diff --git a/scripts/installtests/agent_nas_teardown.py b/scripts/installtests/agent_nas_teardown.py
index 06092aaf68..e5213826f1 100644
--- a/scripts/installtests/agent_nas_teardown.py
+++ b/scripts/installtests/agent_nas_teardown.py
@@ -425,7 +425,20 @@ remove_safe_profile_state_dir() { rm -rf -- "$SAFE_PROFILE_STATE_DIR"; }
                 root = Path(directory).resolve()
                 for name in ('state', 'bin', 'tools', 'flash', 'logs'): (root / name).mkdir(mode=0o700)
                 runtime = root / 'bin/pulse-agent'; stored = root / 'state/stored-agent'
-                stored.write_bytes(Path('/bin/sleep').read_bytes()); stored.chmod(0o700)
+                # Supply a native Go executable like the actual collector,
+                # not a renamed platform-owned /bin/sleep with implicit
+                # executable/process semantics. The generated production
+                # wrapper still copies it to the exact runtime path, and real
+                # kernel rows still drive the unchanged ownership/stop checks.
+                build = subprocess.run(
+                    ['go', 'build', '-trimpath', '-o', str(stored),
+                     './scripts/installtests/nasfixturecollector'],
+                    cwd=ROOT, capture_output=True, text=True, timeout=30,
+                )
+                self.assertEqual(build.returncode, 0, build.stdout + build.stderr)
+                self.assertTrue(stored.is_file())
+                self.assertFalse(stored.is_symlink())
+                stored.chmod(0o700)
                 watchdog = root / 'state/start-pulse-agent.sh'
                 (root / 'tools/pkill').write_text('#!/bin/sh\nexit 0\n'); (root / 'tools/pkill').chmod(0o700)
                 (root / 'tools/flash').write_text('#!/bin/sh\nexit 0\n'); (root / 'tools/flash').chmod(0o700)
@@ -467,6 +480,7 @@ remove_safe_profile_state_dir() { rm -rf -- "$SAFE_PROFILE_STATE_DIR"; }
                 control = root / 'control.sh'
                 control.write_text('set -euo pipefail\n' + setup + '\n' + functions + '\ncommand() { [[ "$*" != "-v systemctl" ]] || return 1; builtin command "$@"; }\nquiesce_nas_agent_for_removal ' + platform + '\n')
                 output = root / 'watchdog.log'
+                collector_log = root / 'logs' / ('pulse-agent-watchdog.log' if platform == 'QNAP' else 'watchdog.log')
                 with output.open('wb') as stream:
                     process = subprocess.Popen([str(watchdog)] if platform == 'QNAP' else ['bash', str(watchdog)], env=env,
                                                stdout=stream, stderr=stream, start_new_session=True)
@@ -474,7 +488,9 @@ remove_safe_profile_state_dir() { rm -rf -- "$SAFE_PROFILE_STATE_DIR"; }
                         deadline = time.monotonic() + 8
                         while time.monotonic() < deadline:
                             listing = subprocess.run([str(fixture_ps), '-ax', '-o', 'comm=', '-o', 'args='], capture_output=True, text=True, check=True).stdout
-                            if generated_collector_is_running(listing, runtime): break
+                            if (generated_collector_is_running(listing, runtime)
+                                    and collector_log.is_file()
+                                    and 'private NAS fixture collector ready\n' in collector_log.read_text()): break
                             self.assertIsNone(process.poll(), output.read_text()); time.sleep(.05)
                         else:
                             # Retain only owned fixture rows/logs, never other
diff --git a/scripts/installtests/nasfixturecollector/main.go b/scripts/installtests/nasfixturecollector/main.go
new file mode 100644
index 0000000000..af6eddbe45
--- /dev/null
+++ b/scripts/installtests/nasfixturecollector/main.go
@@ -0,0 +1,35 @@
+// nasfixturecollector is an inert, native-built input for the private NAS
+// watchdog/removal fixture. It has no agent, service, network or state access.
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"time"
+)
+
+const ready = "private NAS fixture collector ready\n"
+
+func run(args []string, output io.Writer, wait func(time.Duration)) error {
+	// The generated wrapper passes this one fixed lifetime. Reject anything
+	// else rather than allowing an accidentally unbounded fixture process.
+	if len(args) != 1 || args[0] != "30" {
+		return errors.New("private NAS fixture requires its fixed 30-second lifetime")
+	}
+	if n, err := io.WriteString(output, ready); err != nil || n != len(ready) {
+		return errors.New("private NAS fixture could not record readiness")
+	}
+	wait(30 * time.Second)
+	return nil
+}
+
+func main() {
+	// Both generated wrappers discard stdout and retain stderr in their own
+	// watchdog log. This fixed marker discloses no process arguments or paths.
+	if err := run(os.Args[1:], os.Stderr, time.Sleep); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
diff --git a/scripts/installtests/nasfixturecollector/main_test.go b/scripts/installtests/nasfixturecollector/main_test.go
new file mode 100644
index 0000000000..b5e8d0f963
--- /dev/null
+++ b/scripts/installtests/nasfixturecollector/main_test.go
@@ -0,0 +1,58 @@
+package main
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"testing"
+	"time"
+)
+
+func TestCollectorRecordsReadinessBeforeBoundedWait(t *testing.T) {
+	var output bytes.Buffer
+	calls := 0
+	if err := run([]string{"30"}, &output, func(duration time.Duration) {
+		calls++
+		if duration != 30*time.Second || output.String() != ready {
+			t.Fatalf("wait %s before readiness %q", duration, output.String())
+		}
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if calls != 1 {
+		t.Fatalf("wait called %d times", calls)
+	}
+}
+
+func TestCollectorRejectsChangedOrMissingLifetime(t *testing.T) {
+	for _, args := range [][]string{nil, {"0"}, {"-1"}, {"300"}, {"30", "extra"}} {
+		t.Run("invalid", func(t *testing.T) {
+			var output bytes.Buffer
+			err := run(args, &output, func(time.Duration) { t.Fatal("invalid input started a collector") })
+			if err == nil || output.Len() != 0 {
+				t.Fatalf("invalid input produced readiness or success: %v, %q", err, output.String())
+			}
+		})
+	}
+}
+
+type refusedOutput struct{}
+
+func (refusedOutput) Write([]byte) (int, error) { return 0, errors.New("synthetic write refusal") }
+
+type shortOutput struct{}
+
+func (shortOutput) Write([]byte) (int, error) { return 1, nil }
+
+func TestCollectorCannotWaitAfterUnrecordedReadiness(t *testing.T) {
+	for _, output := range []io.Writer{refusedOutput{}, shortOutput{}} {
+		if err := run([]string{"30"}, output, func(time.Duration) {
+			t.Fatal("failed readiness started a collector")
+		}); err == nil {
+			t.Fatal("failed readiness accepted")
+		}
+	}
+	if err := run([]string{"30"}, io.Discard, func(time.Duration) {}); err != nil {
+		t.Fatal(err)
+	}
+}