Add a pause that holds an agent after its current step

mac/Sources/Byre/Chat.swift

@@ -174,6 +174,10 @@ final class ChatModel {
         builder.open && session?.state == .running
     }
 
+    var paused: Bool {
+        liveSession?.paused ?? false
+    }
+
     var reviewing: Bool {
         let state = taskId.flatMap { store.findTask($0) }?.state
         return state == .reviewing || state == .reviewPending || state == .mergeAfterReview
@@ -559,6 +563,20 @@ final class ChatModel {
             }
         }
     }
+
+    func setPaused(_ sessionId: String, _ paused: Bool, _ overlays: Overlays) {
+        Task {
+            do {
+                if paused {
+                    _ = try await store.api.client.pauseSession(path: .init(sessionId: sessionId)).ok
+                } else {
+                    _ = try await store.api.client.resumeSession(path: .init(sessionId: sessionId)).ok
+                }
+            } catch {
+                overlays.showAlert(errorText(error))
+            }
+        }
+    }
 }
 
 struct ChatView: View {
@@ -825,6 +843,24 @@ private struct ScrollMetrics: Equatable {
     let offset: CGFloat
 }
 
+private struct PausedLine: View {
+    let running: Bool
+
+    var body: some View {
+        HStack(spacing: 6) {
+            Image(systemName: "pause.fill")
+                .font(.system(size: 10))
+            Text(running ? "Paused: finishes its current step, then holds until you resume" : "Paused: no turn starts until you resume")
+                .font(Fonts.font(13))
+        }
+        .foregroundStyle(Palette.muted)
+        .padding(.horizontal, 8)
+        .padding(.vertical, 4)
+        .background(Palette.surface, in: RoundedRectangle(cornerRadius: 6))
+        .overlay(RoundedRectangle(cornerRadius: 6).stroke(Palette.border))
+    }
+}
+
 private struct TranscriptScroll: View {
     let model: ChatModel
     @Environment(Store.self) private var store
@@ -855,6 +891,10 @@ private struct TranscriptScroll: View {
                         RowView(row: row, model: model, nested: false)
                             .padding(.top, 12)
                     }
+                    if model.paused {
+                        PausedLine(running: running)
+                            .padding(.top, 12)
+                    }
                     ForEach(model.builder.pending) { p in
                         PendingView(pending: p, model: model)
                             .padding(.top, 12)

mac/Sources/Byre/Composer.swift

@@ -527,7 +527,7 @@ struct ComposerView: View {
                 controls(m)
                     .frame(maxWidth: .infinity, alignment: .leading)
                 status
-                actions(live?.id, running: sessionState == .running)
+                actions(live?.id, running: sessionState == .running, paused: live?.paused ?? false)
                     .frame(maxWidth: .infinity, alignment: .trailing)
             }
         }
@@ -622,7 +622,7 @@ struct ComposerView: View {
         }
     }
 
-    private func actions(_ sessionId: String?, running: Bool) -> some View {
+    private func actions(_ sessionId: String?, running: Bool, paused: Bool) -> some View {
         HStack(spacing: 8) {
             Button("Interrupt") {
                 if let sessionId {
@@ -632,6 +632,19 @@ struct ComposerView: View {
             .buttonStyle(WebButtonStyle(danger: true))
             .disabled(!running)
             .fixedSize()
+            if case .task = chat.kind, !chat.team, !chat.closed {
+                Button {
+                    if let sessionId {
+                        chat.setPaused(sessionId, !paused, overlays)
+                    }
+                } label: {
+                    Image(systemName: paused ? "play.fill" : "pause.fill")
+                        .frame(width: 14, height: 14)
+                }
+                .buttonStyle(WebButtonStyle())
+                .disabled(sessionId == nil)
+                .help(paused ? "Resume the agent" : "Pause the agent after its current step")
+            }
             Button(chat.closed ? "Continue" : "Send") {
                 submit(modelState())
             }

mac/Sources/Byre/Store.swift

@@ -858,7 +858,7 @@ final class Store {
             }
             notifyTask(self, ev)
             reloadTask(ev)
-        case "session.created", "session.state", "session.subagents", "session.model":
+        case "session.created", "session.state", "session.subagents", "session.model", "session.paused":
             if ev.owner != nil {
                 reloadSessions(nil)
             } else if let taskId = ev.taskId {