diff --git a/docs/REFACTORING.md b/docs/REFACTORING.md
index 8ff3c48..37a6d36 100644
--- a/docs/REFACTORING.md
+++ b/docs/REFACTORING.md
@@ -278,7 +278,7 @@ Track progress here. Mark tasks complete as they land and pass review.
 
 ### Phase 5 — Hardening & docs
 - [x] T5.1 — Surface errors from service + storage
-- [ ] T5.2 — Introduce `autostart.Manager` interface
+- [x] T5.2 — Introduce `autostart.Manager` interface
 - [ ] T5.3 — Fill test gaps (folder filtering, cleanup, migration, concurrency)
 - [ ] T5.4 — Run `go test -race ./...` clean on both platforms
 - [ ] T5.5 — Update docs (ARCHITECTURE.md, TESTS.md, README)
diff --git a/src/app/operations.go b/src/app/operations.go
index 2b1f8ab..a932e7e 100644
--- a/src/app/operations.go
+++ b/src/app/operations.go
@@ -240,8 +240,6 @@ func (s *Service) RunDue(now time.Time) {
 // UpdateSettings validates and persists a new application configuration. The
 // loaded jobs are re-saved because the jobs directory may have changed, and log
 // cleanup runs so a tightened retention policy takes effect immediately.
-// Autostart is intentionally left to the caller until T5.2 introduces an
-// injectable autostart.Manager.
 func (s *Service) UpdateSettings(config domain.Config) error {
 	if err := validateConfig(config); err != nil {
 		return err
diff --git a/src/app/platform.go b/src/app/platform.go
index e4680c3..deedf6f 100644
--- a/src/app/platform.go
+++ b/src/app/platform.go
@@ -1,7 +1,6 @@
 package app
 
 import (
-	"gitea.mixdep.ru/mix/gosentry/src/platform/autostart"
 	"gitea.mixdep.ru/mix/gosentry/src/platform/desktop"
 )
 
@@ -20,8 +19,12 @@ func (s *Service) AutostartStatus() (ok bool, message string) {
 	s.mu.Lock()
 	enabled := s.store.Config.StartOnLogin
 	execPath := s.store.Paths.ExecutablePath
+	manager := s.manager
 	s.mu.Unlock()
-	return autostart.AutostartStatus(enabled, execPath)
+	if manager == nil {
+		return false, "autostart not available"
+	}
+	return manager.Status(enabled, execPath)
 }
 
 // ApplyAutostart writes or removes the platform autostart entry to match the
@@ -31,6 +34,10 @@ func (s *Service) ApplyAutostart() error {
 	enabled := s.store.Config.StartOnLogin
 	execPath := s.store.Paths.ExecutablePath
 	iconPath := s.store.Paths.DesktopIcon
+	manager := s.manager
 	s.mu.Unlock()
-	return autostart.SetAutostart(enabled, execPath, iconPath)
+	if manager == nil {
+		return nil
+	}
+	return manager.Set(enabled, execPath, iconPath)
 }
diff --git a/src/app/service.go b/src/app/service.go
index cb69439..5ebf990 100644
--- a/src/app/service.go
+++ b/src/app/service.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"gitea.mixdep.ru/mix/gosentry/src/domain"
+	"gitea.mixdep.ru/mix/gosentry/src/platform/autostart"
 	"gitea.mixdep.ru/mix/gosentry/src/runner"
 	"gitea.mixdep.ru/mix/gosentry/src/scheduler"
 	"gitea.mixdep.ru/mix/gosentry/src/storage"
@@ -58,6 +59,10 @@ type Service struct {
 	sched  *scheduler.Scheduler
 	cancel context.CancelFunc
 
+	// manager is the platform autostart implementation. It is nil in tests that
+	// do not exercise autostart; Open() wires it via autostart.New().
+	manager autostart.Manager
+
 	// observers and their guard live in events.go. dispatchMu is separate from mu
 	// so that emitting an event never requires (or is held under) the state lock:
 	// the Service must release mu before dispatching, per the locking contract.
@@ -136,7 +141,9 @@ func Open() (*Service, error) {
 	if err != nil {
 		return nil, err
 	}
-	return NewService(store, jobs), nil
+	svc := NewService(store, jobs)
+	svc.manager = autostart.New()
+	return svc, nil
 }
 
 // Store returns the underlying store. It is exposed so callers that still need
diff --git a/src/platform/autostart/autostart.go b/src/platform/autostart/autostart.go
new file mode 100644
index 0000000..5139f16
--- /dev/null
+++ b/src/platform/autostart/autostart.go
@@ -0,0 +1,9 @@
+package autostart
+
+// Manager controls platform autostart for the application.
+type Manager interface {
+	// Set writes or removes the platform autostart entry to match enabled.
+	Set(enabled bool, executablePath, iconPath string) error
+	// Status reports whether the platform autostart entry matches expectedEnabled.
+	Status(expectedEnabled bool, executablePath string) (ok bool, message string)
+}
diff --git a/src/platform/autostart/autostart_linux.go b/src/platform/autostart/autostart_linux.go
index 8ccb8c1..5d4dd6d 100644
--- a/src/platform/autostart/autostart_linux.go
+++ b/src/platform/autostart/autostart_linux.go
@@ -13,6 +13,19 @@ import (
 	"gitea.mixdep.ru/mix/gosentry/src/domain"
 )
 
+type linuxManager struct{}
+
+// New returns the Linux autostart Manager.
+func New() Manager { return linuxManager{} }
+
+func (linuxManager) Set(enabled bool, executablePath, iconPath string) error {
+	return SetAutostart(enabled, executablePath, iconPath)
+}
+
+func (linuxManager) Status(expectedEnabled bool, executablePath string) (bool, string) {
+	return AutostartStatus(expectedEnabled, executablePath)
+}
+
 const autostartDesktopFileName = "gosentry.desktop"
 const legacyAutostartDesktopFileName = "pysentry.desktop"
 
diff --git a/src/platform/autostart/autostart_other.go b/src/platform/autostart/autostart_other.go
index 5eab3f7..96a1010 100644
--- a/src/platform/autostart/autostart_other.go
+++ b/src/platform/autostart/autostart_other.go
@@ -4,6 +4,19 @@ package autostart
 
 import "fmt"
 
+type otherManager struct{}
+
+// New returns the stub autostart Manager for unsupported platforms.
+func New() Manager { return otherManager{} }
+
+func (otherManager) Set(enabled bool, executablePath, iconPath string) error {
+	return SetAutostart(enabled, executablePath, iconPath)
+}
+
+func (otherManager) Status(expectedEnabled bool, executablePath string) (bool, string) {
+	return AutostartStatus(expectedEnabled, executablePath)
+}
+
 func SetAutostart(enabled bool, executablePath string, iconPath string) error {
 	if !enabled {
 		return nil
diff --git a/src/platform/autostart/autostart_windows.go b/src/platform/autostart/autostart_windows.go
index 813ef21..9493b96 100644
--- a/src/platform/autostart/autostart_windows.go
+++ b/src/platform/autostart/autostart_windows.go
@@ -11,6 +11,19 @@ import (
 	"gitea.mixdep.ru/mix/gosentry/src/platform/winproc"
 )
 
+type windowsManager struct{}
+
+// New returns the Windows autostart Manager.
+func New() Manager { return windowsManager{} }
+
+func (windowsManager) Set(enabled bool, executablePath, iconPath string) error {
+	return SetAutostart(enabled, executablePath, iconPath)
+}
+
+func (windowsManager) Status(expectedEnabled bool, executablePath string) (bool, string) {
+	return AutostartStatus(expectedEnabled, executablePath)
+}
+
 const autostartName = "GoSentry"
 const legacyAutostartName = "PySentry"
 const startupShortcutFile = autostartName + ".lnk"