diff --git a/acp_adapter/permissions.py b/acp_adapter/permissions.py
index b10b2a169e..72ff7dbfac 100644
--- a/acp_adapter/permissions.py
+++ b/acp_adapter/permissions.py
@@ -39,13 +39,19 @@ def _permission_option_supports_kind(kind: str) -> bool:
 
 
 def _build_permission_options(
-    *, allow_permanent: bool, smart_denied: bool = False,
+    *, allow_permanent: bool, allow_session: bool = True,
+    smart_denied: bool = False,
 ) -> list[PermissionOption]:
     """Return ACP options that match Hermes approval semantics."""
+    # A gate that re-asks every time (allow_session=False, e.g. protected
+    # agent-instruction writes) collapses to the same two options as a
+    # Smart DENY override — the editor must not offer a scope Hermes
+    # discards, or every subsequent write re-prompts (#81887).
+    once_only = smart_denied or not allow_session
     options = [PermissionOption(
         option_id="allow_once", kind="allow_once", name="Allow once",
     )]
-    if not smart_denied:
+    if not once_only:
         options.append(PermissionOption(
             option_id="allow_session",
             # ACP has no session-scoped kind, so use the closest persistent
@@ -53,7 +59,7 @@ def _build_permission_options(
             kind="allow_always",
             name="Allow for session",
         ))
-    if allow_permanent and not smart_denied:
+    if allow_permanent and not once_only:
         options.append(
             PermissionOption(
                 option_id="allow_always",
@@ -62,7 +68,7 @@ def _build_permission_options(
             ),
         )
     options.append(PermissionOption(option_id="deny", kind="reject_once", name="Deny"))
-    if not smart_denied and _permission_option_supports_kind("reject_always"):
+    if not once_only and _permission_option_supports_kind("reject_always"):
         options.append(
             PermissionOption(
                 option_id="deny_always",
@@ -132,6 +138,7 @@ def make_approval_callback(
         description: str,
         *,
         allow_permanent: bool = True,
+        allow_session: bool = True,
         smart_denied: bool = False,
         **_: object,
     ) -> str:
@@ -139,6 +146,7 @@ def make_approval_callback(
 
         options = _build_permission_options(
             allow_permanent=allow_permanent,
+            allow_session=allow_session,
             smart_denied=smart_denied,
         )
 
diff --git a/cli.py b/cli.py
index c04b61a808..6ba6e8ab73 100644
--- a/cli.py
+++ b/cli.py
@@ -15702,14 +15702,16 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
 
     def _approval_callback(self, command: str, description: str,
                            *, allow_permanent: bool = True,
+                           allow_session: bool = True,
                            smart_denied: bool = False) -> str:
         """
         Prompt for dangerous command approval through the prompt_toolkit UI.
 
         Called from the agent thread. Shows a selection UI similar to clarify
         with choices: once / session / always / deny. Smart DENY owner
-        overrides show only once / deny. When allow_permanent is False for
-        another reason (for example tirith), only 'always' is hidden.
+        overrides show only once / deny, as do gates that re-ask every time
+        (allow_session=False). When allow_permanent is False for another
+        reason (for example tirith), only 'always' is hidden.
         Long commands also get a 'view' option so the full command can be
         expanded before deciding.
 
@@ -15729,6 +15731,7 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
                 "choices": self._approval_choices(
                     command,
                     allow_permanent=allow_permanent,
+                    allow_session=allow_session,
                     smart_denied=smart_denied,
                 ),
                 "selected": 0,
@@ -15780,9 +15783,10 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
             return "timeout"
 
     def _approval_choices(self, command: str, *, allow_permanent: bool = True,
+                          allow_session: bool = True,
                           smart_denied: bool = False) -> list[str]:
         """Return approval choices for a dangerous command prompt."""
-        if smart_denied:
+        if smart_denied or not allow_session:
             choices = ["once", "deny"]
         else:
             choices = ["once", "session", "always", "deny"] if allow_permanent else ["once", "session", "deny"]
diff --git a/tests/acp/test_permissions.py b/tests/acp/test_permissions.py
index 3d8576d3e2..8ea5ff45ff 100644
--- a/tests/acp/test_permissions.py
+++ b/tests/acp/test_permissions.py
@@ -23,6 +23,7 @@ def _invoke_callback(
     outcome,
     *,
     allow_permanent=True,
+    allow_session=True,
     smart_denied=False,
     timeout=60.0,
     use_prompt_path=False,
@@ -46,6 +47,7 @@ def _invoke_callback(
                 "rm -rf /",
                 "dangerous command",
                 allow_permanent=allow_permanent,
+                allow_session=allow_session,
                 smart_denied=smart_denied,
                 approval_callback=cb,
             )
@@ -54,6 +56,7 @@ def _invoke_callback(
                 "rm -rf /",
                 "dangerous command",
                 allow_permanent=allow_permanent,
+                allow_session=allow_session,
                 smart_denied=smart_denied,
             )
 
@@ -96,6 +99,21 @@ class TestApprovalBridge:
             "deny_always",
         ]
 
+    def test_session_less_gate_offers_only_once_and_deny(self):
+        """allow_session=False collapses the editor menu to once/deny.
+
+        Hermes discards any scope broader than one operation for the
+        protected agent-instruction gate, so an editor that renders
+        "Allow for session" would re-prompt on the next write (#81887).
+        """
+        _, kwargs, _, _, _ = _invoke_callback(
+            AllowedOutcome(option_id="allow_once", outcome="selected"),
+            allow_permanent=False,
+            allow_session=False,
+        )
+
+        assert [option.option_id for option in kwargs["options"]] == ["allow_once", "deny"]
+
     def test_tool_call_ids_are_unique(self):
         _, first_kwargs, _, _, _ = _invoke_callback(
             AllowedOutcome(option_id="allow_once", outcome="selected"),
diff --git a/tests/cli/test_cli_approval_ui.py b/tests/cli/test_cli_approval_ui.py
index b12112017f..081a94bac8 100644
--- a/tests/cli/test_cli_approval_ui.py
+++ b/tests/cli/test_cli_approval_ui.py
@@ -93,6 +93,38 @@ class TestCliApprovalUi:
         thread.join(timeout=2)
         assert result["value"] == "deny"
 
+    def test_session_less_gate_offers_only_once_and_deny(self):
+        """A gate that re-asks every time must not advertise a session scope.
+
+        The protected agent-instruction gate (tools/file_tools.py) grants one
+        operation and persists nothing, so offering "session" here makes every
+        later write re-prompt and reads as a broken gate (#81887).
+        """
+        cli = _make_cli_stub()
+        result = {}
+
+        def _run_callback():
+            result["value"] = cli._approval_callback(
+                "<write to AGENTS.md>",
+                "protected agent-instruction file",
+                allow_permanent=False,
+                allow_session=False,
+            )
+
+        thread = threading.Thread(target=_run_callback, daemon=True)
+        thread.start()
+
+        deadline = time.time() + 2
+        while cli._approval_state is None and time.time() < deadline:
+            time.sleep(0.01)
+
+        assert cli._approval_state is not None
+        assert cli._approval_state["choices"] == ["once", "deny"]
+
+        cli._approval_state["response_queue"].put("once")
+        thread.join(timeout=2)
+        assert result["value"] == "once"
+
 
     def test_sudo_prompt_restores_existing_draft_after_response(self):
         cli = _make_cli_stub()
diff --git a/tests/tools/test_file_write_safety.py b/tests/tools/test_file_write_safety.py
index 514aba33fb..fc92b55b09 100644
--- a/tests/tools/test_file_write_safety.py
+++ b/tests/tools/test_file_write_safety.py
@@ -463,6 +463,19 @@ class TestProtectedInstructionFiles:
         self._write(target, "second")
         assert len(approvals["calls"]) == 2
 
+    def test_cli_prompt_is_told_no_scope_persists(self, tmp_path, approvals):
+        """The prompt must not advertise a scope this gate discards.
+
+        Since nothing is persisted, a rendered "session"/"always" option
+        re-prompts on the very next write and reads as a broken gate
+        (#81887).
+        """
+        approvals["answer"] = "once"
+        self._write(tmp_path / "SOUL.md")
+        call = approvals["calls"][0]
+        assert call["allow_session"] is False
+        assert call["allow_permanent"] is False
+
     def test_regular_file_never_prompts(self, tmp_path, approvals):
         res = self._write(tmp_path / "notes.md", "hello")
         assert not res.get("error"), res
@@ -644,6 +657,35 @@ class TestProtectedInstructionFiles:
         finally:
             A.reset_current_session_key(token)
 
+    def test_gateway_payload_renders_only_once_and_deny(self, tmp_path):
+        """End-to-end: what this gate emits, a TUI/desktop client can render.
+
+        The transport used to derive its button set from ``allow_permanent``
+        alone, so it re-added a "session" scope the gate refuses to persist —
+        users tapped it and got re-prompted on every write (#81887). Asserting
+        the two layers together is what catches that drift.
+        """
+        import tools.approval as A
+        from tui_gateway.server import _approval_request_payload
+
+        session_key = "protected-files-payload-session"
+        token = A.set_current_session_key(session_key)
+        rendered = {}
+        try:
+            def notify(approval_data):
+                rendered.update(_approval_request_payload(approval_data))
+                A.resolve_gateway_approval(session_key, "once")
+
+            A.register_gateway_notify(session_key, notify)
+            try:
+                self._write(tmp_path / "SOUL.md", "gateway approved")
+            finally:
+                A.unregister_gateway_notify(session_key)
+        finally:
+            A.reset_current_session_key(token)
+
+        assert rendered["choices"] == ["once", "deny"]
+
 
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])
diff --git a/tools/approval.py b/tools/approval.py
index 1ecda55ec4..ac5f4c3ee7 100644
--- a/tools/approval.py
+++ b/tools/approval.py
@@ -2965,20 +2965,27 @@ def prompt_dangerous_approval(command: str, description: str,
                               timeout_seconds: int | None = None,
                               allow_permanent: bool = True,
                               approval_callback=None,
-                              *, smart_denied: bool = False) -> str:
+                              *, allow_session: bool = True,
+                              smart_denied: bool = False) -> str:
     """Prompt the user to approve a dangerous command (CLI only).
 
     Args:
         allow_permanent: When False, hide the [a]lways option (used when
             tirith warnings are present, since broad permanent allowlisting
             is inappropriate for content-level security findings).
+        allow_session: When False, hide the [s]ession option too — the
+            caller grants one operation and re-asks next time (the
+            protected agent-instruction gate in ``tools/file_tools.py``).
+            Offering a scope the caller discards makes every subsequent
+            write re-prompt and reads as a broken gate (#81887).
         smart_denied: When True, this is an owner override of a Smart DENY.
             Offer only one-operation approval or denial.
         approval_callback: Optional callback registered by the CLI for
             prompt_toolkit integration. Signature:
             (command, description, *, allow_permanent=True,
-            smart_denied=False) -> str. Legacy callback signatures remain
-            supported when ``smart_denied`` is false.
+            allow_session=True, smart_denied=False) -> str. Legacy callback
+            signatures remain supported while both keywords hold their
+            defaults.
 
     Returns: 'once', 'session', 'always', 'deny', or 'timeout'.
         'timeout' means the prompt expired without a user response — the
@@ -2999,6 +3006,7 @@ def prompt_dangerous_approval(command: str, description: str,
             timeout_seconds,
             allow_permanent,
             approval_callback,
+            allow_session=allow_session,
             smart_denied=smart_denied,
         )
 
@@ -3007,7 +3015,8 @@ def _prompt_dangerous_approval_inner(command: str, description: str,
                                      timeout_seconds: int,
                                      allow_permanent: bool = True,
                                      approval_callback=None,
-                                     *, smart_denied: bool = False) -> str:
+                                     *, allow_session: bool = True,
+                                     smart_denied: bool = False) -> str:
     # Redact secrets before any user-visible rendering. The original
     # `command` is still what executes after approval; only the displayed
     # copy is scrubbed. Reuses the same redaction module used for memory
@@ -3016,9 +3025,15 @@ def _prompt_dangerous_approval_inner(command: str, description: str,
     display_command = redact_sensitive_text(command)
     display_description = redact_sensitive_text(description)
 
+    # Smart DENY and a session-less gate both reduce the menu to
+    # once/deny; the rendered strings are the same either way.
+    once_only = smart_denied or not allow_session
+
     if approval_callback is not None:
         try:
             callback_kwargs = {"allow_permanent": allow_permanent}
+            if not allow_session:
+                callback_kwargs["allow_session"] = False
             if smart_denied:
                 callback_kwargs["smart_denied"] = True
             return approval_callback(
@@ -3065,7 +3080,7 @@ def _prompt_dangerous_approval_inner(command: str, description: str,
             print(f"  {t('approval.dangerous_header', description=display_description)}")
             print(f"      {display_command}")
             print()
-            if smart_denied:
+            if once_only:
                 print(t("approval.choose_smart_deny"))
             elif allow_permanent:
                 print(t("approval.choose_long"))
@@ -3078,7 +3093,7 @@ def _prompt_dangerous_approval_inner(command: str, description: str,
 
             def get_input():
                 try:
-                    if smart_denied:
+                    if once_only:
                         prompt = t("approval.prompt_smart_deny")
                     else:
                         prompt = t("approval.prompt_long") if allow_permanent else t("approval.prompt_short")
@@ -3098,7 +3113,7 @@ def _prompt_dangerous_approval_inner(command: str, description: str,
                 return "timeout"
 
             choice = result["choice"]
-            if smart_denied:
+            if once_only:
                 choice_map = {
                     **{
                         value: "once"
diff --git a/tools/file_tools.py b/tools/file_tools.py
index 2270fb57f6..2365f335e5 100644
--- a/tools/file_tools.py
+++ b/tools/file_tools.py
@@ -916,6 +916,7 @@ def _request_protected_instruction_approval(
         choice = _approval.prompt_dangerous_approval(
             display, description,
             allow_permanent=False,
+            allow_session=False,
             approval_callback=callback,
         )
         if choice in {"once", "session", "always"}: