fix: keep chat pinned on stream

CHANGELOG.md

@@ -31,6 +31,7 @@ Docs: https://docs.clawd.bot
 - Models: inherit session model overrides in thread/topic sessions (Telegram topics, Slack/Discord threads). (#1376)
 - macOS: keep local auto bind loopback-first; only use tailnet when bind=tailnet.
 - macOS: include Textual syntax highlighting resources in packaged app to prevent chat crashes. (#1362)
+- macOS: keep chat pinned to bottom during streaming replies. (#1279)
 - Cron: cap reminder context history to 10 messages and honor `contextMessages`. (#1103) Thanks @mkbehr.
 - Exec approvals: treat main as the default agent + migrate legacy default allowlists. (#1417) Thanks @czekaj.
 - Exec: avoid defaulting to elevated mode when elevated is not allowed.

apps/shared/ClawdbotKit/Sources/ClawdbotChatUI/ChatView.swift

@@ -12,6 +12,7 @@ public struct ClawdbotChatView: View {
     @State private var scrollPosition: UUID?
     @State private var showSessions = false
     @State private var hasPerformedInitialScroll = false
+    @State private var isPinnedToBottom = true
     private let showsSessionSwitcher: Bool
     private let style: Style
     private let markdownVariant: ChatMarkdownVariant
@@ -87,36 +88,28 @@ public struct ClawdbotChatView: View {
     private var messageList: some View {
         ZStack {
             ScrollView {
+                LazyVStack(spacing: Layout.messageSpacing) {
+                    self.messageListRows
+
+                    Color.clear
                         #if os(macOS)
-                VStack(spacing: 0) {
-                    LazyVStack(spacing: Layout.messageSpacing) {
-                        self.messageListRows
-                    }
-
-                    Color.clear
                         .frame(height: Layout.messageListPaddingBottom)
-                        .id(self.scrollerBottomID)
-                }
-                // Use scroll targets for stable auto-scroll without ScrollViewReader relayout glitches.
-                .scrollTargetLayout()
-                .padding(.top, Layout.messageListPaddingTop)
-                .padding(.horizontal, Layout.messageListPaddingHorizontal)
                         #else
-                LazyVStack(spacing: Layout.messageSpacing) {
-                    self.messageListRows
-
-                    Color.clear
                         .frame(height: Layout.messageListPaddingBottom + 1)
+                        #endif
                         .id(self.scrollerBottomID)
                 }
                 // Use scroll targets for stable auto-scroll without ScrollViewReader relayout glitches.
                 .scrollTargetLayout()
                 .padding(.top, Layout.messageListPaddingTop)
                 .padding(.horizontal, Layout.messageListPaddingHorizontal)
-                #endif
             }
             // Keep the scroll pinned to the bottom for new messages.
             .scrollPosition(id: self.$scrollPosition, anchor: .bottom)
+            .onChange(of: self.scrollPosition) { _, position in
+                guard let position else { return }
+                self.isPinnedToBottom = position == self.scrollerBottomID
+            }
 
             if self.viewModel.isLoading {
                 ProgressView()
@@ -133,18 +126,26 @@ public struct ClawdbotChatView: View {
             guard !isLoading, !self.hasPerformedInitialScroll else { return }
             self.scrollPosition = self.scrollerBottomID
             self.hasPerformedInitialScroll = true
+            self.isPinnedToBottom = true
         }
         .onChange(of: self.viewModel.sessionKey) { _, _ in
             self.hasPerformedInitialScroll = false
+            self.isPinnedToBottom = true
         }
         .onChange(of: self.viewModel.messages.count) { _, _ in
-            guard self.hasPerformedInitialScroll else { return }
+            guard self.hasPerformedInitialScroll, self.isPinnedToBottom else { return }
             withAnimation(.snappy(duration: 0.22)) {
                 self.scrollPosition = self.scrollerBottomID
             }
         }
         .onChange(of: self.viewModel.pendingRunCount) { _, _ in
-            guard self.hasPerformedInitialScroll else { return }
+            guard self.hasPerformedInitialScroll, self.isPinnedToBottom else { return }
+            withAnimation(.snappy(duration: 0.22)) {
+                self.scrollPosition = self.scrollerBottomID
+            }
+        }
+        .onChange(of: self.viewModel.streamingAssistantText) { _, _ in
+            guard self.hasPerformedInitialScroll, self.isPinnedToBottom else { return }
             withAnimation(.snappy(duration: 0.22)) {
                 self.scrollPosition = self.scrollerBottomID
             }