Add /clear command to reset current tab with a new session

Introduces a /clear slash command that resets the current tab and starts
a fresh session in the same working directory. Unlike /new which opens a
new tab, /clear reuses the current tab by creating a new session in-place,
rebuilding UI components, and updating persisted state.

Assisted-By: docker-agent

Author: dgageot

pkg/tui/commands/commands.go

@@ -36,6 +36,16 @@ type Item struct {
 
 func builtInSessionCommands() []Item {
 	cmds := []Item{
+		{
+			ID:           "session.clear",
+			Label:        "Clear",
+			SlashCommand: "/clear",
+			Description:  "Clear the current tab and start a new session",
+			Category:     "Session",
+			Execute: func(string) tea.Cmd {
+				return core.CmdHandler(messages.ClearSessionMsg{})
+			},
+		},
 		{
 			ID:           "session.attach",
 			Label:        "Attach",

pkg/tui/commands/commands_test.go

@@ -71,6 +71,15 @@ func TestParseSlashCommand_OtherCommands(t *testing.T) {
 		assert.True(t, ok)
 	})
 
+	t.Run("clear command", func(t *testing.T) {
+		t.Parallel()
+		cmd := ParseSlashCommand("/clear")
+		require.NotNil(t, cmd)
+		msg := cmd()
+		_, ok := msg.(messages.ClearSessionMsg)
+		assert.True(t, ok)
+	})
+
 	t.Run("star command", func(t *testing.T) {
 		t.Parallel()
 		cmd := ParseSlashCommand("/star")

pkg/tui/messages/session.go

@@ -25,6 +25,10 @@ type (
 	// NewSessionMsg requests creation of a new session.
 	NewSessionMsg struct{}
 
+	// ClearSessionMsg resets the current tab and starts a new session
+	// in the same working directory.
+	ClearSessionMsg struct{}
+
 	// ExitSessionMsg requests exiting the current session.
 	ExitSessionMsg struct{}
 

pkg/tui/tui.go

@@ -702,6 +702,10 @@ func (m *appModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		// /new spawns a new tab when a session spawner is configured.
 		return m.handleSpawnSession("")
 
+	case messages.ClearSessionMsg:
+		// /clear resets the current tab with a fresh session in the same working dir.
+		return m.handleClearSession()
+
 	// --- Exit ---
 
 	case messages.ExitSessionMsg:
@@ -1116,6 +1120,46 @@ func (m *appModel) replaceActiveSession(ctx context.Context, sess *session.Sessi
 	return m, cmd
 }
 
+// handleClearSession resets the current tab by creating a fresh session
+// in the same working directory.
+func (m *appModel) handleClearSession() (tea.Model, tea.Cmd) {
+	activeID := m.supervisor.ActiveID()
+
+	// Cleanup old editor for the active session.
+	if ed, ok := m.editors[activeID]; ok {
+		ed.Cleanup()
+	}
+
+	// Create a fresh session in the same app, preserving the working dir.
+	m.application.NewSession()
+	newSess := m.application.Session()
+
+	// Rebuild all per-session UI components.
+	m.initSessionComponents(activeID, m.application, newSess)
+	m.dialogMgr = dialog.New()
+	m.supervisor.SetRunnerTitle(activeID, "")
+	m.sessionState.SetSessionTitle("")
+	m.sessionState.SetPreviousMessage(nil)
+
+	// Update persisted tab to point to the new session.
+	if m.tuiStore != nil {
+		ctx := context.Background()
+		oldPersistedID := m.persistedSessionID(activeID)
+		if err := m.tuiStore.UpdateTabSessionID(ctx, oldPersistedID, newSess.ID); err != nil {
+			slog.Warn("Failed to update tab session ID after clear", "error", err)
+		}
+	}
+	m.persistActiveTab(newSess.ID)
+
+	m.reapplyKeyboardEnhancements()
+
+	return m, tea.Sequence(
+		m.chatPage.Init(),
+		m.resizeAll(),
+		m.editor.Focus(),
+	)
+}
+
 // handleSpawnSession spawns a new session.
 func (m *appModel) handleSpawnSession(workingDir string) (tea.Model, tea.Cmd) {
 	// If no working dir specified, open the picker