feat(tui): retain cache when cycling between subagent/parent sessions for perf (#1981)

1 files changed, 20 insertions, 1 deletions

diff --git a/packages/tui/internal/components/chat/messages.go b/packages/tui/internal/components/chat/messages.go
index 034f2c4f0..77a9b8100 100644
--- a/packages/tui/internal/components/chat/messages.go
+++ b/packages/tui/internal/components/chat/messages.go
@@ -171,7 +171,11 @@ func (m *messagesComponent) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.showThinkingBlocks = !m.showThinkingBlocks
 		m.app.State.ShowThinkingBlocks = &m.showThinkingBlocks
 		return m, tea.Batch(m.renderView(), m.app.SaveState())
-	case app.SessionLoadedMsg, app.SessionClearedMsg:
+	case app.SessionLoadedMsg:
+		m.tail = true
+		m.loading = true
+		return m, m.renderView()
+	case app.SessionClearedMsg:
 		m.cache.Clear()
 		m.tail = true
 		m.loading = true
@@ -183,6 +187,21 @@ func (m *messagesComponent) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			return m, m.renderView()
 		}
 	case app.SessionSelectedMsg:
+		currentParent := m.app.Session.ParentID
+		if currentParent == "" {
+			currentParent = m.app.Session.ID
+		}
+
+		targetParent := msg.ParentID
+		if targetParent == "" {
+			targetParent = msg.ID
+		}
+
+		// Clear cache only if switching between different session families
+		if currentParent != targetParent {
+			m.cache.Clear()
+		}
+
 		m.viewport.GotoBottom()
 	case app.MessageRevertedMsg:
 		if msg.Session.ID == m.app.Session.ID {