diff --git a/cmd/bd/daemon_autostart.go b/cmd/bd/daemon_autostart.go
index d858c7d8..4fdd0cc0 100644
--- a/cmd/bd/daemon_autostart.go
+++ b/cmd/bd/daemon_autostart.go
@@ -31,6 +31,19 @@ var (
 	daemonStartFailures    int
 )
 
+var (
+	executableFn             = os.Executable
+	execCommandFn            = exec.Command
+	openFileFn               = os.OpenFile
+	findProcessFn            = os.FindProcess
+	removeFileFn             = os.Remove
+	configureDaemonProcessFn = configureDaemonProcess
+	waitForSocketReadinessFn = waitForSocketReadiness
+	startDaemonProcessFn     = startDaemonProcess
+	isDaemonRunningFn        = isDaemonRunning
+	sendStopSignalFn         = sendStopSignal
+)
+
 // shouldAutoStartDaemon checks if daemon auto-start is enabled
 func shouldAutoStartDaemon() bool {
 	// Check BEADS_NO_DAEMON first (escape hatch for single-user workflows)
@@ -53,7 +66,6 @@ func shouldAutoStartDaemon() bool {
 	return config.GetBool("auto-start-daemon") // Defaults to true
 }
 
-
 // restartDaemonForVersionMismatch stops the old daemon and starts a new one
 // Returns true if restart was successful
 func restartDaemonForVersionMismatch() bool {
@@ -67,17 +79,17 @@ func restartDaemonForVersionMismatch() bool {
 
 	// Check if daemon is running and stop it
 	forcedKill := false
-	if isRunning, pid := isDaemonRunning(pidFile); isRunning {
+	if isRunning, pid := isDaemonRunningFn(pidFile); isRunning {
 		debug.Logf("stopping old daemon (PID %d)", pid)
 
-		process, err := os.FindProcess(pid)
+		process, err := findProcessFn(pid)
 		if err != nil {
 			debug.Logf("failed to find process: %v", err)
 			return false
 		}
 
 		// Send stop signal
-		if err := sendStopSignal(process); err != nil {
+		if err := sendStopSignalFn(process); err != nil {
 			debug.Logf("failed to signal daemon: %v", err)
 			return false
 		}
@@ -85,14 +97,14 @@ func restartDaemonForVersionMismatch() bool {
 		// Wait for daemon to stop, then force kill
 		for i := 0; i < daemonShutdownAttempts; i++ {
 			time.Sleep(daemonShutdownPollInterval)
-			if isRunning, _ := isDaemonRunning(pidFile); !isRunning {
+			if isRunning, _ := isDaemonRunningFn(pidFile); !isRunning {
 				debug.Logf("old daemon stopped successfully")
 				break
 			}
 		}
 
 		// Force kill if still running
-		if isRunning, _ := isDaemonRunning(pidFile); isRunning {
+		if isRunning, _ := isDaemonRunningFn(pidFile); isRunning {
 			debug.Logf("force killing old daemon")
 			_ = process.Kill()
 			forcedKill = true
@@ -101,19 +113,19 @@ func restartDaemonForVersionMismatch() bool {
 
 	// Clean up stale socket and PID file after force kill or if not running
 	if forcedKill || !isDaemonRunningQuiet(pidFile) {
-		_ = os.Remove(socketPath)
-		_ = os.Remove(pidFile)
+		_ = removeFileFn(socketPath)
+		_ = removeFileFn(pidFile)
 	}
 
 	// Start new daemon with current binary version
-	exe, err := os.Executable()
+	exe, err := executableFn()
 	if err != nil {
 		debug.Logf("failed to get executable path: %v", err)
 		return false
 	}
 
 	args := []string{"daemon", "--start"}
-	cmd := exec.Command(exe, args...)
+	cmd := execCommandFn(exe, args...)
 	cmd.Env = append(os.Environ(), "BD_DAEMON_FOREGROUND=1")
 
 	// Set working directory to database directory so daemon finds correct DB
@@ -121,9 +133,9 @@ func restartDaemonForVersionMismatch() bool {
 		cmd.Dir = filepath.Dir(dbPath)
 	}
 
-	configureDaemonProcess(cmd)
+	configureDaemonProcessFn(cmd)
 
-	devNull, err := os.OpenFile(os.DevNull, os.O_RDWR, 0)
+	devNull, err := openFileFn(os.DevNull, os.O_RDWR, 0)
 	if err == nil {
 		cmd.Stdin = devNull
 		cmd.Stdout = devNull
@@ -140,7 +152,7 @@ func restartDaemonForVersionMismatch() bool {
 	go func() { _ = cmd.Wait() }()
 
 	// Wait for daemon to be ready using shared helper
-	if waitForSocketReadiness(socketPath, 5*time.Second) {
+	if waitForSocketReadinessFn(socketPath, 5*time.Second) {
 		debug.Logf("new daemon started successfully")
 		return true
 	}
@@ -153,7 +165,7 @@ func restartDaemonForVersionMismatch() bool {
 
 // isDaemonRunningQuiet checks if daemon is running without output
 func isDaemonRunningQuiet(pidFile string) bool {
-	isRunning, _ := isDaemonRunning(pidFile)
+	isRunning, _ := isDaemonRunningFn(pidFile)
 	return isRunning
 }
 
@@ -185,7 +197,7 @@ func tryAutoStartDaemon(socketPath string) bool {
 	}
 
 	socketPath = determineSocketPath(socketPath)
-	return startDaemonProcess(socketPath)
+	return startDaemonProcessFn(socketPath)
 }
 
 func debugLog(msg string, args ...interface{}) {
@@ -269,21 +281,21 @@ func determineSocketPath(socketPath string) string {
 }
 
 func startDaemonProcess(socketPath string) bool {
-	binPath, err := os.Executable()
+	binPath, err := executableFn()
 	if err != nil {
 		binPath = os.Args[0]
 	}
 
 	args := []string{"daemon", "--start"}
 
-	cmd := exec.Command(binPath, args...)
+	cmd := execCommandFn(binPath, args...)
 	setupDaemonIO(cmd)
 
 	if dbPath != "" {
 		cmd.Dir = filepath.Dir(dbPath)
 	}
 
-	configureDaemonProcess(cmd)
+	configureDaemonProcessFn(cmd)
 	if err := cmd.Start(); err != nil {
 		recordDaemonStartFailure()
 		debugLog("failed to start daemon: %v", err)
@@ -292,7 +304,7 @@ func startDaemonProcess(socketPath string) bool {
 
 	go func() { _ = cmd.Wait() }()
 
-	if waitForSocketReadiness(socketPath, 5*time.Second) {
+	if waitForSocketReadinessFn(socketPath, 5*time.Second) {
 		recordDaemonStartSuccess()
 		return true
 	}
@@ -306,7 +318,7 @@ func startDaemonProcess(socketPath string) bool {
 }
 
 func setupDaemonIO(cmd *exec.Cmd) {
-	devNull, err := os.OpenFile(os.DevNull, os.O_RDWR, 0)
+	devNull, err := openFileFn(os.DevNull, os.O_RDWR, 0)
 	if err == nil {
 		cmd.Stdout = devNull
 		cmd.Stderr = devNull
diff --git a/cmd/bd/daemon_autostart_unit_test.go b/cmd/bd/daemon_autostart_unit_test.go
new file mode 100644
index 00000000..625cedf6
--- /dev/null
+++ b/cmd/bd/daemon_autostart_unit_test.go
@@ -0,0 +1,331 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/steveyegge/beads/internal/config"
+)
+
+func tempSockDir(t *testing.T) string {
+	t.Helper()
+
+	base := "/tmp"
+	if runtime.GOOS == windowsOS {
+		base = os.TempDir()
+	} else if _, err := os.Stat(base); err != nil {
+		base = os.TempDir()
+	}
+
+	d, err := os.MkdirTemp(base, "bd-sock-*")
+	if err != nil {
+		t.Fatalf("MkdirTemp: %v", err)
+	}
+	t.Cleanup(func() { _ = os.RemoveAll(d) })
+	return d
+}
+
+func startTestRPCServer(t *testing.T) (socketPath string, cleanup func()) {
+	t.Helper()
+
+	tmpDir := tempSockDir(t)
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	if err := os.MkdirAll(beadsDir, 0o750); err != nil {
+		t.Fatalf("MkdirAll: %v", err)
+	}
+
+	socketPath = filepath.Join(beadsDir, "bd.sock")
+	db := filepath.Join(beadsDir, "test.db")
+	store := newTestStore(t, db)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	log := newTestLogger()
+
+	server, _, err := startRPCServer(ctx, socketPath, store, tmpDir, db, log)
+	if err != nil {
+		cancel()
+		t.Fatalf("startRPCServer: %v", err)
+	}
+
+	cleanup = func() {
+		cancel()
+		if server != nil {
+			_ = server.Stop()
+		}
+	}
+
+	return socketPath, cleanup
+}
+
+func captureStderr(t *testing.T, fn func()) string {
+	t.Helper()
+
+	old := os.Stderr
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("os.Pipe: %v", err)
+	}
+	os.Stderr = w
+
+	var buf bytes.Buffer
+	done := make(chan struct{})
+	go func() {
+		_, _ = io.Copy(&buf, r)
+		close(done)
+	}()
+
+	fn()
+	_ = w.Close()
+	os.Stderr = old
+	<-done
+	_ = r.Close()
+
+	return buf.String()
+}
+
+func TestDaemonAutostart_AcquireStartLock_CreatesAndCleansStale(t *testing.T) {
+	tmpDir := t.TempDir()
+	lockPath := filepath.Join(tmpDir, "bd.sock.startlock")
+	pid, err := readPIDFromFile(lockPath)
+	if err == nil || pid != 0 {
+		// lock doesn't exist yet; expect read to fail.
+	}
+
+	if !acquireStartLock(lockPath, filepath.Join(tmpDir, "bd.sock")) {
+		t.Fatalf("expected acquireStartLock to succeed")
+	}
+	got, err := readPIDFromFile(lockPath)
+	if err != nil {
+		t.Fatalf("readPIDFromFile: %v", err)
+	}
+	if got != os.Getpid() {
+		t.Fatalf("expected lock PID %d, got %d", os.Getpid(), got)
+	}
+
+	// Stale lock: dead/unreadable PID should be removed and recreated.
+	if err := os.WriteFile(lockPath, []byte("0\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile: %v", err)
+	}
+	if !acquireStartLock(lockPath, filepath.Join(tmpDir, "bd.sock")) {
+		t.Fatalf("expected acquireStartLock to succeed on stale lock")
+	}
+	got, err = readPIDFromFile(lockPath)
+	if err != nil {
+		t.Fatalf("readPIDFromFile: %v", err)
+	}
+	if got != os.Getpid() {
+		t.Fatalf("expected recreated lock PID %d, got %d", os.Getpid(), got)
+	}
+}
+
+func TestDaemonAutostart_SocketHealthAndReadiness(t *testing.T) {
+	socketPath, cleanup := startTestRPCServer(t)
+	defer cleanup()
+
+	if !canDialSocket(socketPath, 500*time.Millisecond) {
+		t.Fatalf("expected canDialSocket to succeed")
+	}
+	if !isDaemonHealthy(socketPath) {
+		t.Fatalf("expected isDaemonHealthy to succeed")
+	}
+	if !waitForSocketReadiness(socketPath, 500*time.Millisecond) {
+		t.Fatalf("expected waitForSocketReadiness to succeed")
+	}
+
+	missing := filepath.Join(tempSockDir(t), "missing.sock")
+	if canDialSocket(missing, 50*time.Millisecond) {
+		t.Fatalf("expected canDialSocket to fail")
+	}
+	if waitForSocketReadiness(missing, 200*time.Millisecond) {
+		t.Fatalf("expected waitForSocketReadiness to time out")
+	}
+}
+
+func TestDaemonAutostart_HandleExistingSocket(t *testing.T) {
+	socketPath, cleanup := startTestRPCServer(t)
+	defer cleanup()
+
+	if !handleExistingSocket(socketPath) {
+		t.Fatalf("expected handleExistingSocket true for running daemon")
+	}
+}
+
+func TestDaemonAutostart_HandleExistingSocket_StaleCleansUp(t *testing.T) {
+	tmpDir := t.TempDir()
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	if err := os.MkdirAll(beadsDir, 0o750); err != nil {
+		t.Fatalf("MkdirAll: %v", err)
+	}
+
+	socketPath := filepath.Join(beadsDir, "bd.sock")
+	pidFile := filepath.Join(beadsDir, "daemon.pid")
+	if err := os.WriteFile(socketPath, []byte("not-a-socket"), 0o600); err != nil {
+		t.Fatalf("WriteFile socket: %v", err)
+	}
+	if err := os.WriteFile(pidFile, []byte("0\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile pid: %v", err)
+	}
+
+	if handleExistingSocket(socketPath) {
+		t.Fatalf("expected false for stale socket")
+	}
+	if _, err := os.Stat(socketPath); !os.IsNotExist(err) {
+		t.Fatalf("expected socket removed")
+	}
+	if _, err := os.Stat(pidFile); !os.IsNotExist(err) {
+		t.Fatalf("expected pidfile removed")
+	}
+}
+
+func TestDaemonAutostart_TryAutoStartDaemon_EarlyExits(t *testing.T) {
+	oldFailures := daemonStartFailures
+	oldLast := lastDaemonStartAttempt
+	defer func() {
+		daemonStartFailures = oldFailures
+		lastDaemonStartAttempt = oldLast
+	}()
+
+	daemonStartFailures = 1
+	lastDaemonStartAttempt = time.Now()
+	if tryAutoStartDaemon(filepath.Join(t.TempDir(), "bd.sock")) {
+		t.Fatalf("expected tryAutoStartDaemon to skip due to backoff")
+	}
+
+	daemonStartFailures = 0
+	lastDaemonStartAttempt = time.Time{}
+	socketPath, cleanup := startTestRPCServer(t)
+	defer cleanup()
+	if !tryAutoStartDaemon(socketPath) {
+		t.Fatalf("expected tryAutoStartDaemon true when daemon already healthy")
+	}
+}
+
+func TestDaemonAutostart_MiscHelpers(t *testing.T) {
+	if determineSocketPath("/x") != "/x" {
+		t.Fatalf("determineSocketPath should be identity")
+	}
+
+	if err := config.Initialize(); err != nil {
+		t.Fatalf("config.Initialize: %v", err)
+	}
+	old := config.GetDuration("flush-debounce")
+	defer config.Set("flush-debounce", old)
+
+	config.Set("flush-debounce", 0)
+	if got := getDebounceDuration(); got != 5*time.Second {
+		t.Fatalf("expected default debounce 5s, got %v", got)
+	}
+	config.Set("flush-debounce", 2*time.Second)
+	if got := getDebounceDuration(); got != 2*time.Second {
+		t.Fatalf("expected debounce 2s, got %v", got)
+	}
+}
+
+func TestDaemonAutostart_EmitVerboseWarning(t *testing.T) {
+	old := daemonStatus
+	defer func() { daemonStatus = old }()
+
+	daemonStatus.SocketPath = "/tmp/bd.sock"
+	for _, tt := range []struct {
+		reason      string
+		shouldWrite bool
+	}{
+		{FallbackConnectFailed, true},
+		{FallbackHealthFailed, true},
+		{FallbackAutoStartDisabled, true},
+		{FallbackAutoStartFailed, true},
+		{FallbackDaemonUnsupported, true},
+		{FallbackWorktreeSafety, false},
+		{FallbackFlagNoDaemon, false},
+	} {
+		t.Run(tt.reason, func(t *testing.T) {
+			daemonStatus.FallbackReason = tt.reason
+			out := captureStderr(t, emitVerboseWarning)
+			if tt.shouldWrite && out == "" {
+				t.Fatalf("expected output")
+			}
+			if !tt.shouldWrite && out != "" {
+				t.Fatalf("expected no output, got %q", out)
+			}
+		})
+	}
+}
+
+func TestDaemonAutostart_StartDaemonProcess_Stubbed(t *testing.T) {
+	oldExec := execCommandFn
+	oldWait := waitForSocketReadinessFn
+	oldCfg := configureDaemonProcessFn
+	defer func() {
+		execCommandFn = oldExec
+		waitForSocketReadinessFn = oldWait
+		configureDaemonProcessFn = oldCfg
+	}()
+
+	execCommandFn = func(string, ...string) *exec.Cmd {
+		return exec.Command(os.Args[0], "-test.run=^$")
+	}
+	waitForSocketReadinessFn = func(string, time.Duration) bool { return true }
+	configureDaemonProcessFn = func(*exec.Cmd) {}
+
+	if !startDaemonProcess(filepath.Join(t.TempDir(), "bd.sock")) {
+		t.Fatalf("expected startDaemonProcess true when readiness stubbed")
+	}
+}
+
+func TestDaemonAutostart_RestartDaemonForVersionMismatch_Stubbed(t *testing.T) {
+	oldExec := execCommandFn
+	oldWait := waitForSocketReadinessFn
+	oldRun := isDaemonRunningFn
+	oldCfg := configureDaemonProcessFn
+	defer func() {
+		execCommandFn = oldExec
+		waitForSocketReadinessFn = oldWait
+		isDaemonRunningFn = oldRun
+		configureDaemonProcessFn = oldCfg
+	}()
+
+	tmpDir := t.TempDir()
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	if err := os.MkdirAll(beadsDir, 0o750); err != nil {
+		t.Fatalf("MkdirAll: %v", err)
+	}
+	oldDB := dbPath
+	defer func() { dbPath = oldDB }()
+	dbPath = filepath.Join(beadsDir, "test.db")
+
+	pidFile, err := getPIDFilePath()
+	if err != nil {
+		t.Fatalf("getPIDFilePath: %v", err)
+	}
+	sock := getSocketPath()
+	if err := os.WriteFile(pidFile, []byte("999999\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile pid: %v", err)
+	}
+	if err := os.WriteFile(sock, []byte("stale"), 0o600); err != nil {
+		t.Fatalf("WriteFile sock: %v", err)
+	}
+
+	execCommandFn = func(string, ...string) *exec.Cmd {
+		return exec.Command(os.Args[0], "-test.run=^$")
+	}
+	waitForSocketReadinessFn = func(string, time.Duration) bool { return true }
+	isDaemonRunningFn = func(string) (bool, int) { return false, 0 }
+	configureDaemonProcessFn = func(*exec.Cmd) {}
+
+	if !restartDaemonForVersionMismatch() {
+		t.Fatalf("expected restartDaemonForVersionMismatch true when stubbed")
+	}
+	if _, err := os.Stat(pidFile); !os.IsNotExist(err) {
+		t.Fatalf("expected pidfile removed")
+	}
+	if _, err := os.Stat(sock); !os.IsNotExist(err) {
+		t.Fatalf("expected socket removed")
+	}
+}