Show an interrupt control for working chat turns

src/Capacitor.App/ViewModels/ChatTabViewModel.cs

@@ -394,6 +394,9 @@ public IReadOnlyList<TerminalMenuChoiceViewModel> TerminalMenuChoices {
     /// hides them and leaves the hint — a greyed empty box is the wrong affordance.
     public bool ShowsComposer => _showsComposer.Value;
 
+    readonly ObservableAsPropertyHelper<bool> _showsInterrupt;
+    public bool ShowsInterrupt => _showsInterrupt.Value;
+
     string _vendor = "";
     IReadOnlyList<HarnessOption> _options = HostedHarnessCatalog.Build(null);
 
@@ -670,6 +673,18 @@ public ChatTabViewModel(
             })
             .DisposeWith(_disposables);
 
+        _showsInterrupt = Observable.CombineLatest(
+                _input.WhenAnyValue(i => i.CanInterrupt),
+                this.WhenAnyValue(x => x.IsReadOnlyParticipant),
+                this.WhenAnyValue(x => x.HasTerminalMenu),
+                this.WhenAnyValue(x => x.AgentStatus),
+                (can, readOnly, menu, status) => can && !readOnly && !menu
+                    && (status.Kind == AgentStatusKind.Working || status.IsRunningUnknownTurn))
+            .ToProperty(this, x => x.ShowsInterrupt,
+                initialValue: _input.CanInterrupt && !IsReadOnlyParticipant && !HasTerminalMenu
+                    && (AgentStatus.Kind == AgentStatusKind.Working || AgentStatus.IsRunningUnknownTurn))
+            .DisposeWith(_disposables);
+
         // The banner carries the read-only explanation for a flow participant, so the hint
         // goes blank there instead of offering a reply that can never be sent.
         _composerHint = Observable.CombineLatest(
@@ -783,11 +798,8 @@ public ChatTabViewModel(
         });
         _disposables.Add(SendQueuedCommand);
 
-        var canInterrupt = Observable.CombineLatest(
-            _input.WhenAnyValue(i => i.CanInterrupt),
-            this.WhenAnyValue(x => x.IsReadOnlyParticipant),
-            (can, readOnly) => can && !readOnly);
-        InterruptCommand = ReactiveCommand.CreateFromTask(() => _input.InterruptAsync(_lifetimeToken), canInterrupt);
+        InterruptCommand = ReactiveCommand.CreateFromTask(
+            () => _input.InterruptAsync(_lifetimeToken), this.WhenAnyValue(x => x.ShowsInterrupt));
         _disposables.Add(InterruptCommand);
 
         OpenLinkCommand = ReactiveCommand.Create<string>(url => LinkPolicy.Open(_opener, url));

src/Capacitor.App/Views/ChatTabView.axaml

@@ -433,7 +433,7 @@
                             <TextBlock Text="{Binding ReadOnlyNotice, StringFormat='Read-only: {0}'}"
                                        Foreground="{StaticResource KcapWarningBrush}" TextWrapping="Wrap" />
                         </Border>
-                        <Grid ColumnDefinitions="Auto,*,Auto">
+                        <Grid ColumnDefinitions="Auto,*,Auto,Auto">
                             <!-- The hint exists only while the gate is shut, which is exactly when a tooltip
                                  is suppressed by default. -->
                             <Button x:Name="AttachButton" IsVisible="{Binding ShowsComposer}"
@@ -447,7 +447,12 @@
                             </Button>
                             <TextBlock Grid.Column="1" Text="{Binding ComposerHint}" FontSize="12.5" Foreground="{StaticResource KcapFaintBrush}"
                                        VerticalAlignment="Center" TextTrimming="CharacterEllipsis" />
-                            <Button x:Name="SendButton" Grid.Column="2" Classes="kcapPrimary" Content="Send" Command="{Binding SendCommand}" Margin="12,0,0,0"
+                            <Button x:Name="InterruptButton" Grid.Column="2" Classes="kcapChip" Content="Interrupt (Esc)"
+                                    Command="{Binding InterruptCommand}" IsVisible="{Binding ShowsInterrupt}"
+                                    ToolTip.Tip="Interrupt the current turn without ending the session" Margin="12,0,0,0"
+                                    BorderThickness="1" Height="24" Padding="10,0" VerticalContentAlignment="Center"
+                                    FontSize="13" FontWeight="SemiBold" CornerRadius="7" Cursor="Hand" />
+                            <Button x:Name="SendButton" Grid.Column="3" Classes="kcapPrimary" Content="Send" Command="{Binding SendCommand}" Margin="8,0,0,0"
                                     Height="24" Padding="12,0" VerticalContentAlignment="Center" FontSize="13" FontWeight="SemiBold" CornerRadius="7"
                                     Background="{StaticResource KcapPrimaryBrush}" Foreground="{StaticResource KcapOnPrimaryBrush}"
                                     IsVisible="{Binding ShowsComposer}" />

src/Capacitor.App/Views/ChatTabView.axaml.cs

@@ -418,8 +418,7 @@ bool ListTextBoxOwnsFocus() {
     void OnComposerKeyDown(object? sender, KeyEventArgs e) {
         if (e.Key == Key.Escape && e.KeyModifiers == KeyModifiers.None) {
             e.Handled = true;
-            if (DataContext is ChatTabViewModel chat && ((ICommand)chat.InterruptCommand).CanExecute(null))
-                chat.InterruptCommand.Execute().Subscribe();
+            TryInterrupt();
             return;
         }
         if (e.Key is Key.Up or Key.Down && e.KeyModifiers == KeyModifiers.None) {
@@ -437,5 +436,17 @@ void OnComposerKeyDown(object? sender, KeyEventArgs e) {
             vm.SendCommand.Execute().Subscribe();
     }
 
+    protected override void OnKeyDown(KeyEventArgs e) {
+        base.OnKeyDown(e);
+        if (e.Handled || e.Key != Key.Escape || e.KeyModifiers != KeyModifiers.None || OriginatesFromPendingCard(e)) return;
+        if (TryInterrupt()) e.Handled = true;
+    }
+
+    bool TryInterrupt() {
+        if (DataContext is not ChatTabViewModel chat || !((ICommand)chat.InterruptCommand).CanExecute(null)) return false;
+        chat.InterruptCommand.Execute().Subscribe();
+        return true;
+    }
+
     public void FocusComposer() => ComposerInput.Focus();
 }

test/Capacitor.App.Tests.Unit/ChatComposerTests.cs

@@ -1,7 +1,10 @@
 using System.Reactive.Linq;
+using Avalonia.Controls;
+using Avalonia.Input;
 using Avalonia.Threading;
 using Capacitor.App.Services;
 using Capacitor.App.ViewModels;
+using Capacitor.App.Views;
 using Capacitor.Cli.Core;
 using Capacitor.Cli.Core.LocalIpc;
 using DynamicData;
@@ -13,14 +16,14 @@ namespace Capacitor.App.Tests.Unit;
 
 public class ChatComposerTests {
     static async Task<(FakeDaemonClientService Daemon, FakeTimeProvider Time, TerminalTabViewModel Terminal, ChatTabViewModel Chat, FakeTerminalAttachClient Client, RecordingOpener Opener)>
-            BuildAttachedAsync() {
+            BuildAttachedAsync(FakePermissionService? permissions = null) {
         var daemon = new FakeDaemonClientService();
         var factory = new FakeTerminalAttachClientFactory();
         var time = new FakeTimeProvider();
         var opener = new RecordingOpener();
         var terminal = new TerminalTabViewModel("a1", daemon, factory.Factory, () => new FakeTerminalSurface(), time);
         var chat = new ChatTabViewModel(
-            "a1", daemon, new TerminalChatInput(terminal, "a1", daemon, new ScriptedLocalControlOps(), Observable.Never<AgentPresence>()), new NoAttachmentUploader(), TranscriptChat.For("claude"), opener, time, new FakePermissionService(), new SessionRuns(time));
+            "a1", daemon, new TerminalChatInput(terminal, "a1", daemon, new ScriptedLocalControlOps(), Observable.Never<AgentPresence>()), new NoAttachmentUploader(), TranscriptChat.For("claude"), opener, time, permissions ?? new FakePermissionService(), new SessionRuns(time));
         daemon.SnapshotsSubject.OnNext(FakeDaemonClientService.Snap(supportedVendors: ["claude", "codex"]));
         daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true, repoPath: "/repo", model: "claude-opus-5") with { Status = "Running" });
         // The Avalonia scheduler always posts, even when the caller is already on the UI thread,
@@ -94,9 +97,13 @@ await RunOnUiAsync(async () => {
             await Assert.That(chat.VendorLabel).IsEqualTo("Claude Code");
             await Assert.That(chat.ComposerHint).IsEqualTo("Enter sends · Shift+Enter for a new line");
 
+            daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true) with { Status = "Running", AwaitingInput = false });
+            await Assert.That(chat.ShowsInterrupt).IsTrue();
             client.Result.SetResult(new AttachOutcome.Detached());
             await terminal.CurrentRunForTesting!;
             await Assert.That(chat.ComposerHint).IsEqualTo("Reattach the terminal to send");
+            await Assert.That(chat.ShowsInterrupt).IsFalse();
+            await Assert.That(await chat.InterruptCommand.CanExecute.FirstAsync()).IsFalse();
 
             // Only the run's own Exited/Failed verdict outranks a cache removal, so a removal after
             // a detach lands SessionEnded — and the hint follows the terminal there too.
@@ -233,4 +240,117 @@ public async Task A_pool_thread_state_flip_updates_the_hint_on_the_ui_thread() {
         });
         await Assert.That(onUi).IsTrue();
     }
+
+    [Test]
+    [NotInParallel("AvaloniaSession")]
+    public async Task Working_turn_surfaces_interrupt_and_escape_from_chat_list_preserves_the_draft() {
+        await RunOnUiAsync(async () => {
+            var (daemon, _, _, chat, client, _) = await BuildAttachedAsync();
+            daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true, repoPath: "/repo") with { Status = "Running", AwaitingInput = true });
+            var view = new ChatTabView { DataContext = chat };
+            var window = new Window { Content = view, Width = 550, Height = 600 };
+            try {
+                window.Show();
+                Dispatcher.UIThread.RunJobs();
+                window.UpdateLayout();
+
+                var interruptButton = view.FindControl<Button>("InterruptButton")!;
+                var chatItems = view.FindControl<ItemsControl>("ChatItems")!;
+
+                await Assert.That(chat.ShowsInterrupt).IsFalse();
+                await Assert.That(interruptButton.IsEffectivelyVisible).IsFalse();
+                await Assert.That(chat.ComposerHint).IsEqualTo("Enter sends · Shift+Enter for a new line");
+
+                daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true, repoPath: "/repo") with { Status = "Running", AwaitingInput = false });
+                Dispatcher.UIThread.RunJobs();
+                window.UpdateLayout();
+
+                await Assert.That(chat.ShowsInterrupt).IsTrue();
+                await Assert.That(interruptButton.IsEffectivelyVisible).IsTrue();
+                await Assert.That(await chat.InterruptCommand.CanExecute.FirstAsync()).IsTrue();
+                chat.ComposerText = "keep this draft";
+                chatItems.RaiseEvent(new KeyEventArgs { RoutedEvent = InputElement.KeyDownEvent, Key = Key.Escape, KeyModifiers = KeyModifiers.Control });
+                await Assert.That(client.SentInput).IsEmpty();
+
+                chatItems.RaiseEvent(new KeyEventArgs { RoutedEvent = InputElement.KeyDownEvent, Key = Key.Escape });
+                await WaitUntilAsync(() => client.SentInput.Count == 1, what: "escape sent from chat list");
+                await Assert.That(client.SentInput[0]).IsEquivalentTo(new byte[] { 0x1b });
+                await Assert.That(chat.ComposerText).IsEqualTo("keep this draft");
+
+                daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true, repoPath: "/repo") with { Status = "Running", AwaitingInput = true });
+                Dispatcher.UIThread.RunJobs();
+                window.UpdateLayout();
+
+                await Assert.That(chat.ShowsInterrupt).IsFalse();
+                await Assert.That(interruptButton.IsEffectivelyVisible).IsFalse();
+                await Assert.That(chat.ComposerHint).IsEqualTo("Enter sends · Shift+Enter for a new line");
+
+            } finally {
+                window.Close();
+                Dispatcher.UIThread.RunJobs();
+                await chat.TeardownAsync();
+            }
+        });
+    }
+
+    [Test]
+    [Arguments(false)]
+    [Arguments(true)]
+    [NotInParallel("AvaloniaSession")]
+    public async Task Escape_does_not_interrupt_a_turn_awaiting_input(bool composer) {
+        await RunOnUiAsync(async () => {
+            var (daemon, _, _, chat, client, _) = await BuildAttachedAsync();
+            var view = new ChatTabView { DataContext = chat };
+            var window = new Window { Content = view, Width = 800, Height = 600 };
+            try {
+                daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true, repoPath: "/repo") with { Status = "Running", AwaitingInput = true });
+                window.Show();
+                Dispatcher.UIThread.RunJobs();
+                window.UpdateLayout();
+                await Assert.That(chat.ShowsInterrupt).IsFalse();
+                await Assert.That(await chat.InterruptCommand.CanExecute.FirstAsync()).IsFalse();
+                chat.ComposerText = "keep this draft";
+                var source = view.FindControl<Control>(composer ? "ComposerInput" : "ChatItems")!;
+                source.RaiseEvent(new KeyEventArgs { RoutedEvent = InputElement.KeyDownEvent, Key = Key.Escape });
+                Dispatcher.UIThread.RunJobs();
+                await Assert.That(client.SentInput).IsEmpty();
+                await Assert.That(chat.ComposerText).IsEqualTo("keep this draft");
+            } finally {
+                window.Close();
+                Dispatcher.UIThread.RunJobs();
+                await chat.TeardownAsync();
+            }
+        });
+    }
+
+    [Test]
+    [Arguments("permission")]
+    [Arguments("question")]
+    [Arguments("menu")]
+    [Arguments("limit")]
+    [NotInParallel("AvaloniaSession")]
+    public async Task Interrupt_is_unavailable_while_a_prompt_or_menu_needs_a_response(string prompt) {
+        await RunOnUiAsync(async () => {
+            var permissions = new FakePermissionService();
+            var (daemon, _, _, chat, _, _) = await BuildAttachedAsync(permissions);
+            try {
+                var agent = Agent("a1", "claude", hasTerminal: true) with { Status = "Running", AwaitingInput = false };
+                daemon.Agents.AddOrUpdate(agent);
+                await Assert.That(chat.ShowsInterrupt).IsTrue();
+                switch (prompt) {
+                    case "permission": permissions.Add(PermissionEntries.Entry("r1", "a1")); break;
+                    case "question": permissions.Add(PermissionEntries.Question("r1")); break;
+                    case "menu":
+                        daemon.Agents.AddOrUpdate(agent with { TerminalDialog = new TerminalDialogDto("Continue?", "", ["Yes", "No"], 0, "") });
+                        break;
+                    case "limit":
+                        daemon.Agents.AddOrUpdate(agent with { UsageLimit = new UsageLimitNoticeDto(UsageLimitKinds.Blocked, "Usage limit", "Continue?", [new(1, "Wait")]) });
+                        break;
+                }
+                Dispatcher.UIThread.RunJobs();
+                await Assert.That(chat.ShowsInterrupt).IsFalse();
+                await Assert.That(await chat.InterruptCommand.CanExecute.FirstAsync()).IsFalse();
+            } finally { await chat.TeardownAsync(); }
+        });
+    }
 }

test/Capacitor.App.Tests.Unit/ChatTabViewSmokeTests.cs

@@ -693,18 +693,29 @@ await Assert.That(client.SentInput.Select(Encoding.UTF8.GetString))
     }
 
     [Test]
+    [Arguments(false)]
+    [Arguments(true)]
     [NotInParallel("AvaloniaSession")]
-    public async Task Escape_from_the_composer_sends_a_control_key_and_preserves_the_draft() {
+    public async Task Interrupt_from_the_button_or_composer_preserves_the_draft_and_staged_files(bool button) {
         await RunOnUiAsync(async () => {
-            var host = new Host();
-            var client = await host.AttachAsync(Tmp.CreateFile("escape.jsonl", [UserLine]));
-            host.Type("keep this draft");
-            host.Window.KeyPressQwerty(PhysicalKey.Escape, RawInputModifiers.None);
-            host.Settle();
-            await Assert.That(client.SentInput).Count().IsEqualTo(1);
-            await Assert.That(client.SentInput[0]).IsEquivalentTo(new byte[] { 0x1b });
-            await Assert.That(host.Composer.Text).IsEqualTo("keep this draft");
-            await host.CloseAsync();
+            var host = new Host(show: false);
+            host.Window.Width = 550;
+            host.Show();
+            try {
+                var path = Tmp.CreateFile("escape.jsonl", [UserLine]);
+                var client = await host.AttachAsync(path);
+                host.Daemon.Agents.AddOrUpdate(Agent("a1", "claude", hasTerminal: true) with { TranscriptPath = path, Status = "Running", AwaitingInput = false });
+                host.Type("keep this draft");
+                host.Chat.Tray.AddAll([new StagedAttachment("notes.txt", "text/plain", new byte[] { 1 })]);
+                if (button) Click(host, host.View.FindControl<Button>("InterruptButton")!);
+                else host.Window.KeyPressQwerty(PhysicalKey.Escape, RawInputModifiers.None);
+                host.Settle();
+                await Assert.That(client.SentInput).Count().IsEqualTo(1);
+                await Assert.That(client.SentInput[0]).IsEquivalentTo(new byte[] { 0x1b });
+                await Assert.That(host.Composer.Text).IsEqualTo("keep this draft");
+                await Assert.That(host.Chat.Tray.Items.Select(f => f.FileName)).IsEquivalentTo(["notes.txt"]);
+                await Assert.That(host.Chat.ShowsComposer).IsTrue();
+            } finally { await host.CloseAsync(); }
         });
     }