diff --git a/README.md b/README.md
index 363377a..99e2c25 100644
--- a/README.md
+++ b/README.md
@@ -166,6 +166,7 @@ grut version      # Print the version
 | `--version`, `-v` | Print the version and exit |
 | `--demo` | Launch with a demo project to explore grut |
 | `--no-ai` | Disable AI features for this session |
+| `--layout NAME` | Start with a layout for this launch (`explorer`, `git`, `review`, `agent`, `full`) |
 | `--cpu-profile FILE` | Write CPU profile to FILE (dev/debug) |
 | `--mem-profile FILE` | Write memory profile to FILE (dev/debug) |
 | `--pprof PORT` | Start pprof server on localhost:PORT (dev/debug) |
diff --git a/cmd/root.go b/cmd/root.go
index 9040d58..07d66ce 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -11,6 +11,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"runtime/pprof"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -56,6 +57,7 @@ func buildRootCommand() (rootCmd *cobra.Command, cleanup func()) {
 	// memstatsDone is closed by cleanup to stop the background memstats
 	// goroutine, preventing a goroutine leak when --pprof is used.
 	memstatsDone := make(chan struct{})
+	var startupLayout string
 
 	rootCmd = &cobra.Command{
 		Use:   "grut",
@@ -178,7 +180,10 @@ Environment:
 
 			// Create session manager and attempt to restore previous session.
 			sessMgr := session.NewManager()
-			preset := restoreSessionOrDefault(sessMgr, cfg, cwd, gc)
+			preset, err := restoreSessionOrDefault(sessMgr, cfg, cwd, gc, startupLayout)
+			if err != nil {
+				return err
+			}
 
 			// Create the layout engine
 			engine, err := layout.NewEngine(reg, preset)
@@ -348,6 +353,7 @@ Environment:
 	rootCmd.PersistentFlags().Bool("no-ai", false, "Disable AI features for this operation")
 	rootCmd.PersistentFlags().Bool("demo", false, "Launch with a demo project to explore grut")
 	rootCmd.PersistentFlags().Bool("reset-welcome", false, "Reset first-run state so the welcome screen shows on next launch")
+	rootCmd.PersistentFlags().StringVar(&startupLayout, "layout", "", "Startup layout override (explorer, git, review, agent, full)")
 
 	// Register subcommands via constructors (no init() side effects).
 	rootCmd.AddCommand(newVersionCmd())
@@ -396,12 +402,12 @@ Environment:
 // restoreSessionOrDefault attempts to load a saved session for the given
 // working directory and returns the first tab's preset. Falls back to
 // ExplorerPreset when sessions are disabled or no saved session exists.
-func restoreSessionOrDefault(mgr *session.Manager, cfg *config.Config, workDir string, _ git.GitClient) layout.Preset {
-	defaultPreset := func() layout.Preset { //nolint:gocritic // closure needed for deferred evaluation
-		// v1: always default to ExplorerPreset. The filetree panel
-		// already shows git status indicators when .git exists.
-		// GitPreset and other presets are preserved for v2 multi-tab.
-		return layout.ExplorerPreset()
+func restoreSessionOrDefault(mgr *session.Manager, cfg *config.Config, workDir string, _ git.GitClient, layoutOverride string) (layout.Preset, error) {
+	defaultPreset := func() (layout.Preset, error) { //nolint:gocritic // closure needed for deferred evaluation
+		return startupPreset(cfg, layoutOverride)
+	}
+	if strings.TrimSpace(layoutOverride) != "" {
+		return defaultPreset()
 	}
 
 	if !cfg.Session.Enabled {
@@ -423,11 +429,37 @@ func restoreSessionOrDefault(mgr *session.Manager, cfg *config.Config, workDir s
 		presetName = state.Tabs[0].Name
 	}
 	if p, ok := layout.Presets()[presetName]; ok {
-		return p
+		return p, nil
 	}
 	return defaultPreset()
 }
 
+func startupPreset(cfg *config.Config, layoutOverride string) (layout.Preset, error) {
+	name := strings.TrimSpace(layoutOverride)
+	if name == "" && cfg != nil {
+		name = strings.TrimSpace(cfg.General.DefaultLayout)
+	}
+	if name == "" {
+		name = "explorer"
+	}
+	presets := layout.Presets()
+	preset, ok := presets[name]
+	if ok {
+		return preset, nil
+	}
+	return layout.Preset{}, fmt.Errorf("unknown layout %q (valid: %s)", name, strings.Join(validLayoutNames(), ", "))
+}
+
+func validLayoutNames() []string {
+	presets := layout.Presets()
+	names := make([]string, 0, len(presets))
+	for name := range presets {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
 // addRestoredTabs adds any additional tabs (beyond the first) from a
 // saved session to the engine. The first tab was already used to
 // create the engine, so we start from index 1.
diff --git a/cmd/root_test.go b/cmd/root_test.go
index 1fd22ae..84fcdce 100644
--- a/cmd/root_test.go
+++ b/cmd/root_test.go
@@ -41,6 +41,15 @@ func TestNoAIFlagInheritedBySubcommands(t *testing.T) {
 	}
 }
 
+func TestLayoutFlagRegistered(t *testing.T) {
+	root, cleanup := newRootCommand()
+	defer cleanup()
+	flag := root.PersistentFlags().Lookup("layout")
+	require.NotNil(t, flag, "--layout persistent flag must be registered")
+	assert.Equal(t, "string", flag.Value.Type())
+	assert.Equal(t, "", flag.DefValue)
+}
+
 func TestApplyNoAIFlag_WhenSet(t *testing.T) {
 	cmd := &cobra.Command{}
 	cmd.Flags().Bool("no-ai", false, "")
@@ -289,7 +298,8 @@ func TestRestoreSessionOrDefault_SessionsDisabled(t *testing.T) {
 	cfg := &config.Config{}
 	cfg.Session.Enabled = false
 
-	preset := restoreSessionOrDefault(mgr, cfg, t.TempDir(), nil)
+	preset, err := restoreSessionOrDefault(mgr, cfg, t.TempDir(), nil, "")
+	require.NoError(t, err)
 	// When sessions are disabled, should return the default ExplorerPreset.
 	expected := layout.ExplorerPreset()
 	assert.Equal(t, expected.Name, preset.Name)
@@ -301,11 +311,53 @@ func TestRestoreSessionOrDefault_NoSavedSession(t *testing.T) {
 	cfg.Session.Enabled = true
 
 	// Use a temp dir where no session file exists.
-	preset := restoreSessionOrDefault(mgr, cfg, t.TempDir(), nil)
+	preset, err := restoreSessionOrDefault(mgr, cfg, t.TempDir(), nil, "")
+	require.NoError(t, err)
 	expected := layout.ExplorerPreset()
 	assert.Equal(t, expected.Name, preset.Name)
 }
 
+func TestRestoreSessionOrDefault_UsesConfiguredDefaultLayout(t *testing.T) {
+	mgr := session.NewManager()
+	mgr.SetDataDir(t.TempDir())
+	cfg := &config.Config{}
+	cfg.Session.Enabled = true
+	cfg.General.DefaultLayout = "git"
+
+	preset, err := restoreSessionOrDefault(mgr, cfg, t.TempDir(), nil, "")
+	require.NoError(t, err)
+	assert.Equal(t, layout.GitPreset().Name, preset.Name)
+}
+
+func TestRestoreSessionOrDefault_LayoutOverrideWinsOverSavedSession(t *testing.T) {
+	mgr := session.NewManager()
+	mgr.SetDataDir(t.TempDir())
+	workDir := t.TempDir()
+	cfg := &config.Config{}
+	cfg.Session.Enabled = true
+	cfg.General.DefaultLayout = "explorer"
+	require.NoError(t, mgr.Save(session.SessionState{
+		WorkDir: workDir,
+		Tabs: []session.TabState{
+			{Name: "git", Preset: "git", FocusedPanel: "filetree"},
+		},
+	}))
+
+	preset, err := restoreSessionOrDefault(mgr, cfg, workDir, nil, "review")
+	require.NoError(t, err)
+	assert.Equal(t, layout.ReviewPreset().Name, preset.Name)
+}
+
+func TestStartupPreset_InvalidLayoutReturnsError(t *testing.T) {
+	cfg := &config.Config{}
+	cfg.General.DefaultLayout = "missing"
+
+	_, err := startupPreset(cfg, "")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "unknown layout")
+	assert.Contains(t, err.Error(), "explorer")
+}
+
 // ---------------------------------------------------------------------------
 // addRestoredTabs — single-tab mode guard
 // ---------------------------------------------------------------------------
diff --git a/docs/configuration.md b/docs/configuration.md
index 68dd05c..a7ced2c 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -14,7 +14,7 @@ All paths support tilde (`~`) expansion. Only set values you want to change —
 ```toml
 [general]
 keybinding_scheme = "default"    # "default", "vim", "classic", or path to .toml file
-default_layout = "explorer"      # "explorer", "git", "review", "agent"
+default_layout = "explorer"      # "explorer", "git", "review", "agent", "full"
 auto_save_session = true         # Save/restore tab layout on exit/start
 show_first_run_help = true       # Show help overlay on first launch
 ```
diff --git a/internal/config/validate.go b/internal/config/validate.go
index abd6d38..850b01b 100644
--- a/internal/config/validate.go
+++ b/internal/config/validate.go
@@ -47,7 +47,7 @@ func Validate(cfg *Config) error {
 	errs = appendEnumOrPathErr(errs, "general.keybinding_scheme",
 		cfg.General.KeybindingScheme, "default", "classic", "vim")
 	errs = appendEnumErr(errs, "general.default_layout",
-		cfg.General.DefaultLayout, "explorer", "git", "review", "agent")
+		cfg.General.DefaultLayout, "explorer", "git", "review", "agent", "full")
 
 	// --- file_tree ---
 	errs = appendEnumErr(errs, "file_tree.icon_mode",