diff --git a/internal/app/cli/cli.go b/internal/app/cli/cli.go
index 205a7eb..26c5033 100644
--- a/internal/app/cli/cli.go
+++ b/internal/app/cli/cli.go
@@ -11,6 +11,7 @@ import (
 	"fuku/internal/config/logger"
 )
 
+// Help text constants
 const (
 	Usage = `Usage:
   fuku                            Run services with default profile (with TUI)
diff --git a/internal/app/cli/commands.go b/internal/app/cli/commands.go
index 33f13f7..c077ac8 100644
--- a/internal/app/cli/commands.go
+++ b/internal/app/cli/commands.go
@@ -9,6 +9,7 @@ import (
 // CommandType represents the type of CLI command
 type CommandType int
 
+// Command type values
 const (
 	CommandRun CommandType = iota
 	CommandLogs
diff --git a/internal/app/logs/client.go b/internal/app/logs/client.go
index cafdef9..ede0013 100644
--- a/internal/app/logs/client.go
+++ b/internal/app/logs/client.go
@@ -23,6 +23,7 @@ type Client interface {
 	Close() error
 }
 
+// client implements the Client interface
 type client struct {
 	conn      net.Conn
 	formatter *LogFormatter
diff --git a/internal/app/logs/hub.go b/internal/app/logs/hub.go
index c94c34d..9f455be 100644
--- a/internal/app/logs/hub.go
+++ b/internal/app/logs/hub.go
@@ -48,6 +48,7 @@ func (c *ClientConn) ShouldReceive(service string) bool {
 	return c.Services[service]
 }
 
+// hub implements the Hub interface
 type hub struct {
 	clients    map[*ClientConn]bool
 	register   chan *ClientConn
diff --git a/internal/app/logs/protocol.go b/internal/app/logs/protocol.go
index f6c597e..cae7318 100644
--- a/internal/app/logs/protocol.go
+++ b/internal/app/logs/protocol.go
@@ -8,6 +8,7 @@ type Broadcaster interface {
 // MessageType represents the type of message in the wire protocol
 type MessageType string
 
+// Message types for the wire protocol
 const (
 	// MessageSubscribe is sent from client to server to subscribe to services
 	MessageSubscribe MessageType = "subscribe"
diff --git a/internal/app/logs/runner.go b/internal/app/logs/runner.go
index 43c691e..977942a 100644
--- a/internal/app/logs/runner.go
+++ b/internal/app/logs/runner.go
@@ -16,6 +16,7 @@ type Runner interface {
 	Run(profile string, services []string) int
 }
 
+// runner implements the Runner interface
 type runner struct {
 	client Client
 	log    logger.Logger
diff --git a/internal/app/logs/server.go b/internal/app/logs/server.go
index 30bd972..4e0daad 100644
--- a/internal/app/logs/server.go
+++ b/internal/app/logs/server.go
@@ -24,6 +24,7 @@ type Server interface {
 	SocketPath() string
 }
 
+// server implements the Server interface
 type server struct {
 	profile    string
 	socketPath string
@@ -124,6 +125,7 @@ func (s *server) Broadcast(service, message string) {
 	}
 }
 
+// cleanupStaleSocket removes stale socket file if not in use
 func (s *server) cleanupStaleSocket() error {
 	if _, err := os.Stat(s.socketPath); os.IsNotExist(err) {
 		return nil
@@ -141,6 +143,7 @@ func (s *server) cleanupStaleSocket() error {
 	return os.Remove(s.socketPath)
 }
 
+// acceptConnections handles incoming client connections
 func (s *server) acceptConnections(ctx context.Context) {
 	for s.running.Load() {
 		conn, err := s.listener.Accept()
@@ -162,6 +165,7 @@ func (s *server) acceptConnections(ctx context.Context) {
 	}
 }
 
+// handleConnection processes a single client connection
 func (s *server) handleConnection(ctx context.Context, conn net.Conn) {
 	defer conn.Close()
 
diff --git a/internal/app/monitor/monitor.go b/internal/app/monitor/monitor.go
index 7f33d51..add2e0f 100644
--- a/internal/app/monitor/monitor.go
+++ b/internal/app/monitor/monitor.go
@@ -18,6 +18,7 @@ type Monitor interface {
 	GetStats(ctx context.Context, pid int) (Stats, error)
 }
 
+// monitor implements the Monitor interface
 type monitor struct{}
 
 // NewMonitor creates a new Monitor instance
@@ -25,6 +26,7 @@ func NewMonitor() Monitor {
 	return &monitor{}
 }
 
+// GetStats retrieves CPU and memory statistics for a process
 func (m *monitor) GetStats(ctx context.Context, pid int) (Stats, error) {
 	if pid <= 0 || pid > math.MaxInt32 {
 		return Stats{}, nil
diff --git a/internal/app/runner/discovery.go b/internal/app/runner/discovery.go
index a72b1c7..aa552f9 100644
--- a/internal/app/runner/discovery.go
+++ b/internal/app/runner/discovery.go
@@ -19,6 +19,7 @@ type Discovery interface {
 	Resolve(profile string) ([]Tier, error)
 }
 
+// discovery implements the Discovery interface
 type discovery struct {
 	cfg      *config.Config
 	topology *config.Topology
diff --git a/internal/app/runner/lifecycle.go b/internal/app/runner/lifecycle.go
index 6f01514..5be25e0 100644
--- a/internal/app/runner/lifecycle.go
+++ b/internal/app/runner/lifecycle.go
@@ -16,6 +16,7 @@ type Lifecycle interface {
 	Terminate(proc Process, timeout time.Duration) error
 }
 
+// lifecycle implements the Lifecycle interface
 type lifecycle struct {
 	log logger.Logger
 }
@@ -59,10 +60,12 @@ func (l *lifecycle) Terminate(proc Process, timeout time.Duration) error {
 	}
 }
 
+// signalGroup sends a signal to the process group
 func (l *lifecycle) signalGroup(pid int, sig syscall.Signal) error {
 	return syscall.Kill(-pid, sig)
 }
 
+// forceKill sends SIGKILL to the process group
 func (l *lifecycle) forceKill(proc Process, pid int) error {
 	if err := syscall.Kill(-pid, syscall.SIGKILL); err != nil {
 		l.log.Warn().Err(err).Msgf("Failed to SIGKILL process group, trying direct kill")
diff --git a/internal/app/runner/process.go b/internal/app/runner/process.go
index 3b5039f..6739e98 100644
--- a/internal/app/runner/process.go
+++ b/internal/app/runner/process.go
@@ -16,6 +16,7 @@ type Process interface {
 	StderrReader() *io.PipeReader
 }
 
+// process implements the Process interface
 type process struct {
 	name         string
 	cmd          *exec.Cmd
@@ -25,22 +26,27 @@ type process struct {
 	stderrReader *io.PipeReader
 }
 
+// Name returns the service name
 func (p *process) Name() string {
 	return p.name
 }
 
+// Cmd returns the underlying exec command
 func (p *process) Cmd() *exec.Cmd {
 	return p.cmd
 }
 
+// Done returns a channel that closes when the process exits
 func (p *process) Done() <-chan struct{} {
 	return p.done
 }
 
+// Ready returns a channel that receives when the process is ready
 func (p *process) Ready() <-chan error {
 	return p.ready
 }
 
+// SignalReady signals the ready channel with optional error
 func (p *process) SignalReady(err error) {
 	if err != nil {
 		select {
@@ -52,10 +58,12 @@ func (p *process) SignalReady(err error) {
 	close(p.ready)
 }
 
+// StdoutReader returns the stdout pipe reader
 func (p *process) StdoutReader() *io.PipeReader {
 	return p.stdoutReader
 }
 
+// StderrReader returns the stderr pipe reader
 func (p *process) StderrReader() *io.PipeReader {
 	return p.stderrReader
 }
diff --git a/internal/app/runner/readiness.go b/internal/app/runner/readiness.go
index cafe094..5a95423 100644
--- a/internal/app/runner/readiness.go
+++ b/internal/app/runner/readiness.go
@@ -21,6 +21,7 @@ type Readiness interface {
 	Check(ctx context.Context, name string, service *config.Service, process Process)
 }
 
+// readiness implements the Readiness interface
 type readiness struct {
 	log logger.Logger
 }
diff --git a/internal/app/runner/runner.go b/internal/app/runner/runner.go
index 523a061..670f48d 100644
--- a/internal/app/runner/runner.go
+++ b/internal/app/runner/runner.go
@@ -21,6 +21,7 @@ type Runner interface {
 	Run(ctx context.Context, profile string) error
 }
 
+// runner implements the Runner interface
 type runner struct {
 	cfg       *config.Config
 	discovery Discovery
@@ -158,6 +159,7 @@ func (r *runner) Run(ctx context.Context, profile string) error {
 	return nil
 }
 
+// runStartupPhase handles the service startup phase and waits for completion or interruption
 func (r *runner) runStartupPhase(ctx context.Context, cancel context.CancelFunc, tiers []Tier, registry Registry, sigChan chan os.Signal, commandChan <-chan runtime.Command) error {
 	startupDone := make(chan struct{}, 1)
 
@@ -217,6 +219,7 @@ func (r *runner) runStartupPhase(ctx context.Context, cancel context.CancelFunc,
 	}
 }
 
+// runServicePhase runs the main event loop handling signals and commands
 func (r *runner) runServicePhase(ctx context.Context, cancel context.CancelFunc, sigChan chan os.Signal, registry Registry, commandChan <-chan runtime.Command) {
 	for {
 		select {
@@ -246,6 +249,7 @@ func (r *runner) runServicePhase(ctx context.Context, cancel context.CancelFunc,
 	}
 }
 
+// handleCommand processes a command and returns true if shutdown is requested
 func (r *runner) handleCommand(ctx context.Context, cmd runtime.Command, registry Registry) bool {
 	switch cmd.Type {
 	case runtime.CommandStopService:
@@ -274,6 +278,7 @@ func (r *runner) handleCommand(ctx context.Context, cmd runtime.Command, registr
 	return false
 }
 
+// stopService stops a single service by name
 func (r *runner) stopService(serviceName string, registry Registry) {
 	lookup := registry.Get(serviceName)
 	if !lookup.Exists {
@@ -293,6 +298,7 @@ func (r *runner) stopService(serviceName string, registry Registry) {
 	r.service.Stop(lookup.Proc)
 }
 
+// restartService stops and starts a service, or just starts if not running
 func (r *runner) restartService(ctx context.Context, serviceName string, registry Registry) {
 	lookup := registry.Get(serviceName)
 
@@ -346,6 +352,7 @@ func (r *runner) restartService(ctx context.Context, serviceName string, registr
 	}()
 }
 
+// startTier starts all services in a tier concurrently and returns failed service names
 func (r *runner) startTier(ctx context.Context, tierName string, tierServices []string, registry Registry) []string {
 	failedChan := make(chan string, len(tierServices))
 	procChan := make(chan Process, len(tierServices))
@@ -418,6 +425,7 @@ func (r *runner) startTier(ctx context.Context, tierName string, tierServices []
 	return failedServices
 }
 
+// startServiceWithRetry attempts to start a service with configurable retries
 func (r *runner) startServiceWithRetry(ctx context.Context, name string, tierName string, service *config.Service) (Process, error) {
 	var lastErr error
 
@@ -493,6 +501,7 @@ func (r *runner) startServiceWithRetry(ctx context.Context, name string, tierNam
 	return nil, fmt.Errorf("%w after %d attempts: %w", errors.ErrMaxRetriesExceeded, config.RetryAttempt, lastErr)
 }
 
+// startAllTiers starts services tier by tier in order
 func (r *runner) startAllTiers(ctx context.Context, tiers []Tier, registry Registry) {
 	for tierIdx, tier := range tiers {
 		if len(tier.Services) > 0 {
@@ -524,6 +533,7 @@ func (r *runner) startAllTiers(ctx context.Context, tiers []Tier, registry Regis
 	}
 }
 
+// shutdown stops all services in reverse order and waits for completion
 func (r *runner) shutdown(registry Registry) {
 	processes := registry.SnapshotReverse()
 
diff --git a/internal/app/runner/service.go b/internal/app/runner/service.go
index 4765638..e153782 100644
--- a/internal/app/runner/service.go
+++ b/internal/app/runner/service.go
@@ -16,6 +16,7 @@ import (
 	"fuku/internal/config/logger"
 )
 
+// Scanner buffer size constants
 const (
 	// scannerBufferSize is the initial buffer size for reading service output (64KB)
 	scannerBufferSize = 64 * 1024
@@ -30,6 +31,7 @@ type Service interface {
 	SetBroadcaster(broadcaster logs.Broadcaster)
 }
 
+// service implements the Service interface
 type service struct {
 	lifecycle   Lifecycle
 	readiness   Readiness
@@ -134,6 +136,7 @@ func (s *service) SetBroadcaster(broadcaster logs.Broadcaster) {
 	s.broadcaster = broadcaster
 }
 
+// teeStream reads from source and writes to destination while logging output
 func (s *service) teeStream(src io.Reader, dst *io.PipeWriter, serviceName, streamType string) {
 	scanner := bufio.NewScanner(src)
 	scanner.Buffer(make([]byte, scannerBufferSize), scannerMaxBufferSize)
@@ -156,11 +159,13 @@ func (s *service) teeStream(src io.Reader, dst *io.PipeWriter, serviceName, stre
 	}
 }
 
+// startDraining begins consuming both stdout and stderr pipes
 func (s *service) startDraining(stdout, stderr *io.PipeReader) {
 	go s.drainPipe(stdout)
 	go s.drainPipe(stderr)
 }
 
+// drainPipe consumes all data from a pipe until EOF
 func (s *service) drainPipe(reader *io.PipeReader) {
 	scanner := bufio.NewScanner(reader)
 	scanner.Buffer(make([]byte, scannerBufferSize), scannerMaxBufferSize)
@@ -173,6 +178,7 @@ func (s *service) drainPipe(reader *io.PipeReader) {
 	}
 }
 
+// handleReadinessCheck sets up the appropriate readiness check based on service config
 func (s *service) handleReadinessCheck(ctx context.Context, name string, svc *config.Service, proc *process, stdout, stderr *io.PipeReader) {
 	if svc.Readiness == nil {
 		proc.SignalReady(nil)
diff --git a/internal/app/runner/workerpool.go b/internal/app/runner/workerpool.go
index 5116f5f..4be3975 100644
--- a/internal/app/runner/workerpool.go
+++ b/internal/app/runner/workerpool.go
@@ -12,6 +12,7 @@ type WorkerPool interface {
 	Release()
 }
 
+// workerPool implements the WorkerPool interface
 type workerPool struct {
 	sem chan struct{}
 }
diff --git a/internal/app/runtime/commands.go b/internal/app/runtime/commands.go
index 253aa3f..df60cb4 100644
--- a/internal/app/runtime/commands.go
+++ b/internal/app/runtime/commands.go
@@ -8,6 +8,7 @@ import (
 // CommandType represents the type of command
 type CommandType string
 
+// Command types for service control
 const (
 	CommandStopService    CommandType = "stop_service"
 	CommandRestartService CommandType = "restart_service"
@@ -37,6 +38,7 @@ type CommandBus interface {
 	Close()
 }
 
+// commandBus implements the CommandBus interface
 type commandBus struct {
 	subscribers []chan Command
 	mu          sync.RWMutex
@@ -103,6 +105,7 @@ func (cb *commandBus) Close() {
 	cb.subscribers = nil
 }
 
+// unsubscribe removes a channel from subscribers and closes it
 func (cb *commandBus) unsubscribe(ch chan Command) {
 	cb.mu.Lock()
 	defer cb.mu.Unlock()
@@ -126,6 +129,7 @@ func NewNoOpCommandBus() CommandBus {
 	return &noOpCommandBus{}
 }
 
+// Subscribe returns a channel that closes when context is cancelled
 func (ncb *noOpCommandBus) Subscribe(ctx context.Context) <-chan Command {
 	ch := make(chan Command)
 
@@ -137,6 +141,8 @@ func (ncb *noOpCommandBus) Subscribe(ctx context.Context) <-chan Command {
 	return ch
 }
 
+// Publish is a no-op
 func (ncb *noOpCommandBus) Publish(cmd Command) {}
 
+// Close is a no-op
 func (ncb *noOpCommandBus) Close() {}
diff --git a/internal/app/runtime/events.go b/internal/app/runtime/events.go
index 40582b9..28f9972 100644
--- a/internal/app/runtime/events.go
+++ b/internal/app/runtime/events.go
@@ -9,6 +9,7 @@ import (
 // EventType represents the type of event
 type EventType string
 
+// Event types for runtime notifications
 const (
 	EventProfileResolved EventType = "profile_resolved"
 	EventPhaseChanged    EventType = "phase_changed"
@@ -26,6 +27,7 @@ const (
 // Phase represents the application phase
 type Phase string
 
+// Phase values for application lifecycle
 const (
 	PhaseStartup  Phase = "startup"
 	PhaseRunning  Phase = "running"
@@ -124,6 +126,7 @@ type EventBus interface {
 	Close()
 }
 
+// eventBus implements the EventBus interface
 type eventBus struct {
 	subscribers []chan Event
 	mu          sync.RWMutex
@@ -201,6 +204,7 @@ func (eb *eventBus) Close() {
 	eb.subscribers = nil
 }
 
+// unsubscribe removes a channel from subscribers and closes it
 func (eb *eventBus) unsubscribe(ch chan Event) {
 	eb.mu.Lock()
 	defer eb.mu.Unlock()
@@ -224,6 +228,7 @@ func NewNoOpEventBus() EventBus {
 	return &noOpEventBus{}
 }
 
+// Subscribe returns an immediately closed channel
 func (neb *noOpEventBus) Subscribe(ctx context.Context) <-chan Event {
 	ch := make(chan Event)
 	close(ch)
@@ -231,6 +236,8 @@ func (neb *noOpEventBus) Subscribe(ctx context.Context) <-chan Event {
 	return ch
 }
 
+// Publish is a no-op
 func (neb *noOpEventBus) Publish(event Event) {}
 
+// Close is a no-op
 func (neb *noOpEventBus) Close() {}
diff --git a/internal/app/ui/components/blink.go b/internal/app/ui/components/blink.go
index 2323234..4e13944 100644
--- a/internal/app/ui/components/blink.go
+++ b/internal/app/ui/components/blink.go
@@ -7,6 +7,7 @@ import (
 	"github.com/charmbracelet/lipgloss"
 )
 
+// Blink animation constants
 const (
 	empty = "◯"
 	full  = "◉"
@@ -46,8 +47,10 @@ type Blink struct {
 	state     state
 }
 
+// state represents the current phase of the blink animation
 type state int
 
+// Animation state phases
 const (
 	settle   state = iota // Settle phase (empty)
 	beat1                 // First beat (full)
diff --git a/internal/app/ui/components/constants.go b/internal/app/ui/components/constants.go
index 05195da..bf57d67 100644
--- a/internal/app/ui/components/constants.go
+++ b/internal/app/ui/components/constants.go
@@ -57,6 +57,7 @@ const (
 	ColWidthUptime    = 8
 )
 
+// Unit conversion constants
 const (
 	MBToGB = 1024
 )
diff --git a/internal/app/ui/components/layout.go b/internal/app/ui/components/layout.go
index 4190af8..d65ad0a 100644
--- a/internal/app/ui/components/layout.go
+++ b/internal/app/ui/components/layout.go
@@ -123,6 +123,7 @@ func Truncate(s string, maxWidth int) string {
 	return ellipsis
 }
 
+// buildTopBorder builds the top border with title and status
 func buildTopBorder(border func(string) string, titleText, topRightText string, middleWidth int) string {
 	hLine := func(n int) string { return strings.Repeat(BorderHorizontal, n) }
 	spacer := PanelTitleSpacer.Render("")
@@ -138,6 +139,7 @@ func buildTopBorder(border func(string) string, titleText, topRightText string,
 	return result
 }
 
+// buildBottomBorder builds the bottom border with version
 func buildBottomBorder(border func(string) string, bottomRightText string, innerWidth int) string {
 	hLine := func(n int) string { return strings.Repeat(BorderHorizontal, n) }
 
@@ -160,6 +162,7 @@ func buildBottomBorder(border func(string) string, bottomRightText string, inner
 	return result
 }
 
+// splitAndPadContent splits content into lines and pads to fill height
 func splitAndPadContent(content string, height int) []string {
 	lines := strings.Split(content, "\n")
 
@@ -174,6 +177,7 @@ func splitAndPadContent(content string, height int) []string {
 	return lines
 }
 
+// appendContentLines adds content lines with borders and padding
 func appendContentLines(result, contentLines []string, innerWidth int, border func(string) string) []string {
 	for _, line := range contentLines {
 		lineWidth := lipgloss.Width(line)
@@ -190,6 +194,7 @@ func appendContentLines(result, contentLines []string, innerWidth int, border fu
 	return result
 }
 
+// splitAtDisplayWidth splits a string at half its display width
 func splitAtDisplayWidth(s string) (left, right string) {
 	runes := []rune(s)
 	totalWidth := lipgloss.Width(s)
@@ -212,6 +217,7 @@ func splitAtDisplayWidth(s string) (left, right string) {
 	return string(runes[:splitIdx]), string(runes[splitIdx:])
 }
 
+// renderFooter renders the footer with help and tips
 func renderFooter(help, tips string, width int) string {
 	content := FooterStyle.Render(help)
 
diff --git a/internal/app/ui/services/controller.go b/internal/app/ui/services/controller.go
index 725727a..2032014 100644
--- a/internal/app/ui/services/controller.go
+++ b/internal/app/ui/services/controller.go
@@ -18,17 +18,19 @@ type Controller interface {
 	HandleStopped(ctx context.Context, service *ServiceState) bool
 }
 
+// controller implements the Controller interface
 type controller struct {
 	command runtime.CommandBus
 }
 
-// NewController creates a new service controller
+// NewController creates a new controller with the given command bus
 func NewController(command runtime.CommandBus) Controller {
 	return &controller{
 		command: command,
 	}
 }
 
+// Start requests a service start if it's currently stopped
 func (c *controller) Start(ctx context.Context, service *ServiceState) {
 	if service == nil || service.FSM == nil {
 		return
@@ -45,6 +47,7 @@ func (c *controller) Start(ctx context.Context, service *ServiceState) {
 	_ = service.FSM.Event(ctx, Start)
 }
 
+// Stop requests a service stop if it's currently running
 func (c *controller) Stop(ctx context.Context, service *ServiceState) {
 	if service == nil || service.FSM == nil {
 		return
@@ -62,6 +65,7 @@ func (c *controller) Stop(ctx context.Context, service *ServiceState) {
 	_ = service.FSM.Event(ctx, Stop)
 }
 
+// Restart requests a service restart if it's running, failed, or stopped
 func (c *controller) Restart(ctx context.Context, service *ServiceState) {
 	if service == nil || service.FSM == nil {
 		return
@@ -80,10 +84,12 @@ func (c *controller) Restart(ctx context.Context, service *ServiceState) {
 	_ = service.FSM.Event(ctx, Restart)
 }
 
+// StopAll sends a command to stop all services
 func (c *controller) StopAll() {
 	c.command.Publish(runtime.Command{Type: runtime.CommandStopAll})
 }
 
+// HandleStarting updates service state when a process starts
 func (c *controller) HandleStarting(ctx context.Context, service *ServiceState, pid int) {
 	if service == nil {
 		return
@@ -95,6 +101,7 @@ func (c *controller) HandleStarting(ctx context.Context, service *ServiceState,
 	}
 }
 
+// HandleReady updates service state when it becomes ready
 func (c *controller) HandleReady(ctx context.Context, service *ServiceState) {
 	if service == nil {
 		return
@@ -105,6 +112,7 @@ func (c *controller) HandleReady(ctx context.Context, service *ServiceState) {
 	}
 }
 
+// HandleFailed updates service state when it fails
 func (c *controller) HandleFailed(ctx context.Context, service *ServiceState) {
 	if service == nil {
 		return
@@ -115,6 +123,7 @@ func (c *controller) HandleFailed(ctx context.Context, service *ServiceState) {
 	}
 }
 
+// HandleStopped updates service state when it stops, returns true if it was restarting
 func (c *controller) HandleStopped(ctx context.Context, service *ServiceState) bool {
 	if service == nil {
 		return false
diff --git a/internal/app/ui/services/model.go b/internal/app/ui/services/model.go
index 793774a..64ab75a 100644
--- a/internal/app/ui/services/model.go
+++ b/internal/app/ui/services/model.go
@@ -20,6 +20,7 @@ import (
 // Status represents the status of a service
 type Status string
 
+// Status values for service lifecycle
 const (
 	StatusStarting Status = "Starting"
 	StatusRunning  Status = "Running"
diff --git a/internal/app/ui/services/monitor.go b/internal/app/ui/services/monitor.go
index 4a21942..dcb7d7c 100644
--- a/internal/app/ui/services/monitor.go
+++ b/internal/app/ui/services/monitor.go
@@ -31,6 +31,7 @@ func (m *Model) applyStatsUpdate(msg statsUpdateMsg) {
 	}
 }
 
+// updateBlinkAnimations updates blink state for services in transition states
 func (m *Model) updateBlinkAnimations() bool {
 	hasActiveBlinking := false
 
@@ -58,6 +59,7 @@ func (m *Model) updateBlinkAnimations() bool {
 	return hasActiveBlinking
 }
 
+// getUptime returns formatted uptime string for a service
 func (m *Model) getUptime(service *ServiceState) string {
 	if service.Status == StatusStopped || service.Status == StatusFailed || service.Monitor.StartTime.IsZero() {
 		return ""
@@ -75,6 +77,7 @@ func (m *Model) getUptime(service *ServiceState) string {
 	return pad(minutes) + ":" + pad(seconds)
 }
 
+// getCPU returns formatted CPU usage for a service
 func (m *Model) getCPU(service *ServiceState) string {
 	if !m.isServiceMonitored(service) {
 		return ""
@@ -83,6 +86,7 @@ func (m *Model) getCPU(service *ServiceState) string {
 	return fmt.Sprintf("%.1f%%", service.Monitor.CPU)
 }
 
+// getMem returns formatted memory usage for a service
 func (m *Model) getMem(service *ServiceState) string {
 	if !m.isServiceMonitored(service) {
 		return ""
@@ -95,6 +99,7 @@ func (m *Model) getMem(service *ServiceState) string {
 	return fmt.Sprintf("%.1fGB", service.Monitor.MEM/components.MBToGB)
 }
 
+// getPID returns the process ID string for a running service
 func (m *Model) getPID(service *ServiceState) string {
 	if service.Status == StatusRunning && service.Monitor.PID != 0 {
 		return fmt.Sprintf("%d", service.Monitor.PID)
@@ -103,10 +108,12 @@ func (m *Model) getPID(service *ServiceState) string {
 	return ""
 }
 
+// isServiceMonitored returns true if service has valid monitoring data
 func (m *Model) isServiceMonitored(service *ServiceState) bool {
 	return service.Status != StatusStopped && service.Status != StatusFailed && service.Monitor.PID != 0
 }
 
+// pad formats a number with leading zero
 func pad(n int) string {
 	return fmt.Sprintf("%02d", n)
 }
@@ -123,11 +130,13 @@ func statsWorkerCmd(ctx context.Context, m *Model) tea.Cmd {
 	})
 }
 
+// job represents a stats collection task
 type job struct {
 	name string
 	pid  int
 }
 
+// result holds stats collection output
 type result struct {
 	name  string
 	stats ServiceStats
@@ -169,6 +178,7 @@ func (m *Model) collectStats(ctx context.Context) map[string]ServiceStats {
 	return stats
 }
 
+// launchStatsWorkers spawns goroutines to collect stats concurrently
 func (m *Model) launchStatsWorkers(ctx context.Context, jobs []job, sem chan struct{}, results chan result) int {
 	launched := 0
 
diff --git a/internal/app/ui/services/state.go b/internal/app/ui/services/state.go
index 648df8e..7392ed3 100644
--- a/internal/app/ui/services/state.go
+++ b/internal/app/ui/services/state.go
@@ -35,6 +35,7 @@ const (
 	OnFailed     = "enter_failed"
 )
 
+// newServiceFSM creates a state machine for service lifecycle management
 func newServiceFSM(service *ServiceState, loader *Loader) *fsm.FSM {
 	serviceName := service.Name
 
diff --git a/internal/app/ui/services/update.go b/internal/app/ui/services/update.go
index 28675f2..409e67a 100644
--- a/internal/app/ui/services/update.go
+++ b/internal/app/ui/services/update.go
@@ -11,15 +11,19 @@ import (
 	"fuku/internal/app/ui/components"
 )
 
+// Tick timing constants
 const (
 	tickInterval       = components.UITickInterval
 	tickCounterMaximum = 1000000
 )
 
+// eventMsg wraps a runtime event for tea messaging
 type eventMsg runtime.Event
 
+// tickMsg signals a UI tick for animations
 type tickMsg time.Time
 
+// channelClosedMsg signals the event channel has closed
 type channelClosedMsg struct{}
 
 // Update handles messages and updates the model
@@ -89,6 +93,7 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleKeyPress processes keyboard input
 func (m Model) handleKeyPress(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	if key.Matches(msg, m.ui.servicesKeys.ForceQuit) {
 		m.log.Warn().Msg("TUI: Force quit requested, exiting immediately")
@@ -138,6 +143,7 @@ func (m Model) handleKeyPress(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleUpKey moves selection up one service
 func (m Model) handleUpKey() (tea.Model, tea.Cmd) {
 	if m.state.selected > 0 {
 		m.state.selected--
@@ -148,6 +154,7 @@ func (m Model) handleUpKey() (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleDownKey moves selection down one service
 func (m Model) handleDownKey() (tea.Model, tea.Cmd) {
 	total := m.getTotalServices()
 	if m.state.selected < total-1 {
@@ -159,6 +166,7 @@ func (m Model) handleDownKey() (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleStopKey toggles the selected service between running and stopped
 func (m Model) handleStopKey() (tea.Model, tea.Cmd) {
 	service := m.getSelectedService()
 	if service == nil || service.FSM == nil {
@@ -178,6 +186,7 @@ func (m Model) handleStopKey() (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleRestartKey restarts the selected service
 func (m Model) handleRestartKey() (tea.Model, tea.Cmd) {
 	service := m.getSelectedService()
 	if service == nil || service.FSM == nil {
@@ -189,6 +198,7 @@ func (m Model) handleRestartKey() (tea.Model, tea.Cmd) {
 	return m, m.loader.Model.Tick
 }
 
+// handleEvent dispatches runtime events to specific handlers
 func (m Model) handleEvent(event runtime.Event) (tea.Model, tea.Cmd) {
 	switch event.Type {
 	case runtime.EventProfileResolved:
@@ -215,6 +225,7 @@ func (m Model) handleEvent(event runtime.Event) (tea.Model, tea.Cmd) {
 	return m, waitForEventCmd(m.eventChan)
 }
 
+// handleProfileResolved initializes services from profile data
 func (m Model) handleProfileResolved(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.ProfileResolvedData)
 	if !ok {
@@ -250,6 +261,7 @@ func (m Model) handleProfileResolved(event runtime.Event) Model {
 	return m
 }
 
+// handlePhaseChanged updates the application phase state
 func (m Model) handlePhaseChanged(event runtime.Event) (Model, tea.Cmd) {
 	data, ok := event.Data.(runtime.PhaseChangedData)
 	if !ok {
@@ -266,6 +278,7 @@ func (m Model) handlePhaseChanged(event runtime.Event) (Model, tea.Cmd) {
 	return m, waitForEventCmd(m.eventChan)
 }
 
+// handleTierStarting marks a tier as not ready when starting
 func (m Model) handleTierStarting(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.TierStartingData)
 	if !ok {
@@ -282,6 +295,7 @@ func (m Model) handleTierStarting(event runtime.Event) Model {
 	return m
 }
 
+// handleTierReady marks a tier as ready
 func (m Model) handleTierReady(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.TierReadyData)
 	if !ok {
@@ -298,6 +312,7 @@ func (m Model) handleTierReady(event runtime.Event) Model {
 	return m
 }
 
+// handleServiceStarting updates a service when it begins starting
 func (m Model) handleServiceStarting(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.ServiceStartingData)
 	if !ok {
@@ -313,6 +328,7 @@ func (m Model) handleServiceStarting(event runtime.Event) Model {
 	return m
 }
 
+// handleServiceReady updates a service when it becomes ready
 func (m Model) handleServiceReady(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.ServiceReadyData)
 	if !ok {
@@ -329,6 +345,7 @@ func (m Model) handleServiceReady(event runtime.Event) Model {
 	return m
 }
 
+// handleServiceFailed updates a service when it fails
 func (m Model) handleServiceFailed(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.ServiceFailedData)
 	if !ok {
@@ -344,6 +361,7 @@ func (m Model) handleServiceFailed(event runtime.Event) Model {
 	return m
 }
 
+// handleServiceStopped updates a service when it stops
 func (m Model) handleServiceStopped(event runtime.Event) Model {
 	data, ok := event.Data.(runtime.ServiceStoppedData)
 	if !ok {
@@ -360,6 +378,7 @@ func (m Model) handleServiceStopped(event runtime.Event) Model {
 	return m
 }
 
+// waitForEventCmd returns a command that waits for the next event
 func waitForEventCmd(eventChan <-chan runtime.Event) tea.Cmd {
 	return func() tea.Msg {
 		event, ok := <-eventChan
@@ -371,6 +390,7 @@ func waitForEventCmd(eventChan <-chan runtime.Event) tea.Cmd {
 	}
 }
 
+// tickCmd returns a command that sends a tick after the interval
 func tickCmd() tea.Cmd {
 	return tea.Tick(tickInterval, func(t time.Time) tea.Msg {
 		return tickMsg(t)
diff --git a/internal/app/ui/services/view.go b/internal/app/ui/services/view.go
index 6f8ae1f..d8b3e58 100644
--- a/internal/app/ui/services/view.go
+++ b/internal/app/ui/services/view.go
@@ -34,6 +34,7 @@ func (m Model) View() string {
 	return components.AppContainerStyle.Render(panel)
 }
 
+// renderStatus renders the status bar with phase and service counts
 func (m Model) renderStatus() string {
 	ready := m.getReadyServices()
 	total := m.getTotalServices()
@@ -60,14 +61,17 @@ func (m Model) renderStatus() string {
 	)
 }
 
+// renderVersion renders the version string
 func (m Model) renderVersion() string {
 	return fmt.Sprintf("v%s", config.Version)
 }
 
+// renderHelp renders the help text with keybindings
 func (m Model) renderHelp() string {
 	return components.HelpStyle.Render(m.ui.help.View(m.ui.servicesKeys))
 }
 
+// renderTip returns the current rotating tip or empty string if tips disabled
 func (m Model) renderTip() string {
 	if !m.ui.showTips {
 		return ""
@@ -79,6 +83,7 @@ func (m Model) renderTip() string {
 	return components.Tips[tipIndex]
 }
 
+// renderTitle renders the title with optional loading spinner
 func (m Model) renderTitle() string {
 	if m.loader.Active {
 		var b strings.Builder
@@ -91,6 +96,7 @@ func (m Model) renderTitle() string {
 	return "services"
 }
 
+// renderServices renders the services list or empty state
 func (m Model) renderServices() string {
 	if len(m.state.tiers) == 0 {
 		return components.EmptyStateStyle.Render("No services configured")
@@ -99,6 +105,7 @@ func (m Model) renderServices() string {
 	return m.ui.servicesViewport.View()
 }
 
+// getRowWidth returns the available width for service rows
 func (m Model) getRowWidth() int {
 	rowWidth := m.ui.servicesViewport.Width
 	if rowWidth < 1 {
@@ -108,6 +115,7 @@ func (m Model) getRowWidth() int {
 	return rowWidth
 }
 
+// clampNameWidth constrains service name width to available space
 func (m Model) clampNameWidth(maxNameLen int) int {
 	availableWidth := m.getRowWidth() - components.FixedColumnsWidth
 	if availableWidth < components.ServiceNameMinWidth {
@@ -121,6 +129,7 @@ func (m Model) clampNameWidth(maxNameLen int) int {
 	return maxNameLen
 }
 
+// renderColumnHeaders renders the column headers row
 func (m Model) renderColumnHeaders(maxNameLen int) string {
 	rowWidth := m.getRowWidth()
 	maxNameLen = m.clampNameWidth(maxNameLen)
@@ -139,6 +148,7 @@ func (m Model) renderColumnHeaders(maxNameLen int) string {
 	return components.ServiceHeaderStyle.Width(rowWidth).Render(header)
 }
 
+// renderTier renders a tier header and its service rows
 func (m Model) renderTier(tier Tier, currentIdx *int, maxNameLen int) string {
 	rowWidth := m.getRowWidth()
 	rows := make([]string, 0, len(tier.Services)+1)
@@ -162,6 +172,7 @@ func (m Model) renderTier(tier Tier, currentIdx *int, maxNameLen int) string {
 	return components.TierContainerStyle.Render(content)
 }
 
+// getServiceIndicator returns the selection or status indicator for a service
 func (m Model) getServiceIndicator(service *ServiceState, isSelected bool) string {
 	defaultIndicator := components.IndicatorEmpty
 	if isSelected {
@@ -188,6 +199,7 @@ func (m Model) getServiceIndicator(service *ServiceState, isSelected bool) strin
 	return service.Blink.Render(components.IndicatorActiveStyle)
 }
 
+// renderServiceRow renders a single service row with all columns
 func (m Model) renderServiceRow(service *ServiceState, isSelected bool, maxNameLen int) string {
 	rowWidth := m.getRowWidth()
 	maxNameLen = m.clampNameWidth(maxNameLen)
@@ -227,6 +239,7 @@ func (m Model) renderServiceRow(service *ServiceState, isSelected bool, maxNameL
 	return components.ServiceRowStyle.Width(rowWidth).Render(row)
 }
 
+// getStyledAndPaddedStatus returns the styled status string with padding
 func (m Model) getStyledAndPaddedStatus(service *ServiceState, isSelected bool) string {
 	statusStr := string(service.Status)
 	padding := strings.Repeat(components.IndicatorEmpty, components.ColWidthStatus-len(statusStr))
diff --git a/internal/config/logger/logger.go b/internal/config/logger/logger.go
index f6fe71d..207fb3c 100644
--- a/internal/config/logger/logger.go
+++ b/internal/config/logger/logger.go
@@ -12,6 +12,7 @@ import (
 	"fuku/internal/config"
 )
 
+// Logger configuration constants
 const (
 	DebugLevel = "debug"
 	InfoLevel  = "info"