--- a/tests/test_sops_private.py
+++ b/tests/test_sops_private.py
@@ -10,6 +10,40 @@
 ROOT = Path(__file__).resolve().parents[1]
 SOPS = shutil.which('sops')
 pytestmark = pytest.mark.skipif(SOPS is None, reason='SOPS required for real crypto regression')
+
+
+@pytest.mark.parametrize('wrong_recipient', [False, True])
+def test_real_sops_decrypt_with_only_sealed_descriptor(case, wrong_recipient):
+    import fcntl
+    original = case[1].read_bytes()
+    material = (subprocess.run(['age-keygen'], capture_output=True, check=True).stdout
+                if wrong_recipient else original)
+    fd = os.memfd_create('generated-sops-custody', os.MFD_ALLOW_SEALING)
+    try:
+        os.fchmod(fd, 0o600); os.write(fd, material); os.lseek(fd, 0, os.SEEK_SET)
+        fcntl.fcntl(fd, fcntl.F_ADD_SEALS,
+                    fcntl.F_SEAL_WRITE | fcntl.F_SEAL_GROW | fcntl.F_SEAL_SHRINK | fcntl.F_SEAL_SEAL)
+        case[1].unlink()
+        env = {**case[2], 'NETKINGDOM_CUSTODY_AGE_KEY_FD': str(fd)}
+        env.pop('NETKINGDOM_CUSTODY_AGE_KEY_FILE')
+        if wrong_recipient:
+            # A correct ambient key must never rescue the wrong explicit FD.
+            env['SOPS_AGE_KEY'] = original.decode()
+        result = subprocess.run(['make', '-s', 'sops-decrypt', 'FILE=' + str(case[3]),
+                                 'OUTPUT=' + str(case[4])], cwd=case[0], env=env,
+                                pass_fds=(fd,), capture_output=True, text=True, timeout=15)
+        assert not case[1].exists()
+        assert 'synthetic-secret-payload' not in result.stdout + result.stderr
+        if wrong_recipient:
+            assert result.returncode != 0
+            assert not case[4].exists()
+        else:
+            assert result.returncode == 0
+            assert json.loads(case[4].read_text()) == {'credential': 'synthetic-secret-payload'}
+            assert case[4].stat().st_mode & 0o077 == 0
+        assert not list(case[4].parent.glob('.netkingdom-sops-*'))
+    finally:
+        os.close(fd)
 
 
 @pytest.fixture
--- a/tests/test_sops_write.py
+++ b/tests/test_sops_write.py
@@ -11,6 +11,36 @@
 SOPS=shutil.which('sops')
 pytestmark=pytest.mark.skipif(SOPS is None,reason='real SOPS required')
 PLAIN='synthetic-sops-write-value'
+
+
+@pytest.mark.parametrize('action', ['rotate', 'edit'])
+def test_real_sops_write_with_only_sealed_descriptor(case, action):
+    import fcntl
+    fd = os.memfd_create('generated-sops-write-custody', os.MFD_ALLOW_SEALING)
+    try:
+        os.fchmod(fd, 0o600); os.write(fd, case['key'].read_bytes()); os.lseek(fd, 0, os.SEEK_SET)
+        fcntl.fcntl(fd, fcntl.F_ADD_SEALS,
+                    fcntl.F_SEAL_WRITE | fcntl.F_SEAL_GROW | fcntl.F_SEAL_SHRINK | fcntl.F_SEAL_SEAL)
+        case['key'].unlink()
+        env = {**case['env'], 'NETKINGDOM_CUSTODY_AGE_KEY_FD': str(fd)}
+        env.pop('NETKINGDOM_CUSTODY_AGE_KEY_FILE'); env.pop('SOPS_AGE_KEY_FILE')
+        before = case['cipher'].read_bytes()
+        result = subprocess.run(['make', '-s', 'sops-' + action,
+                                 'FILE=' + str(case['cipher']), 'INPUT=' + str(case['input'])],
+                                cwd=case['repo'], env=env, pass_fds=(fd,),
+                                capture_output=True, text=True, timeout=15)
+        assert result.returncode == 0
+        assert PLAIN not in result.stdout + result.stderr
+        assert not case['key'].exists()
+        assert before != case['cipher'].read_bytes()
+        clear = subprocess.run([SOPS, '--decrypt', str(case['cipher'])],
+                               env={**env, 'SOPS_AGE_KEY_FILE': '/proc/self/fd/' + str(fd)},
+                               pass_fds=(fd,), capture_output=True, check=True)
+        assert json.loads(clear.stdout) == {'credential': PLAIN + ('-edited' if action == 'edit' else '')}
+        assert case['cipher'].stat().st_mode & 0o077 == 0
+        assert not list(case['cipher'].parent.glob('.netkingdom-sops-write-*'))
+    finally:
+        os.close(fd)
 
 
 @pytest.fixture