feat: add gt daemon for town-level background service

Implements the town daemon (gt-99m) that handles: - Periodic heartbeat to poke Mayor and Witnesses - Lifecycle request processing (cycle, restart, shutdown) - Session management for agent restarts Commands: - gt daemon start: Start daemon in background - gt daemon stop: Stop running daemon - gt daemon status: Show daemon status and stats - gt daemon logs: View daemon log file The daemon is a "dumb scheduler" - all intelligence remains in agents. It simply pokes them on schedule and executes lifecycle requests. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2025-12-18 13:06:20 -08:00
parent 7f29a048a5
commit 1265df70f9
4 changed files with 835 additions and 0 deletions
--- a/internal/cmd/daemon.go
+++ b/internal/cmd/daemon.go
@@ -0,0 +1,233 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"time"
+
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/daemon"
+	"github.com/steveyegge/gastown/internal/style"
+	"github.com/steveyegge/gastown/internal/workspace"
+)
+
+var daemonCmd = &cobra.Command{
+	Use:   "daemon",
+	Short: "Manage the Gas Town daemon",
+	Long: `Manage the Gas Town background daemon.
+
+The daemon is a simple Go process that:
+- Pokes agents periodically (heartbeat)
+- Processes lifecycle requests (cycle, restart, shutdown)
+- Restarts sessions when agents request cycling
+
+The daemon is a "dumb scheduler" - all intelligence is in agents.`,
+}
+
+var daemonStartCmd = &cobra.Command{
+	Use:   "start",
+	Short: "Start the daemon",
+	Long: `Start the Gas Town daemon in the background.
+
+The daemon will run until stopped with 'gt daemon stop'.`,
+	RunE: runDaemonStart,
+}
+
+var daemonStopCmd = &cobra.Command{
+	Use:   "stop",
+	Short: "Stop the daemon",
+	Long:  `Stop the running Gas Town daemon.`,
+	RunE:  runDaemonStop,
+}
+
+var daemonStatusCmd = &cobra.Command{
+	Use:   "status",
+	Short: "Show daemon status",
+	Long:  `Show the current status of the Gas Town daemon.`,
+	RunE:  runDaemonStatus,
+}
+
+var daemonLogsCmd = &cobra.Command{
+	Use:   "logs",
+	Short: "View daemon logs",
+	Long:  `View the daemon log file.`,
+	RunE:  runDaemonLogs,
+}
+
+var daemonRunCmd = &cobra.Command{
+	Use:    "run",
+	Short:  "Run daemon in foreground (internal)",
+	Hidden: true,
+	RunE:   runDaemonRun,
+}
+
+var (
+	daemonLogLines int
+	daemonLogFollow bool
+)
+
+func init() {
+	daemonCmd.AddCommand(daemonStartCmd)
+	daemonCmd.AddCommand(daemonStopCmd)
+	daemonCmd.AddCommand(daemonStatusCmd)
+	daemonCmd.AddCommand(daemonLogsCmd)
+	daemonCmd.AddCommand(daemonRunCmd)
+
+	daemonLogsCmd.Flags().IntVarP(&daemonLogLines, "lines", "n", 50, "Number of lines to show")
+	daemonLogsCmd.Flags().BoolVarP(&daemonLogFollow, "follow", "f", false, "Follow log output")
+
+	rootCmd.AddCommand(daemonCmd)
+}
+
+func runDaemonStart(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	// Check if already running
+	running, pid, err := daemon.IsRunning(townRoot)
+	if err != nil {
+		return fmt.Errorf("checking daemon status: %w", err)
+	}
+	if running {
+		return fmt.Errorf("daemon already running (PID %d)", pid)
+	}
+
+	// Start daemon in background
+	// We use 'gt daemon run' as the actual daemon process
+	gtPath, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("finding executable: %w", err)
+	}
+
+	daemonCmd := exec.Command(gtPath, "daemon", "run")
+	daemonCmd.Dir = townRoot
+
+	// Detach from terminal
+	daemonCmd.Stdin = nil
+	daemonCmd.Stdout = nil
+	daemonCmd.Stderr = nil
+
+	if err := daemonCmd.Start(); err != nil {
+		return fmt.Errorf("starting daemon: %w", err)
+	}
+
+	// Wait a moment for the daemon to initialize
+	time.Sleep(200 * time.Millisecond)
+
+	// Verify it started
+	running, pid, err = daemon.IsRunning(townRoot)
+	if err != nil {
+		return fmt.Errorf("checking daemon status: %w", err)
+	}
+	if !running {
+		return fmt.Errorf("daemon failed to start (check logs with 'gt daemon logs')")
+	}
+
+	fmt.Printf("%s Daemon started (PID %d)\n", style.Bold.Render("✓"), pid)
+	return nil
+}
+
+func runDaemonStop(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	running, pid, err := daemon.IsRunning(townRoot)
+	if err != nil {
+		return fmt.Errorf("checking daemon status: %w", err)
+	}
+	if !running {
+		return fmt.Errorf("daemon is not running")
+	}
+
+	if err := daemon.StopDaemon(townRoot); err != nil {
+		return fmt.Errorf("stopping daemon: %w", err)
+	}
+
+	fmt.Printf("%s Daemon stopped (was PID %d)\n", style.Bold.Render("✓"), pid)
+	return nil
+}
+
+func runDaemonStatus(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	running, pid, err := daemon.IsRunning(townRoot)
+	if err != nil {
+		return fmt.Errorf("checking daemon status: %w", err)
+	}
+
+	if running {
+		fmt.Printf("%s Daemon is %s (PID %d)\n",
+			style.Bold.Render("●"),
+			style.Bold.Render("running"),
+			pid)
+
+		// Load state for more details
+		state, err := daemon.LoadState(townRoot)
+		if err == nil && !state.StartedAt.IsZero() {
+			fmt.Printf("  Started: %s\n", state.StartedAt.Format("2006-01-02 15:04:05"))
+			if !state.LastHeartbeat.IsZero() {
+				fmt.Printf("  Last heartbeat: %s (#%d)\n",
+					state.LastHeartbeat.Format("15:04:05"),
+					state.HeartbeatCount)
+			}
+		}
+	} else {
+		fmt.Printf("%s Daemon is %s\n",
+			style.Dim.Render("○"),
+			"not running")
+		fmt.Printf("\nStart with: %s\n", style.Dim.Render("gt daemon start"))
+	}
+
+	return nil
+}
+
+func runDaemonLogs(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	logFile := filepath.Join(townRoot, "daemon", "daemon.log")
+
+	if _, err := os.Stat(logFile); os.IsNotExist(err) {
+		return fmt.Errorf("no log file found at %s", logFile)
+	}
+
+	if daemonLogFollow {
+		// Use tail -f for following
+		tailCmd := exec.Command("tail", "-f", logFile)
+		tailCmd.Stdout = os.Stdout
+		tailCmd.Stderr = os.Stderr
+		return tailCmd.Run()
+	}
+
+	// Use tail -n for last N lines
+	tailCmd := exec.Command("tail", "-n", fmt.Sprintf("%d", daemonLogLines), logFile)
+	tailCmd.Stdout = os.Stdout
+	tailCmd.Stderr = os.Stderr
+	return tailCmd.Run()
+}
+
+func runDaemonRun(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	config := daemon.DefaultConfig(townRoot)
+	d, err := daemon.New(config)
+	if err != nil {
+		return fmt.Errorf("creating daemon: %w", err)
+	}
+
+	return d.Run()
+}
--- a/internal/daemon/daemon.go
+++ b/internal/daemon/daemon.go
@@ -0,0 +1,274 @@
+package daemon
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strconv"
+	"syscall"
+	"time"
+
+	"github.com/steveyegge/gastown/internal/tmux"
+)
+
+// Daemon is the town-level background service.
+type Daemon struct {
+	config *Config
+	tmux   *tmux.Tmux
+	logger *log.Logger
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+// New creates a new daemon instance.
+func New(config *Config) (*Daemon, error) {
+	// Ensure daemon directory exists
+	daemonDir := filepath.Dir(config.LogFile)
+	if err := os.MkdirAll(daemonDir, 0755); err != nil {
+		return nil, fmt.Errorf("creating daemon directory: %w", err)
+	}
+
+	// Open log file
+	logFile, err := os.OpenFile(config.LogFile, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
+	if err != nil {
+		return nil, fmt.Errorf("opening log file: %w", err)
+	}
+
+	logger := log.New(logFile, "", log.LstdFlags)
+	ctx, cancel := context.WithCancel(context.Background())
+
+	return &Daemon{
+		config: config,
+		tmux:   tmux.NewTmux(),
+		logger: logger,
+		ctx:    ctx,
+		cancel: cancel,
+	}, nil
+}
+
+// Run starts the daemon main loop.
+func (d *Daemon) Run() error {
+	d.logger.Printf("Daemon starting (PID %d)", os.Getpid())
+
+	// Write PID file
+	if err := os.WriteFile(d.config.PidFile, []byte(strconv.Itoa(os.Getpid())), 0644); err != nil {
+		return fmt.Errorf("writing PID file: %w", err)
+	}
+	defer os.Remove(d.config.PidFile)
+
+	// Update state
+	state := &State{
+		Running:   true,
+		PID:       os.Getpid(),
+		StartedAt: time.Now(),
+	}
+	if err := SaveState(d.config.TownRoot, state); err != nil {
+		d.logger.Printf("Warning: failed to save state: %v", err)
+	}
+
+	// Handle signals
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	// Heartbeat ticker
+	ticker := time.NewTicker(d.config.HeartbeatInterval)
+	defer ticker.Stop()
+
+	d.logger.Printf("Daemon running, heartbeat every %v", d.config.HeartbeatInterval)
+
+	// Initial heartbeat
+	d.heartbeat(state)
+
+	for {
+		select {
+		case <-d.ctx.Done():
+			d.logger.Println("Daemon context cancelled, shutting down")
+			return d.shutdown(state)
+
+		case sig := <-sigChan:
+			d.logger.Printf("Received signal %v, shutting down", sig)
+			return d.shutdown(state)
+
+		case <-ticker.C:
+			d.heartbeat(state)
+		}
+	}
+}
+
+// heartbeat performs one heartbeat cycle.
+func (d *Daemon) heartbeat(state *State) {
+	d.logger.Println("Heartbeat starting")
+
+	// 1. Poke Mayor
+	d.pokeMayor()
+
+	// 2. Poke Witnesses (for each rig)
+	d.pokeWitnesses()
+
+	// 3. Process lifecycle requests
+	d.processLifecycleRequests()
+
+	// Update state
+	state.LastHeartbeat = time.Now()
+	state.HeartbeatCount++
+	if err := SaveState(d.config.TownRoot, state); err != nil {
+		d.logger.Printf("Warning: failed to save state: %v", err)
+	}
+
+	d.logger.Printf("Heartbeat complete (#%d)", state.HeartbeatCount)
+}
+
+// pokeMayor sends a heartbeat to the Mayor session.
+func (d *Daemon) pokeMayor() {
+	const mayorSession = "gt-mayor"
+
+	running, err := d.tmux.HasSession(mayorSession)
+	if err != nil {
+		d.logger.Printf("Error checking Mayor session: %v", err)
+		return
+	}
+
+	if !running {
+		d.logger.Println("Mayor session not running, skipping poke")
+		return
+	}
+
+	// Send heartbeat message via tmux
+	msg := "HEARTBEAT: check your rigs"
+	if err := d.tmux.SendKeys(mayorSession, msg); err != nil {
+		d.logger.Printf("Error poking Mayor: %v", err)
+		return
+	}
+
+	d.logger.Println("Poked Mayor")
+}
+
+// pokeWitnesses sends heartbeats to all Witness sessions.
+func (d *Daemon) pokeWitnesses() {
+	// Find all rigs by looking for witness sessions
+	// Session naming: gt-<rig>-witness
+	sessions, err := d.tmux.ListSessions()
+	if err != nil {
+		d.logger.Printf("Error listing sessions: %v", err)
+		return
+	}
+
+	for _, session := range sessions {
+		// Check if it's a witness session
+		if !isWitnessSession(session) {
+			continue
+		}
+
+		msg := "HEARTBEAT: check your workers"
+		if err := d.tmux.SendKeys(session, msg); err != nil {
+			d.logger.Printf("Error poking Witness %s: %v", session, err)
+			continue
+		}
+
+		d.logger.Printf("Poked Witness: %s", session)
+	}
+}
+
+// isWitnessSession checks if a session name is a witness session.
+func isWitnessSession(name string) bool {
+	// Pattern: gt-<rig>-witness
+	if len(name) < 12 { // "gt-x-witness" minimum
+		return false
+	}
+	return name[:3] == "gt-" && name[len(name)-8:] == "-witness"
+}
+
+// processLifecycleRequests checks for and processes lifecycle requests.
+func (d *Daemon) processLifecycleRequests() {
+	d.ProcessLifecycleRequests()
+}
+
+// shutdown performs graceful shutdown.
+func (d *Daemon) shutdown(state *State) error {
+	d.logger.Println("Daemon shutting down")
+
+	state.Running = false
+	if err := SaveState(d.config.TownRoot, state); err != nil {
+		d.logger.Printf("Warning: failed to save final state: %v", err)
+	}
+
+	d.logger.Println("Daemon stopped")
+	return nil
+}
+
+// Stop signals the daemon to stop.
+func (d *Daemon) Stop() {
+	d.cancel()
+}
+
+// IsRunning checks if a daemon is running for the given town.
+func IsRunning(townRoot string) (bool, int, error) {
+	pidFile := filepath.Join(townRoot, "daemon", "daemon.pid")
+	data, err := os.ReadFile(pidFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, 0, nil
+		}
+		return false, 0, err
+	}
+
+	pid, err := strconv.Atoi(string(data))
+	if err != nil {
+		return false, 0, nil
+	}
+
+	// Check if process is running
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		return false, 0, nil
+	}
+
+	// On Unix, FindProcess always succeeds. Send signal 0 to check if alive.
+	err = process.Signal(syscall.Signal(0))
+	if err != nil {
+		// Process not running, clean up stale PID file
+		os.Remove(pidFile)
+		return false, 0, nil
+	}
+
+	return true, pid, nil
+}
+
+// StopDaemon stops the running daemon for the given town.
+func StopDaemon(townRoot string) error {
+	running, pid, err := IsRunning(townRoot)
+	if err != nil {
+		return err
+	}
+	if !running {
+		return fmt.Errorf("daemon is not running")
+	}
+
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		return fmt.Errorf("finding process: %w", err)
+	}
+
+	// Send SIGTERM for graceful shutdown
+	if err := process.Signal(syscall.SIGTERM); err != nil {
+		return fmt.Errorf("sending SIGTERM: %w", err)
+	}
+
+	// Wait a bit for graceful shutdown
+	time.Sleep(500 * time.Millisecond)
+
+	// Check if still running
+	if err := process.Signal(syscall.Signal(0)); err == nil {
+		// Still running, force kill
+		process.Signal(syscall.SIGKILL)
+	}
+
+	// Clean up PID file
+	pidFile := filepath.Join(townRoot, "daemon", "daemon.pid")
+	os.Remove(pidFile)
+
+	return nil
+}
--- a/internal/daemon/lifecycle.go
+++ b/internal/daemon/lifecycle.go
@@ -0,0 +1,202 @@
+package daemon
+
+import (
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+// BeadsMessage represents a message from beads mail.
+type BeadsMessage struct {
+	ID          string `json:"id"`
+	Title       string `json:"title"`
+	Description string `json:"description"`
+	Sender      string `json:"sender"`
+	Assignee    string `json:"assignee"`
+	Priority    int    `json:"priority"`
+	Status      string `json:"status"`
+}
+
+// ProcessLifecycleRequests checks for and processes lifecycle requests from the daemon inbox.
+func (d *Daemon) ProcessLifecycleRequests() {
+	// Get mail for daemon identity
+	cmd := exec.Command("bd", "mail", "inbox", "--identity", "daemon", "--json")
+	cmd.Dir = d.config.TownRoot
+
+	output, err := cmd.Output()
+	if err != nil {
+		// bd mail might not be available or inbox empty
+		return
+	}
+
+	if len(output) == 0 || string(output) == "[]" || string(output) == "[]\n" {
+		return
+	}
+
+	var messages []BeadsMessage
+	if err := json.Unmarshal(output, &messages); err != nil {
+		d.logger.Printf("Error parsing mail: %v", err)
+		return
+	}
+
+	for _, msg := range messages {
+		if msg.Status == "closed" {
+			continue // Already processed
+		}
+
+		request := d.parseLifecycleRequest(&msg)
+		if request == nil {
+			continue // Not a lifecycle request
+		}
+
+		d.logger.Printf("Processing lifecycle request from %s: %s", request.From, request.Action)
+
+		if err := d.executeLifecycleAction(request); err != nil {
+			d.logger.Printf("Error executing lifecycle action: %v", err)
+			continue
+		}
+
+		// Mark message as read (close the issue)
+		if err := d.closeMessage(msg.ID); err != nil {
+			d.logger.Printf("Warning: failed to close message %s: %v", msg.ID, err)
+		}
+	}
+}
+
+// parseLifecycleRequest extracts a lifecycle request from a message.
+func (d *Daemon) parseLifecycleRequest(msg *BeadsMessage) *LifecycleRequest {
+	// Look for lifecycle keywords in subject/title
+	title := strings.ToLower(msg.Title)
+
+	var action LifecycleAction
+
+	if strings.Contains(title, "cycle") || strings.Contains(title, "cycling") {
+		action = ActionCycle
+	} else if strings.Contains(title, "restart") {
+		action = ActionRestart
+	} else if strings.Contains(title, "shutdown") || strings.Contains(title, "stop") {
+		action = ActionShutdown
+	} else {
+		// Not a lifecycle request
+		return nil
+	}
+
+	return &LifecycleRequest{
+		From:      msg.Sender,
+		Action:    action,
+		Timestamp: time.Now(),
+	}
+}
+
+// executeLifecycleAction performs the requested lifecycle action.
+func (d *Daemon) executeLifecycleAction(request *LifecycleRequest) error {
+	// Determine session name from sender identity
+	sessionName := d.identityToSession(request.From)
+	if sessionName == "" {
+		return fmt.Errorf("unknown agent identity: %s", request.From)
+	}
+
+	d.logger.Printf("Executing %s for session %s", request.Action, sessionName)
+
+	// Check if session exists
+	running, err := d.tmux.HasSession(sessionName)
+	if err != nil {
+		return fmt.Errorf("checking session: %w", err)
+	}
+
+	switch request.Action {
+	case ActionShutdown:
+		if running {
+			if err := d.tmux.KillSession(sessionName); err != nil {
+				return fmt.Errorf("killing session: %w", err)
+			}
+			d.logger.Printf("Killed session %s", sessionName)
+		}
+		return nil
+
+	case ActionCycle, ActionRestart:
+		if running {
+			// Kill the session first
+			if err := d.tmux.KillSession(sessionName); err != nil {
+				return fmt.Errorf("killing session: %w", err)
+			}
+			d.logger.Printf("Killed session %s for restart", sessionName)
+
+			// Wait a moment
+			time.Sleep(500 * time.Millisecond)
+		}
+
+		// Restart the session
+		if err := d.restartSession(sessionName, request.From); err != nil {
+			return fmt.Errorf("restarting session: %w", err)
+		}
+		d.logger.Printf("Restarted session %s", sessionName)
+		return nil
+
+	default:
+		return fmt.Errorf("unknown action: %s", request.Action)
+	}
+}
+
+// identityToSession converts a beads identity to a tmux session name.
+func (d *Daemon) identityToSession(identity string) string {
+	// Handle known identities
+	switch identity {
+	case "mayor":
+		return "gt-mayor"
+	default:
+		// Pattern: <rig>-witness → gt-<rig>-witness
+		if strings.HasSuffix(identity, "-witness") {
+			return "gt-" + identity
+		}
+		// Unknown identity
+		return ""
+	}
+}
+
+// restartSession starts a new session for the given agent.
+func (d *Daemon) restartSession(sessionName, identity string) error {
+	// Determine working directory and startup command based on agent type
+	var workDir, startCmd string
+
+	if identity == "mayor" {
+		workDir = d.config.TownRoot
+		startCmd = "exec claude --dangerously-skip-permissions"
+	} else if strings.HasSuffix(identity, "-witness") {
+		// Extract rig name: <rig>-witness → <rig>
+		rigName := strings.TrimSuffix(identity, "-witness")
+		workDir = d.config.TownRoot + "/" + rigName
+		startCmd = "exec claude --dangerously-skip-permissions"
+	} else {
+		return fmt.Errorf("don't know how to restart %s", identity)
+	}
+
+	// Create session
+	if err := d.tmux.NewSession(sessionName, workDir); err != nil {
+		return fmt.Errorf("creating session: %w", err)
+	}
+
+	// Set environment
+	d.tmux.SetEnvironment(sessionName, "GT_ROLE", identity)
+
+	// Send startup command
+	if err := d.tmux.SendKeys(sessionName, startCmd); err != nil {
+		return fmt.Errorf("sending startup command: %w", err)
+	}
+
+	// Prime after delay
+	if err := d.tmux.SendKeysDelayed(sessionName, "gt prime", 2000); err != nil {
+		d.logger.Printf("Warning: could not send prime: %v", err)
+	}
+
+	return nil
+}
+
+// closeMessage marks a mail message as read by closing the beads issue.
+func (d *Daemon) closeMessage(id string) error {
+	cmd := exec.Command("bd", "close", id)
+	cmd.Dir = d.config.TownRoot
+	return cmd.Run()
+}
--- a/internal/daemon/types.go
+++ b/internal/daemon/types.go
@@ -0,0 +1,126 @@
+// Package daemon provides the town-level background service for Gas Town.
+//
+// The daemon is a simple Go process (not a Claude agent) that:
+// 1. Pokes agents periodically (heartbeat)
+// 2. Processes lifecycle requests (cycle, restart, shutdown)
+// 3. Restarts sessions when agents request cycling
+//
+// The daemon is a "dumb scheduler" - all intelligence is in agents.
+package daemon
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// Config holds daemon configuration.
+type Config struct {
+	// HeartbeatInterval is how often to poke agents.
+	HeartbeatInterval time.Duration `json:"heartbeat_interval"`
+
+	// TownRoot is the Gas Town workspace root.
+	TownRoot string `json:"town_root"`
+
+	// LogFile is the path to the daemon log file.
+	LogFile string `json:"log_file"`
+
+	// PidFile is the path to the PID file.
+	PidFile string `json:"pid_file"`
+}
+
+// DefaultConfig returns the default daemon configuration.
+func DefaultConfig(townRoot string) *Config {
+	daemonDir := filepath.Join(townRoot, "daemon")
+	return &Config{
+		HeartbeatInterval: 60 * time.Second,
+		TownRoot:          townRoot,
+		LogFile:           filepath.Join(daemonDir, "daemon.log"),
+		PidFile:           filepath.Join(daemonDir, "daemon.pid"),
+	}
+}
+
+// State represents the daemon's runtime state.
+type State struct {
+	// Running indicates if the daemon is running.
+	Running bool `json:"running"`
+
+	// PID is the process ID of the daemon.
+	PID int `json:"pid"`
+
+	// StartedAt is when the daemon started.
+	StartedAt time.Time `json:"started_at"`
+
+	// LastHeartbeat is when the last heartbeat completed.
+	LastHeartbeat time.Time `json:"last_heartbeat"`
+
+	// HeartbeatCount is how many heartbeats have completed.
+	HeartbeatCount int64 `json:"heartbeat_count"`
+}
+
+// StateFile returns the path to the state file.
+func StateFile(townRoot string) string {
+	return filepath.Join(townRoot, "daemon", "state.json")
+}
+
+// LoadState loads daemon state from disk.
+func LoadState(townRoot string) (*State, error) {
+	stateFile := StateFile(townRoot)
+	data, err := os.ReadFile(stateFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return &State{}, nil
+		}
+		return nil, err
+	}
+
+	var state State
+	if err := json.Unmarshal(data, &state); err != nil {
+		return nil, err
+	}
+	return &state, nil
+}
+
+// SaveState saves daemon state to disk.
+func SaveState(townRoot string, state *State) error {
+	stateFile := StateFile(townRoot)
+
+	// Ensure daemon directory exists
+	if err := os.MkdirAll(filepath.Dir(stateFile), 0755); err != nil {
+		return err
+	}
+
+	data, err := json.MarshalIndent(state, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(stateFile, data, 0644)
+}
+
+// LifecycleAction represents a lifecycle request action.
+type LifecycleAction string
+
+const (
+	// ActionCycle restarts the session with handoff.
+	ActionCycle LifecycleAction = "cycle"
+
+	// ActionRestart does a fresh restart without handoff.
+	ActionRestart LifecycleAction = "restart"
+
+	// ActionShutdown terminates without restart.
+	ActionShutdown LifecycleAction = "shutdown"
+)
+
+// LifecycleRequest represents a request from an agent to the daemon.
+type LifecycleRequest struct {
+	// From is the agent requesting the action (e.g., "mayor/", "gastown/witness").
+	From string `json:"from"`
+
+	// Action is what lifecycle action to perform.
+	Action LifecycleAction `json:"action"`
+
+	// Timestamp is when the request was made.
+	Timestamp time.Time `json:"timestamp"`
+}