diff --git a/litellm/proxy/response_api_endpoints/endpoints.py b/litellm/proxy/response_api_endpoints/endpoints.py
index 685f1086eb2..0578de15f3d 100644
--- a/litellm/proxy/response_api_endpoints/endpoints.py
+++ b/litellm/proxy/response_api_endpoints/endpoints.py
@@ -2399,7 +2399,7 @@ def _frame_guardrail_selections(body: Mapping[str, object]) -> tuple[_FrameGuard
     ``litellm_metadata``, the top level last so its ``guardrail_config`` wins"""
     return (
         *(
-            _frame_guardrail_selection((key,), _WS_FRAME.validate_python(value), _METADATA_GUARDRAIL_SELECTORS)
+            _frame_guardrail_selection((key,), _metadata_picks(key, value), _METADATA_GUARDRAIL_SELECTORS)
             for key, value in body.items()
             if key in _CLIENT_METADATA_KEYS and isinstance(value, dict)
         ),
@@ -2407,6 +2407,14 @@ def _frame_guardrail_selections(body: Mapping[str, object]) -> tuple[_FrameGuard
     )
 
 
+def _metadata_picks(key: str, metadata: object) -> Mapping[str, object]:
+    """OpenAI ``metadata`` values are strings, so a string there is the client's own metadata and never a pick"""
+    validated: Final = _WS_FRAME.validate_python(metadata)
+    if key != "metadata":
+        return validated
+    return {name: item for name, item in validated.items() if not isinstance(item, str)}
+
+
 def _frame_guardrail_selection(
     location: tuple[str, ...], source: Mapping[str, object], selectors: tuple[str, ...]
 ) -> _FrameGuardrailSelection:
@@ -2422,7 +2430,7 @@ def _without_guardrail_selection(metadata: object) -> object:
     return {
         name: item
         for name, item in _WS_FRAME.validate_python(metadata).items()
-        if name not in _METADATA_GUARDRAIL_SELECTORS
+        if name not in _METADATA_GUARDRAIL_SELECTORS or isinstance(item, str)
     }
 
 
diff --git a/tests/unit/proxy/response_api_endpoints/test_endpoints.py b/tests/unit/proxy/response_api_endpoints/test_endpoints.py
index 9dea7fa0af9..74f9162c992 100644
--- a/tests/unit/proxy/response_api_endpoints/test_endpoints.py
+++ b/tests/unit/proxy/response_api_endpoints/test_endpoints.py
@@ -2530,7 +2530,7 @@ class TestResponsesWSFirstFrameModelAuth:
         ],
         ids=["top-level", "with-extra-body", "metadata", "litellm-metadata", "nested"],
     )
-    async def test_frame_guard_runs_the_guardrails_a_frame_selects_on_top_of_the_admitted_ones(self, selected):
+    async def test_frame_guard_runs_the_guardrails_a_frame_selects_on_top_of_the_admitted_ones(self, selected: dict[str, object]):
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
 
         key_required = _FrameGuardrail("key-required")
@@ -2557,6 +2557,27 @@ class TestResponsesWSFirstFrameModelAuth:
         assert unselected.inputs == []
         assert admitted["litellm_metadata"] == {"guardrails": ["key-required"]}
 
+    @pytest.mark.asyncio
+    async def test_frame_guard_forwards_string_metadata_named_like_a_pick_without_running_it(self):
+        from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
+
+        key_required = _FrameGuardrail("key-required")
+        frame_pick = _FrameGuardrail("frame-pick")
+        metadata = {"guardrails": "frame-pick", "guardrail_config": "strict", "trace": "t1"}
+
+        with _guardrails_on(key_required, frame_pick) as proxy_logging_obj:
+            guard = _responses_ws_frame_guard(
+                {"model": "gpt-4o-mini", "litellm_metadata": {"guardrails": ["key-required"]}},
+                _key(),
+                proxy_logging_obj,
+                MagicMock(),
+            )
+            guarded = await guard(json.dumps({"type": "response.create", "input": "hi", "metadata": metadata}))
+
+        assert json.loads(guarded.frame) == {"type": "response.create", "input": "hi", "metadata": metadata}
+        assert key_required.inputs == ["hi"]
+        assert frame_pick.inputs == []
+
     @pytest.mark.asyncio
     async def test_frame_guard_hands_a_selected_guardrail_its_config_with_the_top_level_winning(self):
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
@@ -2672,8 +2693,8 @@ class TestResponsesWSFirstFrameModelAuth:
             ),
             ({"policies": [1]}, "response.create policies.0: Input should be a valid string"),
             (
-                {"metadata": {"guardrails": "frame-pick"}},
-                "response.create metadata.guardrails: 'str' instances are not allowed as a Sequence value",
+                {"litellm_metadata": {"guardrails": "frame-pick"}},
+                "response.create litellm_metadata.guardrails: 'str' instances are not allowed as a Sequence value",
             ),
             (
                 {"litellm_metadata": {"guardrail_config": []}},
@@ -2682,7 +2703,7 @@ class TestResponsesWSFirstFrameModelAuth:
         ],
     )
     async def test_frame_guard_refuses_and_bills_a_frame_whose_guardrail_selection_is_malformed(
-        self, selection, message
+        self, selection: dict[str, object], message: str
     ):
         from litellm.proxy.hooks.proxy_track_cost_callback import ProxyDBLogger
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
@@ -2879,7 +2900,7 @@ class TestResponsesWSFirstFrameModelAuth:
 
     @pytest.mark.asyncio
     @pytest.mark.parametrize("field", ["input", "instructions", "tools"])
-    async def test_frame_guard_rejects_and_bills_a_guarded_field_beside_a_nested_response(self, field):
+    async def test_frame_guard_rejects_and_bills_a_guarded_field_beside_a_nested_response(self, field: str):
         from litellm.proxy.hooks.proxy_track_cost_callback import ProxyDBLogger
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
 
@@ -2911,7 +2932,7 @@ class TestResponsesWSFirstFrameModelAuth:
         ],
         ids=["top-level", "metadata", "litellm-metadata"],
     )
-    async def test_frame_guard_runs_the_guardrails_a_nested_frame_selects_beside_its_response(self, top_level):
+    async def test_frame_guard_runs_the_guardrails_a_nested_frame_selects_beside_its_response(self, top_level: dict[str, object]):
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard
 
         key_required = _FrameGuardrail("key-required")
@@ -2951,7 +2972,7 @@ class TestResponsesWSFirstFrameModelAuth:
         ],
         ids=["top-level", "metadata", "global-toggle", "nested", "beside-nested", "policies", "nested-policies"],
     )
-    async def test_frame_guard_refuses_guardrail_and_policy_picks_from_a_team_without_permission(self, frame):
+    async def test_frame_guard_refuses_guardrail_and_policy_picks_from_a_team_without_permission(self, frame: dict[str, object]):
         from litellm.proxy._types import LiteLLM_TeamTable
         from litellm.proxy.hooks.proxy_track_cost_callback import ProxyDBLogger
         from litellm.proxy.response_api_endpoints.endpoints import _responses_ws_frame_guard