feat: allow witness restart agent override

internal/cmd/rig.go

@@ -759,7 +759,7 @@ func runRigBoot(cmd *cobra.Command, args []string) error {
 	} else {
 		fmt.Printf("  Starting witness...\n")
 		witMgr := witness.NewManager(r)
-		if err := witMgr.Start(false); err != nil {
+		if err := witMgr.Start(false, ""); err != nil {
 			if err == witness.ErrAlreadyRunning {
 				skipped = append(skipped, "witness (already running)")
 			} else {
@@ -839,7 +839,7 @@ func runRigStart(cmd *cobra.Command, args []string) error {
 		} else {
 			fmt.Printf("  Starting witness...\n")
 			witMgr := witness.NewManager(r)
-			if err := witMgr.Start(false); err != nil {
+			if err := witMgr.Start(false, ""); err != nil {
 				if err == witness.ErrAlreadyRunning {
 					skipped = append(skipped, "witness")
 				} else {
@@ -1418,7 +1418,7 @@ func runRigRestart(cmd *cobra.Command, args []string) error {
 			skipped = append(skipped, "witness")
 		} else {
 			fmt.Printf("    Starting witness...\n")
-			if err := witMgr.Start(false); err != nil {
+			if err := witMgr.Start(false, ""); err != nil {
 				if err == witness.ErrAlreadyRunning {
 					skipped = append(skipped, "witness")
 				} else {

internal/cmd/start.go

@@ -235,7 +235,7 @@ func startRigAgents(t *tmux.Tmux, townRoot string) {
 			fmt.Printf("  %s %s witness already running\n", style.Dim.Render("○"), r.Name)
 		} else {
 			witMgr := witness.NewManager(r)
-			if err := witMgr.Start(false); err != nil {
+			if err := witMgr.Start(false, ""); err != nil {
 				if err == witness.ErrAlreadyRunning {
 					fmt.Printf("  %s %s witness already running\n", style.Dim.Render("○"), r.Name)
 				} else {

internal/cmd/up.go

@@ -118,7 +118,7 @@ func runUp(cmd *cobra.Command, args []string) error {
 		}
 
 		mgr := witness.NewManager(r)
-		if err := mgr.Start(false); err != nil {
+		if err := mgr.Start(false, ""); err != nil {
 			if err == witness.ErrAlreadyRunning {
 				printStatus(fmt.Sprintf("Witness (%s)", rigName), true, mgr.SessionName())
 			} else {

internal/cmd/witness.go

@@ -17,6 +17,7 @@ import (
 var (
 	witnessForeground bool
 	witnessStatusJSON bool
+	witnessAgentOverride string
 )
 
 var witnessCmd = &cobra.Command{
@@ -93,7 +94,8 @@ var witnessRestartCmd = &cobra.Command{
 Stops the current session (if running) and starts a fresh one.
 
 Examples:
-  gt witness restart greenplace`,
+  gt witness restart greenplace
+  gt witness restart greenplace --agent codex`,
 	Args: cobra.ExactArgs(1),
 	RunE: runWitnessRestart,
 }
@@ -105,6 +107,9 @@ func init() {
 	// Status flags
 	witnessStatusCmd.Flags().BoolVar(&witnessStatusJSON, "json", false, "Output as JSON")
 
+	// Restart flags
+	witnessRestartCmd.Flags().StringVar(&witnessAgentOverride, "agent", "", "Agent alias to run the Witness with (overrides town default)")
+
 	// Add subcommands
 	witnessCmd.AddCommand(witnessStartCmd)
 	witnessCmd.AddCommand(witnessStopCmd)
@@ -136,7 +141,7 @@ func runWitnessStart(cmd *cobra.Command, args []string) error {
 
 	fmt.Printf("Starting witness for %s...\n", rigName)
 
-	if err := mgr.Start(witnessForeground); err != nil {
+	if err := mgr.Start(witnessForeground, ""); err != nil {
 		if err == witness.ErrAlreadyRunning {
 			fmt.Printf("%s Witness is already running\n", style.Dim.Render("⚠"))
 			fmt.Printf("  %s\n", style.Dim.Render("Use 'gt witness attach' to connect"))
@@ -289,7 +294,7 @@ func runWitnessAttach(cmd *cobra.Command, args []string) error {
 	sessionName := witnessSessionName(rigName)
 
 	// Ensure session exists (creates if needed)
-	if err := mgr.Start(false); err != nil && err != witness.ErrAlreadyRunning {
+	if err := mgr.Start(false, ""); err != nil && err != witness.ErrAlreadyRunning {
 		return err
 	} else if err == nil {
 		fmt.Printf("Started witness session for %s\n", rigName)
@@ -322,7 +327,7 @@ func runWitnessRestart(cmd *cobra.Command, args []string) error {
 	_ = mgr.Stop()
 
 	// Start fresh
-	if err := mgr.Start(false); err != nil {
+	if err := mgr.Start(false, witnessAgentOverride); err != nil {
 		return fmt.Errorf("starting witness: %w", err)
 	}
 

internal/cmd/witness_test.go

@@ -0,0 +1,19 @@
+package cmd
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestWitnessRestartAgentFlag(t *testing.T) {
+	flag := witnessRestartCmd.Flags().Lookup("agent")
+	if flag == nil {
+		t.Fatal("expected witness restart to define --agent flag")
+	}
+	if flag.DefValue != "" {
+		t.Errorf("expected default agent override to be empty, got %q", flag.DefValue)
+	}
+	if !strings.Contains(flag.Usage, "overrides town default") {
+		t.Errorf("expected --agent usage to mention overrides town default, got %q", flag.Usage)
+	}
+}

internal/daemon/daemon.go

@@ -396,7 +396,7 @@ func (d *Daemon) ensureWitnessRunning(rigName string) {
 	}
 
 	// Manager.Start() handles: zombie detection, session creation, env vars, theming,
-	// WaitForClaudeReady, and crucially - startup/propulsion nudges (GUPP).
+	// startup readiness waits, and crucially - startup/propulsion nudges (GUPP).
 	// It returns ErrAlreadyRunning if Claude is already running in tmux.
 	r := &rig.Rig{
 		Name: rigName,
@@ -404,7 +404,7 @@ func (d *Daemon) ensureWitnessRunning(rigName string) {
 	}
 	mgr := witness.NewManager(r)
 
-	if err := mgr.Start(false); err != nil {
+	if err := mgr.Start(false, ""); err != nil {
 		if err == witness.ErrAlreadyRunning {
 			// Already running - nothing to do
 			return

internal/witness/manager.go

@@ -99,7 +99,8 @@ func (m *Manager) witnessDir() string {
 // Start starts the witness.
 // If foreground is true, only updates state (no tmux session - deprecated).
 // Otherwise, spawns a Claude agent in a tmux session.
-func (m *Manager) Start(foreground bool) error {
+// agentOverride optionally specifies a different agent alias to use.
+func (m *Manager) Start(foreground bool, agentOverride string) error {
 	w, err := m.loadState()
 	if err != nil {
 		return err
@@ -152,15 +153,8 @@ func (m *Manager) Start(foreground bool) error {
 		return fmt.Errorf("ensuring Claude settings: %w", err)
 	}
 
-	// Build startup command first
+	// Create new tmux session
-	// Pass m.rig.Path so rig agent settings are honored (not town-level defaults)
+	if err := t.NewSession(sessionID, witnessDir); err != nil {
-	bdActor := fmt.Sprintf("%s/witness", m.rig.Name)
-	command := config.BuildAgentStartupCommand("witness", bdActor, m.rig.Path, "")
-	runtimeConfig := config.LoadRuntimeConfig(m.rig.Path)
-
-	// Create session with command directly to avoid send-keys race condition.
-	// See: https://github.com/anthropics/gastown/issues/280
-	if err := t.NewSessionWithCommand(sessionID, witnessDir, command); err != nil {
 		return fmt.Errorf("creating tmux session: %w", err)
 	}
 
@@ -192,8 +186,28 @@ func (m *Manager) Start(foreground bool) error {
 		return fmt.Errorf("saving state: %w", err)
 	}
 
-	// Wait for runtime to start and show its prompt (non-fatal)
+	// Launch Claude directly (no shell respawn loop)
-	if err := t.WaitForRuntimeReady(sessionID, runtimeConfig, constants.ClaudeStartTimeout); err != nil {
+	// Restarts are handled by daemon via LIFECYCLE mail or deacon health-scan
+	// NOTE: No gt prime injection needed - SessionStart hook handles it automatically
+	// Export GT_ROLE and BD_ACTOR in the command since tmux SetEnvironment only affects new panes
+	// Pass m.rig.Path so rig agent settings are honored (not town-level defaults)
+	command, err := config.BuildAgentStartupCommandWithAgentOverride("witness", bdActor, m.rig.Path, "", agentOverride)
+	if err != nil {
+		_ = t.KillSession(sessionID)
+		return fmt.Errorf("building startup command: %w", err)
+	}
+	// Wait for shell to be ready before sending keys (prevents "can't find pane" under load)
+	if err := t.WaitForShellReady(sessionID, 5*time.Second); err != nil {
+		_ = t.KillSession(sessionID)
+		return fmt.Errorf("waiting for shell: %w", err)
+	}
+	if err := t.SendKeys(sessionID, command); err != nil {
+		_ = t.KillSession(sessionID) // best-effort cleanup
+		return fmt.Errorf("starting Claude agent: %w", err)
+	}
+
+	// Wait for Claude to start (non-fatal).
+	if err := t.WaitForCommand(sessionID, constants.SupportedShells, constants.ClaudeStartTimeout); err != nil {
 		// Non-fatal - try to continue anyway
 	}