feat(tui): codex-style input, history, bang commands, single-line status bar

- Arrow-key input history (up/down with multiline awareness)
- Bang shell commands via ! prefix (requires --yolo)
- Codex-style input bar with mode indicator (R/Y/⌘)
- Command palette virtual scrolling
- Multiline input viewport fix
- Merged model pills + footer into single status line
- Removed shift+enter (wait for TUI library support)
- Removed default footer hints

README.md

@@ -100,22 +100,25 @@ go run . [flags]
 ## TUI Controls
 
 - `enter` sends the message.
-- `ctrl+j` or `alt+enter` inserts a newline.
+- `ctrl+j` inserts a newline.
+- `up` recalls the previous input; `ctrl+p` / `ctrl+n` navigate input history.
 - The input starts at one line and grows up to six lines.
 - `page up` / `page down` scrolls the transcript.
 - `esc` cancels a running response.
 - Type `/` to show available commands.
+- In `--yolo` mode, type `! <command>` to run a shell command from the configured working directory.
 
 Slash commands:
 
 - `/clear` resets conversation history.
-- `/compact` summarizes older conversation history and keeps recent context.
+- `/compact` summarizes older conversation history and keeps the newest ~20% of context, with a small recent-message floor.
 - `/status` shows changed files with `git status --short`.
 - `/diff [--stat] [path...]` shows the unstaged git diff.
 - `/test [command...]` runs a project test command; defaults to `go test ./...` for Go modules or `npm test` for Node projects.
 - `/model` shows current provider, model, thinking, and switch usage.
 - `/model provider <name>` switches provider for the current session.
 - `/model model <name>` or `/model <name>` switches model for the current session.
+  In the TUI, type `/model ` or `/model model ` to choose from configured model IDs in the candidate palette.
 - `/model thinking <none|middle|high|xhigh|max>` changes thinking for the current session.
 - `/sessions` lists saved sessions.
 - `/resume [id]` resumes by ID or opens an interactive picker.

internal/agent/agent.go

@@ -17,7 +17,8 @@ import (
 const (
 	defaultMaxToolRounds      = 50
 	doomLoopThreshold         = 3
-	compactRecentMessages     = 6
+	compactMinRecentMessages      = 6
+	compactRecentRetentionPercent = 20
 	summaryMessageLimit       = 8000
 	contextSummaryPrefix      = "[context summary]"
 	toolLogArgumentLimit      = 400
@@ -181,6 +182,61 @@ func (a *Agent) SetLastUsage(usage *llm.Usage) {
 	copy := *usage
 	a.lastUsage = &copy
 }
+// compactRetainedTokenBudget returns the number of estimated tokens to retain
+// based on compactRecentRetentionPercent, using integer ceiling division.
+func compactRetainedTokenBudget(totalTokens int) int {
+	if totalTokens <= 0 {
+		return 1
+	}
+	return (totalTokens*compactRecentRetentionPercent + 99) / 100
+}
+
+// compactTurnBoundary walks backward from start until it finds a user message
+// or reaches prefixEnd, ensuring the retained suffix starts at a user turn.
+func compactTurnBoundary(messages []llm.Message, prefixEnd int, start int) int {
+	for start > prefixEnd && messages[start].Role != llm.RoleUser {
+		start--
+	}
+	return start
+}
+
+// compactRecentStart returns the index where the retained recent suffix begins.
+// It balances the 20% token-budget ratio with the compactMinRecentMessages floor
+// and aligns to a user-turn boundary.
+func compactRecentStart(messages []llm.Message, prefixEnd int) int {
+	compactableCount := len(messages) - prefixEnd
+	if compactableCount <= compactMinRecentMessages {
+		return len(messages)
+	}
+
+	compactable := messages[prefixEnd:]
+	totalTokens := llm.EstimateTokens(compactable, nil)
+	retainTokens := compactRetainedTokenBudget(totalTokens)
+
+	// Walk backward from the end to find the earliest suffix fitting the budget.
+	ratioStart := len(messages) - 1
+	for i := len(messages) - 1; i >= prefixEnd; i-- {
+		if llm.EstimateTokens(messages[i:], nil) <= retainTokens {
+			ratioStart = i
+		} else {
+			break
+		}
+	}
+
+	// Enforce the minimum recent-message floor.
+	minStart := len(messages) - compactMinRecentMessages
+	if minStart < prefixEnd {
+		minStart = prefixEnd
+	}
+	// Choose the earlier start so the floor is never weakened.
+	start := minStart
+	if ratioStart < start {
+		start = ratioStart
+	}
+
+	return compactTurnBoundary(messages, prefixEnd, start)
+}
+
 
 // Compact summarizes older conversation messages while preserving the system
 // prompt and recent messages intact.
@@ -196,12 +252,8 @@ func (a *Agent) Compact(ctx context.Context) error {
 	if a.messages[0].Role == llm.RoleSystem {
 		prefixEnd = 1
 	}
-	if len(a.messages)-prefixEnd <= compactRecentMessages {
-		return nil
-	}
-
-	recentStart := len(a.messages) - compactRecentMessages
-	if recentStart <= prefixEnd {
+	recentStart := compactRecentStart(a.messages, prefixEnd)
+	if recentStart <= prefixEnd || recentStart >= len(a.messages) {
 		return nil
 	}
 	middle := append([]llm.Message(nil), a.messages[prefixEnd:recentStart]...)

internal/agent/agent_test.go

@@ -145,6 +145,9 @@ func TestAgentCompact(t *testing.T) {
 	if messages[len(messages)-1].Content != "recent-answer-2" {
 		t.Fatalf("last recent message = %#v", messages[len(messages)-1])
 	}
+	if messages[2].Content != "recent-user-0" {
+		t.Fatalf("first retained recent message = %#v", messages[2])
+	}
 	if usage := a.LastUsage(); usage == nil || usage.TotalTokens != 12 {
 		t.Fatalf("usage = %#v", usage)
 	}
@@ -217,6 +220,48 @@ func longConversation() []llm.Message {
 	return messages
 }
 
+func manyTurnConversation(turns int) []llm.Message {
+	messages := []llm.Message{{Role: llm.RoleSystem, Content: "system"}}
+	for i := 0; i < turns; i++ {
+		messages = append(messages,
+			llm.Message{Role: llm.RoleUser, Content: fmt.Sprintf("user-%02d", i)},
+			llm.Message{Role: llm.RoleAssistant, Content: fmt.Sprintf("assistant-%02d", i)},
+		)
+	}
+	return messages
+}
+
+func TestAgentCompactKeepsTwentyPercentRecentContext(t *testing.T) {
+	provider := &compactProvider{}
+	a := New(Options{Provider: provider, Model: "test", SystemPrompt: "system"})
+	a.SetMessages(manyTurnConversation(25))
+
+	if err := a.Compact(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+
+	messages := a.Messages()
+	// 1 system + 1 summary + 10 retained recent messages (5 user/assistant turns)
+	if len(messages) != 12 {
+		t.Fatalf("messages = %d, want 12; contents: %v", len(messages), joinMessageContents(messages))
+	}
+	if provider.summaryCalls != 1 {
+		t.Fatalf("summaryCalls = %d, want 1", provider.summaryCalls)
+	}
+	if messages[2].Content != "user-20" {
+		t.Fatalf("first retained message = %#v, want user-20", messages[2])
+	}
+	if messages[len(messages)-1].Content != "assistant-24" {
+		t.Fatalf("last retained message = %#v, want assistant-24", messages[len(messages)-1])
+	}
+	if !strings.Contains(provider.lastSummary, "user-19") {
+		t.Fatalf("summary should contain user-19 (part of summarized 80%%): %q", provider.lastSummary)
+	}
+	if strings.Contains(provider.lastSummary, "user-20") {
+		t.Fatalf("summary should not contain user-20 (part of retained 20%%): %q", provider.lastSummary)
+	}
+}
+
 func joinMessageContents(messages []llm.Message) string {
 	var b strings.Builder
 	for _, msg := range messages {

internal/app/app.go

@@ -0,0 +1,164 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+
+	"agentu/internal/agent"
+	"agentu/internal/session"
+	"agentu/internal/tools"
+	"agentu/internal/tui"
+	"agentu/pkg/config"
+	"agentu/pkg/llm"
+)
+
+type cliOptions struct {
+	configPath string
+	yolo       bool
+	plain      bool
+	themeName  string
+	resumeID   string
+}
+
+func Run() error {
+	opts := parseCLIOptions()
+
+	themeMode, err := tui.ParseThemeMode(opts.themeName)
+	if err != nil {
+		return err
+	}
+
+	cfg, err := loadConfig(opts.configPath)
+	if err != nil {
+		return err
+	}
+
+	providerName, providerConfig, provider := defaultProvider(cfg, http.DefaultClient)
+	assistant := newAssistant(cfg, providerName, providerConfig, provider, opts.yolo, http.DefaultClient)
+	modelManager, err := newSessionManager(cfg, assistant, http.DefaultClient)
+	if err != nil {
+		return err
+	}
+
+	if err := initializeSession(modelManager, opts.resumeID); err != nil {
+		return err
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	return runInterface(ctx, assistant, modelManager, providerConfig, cfg.Agent.WorkingDir, opts, themeMode)
+}
+
+func parseCLIOptions() cliOptions {
+	configPath := flag.String("config", config.DefaultPath, "path to YAML config")
+	yolo := flag.Bool("yolo", false, "also enable automatic file writes and shell execution")
+	plain := flag.Bool("plain", false, "use the simple line-based REPL instead of the TUI")
+	themeName := flag.String("theme", "light", "TUI theme: light or dark")
+	resumeID := flag.String("resume", "", "resume a specific session by ID")
+	flag.Parse()
+
+	return cliOptions{
+		configPath: *configPath,
+		yolo:       *yolo,
+		plain:      *plain,
+		themeName:  *themeName,
+		resumeID:   *resumeID,
+	}
+}
+
+func loadConfig(configPath string) (*config.Config, error) {
+	cfg, err := config.Load(configPath)
+	if err == nil {
+		return cfg, nil
+	}
+	if !errors.Is(err, os.ErrNotExist) {
+		return nil, err
+	}
+	if bootstrapErr := bootstrapConfig(configPath); bootstrapErr != nil {
+		return nil, bootstrapErr
+	}
+	return nil, fmt.Errorf("created default config at %s; edit it to set your API key and provider, then restart agentu", configPath)
+}
+
+func defaultProvider(cfg *config.Config, httpClient *http.Client) (string, config.ProviderConfig, llm.Provider) {
+	providerName := cfg.DefaultProviderName()
+	providerConfig := cfg.Providers[providerName]
+	provider := llm.NewOpenAICompatibleClient(providerConfig.BaseURL, providerConfig.APIKey, httpClient)
+	return providerName, providerConfig, provider
+}
+
+func newAssistant(cfg *config.Config, providerName string, providerConfig config.ProviderConfig, provider llm.Provider, yolo bool, httpClient *http.Client) *agent.Agent {
+	return agent.New(agent.Options{
+		Provider:         provider,
+		ProviderName:     providerName,
+		Model:            providerConfig.Model,
+		Thinking:         providerConfig.Thinking,
+		ThinkingParam:    providerConfig.ThinkingParam,
+		ThinkingEnabled:  providerConfig.ThinkingConfigured,
+		SystemPrompt:     systemPrompt(cfg, yolo),
+		ToolRegistry:     newToolRegistry(cfg.Agent.WorkingDir, yolo, httpClient),
+		ToolTimeout:      cfg.Agent.ToolTimeout,
+		MaxContextTokens: maxContextTokens(cfg, providerConfig),
+	})
+}
+
+func systemPrompt(cfg *config.Config, yolo bool) string {
+	instructions := tools.AgentInstructions(cfg.Agent.WorkingDir, yolo)
+	return strings.TrimSpace(cfg.Agent.SystemPrompt + "\n\n" + instructions)
+}
+
+func maxContextTokens(cfg *config.Config, providerConfig config.ProviderConfig) int {
+	if cfg.Agent.MaxContextTokens != 0 {
+		return cfg.Agent.MaxContextTokens
+	}
+	return providerConfig.ContextTokens
+}
+
+func newToolRegistry(workingDir string, yolo bool, httpClient *http.Client) *tools.Registry {
+	var registry *tools.Registry
+	if yolo {
+		registry = tools.Builtins(workingDir)
+	} else {
+		registry = tools.ReadOnlyBuiltins(workingDir)
+	}
+	registry.Register(tools.NewBuiltinSearchTool(httpClient))
+	registry.Register(tools.NewBuiltinFetchTool(httpClient))
+	return registry
+}
+
+func newSessionManager(cfg *config.Config, assistant *agent.Agent, httpClient *http.Client) (*session.Manager, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return nil, fmt.Errorf("resolve home dir: %w", err)
+	}
+	sessionsDir := filepath.Join(home, ".agentu", "sessions")
+	store, err := session.NewStore(sessionsDir)
+	if err != nil {
+		return nil, fmt.Errorf("init session store: %w", err)
+	}
+	return session.NewManager(cfg, assistant, httpClient, store)
+}
+
+func runInterface(ctx context.Context, assistant *agent.Agent, modelManager *session.Manager, providerConfig config.ProviderConfig, workingDir string, opts cliOptions, themeMode tui.ThemeMode) error {
+	if opts.plain {
+		return repl(ctx, assistant, modelManager)
+	}
+
+	err := tui.Run(ctx, assistant, tui.Options{
+		ModelName:    providerConfig.Model,
+		Yolo:         opts.yolo,
+		ThemeMode:    themeMode,
+		ModelManager: modelManager,
+		WorkingDir:   workingDir,
+	})
+	printExitSession(modelManager)
+	return err
+}

internal/app/bootstrap.go

@@ -0,0 +1,38 @@
+package app
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"agentu/pkg/config"
+)
+
+const defaultConfigContent = `# agentu configuration
+# Replace the placeholder values below with your actual provider settings.
+# See agentu.example.yaml for the full reference.
+providers:
+  default:
+    base_url: https://api.openai.com
+    api_key: YOUR_API_KEY_HERE
+    models:
+      - id: gpt-4o
+        context: 128000
+      - id: gpt-4o-mini
+        context: 128000
+`
+
+func bootstrapConfig(configPath string) error {
+	resolved, err := config.ResolvePath(configPath)
+	if err != nil {
+		return fmt.Errorf("resolve config path: %w", err)
+	}
+	dir := filepath.Dir(resolved)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return fmt.Errorf("create config directory: %w", err)
+	}
+	if err := os.WriteFile(resolved, []byte(defaultConfigContent), 0o644); err != nil {
+		return fmt.Errorf("write default config: %w", err)
+	}
+	return nil
+}

internal/app/main_test.go

@@ -1,4 +1,4 @@
-package main
+package app
 
 import (
 	"context"

internal/app/repl.go

@@ -0,0 +1,60 @@
+package app
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"agentu/internal/agent"
+	"agentu/internal/session"
+)
+
+func repl(ctx context.Context, assistant *agent.Agent, modelManager *session.Manager) error {
+	scanner := bufio.NewScanner(os.Stdin)
+	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+
+	fmt.Println("agentu")
+	fmt.Println("Type /exit to quit, /clear to reset context, /compact to compress context.")
+	for {
+		fmt.Print("> ")
+		if !scanner.Scan() {
+			if err := scanner.Err(); err != nil {
+				return err
+			}
+			fmt.Println()
+			printExitSession(modelManager)
+			return nil
+		}
+
+		input := strings.TrimSpace(scanner.Text())
+		switch input {
+		case "":
+			continue
+		case "/exit", "/quit":
+			printExitSession(modelManager)
+			return nil
+		case "/clear":
+			assistant.Clear()
+			fmt.Println("context cleared")
+			continue
+		case "/compact":
+			if err := assistant.Compact(ctx); err != nil {
+				fmt.Fprintln(os.Stderr, "compact error:", err)
+			} else {
+				fmt.Println("context compacted")
+				if modelManager != nil {
+					_ = modelManager.Save()
+				}
+			}
+			continue
+		}
+
+		if err := assistant.RunTurn(ctx, input, os.Stdout, os.Stderr); err != nil {
+			fmt.Fprintln(os.Stderr, "\nerror:", err)
+		}
+		_ = modelManager.Save()
+		fmt.Println()
+	}
+}

internal/app/session_startup.go

@@ -0,0 +1,38 @@
+package app
+
+import (
+	"fmt"
+	"os"
+
+	"agentu/internal/session"
+)
+
+func initializeSession(modelManager *session.Manager, resumeID string) error {
+	if resumeID != "" {
+		if err := modelManager.Resume(resumeID); err != nil {
+			return fmt.Errorf("resume session: %w", err)
+		}
+		return nil
+	}
+	if _, err := modelManager.NewSession(); err != nil {
+		return fmt.Errorf("start new session: %w", err)
+	}
+	return nil
+}
+
+func printExitSession(m *session.Manager) {
+	if m == nil {
+		return
+	}
+	_ = m.Save()
+	id := m.CurrentSessionID()
+	name := m.CurrentSessionName()
+	if id != "" {
+		if name != "" && name != id {
+			fmt.Fprintf(os.Stderr, "session: %s (%s)\n", id, name)
+		} else {
+			fmt.Fprintf(os.Stderr, "session: %s\n", id)
+		}
+		fmt.Fprintf(os.Stderr, "resume:  agentu --resume %s\n", id)
+	}
+}

internal/session/manager.go

@@ -288,9 +288,13 @@ func (m *Manager) providerNames() []string {
 	return names
 }
 
+func (m *Manager) AvailableModels() []string {
+	return append([]string(nil), m.provider.Models...)
+}
+
 func contains(values []string, value string) bool {
-	for _, item := range values {
-		if item == value {
+	for _, v := range values {
+		if v == value {
 			return true
 		}
 	}

internal/session/manager_test.go

@@ -109,6 +109,18 @@ func TestManagerRejectsUnknownModelAndThinking(t *testing.T) {
 	}
 }
 
+func TestManagerExposesModelCommandCandidates(t *testing.T) {
+	manager, _, _ := testManager(t)
+	models := manager.AvailableModels()
+	if len(models) != 2 || models[0] != "model-a" || models[1] != "model-b" {
+		t.Fatalf("AvailableModels() = %v", models)
+	}
+	models[0] = "mutated"
+	if got := manager.AvailableModels()[0]; got != "model-a" {
+		t.Fatalf("mutation leaked: %q", got)
+	}
+}
+
 func TestManagerSaveAndResume(t *testing.T) {
 	manager, assistant, _ := testManager(t)
 

internal/tui/app.go

@@ -50,6 +50,7 @@ type ModelManager interface {
 	Rename(name string) (string, error)
 	Sessions() (string, error)
 	NewSession() (string, error)
+	AvailableModels() []string
 }
 
 func Run(ctx context.Context, assistant *agent.Agent, opts Options) error {
@@ -96,6 +97,7 @@ type model struct {
 	inputHistory  []string
 	historyIndex  int
 	draftInput    string
+	commandCursor int
 
 	running bool
 	cancel  context.CancelFunc
@@ -133,6 +135,13 @@ type commandMatch struct {
 	score   int
 }
 
+type commandSuggestion struct {
+	label       string
+	description string
+	value       string
+	executable  bool
+}
+
 var slashCommands = []slashCommand{
 	{Name: "/clear", Description: "reset context"},
 	{Name: "/compact", Description: "compress context"},
@@ -157,7 +166,7 @@ func newModel(ctx context.Context, assistant *agent.Agent, opts Options) model {
 	st := th.styles()
 
 	input := textarea.New()
-	input.Placeholder = "Message agentu..."
+	input.Placeholder = ""
 	input.Prompt = ""
 	input.ShowLineNumbers = false
 	input.MaxHeight = maxInputLines
@@ -197,8 +206,6 @@ func (m model) Init() tea.Cmd {
 	m.syncMessages()
 	return textarea.Blink
 }
-
-// syncMessages rebuilds the TUI display messages from the agent's conversation history.
 func (m *model) syncMessages() {
 	if m.agent == nil {
 		return
@@ -246,6 +253,9 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		if m.picking {
 			return m.updatePicker(msg)
 		}
+		if handled, next, cmd := m.updateCommandSuggestions(msg); handled {
+			return next, cmd
+		}
 		switch msg.String() {
 		case "ctrl+c":
 			if m.cancel != nil {
@@ -263,6 +273,29 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				return m, nil
 			}
 			return m.submit()
+		case "up":
+			if m.running {
+				return m, nil
+			}
+			if m.input.Line() == 0 {
+				m.previousInputHistory()
+				m.afterInputChanged()
+				return m, nil
+			}
+		case "down":
+			if m.running {
+				return m, nil
+			}
+			value := m.input.Value()
+			lineCount := 1
+			if value != "" {
+				lineCount = len(strings.Split(value, "\n"))
+			}
+			if m.input.Line() >= lineCount-1 {
+				m.nextInputHistory()
+				m.afterInputChanged()
+				return m, nil
+			}
 		case "ctrl+p":
 			if m.running {
 				return m, nil
@@ -277,7 +310,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			m.nextInputHistory()
 			m.afterInputChanged()
 			return m, nil
-		case "alt+enter", "ctrl+j":
+		case "ctrl+j":
 			return m.insertInputNewline()
 		}
 
@@ -338,7 +371,6 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	if !m.running {
 		nextInput, cmd := m.input.Update(msg)
 		m.input = nextInput
-		m.afterInputChanged()
 		cmds = append(cmds, cmd)
 	}
 
@@ -356,7 +388,7 @@ func (m model) View() string {
 
 	if m.picking {
 		parts := []string{m.viewport.View()}
-		parts = append(parts, m.pickerView(), m.modelMetaView(), m.footerView())
+		parts = append(parts, m.pickerView(), m.footerView())
 		body := lipgloss.JoinVertical(lipgloss.Left, parts...)
 		return m.styles.App.Width(m.width).Height(m.height).Render(body)
 	}
@@ -365,7 +397,7 @@ func (m model) View() string {
 	if activity := m.activityView(); activity != "" {
 		parts = append(parts, activity)
 	}
-	parts = append(parts, m.inputView(), m.modelMetaView(), m.footerView())
+	parts = append(parts, m.inputView(), m.footerView())
 	body := lipgloss.JoinVertical(lipgloss.Left, parts...)
 	return m.styles.App.Width(m.width).Height(m.height).Render(body)
 }
@@ -393,6 +425,10 @@ func (m *model) submit() (tea.Model, tea.Cmd) {
 		return m.runLocalCommand(input)
 	}
 
+	if strings.HasPrefix(input, "!") {
+		return m.runLocalCommand(input)
+	}
+
 	if strings.HasPrefix(input, "/") {
 		return m.runLocalCommand(input)
 	}
@@ -438,6 +474,16 @@ func (m *model) insertInputNewline() (tea.Model, tea.Cmd) {
 	m.historyIndex = -1
 	m.draftInput = ""
 	m.afterInputChanged()
+	// The textarea's repositionView was called inside Update with the old
+	// viewport height, so the YOffset may be stale after syncInputHeight
+	// changed the height. Send up then down to force repositionView to
+	// recalculate with the new height.
+	up := tea.KeyMsg{Type: tea.KeyUp}
+	vp, _ := m.input.Update(up)
+	m.input = vp
+	down := tea.KeyMsg{Type: tea.KeyDown}
+	vp, _ = m.input.Update(down)
+	m.input = vp
 	return *m, cmd
 }
 
@@ -467,7 +513,7 @@ func (m *model) appendAssistantChunk(chunk string) {
 
 func (m *model) resize() {
 	width := max(40, m.width)
-	inputWidth := max(20, width-m.styles.InputBox.GetHorizontalFrameSize())
+	inputWidth := max(20, width-m.styles.InputBox.GetHorizontalFrameSize()-m.inputModeWidth()-1)
 	m.input.SetWidth(inputWidth)
 	m.syncInputHeight()
 
@@ -668,72 +714,25 @@ type metaPill struct {
 	accent bool
 }
 
-func (m model) renderMetaPills(parts []metaPill) string {
-	if len(parts) == 0 {
-		return ""
+func (m model) inputModeView() string {
+	if strings.HasPrefix(strings.TrimSpace(m.input.Value()), "!") {
+		return m.styles.InputModeCommand.Render(iconCommand)
 	}
-
-	plain := make([]string, len(parts))
-	for i, part := range parts {
-		plain[i] = part.text
+	if m.yolo {
+		return m.styles.InputModeYolo.Render("Y")
 	}
-
-	width := max(1, m.width-2)
-	visible := len(plain)
-	for visible > 1 && lipgloss.Width(strings.Join(plain[:visible], " ")) > width {
-		visible--
-	}
-	if lipgloss.Width(strings.Join(plain[:visible], " ")) > width {
-		return m.styles.PillAccent.Render(fitLine(plain[0], width))
-	}
-
-	rendered := make([]string, 0, visible)
-	for i := 0; i < visible; i++ {
-		style := m.styles.Pill
-		if parts[i].accent {
-			style = m.styles.PillAccent
-		}
-		rendered = append(rendered, style.Render(parts[i].text))
-	}
-	return strings.Join(rendered, " ")
+	return m.styles.InputModeReadonly.Render("R")
 }
 
-func (m model) modelMetaView() string {
-	mode := "read-only tools"
-	if m.yolo {
-		mode = "yolo tools"
-	}
-
-	modelName := m.modelName
-	if m.models != nil {
-		if currentModel := m.models.CurrentModel(); currentModel != "" {
-			modelName = currentModel
-		}
-	}
-
-	parts := []metaPill{{text: iconModel + " " + modelName, accent: true}}
-	if m.models != nil {
-		if provider := m.models.CurrentProvider(); provider != "" {
-			parts = append(parts, metaPill{text: "provider " + provider})
-		}
-		if currentThinking := m.models.CurrentThinking(); currentThinking != "" && currentThinking != "unset" {
-			parts = append(parts, metaPill{text: "thinking " + currentThinking})
-		}
-		if sessionName := m.models.CurrentSessionName(); sessionName != "" {
-			parts = append(parts, metaPill{text: iconSession + " " + sessionName})
-		}
-	}
-	if m.contextUsage != "" {
-		parts = append(parts, metaPill{text: iconContext + " " + m.contextUsage})
-	}
-	parts = append(parts, metaPill{text: mode}, metaPill{text: "theme " + string(m.theme.Mode)})
-
-	return m.styles.ModelMeta.Width(max(1, m.width)).Render(m.renderMetaPills(parts))
+func (m model) inputModeWidth() int {
+	return lipgloss.Width(m.inputModeView())
 }
 
 func (m model) inputView() string {
 	palette := m.commandPaletteView()
-	box := m.styles.InputBox.Width(max(20, m.width-2)).Render(m.input.View())
+	gap := lipgloss.NewStyle().Background(m.styles.InputBox.GetBackground()).Render(" ")
+	content := lipgloss.JoinHorizontal(lipgloss.Top, m.inputModeView(), gap, m.input.View())
+	box := m.styles.InputBox.Width(max(20, m.width)).Render(content)
 	if palette != "" {
 		return lipgloss.JoinVertical(lipgloss.Left, palette, box)
 	}
@@ -751,13 +750,85 @@ func (m model) activityView() string {
 	line := m.styles.StatusInfo.Render(iconWorking) + " Working " + m.spinner.View() + " " + status + " · esc cancels"
 	return m.styles.Activity.Render(fitLine(line, max(1, m.width-2)))
 }
-
 func (m model) footerView() string {
-	hint := "enter send · ctrl+j newline · alt+enter newline · ctrl+p/ctrl+n history · / commands"
+	hint := ""
 	if m.running {
 		hint = "esc cancel · ctrl+c quit"
 	}
-	return m.styles.Footer.Width(max(1, m.width)).Render(fitLine(hint, max(1, m.width-2)))
+	if m.showCommandPalette() {
+		if sug, ok := m.selectedCommandSuggestion(); ok && sug.executable {
+			hint = "↑/↓ select · enter apply · tab fill"
+		}
+	}
+
+	inner := max(1, m.width-2) // Footer padding(0,1)
+	pills := m.modelMetaPillsClamped(inner / 3)
+	pillsW := lipgloss.Width(pills)
+
+	var line string
+	if pills != "" {
+		remain := max(1, inner-pillsW-1)
+		line = pills + " " + fitLine(hint, remain)
+	} else {
+		line = fitLine(hint, inner)
+	}
+	return m.styles.Footer.Width(max(1, m.width)).Render(line)
+}
+
+func (m model) modelMetaPillsClamped(maxW int) string {
+	modelName := m.modelName
+	if m.models != nil {
+		if currentModel := m.models.CurrentModel(); currentModel != "" {
+			modelName = currentModel
+		}
+	}
+
+	parts := []metaPill{{text: iconModel + " " + modelName, accent: true}}
+	if m.models != nil {
+		if provider := m.models.CurrentProvider(); provider != "" {
+			parts = append(parts, metaPill{text: provider})
+		}
+		if currentThinking := m.models.CurrentThinking(); currentThinking != "" && currentThinking != "unset" {
+			parts = append(parts, metaPill{text: currentThinking})
+		}
+		if sessionName := m.models.CurrentSessionName(); sessionName != "" {
+			parts = append(parts, metaPill{text: iconSession + " " + sessionName})
+		}
+	}
+	if m.contextUsage != "" {
+		parts = append(parts, metaPill{text: iconContext + " " + m.contextUsage})
+	}
+
+	return m.renderMetaPillsClamped(parts, maxW)
+}
+
+func (m model) renderMetaPillsClamped(parts []metaPill, width int) string {
+	if len(parts) == 0 {
+		return ""
+	}
+
+	plain := make([]string, len(parts))
+	for i, part := range parts {
+		plain[i] = part.text
+	}
+
+	visible := len(plain)
+	for visible > 1 && lipgloss.Width(strings.Join(plain[:visible], " ")) > width {
+		visible--
+	}
+	if visible > 0 && lipgloss.Width(strings.Join(plain[:visible], " ")) > width {
+		return ""
+	}
+
+	rendered := make([]string, 0, visible)
+	for i := 0; i < visible; i++ {
+		style := m.styles.Pill
+		if parts[i].accent {
+			style = m.styles.PillAccent
+		}
+		rendered = append(rendered, style.Render(parts[i].text))
+	}
+	return strings.Join(rendered, " ")
 }
 
 type eventWriter struct {
@@ -801,6 +872,7 @@ func isViewportKey(key string) bool {
 }
 
 func (m *model) afterInputChanged() {
+	m.commandCursor = 0
 	m.syncInputHeight()
 	if m.width > 0 && m.height > 0 {
 		m.resize()
@@ -882,18 +954,37 @@ func (m model) inputBlockHeight() int {
 }
 
 func (m model) commandPaletteHeight() int {
-	matches := commandMatches(commandPaletteQuery(m.input.Value()))
-	count := len(matches)
-	if count > maxCommandPaletteItems {
-		count = maxCommandPaletteItems
+	sugs := m.commandSuggestions()
+	total := len(sugs)
+	if !m.showCommandPalette() {
+		return 0
 	}
+	count := min(total, maxCommandPaletteItems)
 	if count == 0 {
 		count = 1
 	}
-	return 1 + count + m.styles.Palette.GetVerticalFrameSize()
+	scrollUp := 0
+	scrollDown := 0
+	if total > maxCommandPaletteItems {
+		visible := min(total, maxCommandPaletteItems)
+		scroll := max(0, m.commandCursor-visible+1)
+		if m.commandCursor < scroll {
+			scroll = m.commandCursor
+		}
+		if scroll > 0 {
+			scrollUp = 1
+		}
+		if scroll+visible < total {
+			scrollDown = 1
+		}
+	}
+	return 1 + scrollUp + count + scrollDown + m.styles.Palette.GetVerticalFrameSize()
 }
 
 func (m model) showCommandPalette() bool {
+	if len(m.commandSuggestions()) > 0 {
+		return true
+	}
 	value := strings.TrimSpace(m.input.Value())
 	return strings.HasPrefix(value, "/") && !strings.Contains(value, " ")
 }
@@ -902,18 +993,42 @@ func (m model) commandPaletteView() string {
 	if !m.showCommandPalette() {
 		return ""
 	}
-	matches := commandMatches(commandPaletteQuery(m.input.Value()))
+	sugs := m.commandSuggestions()
+	if len(sugs) > 0 {
+		header := iconCommand + " Commands"
+		if sugs[0].executable {
+			header = iconCommand + " Model candidates"
+		}
+		lines := []string{m.styles.Header.Render(header)}
+		m.clampCommandCursor()
+		total := len(sugs)
+		visible := min(total, maxCommandPaletteItems)
+		scroll := max(0, m.commandCursor-visible+1)
+		if m.commandCursor < scroll {
+			scroll = m.commandCursor
+		}
+		if scroll > 0 {
+			lines = append(lines, m.styles.Muted.Render("  ↑ more"))
+		}
+		for i := scroll; i < scroll+visible && i < total; i++ {
+			s := sugs[i]
+			prefix := "  "
+			if i == m.commandCursor {
+				prefix = "▸ "
+			}
+			lines = append(lines, fmt.Sprintf("%s%s %s", prefix, m.styles.PaletteMatch.Render(s.label), m.styles.Muted.Render(s.description)))
+		}
+		if scroll+visible < total {
+			lines = append(lines, m.styles.Muted.Render("  ↓ more"))
+		}
+		return m.styles.Palette.Width(max(20, m.width-2)).Render(strings.Join(lines, "\n"))
+	}
+	value := strings.TrimSpace(m.input.Value())
+	if strings.Contains(value, " ") {
+		return ""
+	}
 	lines := []string{m.styles.Header.Render(iconCommand + " Commands")}
-	if len(matches) == 0 {
 	lines = append(lines, m.styles.Muted.Render("No matching commands"))
-	} else {
-		for i, match := range matches {
-			if i >= maxCommandPaletteItems {
-				break
-			}
-			lines = append(lines, fmt.Sprintf("%s %s", m.styles.PaletteMatch.Render(match.command.Name), m.styles.Muted.Render(match.command.Description)))
-		}
-	}
 	return m.styles.Palette.Width(max(20, m.width-2)).Render(strings.Join(lines, "\n"))
 }
 
@@ -991,6 +1106,162 @@ func subsequenceScore(candidate string, query string, base int) (int, bool) {
 	return base + gaps, true
 }
 
+func (m model) commandSuggestions() []commandSuggestion {
+	input := m.input.Value()
+	if sugs := m.modelCommandSuggestions(input); len(sugs) > 0 {
+		return sugs
+	}
+	value := strings.TrimSpace(input)
+	if strings.HasPrefix(value, "/") && !strings.Contains(value, " ") {
+		return slashCommandSuggestions(commandPaletteQuery(input))
+	}
+	return nil
+}
+
+func slashCommandSuggestions(query string) []commandSuggestion {
+	matches := commandMatches(query)
+	sugs := make([]commandSuggestion, 0, len(matches))
+	for _, m := range matches {
+		sugs = append(sugs, commandSuggestion{
+			label:       m.command.Name,
+			description: m.command.Description,
+			value:       m.command.Name,
+		})
+	}
+	return sugs
+}
+
+func splitModelCommandTail(input string) (query string, ok bool) {
+	fields := strings.Fields(input)
+	if len(fields) == 0 || fields[0] != "/model" {
+		return "", false
+	}
+	hasTrailingSpace := strings.TrimRight(input, " \t") != input
+	switch len(fields) {
+	case 1:
+		if !hasTrailingSpace {
+			return "", false
+		}
+		return "", true
+	case 2:
+		if fields[1] == "provider" || fields[1] == "thinking" {
+			return "", false
+		}
+		if fields[1] == "model" {
+			if !hasTrailingSpace {
+				return "", false
+			}
+			return "", true
+		}
+		if hasTrailingSpace {
+			return fields[1], true
+		}
+		return fields[1], true
+	case 3:
+		if fields[1] != "model" {
+			return "", false
+		}
+		if hasTrailingSpace {
+			return fields[2], true
+		}
+		return fields[2], true
+	default:
+		return "", false
+	}
+}
+
+func (m model) modelCommandSuggestions(input string) []commandSuggestion {
+	if m.models == nil {
+		return nil
+	}
+	query, ok := splitModelCommandTail(input)
+	if !ok {
+		return nil
+	}
+	available := m.models.AvailableModels()
+	if len(available) == 0 {
+		return nil
+	}
+	current := m.models.CurrentModel()
+	candidates := make([]commandSuggestion, 0, len(available))
+	for _, id := range available {
+		desc := "switch model"
+		if id == current {
+			desc = "current model"
+		}
+		candidates = append(candidates, commandSuggestion{
+			label:       id,
+			description: desc,
+			value:       "/model model " + id,
+			executable:  true,
+		})
+	}
+	return scoredCommandSuggestions(candidates, query)
+}
+
+func scoredCommandSuggestions(candidates []commandSuggestion, query string) []commandSuggestion {
+	if query == "" {
+		return candidates
+	}
+	type scored struct {
+		sug   commandSuggestion
+		score int
+		idx   int
+	}
+	var kept []scored
+	for i, c := range candidates {
+		if s, ok := scoreCommandSuggestion(c.label, query); ok {
+			kept = append(kept, scored{sug: c, score: s, idx: i})
+		}
+	}
+	sort.Slice(kept, func(i, j int) bool {
+		if kept[i].score != kept[j].score {
+			return kept[i].score < kept[j].score
+		}
+		return kept[i].idx < kept[j].idx
+	})
+	out := make([]commandSuggestion, 0, len(kept))
+	for _, s := range kept {
+		out = append(out, s.sug)
+	}
+	return out
+}
+
+func scoreCommandSuggestion(label string, query string) (int, bool) {
+	query = strings.ToLower(strings.TrimSpace(query))
+	name := strings.ToLower(label)
+	if query == "" || query == name {
+		return 0, true
+	}
+	if strings.HasPrefix(name, query) {
+		return 100 + len(name) - len(query), true
+	}
+	return subsequenceScore(name, query, 200)
+}
+
+func (m model) selectedCommandSuggestion() (commandSuggestion, bool) {
+	sugs := m.commandSuggestions()
+	m.clampCommandCursor()
+	if m.commandCursor >= 0 && m.commandCursor < len(sugs) {
+		return sugs[m.commandCursor], true
+	}
+	return commandSuggestion{}, false
+}
+
+func (m *model) clampCommandCursor() {
+	sugs := m.commandSuggestions()
+	if len(sugs) == 0 {
+		m.commandCursor = 0
+		return
+	}
+	if m.commandCursor < 0 {
+		m.commandCursor = 0
+	}
+	if m.commandCursor >= len(sugs) {
+		m.commandCursor = len(sugs) - 1
+	}
+}
+
 func (m model) slashSuggestionCount() int {
 	return m.commandPaletteHeight()
 }
@@ -1007,11 +1278,7 @@ func (m model) modelInfo() string {
 	if m.models != nil {
 		return m.models.Info()
 	}
-	mode := "read-only tools"
-	if m.yolo {
-		mode = "yolo tools"
-	}
-	return fmt.Sprintf("model: %s\nmode: %s\ntheme: %s", m.modelName, mode, m.theme.Mode)
+	return m.modelName
 }
 
 func (m *model) refreshContextUsage() {
@@ -1146,7 +1413,31 @@ func (m *model) handleThemeCommand(input string) (tea.Model, tea.Cmd) {
 	return *m, nil
 }
 
+func (m model) handleBangCommand(input string) (string, error) {
+	command := strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(input), "!"))
+	if command == "" {
+		return "", fmt.Errorf("usage: ! <command>")
+	}
+	if !m.yolo {
+		return "", fmt.Errorf("shell command input requires --yolo")
+	}
+	out, err := m.runShellCommand(command)
+	if err != nil {
+		if strings.TrimSpace(out) != "" {
+			return "", fmt.Errorf("%s\n%w", strings.TrimRight(out, "\n"), err)
+		}
+		return "", err
+	}
+	if strings.TrimSpace(out) == "" {
+		return fmt.Sprintf("$ %s\n(no output)", command), nil
+	}
+	return out, nil
+}
+
 func (m model) handleLocalCommand(input string) (string, error) {
+	if strings.HasPrefix(strings.TrimSpace(input), "!") {
+		return m.handleBangCommand(input)
+	}
 	fields := strings.Fields(input)
 	if len(fields) == 0 {
 		return "", fmt.Errorf("empty command")
@@ -1342,6 +1633,41 @@ func (m *model) updatePicker(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	return *m, nil
 }
 
+func (m *model) updateCommandSuggestions(msg tea.KeyMsg) (bool, tea.Model, tea.Cmd) {
+	if m.running || len(m.commandSuggestions()) == 0 {
+		return false, *m, nil
+	}
+	m.clampCommandCursor()
+	switch msg.String() {
+	case "up":
+		if m.commandCursor > 0 {
+			m.commandCursor--
+		}
+		return true, *m, nil
+	case "down":
+		if m.commandCursor < len(m.commandSuggestions())-1 {
+			m.commandCursor++
+		}
+		return true, *m, nil
+	case "tab":
+		if sug, ok := m.selectedCommandSuggestion(); ok {
+			m.input.SetValue(sug.value)
+			m.afterInputChanged()
+		}
+		return true, *m, nil
+	case "enter":
+		if sug, ok := m.selectedCommandSuggestion(); ok && sug.executable {
+			m.rememberInput(sug.value)
+			m.input.SetValue(sug.value)
+			m.afterInputChanged()
+			next, cmd := m.runLocalCommand(sug.value)
+			return true, next, cmd
+		}
+		return false, *m, nil
+	}
+	return false, *m, nil
+}
+
 func (m model) pickerView() string {
 	if !m.picking || len(m.pickerItems) == 0 {
 		return ""

internal/tui/app_test.go

@@ -21,7 +21,7 @@ func TestModelRendersChatShell(t *testing.T) {
 	m = next.(model)
 	rendered := m.View()
 
-	for _, want := range []string{"test-model", "yolo tools", "light", "ctrl+j", "alt+enter", "ctrl+p/ctrl+n history"} {
+	for _, want := range []string{"test-model"} {
 		if !strings.Contains(rendered, want) {
 			t.Fatalf("rendered view missing %q:\n%s", want, rendered)
 		}
@@ -37,18 +37,16 @@ func TestModelRendersChatShell(t *testing.T) {
 	}
 }
 
-func TestInputTextDoesNotPaintBackground(t *testing.T) {
+func TestInputTextBackgroundMatchesInputBox(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model"})
-	for name, color := range map[string]any{
-		"input box":           m.styles.InputBox.GetBackground(),
+	want := lightTheme().InputBg
+	for name, color := range map[string]lipgloss.TerminalColor{
 		"focused base":        m.input.FocusedStyle.Base.GetBackground(),
 		"focused cursor line": m.input.FocusedStyle.CursorLine.GetBackground(),
 		"blurred base":        m.input.BlurredStyle.Base.GetBackground(),
 		"blurred cursor line": m.input.BlurredStyle.CursorLine.GetBackground(),
 	} {
-		if _, ok := color.(lipgloss.NoColor); !ok {
-			t.Fatalf("%s should not paint input text background", name)
-		}
+		requireStyleColor(t, name, color, want)
 	}
 }
 
@@ -58,12 +56,12 @@ func TestInputBoxIsRoomier(t *testing.T) {
 	m = next.(model)
 
 	if got := m.styles.InputBox.GetVerticalFrameSize(); got != 2 {
-		t.Fatalf("input box vertical frame should stay compact, got %d", got)
+		t.Fatalf("input box vertical frame should be 2 with vertical padding, got %d", got)
 	}
-	if got := m.styles.InputBox.GetHorizontalFrameSize(); got < 6 {
-		t.Fatalf("input box horizontal frame should include roomier padding, got %d", got)
+	if got := m.styles.InputBox.GetHorizontalFrameSize(); got != 3 {
+		t.Fatalf("input box horizontal frame should be 3 (asymmetric padding), got %d", got)
 	}
-	if got, want := m.input.Width(), 100-m.styles.InputBox.GetHorizontalFrameSize(); got != want {
+	if got, want := m.input.Width(), 100-m.styles.InputBox.GetHorizontalFrameSize()-m.inputModeWidth()-1; got != want {
 		t.Fatalf("input content width = %d, want %d", got, want)
 	}
 	rendered := m.inputView()
@@ -78,13 +76,8 @@ func TestModelMetaRendersBelowInput(t *testing.T) {
 	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
 	rendered := next.(model).View()
 
-	inputIndex := strings.Index(rendered, "Message agentu")
-	modelIndex := strings.Index(rendered, "test-model")
-	if inputIndex < 0 || modelIndex < 0 {
-		t.Fatalf("rendered view missing input or model meta:\n%s", rendered)
-	}
-	if modelIndex < inputIndex {
-		t.Fatalf("model meta should render below input:\n%s", rendered)
+	if !strings.Contains(rendered, "test-model") {
+		t.Fatalf("rendered view missing %q:\n%s", "test-model", rendered)
 	}
 }
 
@@ -93,7 +86,7 @@ func TestModelMetaRendersContextUsage(t *testing.T) {
 	assistant.SetMessages([]llm.Message{{Role: llm.RoleUser, Content: strings.Repeat("x", 800)}})
 	m := newModel(context.Background(), assistant, Options{ModelName: "test-model"})
 	next, _ := m.Update(tea.WindowSizeMsg{Width: 120, Height: 30})
-	rendered := next.(model).modelMetaView()
+	rendered := next.(model).footerView()
 
 	for _, want := range []string{"ctx ~", "/1k", "%"} {
 		if !strings.Contains(rendered, want) {
@@ -336,6 +329,23 @@ func TestInputHistoryNavigation(t *testing.T) {
 	}
 }
 
+func TestUpArrowRecallsPreviousInput(t *testing.T) {
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model"})
+	m.rememberInput("first")
+	m.rememberInput("second")
+
+	next, _ := m.Update(tea.KeyMsg{Type: tea.KeyUp})
+	m = next.(model)
+	if got := m.input.Value(); got != "second" {
+		t.Fatalf("after first up input = %q, want %q", got, "second")
+	}
+	next, _ = m.Update(tea.KeyMsg{Type: tea.KeyUp})
+	m = next.(model)
+	if got := m.input.Value(); got != "first" {
+		t.Fatalf("after second up input = %q, want %q", got, "first")
+	}
+}
+
 func TestToolMessageRendersStructuredCard(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model"})
 	m.messages = append(m.messages, message{role: roleTool, content: `file_read {"path":"README.md"}`})
@@ -480,16 +490,60 @@ func runInDir(t *testing.T, dir string, name string, args ...string) {
 	}
 }
 
+func TestBangShellCommandRunsFromInput(t *testing.T) {
+	dir := t.TempDir()
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true, WorkingDir: dir})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("! printf hello")
+	next, _ = m.submit()
+	m = next.(model)
+	if m.input.Value() != "" {
+		t.Fatalf("input not cleared after bang command: %q", m.input.Value())
+	}
+	rendered := stripANSI(m.renderMessages())
+	if !strings.Contains(rendered, "$ printf hello") {
+		t.Fatalf("rendered output missing shell echo:\n%s", rendered)
+	}
+	if !strings.Contains(rendered, "hello") {
+		t.Fatalf("rendered output missing 'hello':\n%s", rendered)
+	}
+}
+
+func TestBangShellCommandRequiresYolo(t *testing.T) {
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: false})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("! printf hello")
+	next, _ = m.submit()
+	m = next.(model)
+	rendered := stripANSI(m.renderMessages())
+	if !strings.Contains(rendered, "shell command input requires --yolo") {
+		t.Fatalf("rendered output missing yolo requirement:\n%s", rendered)
+	}
+}
+
+func TestBangShellCommandRejectsEmptyCommand(t *testing.T) {
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("!")
+	next, _ = m.submit()
+	m = next.(model)
+	rendered := stripANSI(m.renderMessages())
+	if !strings.Contains(rendered, "usage: ! <command>") {
+		t.Fatalf("rendered output missing usage hint:\n%s", rendered)
+	}
+}
+
 func TestModelCommand(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
 	m.input.SetValue("/model")
 
 	next, _ := m.submit()
 	rendered := next.(model).renderMessages()
-	for _, want := range []string{"model: test-model", "mode: yolo tools", "theme: light"} {
-		if !strings.Contains(rendered, want) {
-			t.Fatalf("model command output missing %q:\n%s", want, rendered)
-		}
+	if !strings.Contains(rendered, "test-model") {
+		t.Fatalf("model command output missing %q:\n%s", "test-model", rendered)
 	}
 }
 
@@ -508,11 +562,124 @@ func TestModelThinkingCommand(t *testing.T) {
 	}
 }
 
+func TestModelCommandPaletteShowsConfiguredModels(t *testing.T) {
+	manager := &fakeModelManager{model: "model-a", models: []string{"model-a", "model-b"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "model-a", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("/model ")
+	m.afterInputChanged()
+	plain := stripANSI(m.View())
+	for _, want := range []string{iconCommand + " Model candidates", "model-a", "current model", "model-b", "switch model"} {
+		if !strings.Contains(plain, want) {
+			t.Fatalf("rendered palette missing %q:\n%s", want, plain)
+		}
+	}
+}
+
+func TestModelCommandPaletteSelectsConfiguredModel(t *testing.T) {
+	manager := &fakeModelManager{model: "model-a", models: []string{"model-a", "model-b"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "model-a", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("/model ")
+	m.afterInputChanged()
+	next, _ = m.Update(tea.KeyMsg{Type: tea.KeyDown})
+	m = next.(model)
+	next, _ = m.Update(tea.KeyMsg{Type: tea.KeyEnter})
+	m = next.(model)
+	if manager.model != "model-b" {
+		t.Fatalf("model = %q", manager.model)
+	}
+	if got := m.input.Value(); got != "" {
+		t.Fatalf("input = %q", got)
+	}
+	rendered := stripANSI(m.renderMessages())
+	if !strings.Contains(rendered, "model: model-b") {
+		t.Fatalf("rendered output missing model switch:\n%s", rendered)
+	}
+}
+
+func TestModelCommandPaletteFiltersBareModelPartial(t *testing.T) {
+	manager := &fakeModelManager{model: "claude-sonnet", models: []string{"claude-sonnet", "deepseek-v4-flash"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "claude-sonnet", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("/model deep")
+	m.afterInputChanged()
+	palette := stripANSI(m.commandPaletteView())
+	if !strings.Contains(palette, "deepseek-v4-flash") {
+		t.Fatalf("expected deepseek-v4-flash in palette:\n%s", palette)
+	}
+	if strings.Contains(palette, "claude-sonnet") {
+		t.Fatalf("unexpected claude-sonnet in palette:\n%s", palette)
+	}
+}
+
+func TestModelCommandPaletteFiltersExplicitModelSubcommand(t *testing.T) {
+	manager := &fakeModelManager{model: "claude-sonnet", models: []string{"claude-sonnet", "deepseek-v4-flash"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "claude-sonnet", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("/model model deep")
+	m.afterInputChanged()
+	palette := stripANSI(m.commandPaletteView())
+	if !strings.Contains(palette, "deepseek-v4-flash") {
+		t.Fatalf("expected deepseek-v4-flash in palette:\n%s", palette)
+	}
+	if strings.Contains(palette, "claude-sonnet") {
+		t.Fatalf("unexpected claude-sonnet in palette:\n%s", palette)
+	}
+}
+
+func TestModelCommandPaletteTabFillsConfiguredModel(t *testing.T) {
+	manager := &fakeModelManager{model: "claude-sonnet", models: []string{"claude-sonnet", "deepseek-v4-flash"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "claude-sonnet", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+	m.input.SetValue("/model deep")
+	m.afterInputChanged()
+	next, _ = m.Update(tea.KeyMsg{Type: tea.KeyTab})
+	m = next.(model)
+	if got := m.input.Value(); got != "/model model deepseek-v4-flash" {
+		t.Fatalf("input = %q", got)
+	}
+	if manager.model != "claude-sonnet" {
+		t.Fatalf("model should not change on tab: %q", manager.model)
+	}
+}
+
+func TestModelCommandPaletteIgnoresProviderAndThinkingSubcommands(t *testing.T) {
+	manager := &fakeModelManager{model: "model-a", models: []string{"model-a", "model-b"}}
+	m := newModel(context.Background(), nil, Options{ModelName: "model-a", ModelManager: manager})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+
+	m.input.SetValue("/model provider ")
+	m.afterInputChanged()
+	if sugs := m.commandSuggestions(); len(sugs) != 0 {
+		t.Fatalf("provider suggestions should be empty, got %d", len(sugs))
+	}
+	if view := m.commandPaletteView(); view != "" {
+		t.Fatalf("provider palette should be empty:\n%s", view)
+	}
+
+	m.input.SetValue("/model thinking ")
+	m.afterInputChanged()
+	if sugs := m.commandSuggestions(); len(sugs) != 0 {
+		t.Fatalf("thinking suggestions should be empty, got %d", len(sugs))
+	}
+	if view := m.commandPaletteView(); view != "" {
+		t.Fatalf("thinking palette should be empty:\n%s", view)
+	}
+}
+
 type fakeModelManager struct {
 	provider    string
 	model       string
 	thinking    string
 	sessionName string
+	models      []string
 	saved       bool
 }
 
@@ -583,6 +750,16 @@ func (f *fakeModelManager) NewSession() (string, error) {
 	return "New session.", nil
 }
 
+func (f *fakeModelManager) AvailableModels() []string {
+	if len(f.models) > 0 {
+		return append([]string(nil), f.models...)
+	}
+	if f.model != "" {
+		return []string{f.model}
+	}
+	return nil
+}
+
 func TestParseThemeMode(t *testing.T) {
 	for input, want := range map[string]ThemeMode{
 		"":      ThemeLight,
@@ -627,9 +804,7 @@ func TestDarkThemePaintsAppBackground(t *testing.T) {
 	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
 	m = next.(model)
 	rendered := stripANSI(m.View())
-	if !strings.Contains(rendered, "theme dark") {
-		t.Fatalf("rendered view missing 'theme dark':\n%s", rendered)
-	}
+	_ = rendered
 	if m.theme.Mode != ThemeDark {
 		t.Fatalf("theme.Mode = %q, want %q", m.theme.Mode, ThemeDark)
 	}
@@ -643,8 +818,7 @@ func TestDarkThemeKeepsComponentBackgroundsLightweight(t *testing.T) {
 	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
 	m = next.(model)
 	requireNoStyleColor(t, "Viewport.Background", m.styles.Viewport.GetBackground())
-	requireNoStyleColor(t, "InputBox.Background", m.styles.InputBox.GetBackground())
-	requireNoStyleColor(t, "AssistantMsg.Background", m.styles.AssistantMsg.GetBackground())
+	requireStyleColor(t, "InputBox.Background", m.styles.InputBox.GetBackground(), darkTheme().InputBg)
 	requireNoStyleColor(t, "Activity.Background", m.styles.Activity.GetBackground())
 	m.running = true
 	m.status = "thinking..."
@@ -662,16 +836,34 @@ func TestDarkThemeStylesUseDarkPalette(t *testing.T) {
 	requireStyleColor(t, "Pill.Background", m.styles.Pill.GetBackground(), want.SurfaceAlt)
 	requireStyleColor(t, "input.FocusedStyle.Base.Foreground", m.input.FocusedStyle.Base.GetForeground(), want.Text)
 	requireStyleColor(t, "input.FocusedStyle.Placeholder.Foreground", m.input.FocusedStyle.Placeholder.GetForeground(), want.Muted)
+	requireStyleColor(t, "InputModeYolo.Foreground", m.styles.InputModeYolo.GetForeground(), want.Error)
+	requireStyleColor(t, "InputModeCommand.Foreground", m.styles.InputModeCommand.GetForeground(), want.User)
 }
 
-func TestModelCommandShowsDarkTheme(t *testing.T) {
-	m := newModel(context.Background(), nil, Options{ModelName: "test-model", ThemeMode: ThemeDark})
-	m.input.SetValue("/model")
-	next, _ := m.submit()
-	rendered := next.(model).renderMessages()
-	if !strings.Contains(rendered, "theme: dark") {
-		t.Fatalf("model command output missing 'theme: dark':\n%s", rendered)
+func TestInputModeSymbolReflectsYoloAndBangCommand(t *testing.T) {
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
+	m = next.(model)
+
+	rendered := stripANSI(m.inputView())
+	if !strings.Contains(rendered, "Y") {
+		t.Fatalf("YOLO input view should contain Y symbol:\n%s", rendered)
 	}
+
+	m.input.SetValue("! pwd")
+	m.afterInputChanged()
+	rendered = stripANSI(m.inputView())
+	if !strings.Contains(rendered, iconCommand) {
+		t.Fatalf("bang input view should contain command icon:\n%s", rendered)
+	}
+	if strings.Contains(rendered, "Y") {
+		t.Fatalf("bang input view should not contain Y symbol:\n%s", rendered)
+	}
+}
+
+func TestInputModeYoloUsesWarningColor(t *testing.T) {
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
+	requireStyleColor(t, "InputModeYolo.Foreground", m.styles.InputModeYolo.GetForeground(), lightTheme().Error)
 }
 
 func TestThemeSlashCommandSwitchesAtRuntime(t *testing.T) {

internal/tui/theme.go

@@ -43,6 +43,7 @@ type theme struct {
 	Background string
 	Surface    string
 	SurfaceAlt string
+	InputBg    string
 	Border     string
 	Text       string
 	Muted      string
@@ -60,11 +61,13 @@ type styles struct {
 	Muted             lipgloss.Style
 	Activity          lipgloss.Style
 	Header            lipgloss.Style
-	ModelMeta     lipgloss.Style
 	Footer            lipgloss.Style
 	Viewport          lipgloss.Style
 	InputBox          lipgloss.Style
 	CommandHint       lipgloss.Style
+	InputModeReadonly lipgloss.Style
+	InputModeYolo     lipgloss.Style
+	InputModeCommand  lipgloss.Style
 	StatusReady       lipgloss.Style
 	StatusWarn        lipgloss.Style
 	StatusError       lipgloss.Style
@@ -98,8 +101,8 @@ func lightTheme() theme {
 	return theme{
 		Mode:       ThemeLight,
 		Background: "#F8FAFC",
-		Surface:    "#FFFFFF",
 		SurfaceAlt: "#EEF2F7",
+		InputBg:    "#E4E4E4",
 		Border:     "#CBD5E1",
 		Text:       "#111827",
 		Muted:      "#64748B",
@@ -116,8 +119,8 @@ func darkTheme() theme {
 	return theme{
 		Mode:       ThemeDark,
 		Background: "#111827",
-		Surface:    "#1F2937",
 		SurfaceAlt: "#0F172A",
+		InputBg:    "#383838",
 		Border:     "#475569",
 		Text:       "#E5E7EB",
 		Muted:      "#94A3B8",
@@ -153,10 +156,6 @@ func (t theme) styles() styles {
 			Bold(true).
 			Foreground(lipgloss.Color(t.Title)),
 
-		ModelMeta: lipgloss.NewStyle().
-			Foreground(lipgloss.Color(t.Muted)).
-			Padding(0, 1),
-
 		Footer: lipgloss.NewStyle().
 			Foreground(lipgloss.Color(t.Muted)).
 			Padding(0, 1),
@@ -166,14 +165,31 @@ func (t theme) styles() styles {
 
 		InputBox: lipgloss.NewStyle().
 			Foreground(lipgloss.Color(t.Text)).
-			Border(lipgloss.ThickBorder()).
-			BorderForeground(lipgloss.Color(t.Border)).
-			Padding(0, 2),
+			Background(lipgloss.Color(t.InputBg)).
+			Padding(1, 2, 1, 1),
 
 		CommandHint: lipgloss.NewStyle().
 			Foreground(lipgloss.Color(t.Muted)).
 			Padding(0, 1),
 
+		InputModeReadonly: lipgloss.NewStyle().
+			Bold(true).
+			Foreground(lipgloss.Color(t.Muted)).
+			Background(lipgloss.Color(t.InputBg)).
+			Padding(0, 1),
+
+		InputModeYolo: lipgloss.NewStyle().
+			Bold(true).
+			Foreground(lipgloss.Color(t.Error)).
+			Background(lipgloss.Color(t.InputBg)).
+			Padding(0, 1),
+
+		InputModeCommand: lipgloss.NewStyle().
+			Bold(true).
+			Foreground(lipgloss.Color(t.User)).
+			Background(lipgloss.Color(t.InputBg)).
+			Padding(0, 1),
+
 		StatusReady: lipgloss.NewStyle().
 			Foreground(lipgloss.Color(t.Assistant)),
 
@@ -258,8 +274,10 @@ func bubbleMessageStyle(textColor, backgroundColor string) lipgloss.Style {
 func applyTextareaTheme(input *textarea.Model, t theme) {
 	focused := textarea.Style{
 		Base: lipgloss.NewStyle().
-			Foreground(lipgloss.Color(t.Text)),
-		CursorLine: lipgloss.NewStyle(),
+			Foreground(lipgloss.Color(t.Text)).
+			Background(lipgloss.Color(t.InputBg)),
+		CursorLine: lipgloss.NewStyle().
+			Background(lipgloss.Color(t.InputBg)),
 		Placeholder: lipgloss.NewStyle().
 			Foreground(lipgloss.Color(t.Muted)),
 		Prompt: lipgloss.NewStyle().
@@ -270,7 +288,7 @@ func applyTextareaTheme(input *textarea.Model, t theme) {
 			Foreground(lipgloss.Color(t.Surface)),
 	}
 	blurred := focused
-	blurred.CursorLine = lipgloss.NewStyle()
+	blurred.CursorLine = lipgloss.NewStyle().Background(lipgloss.Color(t.InputBg))
 
 	input.FocusedStyle = focused
 	input.BlurredStyle = blurred

main.go

@@ -1,228 +1,15 @@
 package main
 
 import (
-	"bufio"
-	"context"
-	"errors"
-	"flag"
 	"fmt"
-	"net/http"
 	"os"
-	"os/signal"
-	"path/filepath"
-	"strings"
 
-	"agentu/internal/agent"
-	"agentu/internal/session"
-	"agentu/internal/tools"
-	"agentu/internal/tui"
-	"agentu/pkg/config"
-	"agentu/pkg/llm"
+	"agentu/internal/app"
 )
 
-const defaultConfigContent = `# agentu configuration
-# Replace the placeholder values below with your actual provider settings.
-# See agentu.example.yaml for the full reference.
-providers:
-  default:
-    base_url: https://api.openai.com
-    api_key: YOUR_API_KEY_HERE
-    models:
-      - id: gpt-4o
-        context: 128000
-      - id: gpt-4o-mini
-        context: 128000
-`
-
 func main() {
-	if err := run(); err != nil {
+	if err := app.Run(); err != nil {
 		fmt.Fprintln(os.Stderr, "agentu:", err)
 		os.Exit(1)
 	}
 }
-
-func run() error {
-	configPath := flag.String("config", config.DefaultPath, "path to YAML config")
-	yolo := flag.Bool("yolo", false, "also enable automatic file writes and shell execution")
-	plain := flag.Bool("plain", false, "use the simple line-based REPL instead of the TUI")
-	themeName := flag.String("theme", "light", "TUI theme: light or dark")
-	resumeID := flag.String("resume", "", "resume a specific session by ID")
-	flag.Parse()
-
-	themeMode, err := tui.ParseThemeMode(*themeName)
-	if err != nil {
-		return err
-	}
-
-	cfg, err := config.Load(*configPath)
-	if err != nil {
-		if errors.Is(err, os.ErrNotExist) {
-			if bootstrapErr := bootstrapConfig(*configPath); bootstrapErr != nil {
-				return bootstrapErr
-			}
-			return fmt.Errorf("created default config at %s; edit it to set your API key and provider, then restart agentu", *configPath)
-		}
-		return err
-	}
-
-	providerName := cfg.DefaultProviderName()
-	providerConfig := cfg.Providers[providerName]
-	provider := llm.NewOpenAICompatibleClient(providerConfig.BaseURL, providerConfig.APIKey, http.DefaultClient)
-
-	var registry *tools.Registry
-	if *yolo {
-		registry = tools.Builtins(cfg.Agent.WorkingDir)
-	} else {
-		registry = tools.ReadOnlyBuiltins(cfg.Agent.WorkingDir)
-	}
-	registry.Register(tools.NewBuiltinSearchTool(http.DefaultClient))
-	registry.Register(tools.NewBuiltinFetchTool(http.DefaultClient))
-	systemPrompt := strings.TrimSpace(cfg.Agent.SystemPrompt + "\n\n" + tools.AgentInstructions(cfg.Agent.WorkingDir, *yolo))
-	maxContextTokens := cfg.Agent.MaxContextTokens
-	if maxContextTokens == 0 {
-		maxContextTokens = providerConfig.ContextTokens
-	}
-
-	assistant := agent.New(agent.Options{
-		Provider:         provider,
-		ProviderName:     providerName,
-		Model:            providerConfig.Model,
-		Thinking:         providerConfig.Thinking,
-		ThinkingParam:    providerConfig.ThinkingParam,
-		ThinkingEnabled:  providerConfig.ThinkingConfigured,
-		SystemPrompt:     systemPrompt,
-		ToolRegistry:     registry,
-		ToolTimeout:      cfg.Agent.ToolTimeout,
-		MaxContextTokens: maxContextTokens,
-	})
-
-	// Initialize session store
-	home, err := os.UserHomeDir()
-	if err != nil {
-		return fmt.Errorf("resolve home dir: %w", err)
-	}
-	sessionsDir := filepath.Join(home, ".agentu", "sessions")
-	store, err := session.NewStore(sessionsDir)
-	if err != nil {
-		return fmt.Errorf("init session store: %w", err)
-	}
-
-	modelManager, err := session.NewManager(cfg, assistant, http.DefaultClient, store)
-	if err != nil {
-		return err
-	}
-
-	if err := initializeSession(modelManager, *resumeID); err != nil {
-		return err
-	}
-
-	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
-	defer stop()
-
-	if !*plain {
-		err := tui.Run(ctx, assistant, tui.Options{
-			ModelName:    providerConfig.Model,
-			Yolo:         *yolo,
-			ThemeMode:    themeMode,
-			ModelManager: modelManager,
-			WorkingDir:   cfg.Agent.WorkingDir,
-		})
-		printExitSession(modelManager)
-		return err
-	}
-
-	return repl(ctx, assistant, modelManager)
-}
-
-func initializeSession(modelManager *session.Manager, resumeID string) error {
-	if resumeID != "" {
-		if err := modelManager.Resume(resumeID); err != nil {
-			return fmt.Errorf("resume session: %w", err)
-		}
-		return nil
-	}
-	if _, err := modelManager.NewSession(); err != nil {
-		return fmt.Errorf("start new session: %w", err)
-	}
-	return nil
-}
-
-func bootstrapConfig(configPath string) error {
-	resolved, err := config.ResolvePath(configPath)
-	if err != nil {
-		return fmt.Errorf("resolve config path: %w", err)
-	}
-	dir := filepath.Dir(resolved)
-	if err := os.MkdirAll(dir, 0o755); err != nil {
-		return fmt.Errorf("create config directory: %w", err)
-	}
-	if err := os.WriteFile(resolved, []byte(defaultConfigContent), 0o644); err != nil {
-		return fmt.Errorf("write default config: %w", err)
-	}
-	return nil
-}
-
-func repl(ctx context.Context, assistant *agent.Agent, modelManager *session.Manager) error {
-	scanner := bufio.NewScanner(os.Stdin)
-	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
-
-	fmt.Println("agentu")
-	fmt.Println("Type /exit to quit, /clear to reset context, /compact to compress context.")
-	for {
-		fmt.Print("> ")
-		if !scanner.Scan() {
-			if err := scanner.Err(); err != nil {
-				return err
-			}
-			fmt.Println()
-			printExitSession(modelManager)
-			return nil
-		}
-
-		input := strings.TrimSpace(scanner.Text())
-		switch input {
-		case "":
-			continue
-		case "/exit", "/quit":
-			printExitSession(modelManager)
-			return nil
-		case "/clear":
-			assistant.Clear()
-			fmt.Println("context cleared")
-			continue
-		case "/compact":
-			if err := assistant.Compact(ctx); err != nil {
-				fmt.Fprintln(os.Stderr, "compact error:", err)
-			} else {
-				fmt.Println("context compacted")
-				if modelManager != nil {
-					_ = modelManager.Save()
-				}
-			}
-			continue
-		}
-
-		if err := assistant.RunTurn(ctx, input, os.Stdout, os.Stderr); err != nil {
-			fmt.Fprintln(os.Stderr, "\nerror:", err)
-		}
-		_ = modelManager.Save()
-		fmt.Println()
-	}
-}
-
-func printExitSession(m *session.Manager) {
-	if m == nil {
-		return
-	}
-	_ = m.Save()
-	id := m.CurrentSessionID()
-	name := m.CurrentSessionName()
-	if id != "" {
-		if name != "" && name != id {
-			fmt.Fprintf(os.Stderr, "session: %s (%s)\n", id, name)
-		} else {
-			fmt.Fprintf(os.Stderr, "session: %s\n", id)
-		}
-		fmt.Fprintf(os.Stderr, "resume:  agentu --resume %s\n", id)
-	}
-}