), findsOneWidget);
+  });
+
+  testWidgets('hides while anything covers Home, then returns', (tester) async {
+    await pumpHome(tester);
+    final navigator = tester.state<NavigatorState>(find.byType(Navigator));
+    // A sheet leaves Home painted underneath, so only the route check hides
+    // the tip there.
+    unawaited(
+      showModalBottomSheet<void>(
+        context: navigator.context,
+        builder: (_) => const Text('Sheet'),
+      ),
+    );
+    await tester.pumpAndSettle();
+    expect(find.text('Channel'), findsOneWidget);
+    expect(find.text(_tip), findsNothing);
+    navigator.pop();
+    await tester.pumpAndSettle();
+    expect(find.text(_tip), findsOneWidget);
+    expect(seen('https://a.test'), isFalse);
+  });
+}
diff --git a/mobile/test/shared/widgets/buzz_callout_test.dart b/mobile/test/shared/widgets/buzz_callout_test.dart
new file mode 100644
index 0000000000..32eb145d25
--- /dev/null
+++ b/mobile/test/shared/widgets/buzz_callout_test.dart
@@ -0,0 +1,49 @@
+import 'package:buzz/shared/theme/theme.dart';
+import 'package:buzz/shared/widgets/buzz_callout.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  for (final (width, scale) in [(320.0, 1.0), (320.0, 3.0), (1024.0, 1.0)]) {
+    testWidgets(
+      'stays on screen beside an edge target, $width wide at ${scale}x',
+      (tester) async {
+        tester.view.physicalSize = Size(width, 700);
+        tester.view.devicePixelRatio = 1;
+        tester.platformDispatcher.textScaleFactorTestValue = scale;
+        addTearDown(tester.view.reset);
+        addTearDown(tester.platformDispatcher.clearTextScaleFactorTestValue);
+        await tester.pumpWidget(
+          MaterialApp(
+            theme: AppTheme.dark(),
+            home: Scaffold(
+              body: Align(
+                alignment: Alignment.bottomRight,
+                child: BuzzCallout(
+                  message: 'A tip long enough to need room',
+                  visible: true,
+                  onDismiss: () {},
+                  child: const SizedBox.square(
+                    key: Key('target'),
+                    dimension: 56,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        );
+        await tester.pump();
+        final tip = tester.getRect(
+          find.ancestor(
+            of: find.text('A tip long enough to need room'),
+            matching: find.byType(TapRegion),
+          ),
+        );
+        final target = tester.getRect(find.byKey(const Key('target')));
+        expect(tip.right, lessThanOrEqualTo(width - Grid.xs));
+        expect(tip.left, greaterThanOrEqualTo(Grid.xs));
+        expect(tip.bottom, lessThan(target.top));
+      },
+    );
+  }
+}