diff --git a/internal/daemon/lifecycle.go b/internal/daemon/lifecycle.go
index ba1d7b7..e55e56a 100644
--- a/internal/daemon/lifecycle.go
+++ b/internal/daemon/lifecycle.go
@@ -233,15 +233,16 @@ func (d *Daemon) Reconcile(ctx context.Context) error {
 		return err
 	}
 	for _, record := range records {
-		if _, err := d.reconcileMachine(ctx, record.ID); err != nil {
+		reconciled, err := d.reconcileMachine(ctx, record.ID)
+		if err != nil {
 			return err
 		}
-		if record.Phase == contracthost.MachinePhaseRunning {
-			if err := d.ensurePublishedPortsForMachine(ctx, record); err != nil {
+		if reconciled.Phase == contracthost.MachinePhaseRunning {
+			if err := d.ensurePublishedPortsForMachine(ctx, *reconciled); err != nil {
 				return err
 			}
 		} else {
-			d.stopPublishedPortsForMachine(record.ID)
+			d.stopPublishedPortsForMachine(reconciled.ID)
 		}
 	}
 	return nil
diff --git a/internal/daemon/review_regressions_test.go b/internal/daemon/review_regressions_test.go
index 22cbd1d..08c7082 100644
--- a/internal/daemon/review_regressions_test.go
+++ b/internal/daemon/review_regressions_test.go
@@ -3,6 +3,7 @@ package daemon
 import (
 	"context"
 	"errors"
+	"net"
 	"os"
 	"path/filepath"
 	"strings"
@@ -10,6 +11,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/getcompanion-ai/computer-host/internal/firecracker"
 	"github.com/getcompanion-ai/computer-host/internal/model"
 	hoststore "github.com/getcompanion-ai/computer-host/internal/store"
 	contracthost "github.com/getcompanion-ai/computer-host/contract"
@@ -57,6 +59,16 @@ type publishedPortResult struct {
 	err      error
 }
 
+type failingInspectRuntime struct {
+	fakeRuntime
+}
+
+func (r *failingInspectRuntime) Inspect(state firecracker.MachineState) (*firecracker.MachineState, error) {
+	state.Phase = firecracker.PhaseFailed
+	state.Error = "vm exited unexpectedly"
+	return &state, nil
+}
+
 func TestCreatePublishedPortSerializesHostPortAllocationAcrossMachines(t *testing.T) {
 	root := t.TempDir()
 	cfg := testConfig(root)
@@ -267,6 +279,132 @@ func TestReconcileRestorePreservesArtifactsOnUnexpectedStoreError(t *testing.T)
 	assertOperationCount(t, baseStore, 1)
 }
 
+func TestCreateSnapshotRejectsDuplicateSnapshotIDWithoutTouchingExistingArtifacts(t *testing.T) {
+	root := t.TempDir()
+	cfg := testConfig(root)
+	fileStore, err := hoststore.NewFileStore(cfg.StatePath, cfg.OperationsPath)
+	if err != nil {
+		t.Fatalf("create file store: %v", err)
+	}
+
+	hostDaemon, err := New(cfg, fileStore, &fakeRuntime{})
+	if err != nil {
+		t.Fatalf("create daemon: %v", err)
+	}
+
+	machineID := contracthost.MachineID("vm-1")
+	snapshotID := contracthost.SnapshotID("snap-1")
+	if err := fileStore.CreateMachine(context.Background(), model.MachineRecord{
+		ID:             machineID,
+		SystemVolumeID: hostDaemon.systemVolumeID(machineID),
+		RuntimeHost:    "127.0.0.1",
+		SocketPath:     filepath.Join(cfg.RuntimeDir, "machines", string(machineID), "root", "run", "firecracker.sock"),
+		Phase:          contracthost.MachinePhaseRunning,
+		CreatedAt:      time.Now().UTC(),
+	}); err != nil {
+		t.Fatalf("create machine: %v", err)
+	}
+
+	snapshotDir := filepath.Join(cfg.SnapshotsDir, string(snapshotID))
+	if err := os.MkdirAll(snapshotDir, 0o755); err != nil {
+		t.Fatalf("create snapshot dir: %v", err)
+	}
+	markerPath := filepath.Join(snapshotDir, "keep.txt")
+	if err := os.WriteFile(markerPath, []byte("keep"), 0o644); err != nil {
+		t.Fatalf("write marker file: %v", err)
+	}
+	if err := fileStore.CreateSnapshot(context.Background(), model.SnapshotRecord{
+		ID:          snapshotID,
+		MachineID:   machineID,
+		MemFilePath: markerPath,
+		CreatedAt:   time.Now().UTC(),
+	}); err != nil {
+		t.Fatalf("create snapshot: %v", err)
+	}
+
+	_, err = hostDaemon.CreateSnapshot(context.Background(), machineID, contracthost.CreateSnapshotRequest{
+		SnapshotID: snapshotID,
+	})
+	if err == nil || !strings.Contains(err.Error(), "already exists") {
+		t.Fatalf("CreateSnapshot error = %v, want duplicate snapshot failure", err)
+	}
+	if _, statErr := os.Stat(markerPath); statErr != nil {
+		t.Fatalf("marker file should be preserved, stat error: %v", statErr)
+	}
+	assertOperationCount(t, fileStore, 0)
+}
+
+func TestReconcileUsesReconciledMachineStateForPublishedPorts(t *testing.T) {
+	root := t.TempDir()
+	cfg := testConfig(root)
+	fileStore, err := hoststore.NewFileStore(cfg.StatePath, cfg.OperationsPath)
+	if err != nil {
+		t.Fatalf("create file store: %v", err)
+	}
+
+	hostDaemon, err := New(cfg, fileStore, &failingInspectRuntime{})
+	if err != nil {
+		t.Fatalf("create daemon: %v", err)
+	}
+
+	t.Cleanup(func() {
+		hostDaemon.stopPublishedPortProxy("port-1")
+	})
+
+	reserved, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("reserve host port: %v", err)
+	}
+	hostPort := uint16(reserved.Addr().(*net.TCPAddr).Port)
+	if err := reserved.Close(); err != nil {
+		t.Fatalf("close reserved host port: %v", err)
+	}
+
+	machineID := contracthost.MachineID("vm-1")
+	if err := fileStore.CreateMachine(context.Background(), model.MachineRecord{
+		ID:          machineID,
+		RuntimeHost: "127.0.0.1",
+		SocketPath:  filepath.Join(cfg.RuntimeDir, "machines", string(machineID), "root", "run", "firecracker.sock"),
+		TapDevice:   "fctap0",
+		Phase:       contracthost.MachinePhaseRunning,
+		CreatedAt:   time.Now().UTC(),
+	}); err != nil {
+		t.Fatalf("create machine: %v", err)
+	}
+	if err := fileStore.CreatePublishedPort(context.Background(), model.PublishedPortRecord{
+		ID:        "port-1",
+		MachineID: machineID,
+		Port:      8080,
+		HostPort:  hostPort,
+		Protocol:  contracthost.PortProtocolTCP,
+		CreatedAt: time.Now().UTC(),
+	}); err != nil {
+		t.Fatalf("create published port: %v", err)
+	}
+
+	if err := hostDaemon.Reconcile(context.Background()); err != nil {
+		t.Fatalf("Reconcile returned error: %v", err)
+	}
+
+	updated, err := fileStore.GetMachine(context.Background(), machineID)
+	if err != nil {
+		t.Fatalf("get machine after reconcile: %v", err)
+	}
+	if updated.Phase != contracthost.MachinePhaseFailed {
+		t.Fatalf("machine phase = %q, want failed", updated.Phase)
+	}
+	if updated.RuntimeHost != "" {
+		t.Fatalf("machine runtime host = %q, want cleared", updated.RuntimeHost)
+	}
+
+	hostDaemon.publishedPortsMu.Lock()
+	listenerCount := len(hostDaemon.publishedPortListeners)
+	hostDaemon.publishedPortsMu.Unlock()
+	if listenerCount != 0 {
+		t.Fatalf("published port listeners = %d, want 0", listenerCount)
+	}
+}
+
 func waitPublishedPortResult(t *testing.T, ch <-chan publishedPortResult) publishedPortResult {
 	t.Helper()
 
diff --git a/internal/daemon/snapshot.go b/internal/daemon/snapshot.go
index d868291..ac92944 100644
--- a/internal/daemon/snapshot.go
+++ b/internal/daemon/snapshot.go
@@ -42,6 +42,11 @@ func (d *Daemon) CreateSnapshot(ctx context.Context, machineID contracthost.Mach
 	}
 
 	snapshotID := req.SnapshotID
+	if _, err := d.store.GetSnapshot(ctx, snapshotID); err == nil {
+		return nil, fmt.Errorf("snapshot %q already exists", snapshotID)
+	} else if err != nil && err != store.ErrNotFound {
+		return nil, err
+	}
 
 	if err := d.store.UpsertOperation(ctx, model.OperationRecord{
 		MachineID:  machineID,
@@ -60,7 +65,10 @@ func (d *Daemon) CreateSnapshot(ctx context.Context, machineID contracthost.Mach
 	}()
 
 	snapshotDir := filepath.Join(d.config.SnapshotsDir, string(snapshotID))
-	if err := os.MkdirAll(snapshotDir, 0o755); err != nil {
+	if err := os.Mkdir(snapshotDir, 0o755); err != nil {
+		if os.IsExist(err) {
+			return nil, fmt.Errorf("snapshot %q already exists", snapshotID)
+		}
 		return nil, fmt.Errorf("create snapshot dir: %w", err)
 	}