diff --git a/audit/internal/webui/jobs.go b/audit/internal/webui/jobs.go
index 496537a..cab211b 100644
--- a/audit/internal/webui/jobs.go
+++ b/audit/internal/webui/jobs.go
@@ -91,6 +91,7 @@ func (j *jobState) writeLogLineLocked(line string) {
 		j.logBuf = bufio.NewWriterSize(f, 64*1024)
 	}
 	_, _ = j.logBuf.WriteString(line + "\n")
+	_ = j.logBuf.Flush()
 }
 
 // closeLog flushes and closes the log file. Called after all task output is done.
diff --git a/audit/internal/webui/tasks.go b/audit/internal/webui/tasks.go
index f5f9d2a..c14b27d 100644
--- a/audit/internal/webui/tasks.go
+++ b/audit/internal/webui/tasks.go
@@ -600,6 +600,17 @@ func (q *taskQueue) startRecoveredTaskMonitorLocked(t *Task, j *jobState) {
 }
 
 func (q *taskQueue) runTaskExternal(t *Task, j *jobState) {
+	startedKmsgWatch := false
+	if q.kmsgWatcher != nil && isSATTarget(t.Target) {
+		q.kmsgWatcher.NotifyTaskStarted(t.ID, t.Target)
+		startedKmsgWatch = true
+	}
+	defer func() {
+		if startedKmsgWatch && q.kmsgWatcher != nil {
+			q.kmsgWatcher.NotifyTaskFinished(t.ID)
+		}
+	}()
+
 	stopTail := make(chan struct{})
 	doneTail := make(chan struct{})
 	defer func() {
diff --git a/audit/internal/webui/tasks_test.go b/audit/internal/webui/tasks_test.go
index 4ad5c03..8251b26 100644
--- a/audit/internal/webui/tasks_test.go
+++ b/audit/internal/webui/tasks_test.go
@@ -126,6 +126,23 @@ func TestNewTaskJobStateLoadsExistingLog(t *testing.T) {
 	}
 }
 
+func TestJobAppendFlushesTaskLogImmediately(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "task.log")
+	j := newTaskJobState(path)
+
+	j.append("live-line")
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(data) != "live-line\n" {
+		t.Fatalf("log=%q want live-line newline", string(data))
+	}
+	j.closeLog()
+}
+
 func TestTaskQueueSnapshotSortsNewestFirst(t *testing.T) {
 	now := time.Date(2026, 4, 2, 12, 0, 0, 0, time.UTC)
 	q := &taskQueue{
@@ -849,3 +866,82 @@ func TestExecuteTaskMarksPanicsAsFailedAndClosesKmsgWindow(t *testing.T) {
 		t.Fatalf("expected kmsg window to be cleared, got %+v", window)
 	}
 }
+
+func TestRunTaskExternalOpensAndClosesKmsgWindow(t *testing.T) {
+	dir := t.TempDir()
+	releasePath := filepath.Join(dir, "release")
+	readyPath := filepath.Join(dir, "ready")
+	q := &taskQueue{
+		opts:        &HandlerOptions{ExportDir: dir},
+		logsDir:     filepath.Join(dir, "tasks"),
+		kmsgWatcher: newKmsgWatcher(nil),
+		trigger:     make(chan struct{}, 1),
+	}
+	if err := os.MkdirAll(q.logsDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	tk := &Task{
+		ID:        "cpu-external-1",
+		Name:      "CPU SAT",
+		Target:    "cpu",
+		Status:    TaskRunning,
+		CreatedAt: time.Now(),
+	}
+	q.assignTaskLogPathLocked(tk)
+	j := newTaskJobState(tk.LogPath)
+
+	orig := externalTaskRunnerCommand
+	externalTaskRunnerCommand = func(exportDir, taskID string) (*exec.Cmd, error) {
+		script := "printf ready > \"$1\"; while [ ! -f \"$2\" ]; do sleep 0.05; done"
+		return exec.Command("sh", "-c", script, "sh", readyPath, releasePath), nil
+	}
+	defer func() { externalTaskRunnerCommand = orig }()
+
+	done := make(chan struct{})
+	go func() {
+		q.runTaskExternal(tk, j)
+		close(done)
+	}()
+
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if _, err := os.Stat(readyPath); err == nil {
+			break
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+	if _, err := os.Stat(readyPath); err != nil {
+		t.Fatalf("external runner did not start: %v", err)
+	}
+
+	q.kmsgWatcher.mu.Lock()
+	activeCount := q.kmsgWatcher.activeCount
+	window := q.kmsgWatcher.window
+	q.kmsgWatcher.mu.Unlock()
+	if activeCount != 1 {
+		t.Fatalf("activeCount while running=%d want 1", activeCount)
+	}
+	if window == nil || len(window.targets) != 1 || window.targets[0] != "cpu" {
+		t.Fatalf("window while running=%+v", window)
+	}
+
+	if err := os.WriteFile(releasePath, []byte("1\n"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("runTaskExternal did not return")
+	}
+
+	q.kmsgWatcher.mu.Lock()
+	activeCount = q.kmsgWatcher.activeCount
+	window = q.kmsgWatcher.window
+	q.kmsgWatcher.mu.Unlock()
+	if activeCount != 0 {
+		t.Fatalf("activeCount after finish=%d want 0", activeCount)
+	}
+	if window != nil {
+		t.Fatalf("expected kmsg window to be cleared, got %+v", window)
+	}
+}