diff --git a/litellm/completion_extras/litellm_responses_transformation/transformation.py b/litellm/completion_extras/litellm_responses_transformation/transformation.py
index 9902fe1d8fc..97a35951d03 100644
--- a/litellm/completion_extras/litellm_responses_transformation/transformation.py
+++ b/litellm/completion_extras/litellm_responses_transformation/transformation.py
@@ -426,6 +426,17 @@ def replayed_tool_search_tool_names(request: object) -> tuple[str, ...]:
     return tuple(chain.from_iterable(_tool_definition_name(tool) for tool in replayed_tool_search_tools(request)))
 
 
+def with_namespace_members(tools: Sequence[object]) -> tuple[object, ...]:
+    """A Responses ``namespace`` tool stands for its member tools, as in a replayed search."""
+    return tuple(chain.from_iterable(_namespace_members(tool) for tool in tools))
+
+
+def input_tool_search_tools(request: object) -> tuple[object, ...]:
+    """The tools a ``tool_search_output`` item in a Responses ``input`` loads."""
+    items: Final = _tool_search_items_from_output_items(_json_field(request, "input"))
+    return with_namespace_members(tuple(chain.from_iterable(_loaded_tools(item) for item in items)))
+
+
 def _loads_any_tool(message: object, names: frozenset[str]) -> bool:
     loaded_names: Final = chain.from_iterable(_tool_definition_name(tool) for tool in _message_loaded_tools(message))
     return any(name in names for name in loaded_names)
diff --git a/litellm/llms/openai/responses/guardrail_translation/handler.py b/litellm/llms/openai/responses/guardrail_translation/handler.py
index a18cbe13925..bf9c4c79ee7 100644
--- a/litellm/llms/openai/responses/guardrail_translation/handler.py
+++ b/litellm/llms/openai/responses/guardrail_translation/handler.py
@@ -50,7 +50,9 @@ from litellm._logging import verbose_proxy_logger
 from litellm.completion_extras.litellm_responses_transformation.transformation import (
     LiteLLMResponsesTransformationHandler,
     OpenAiResponsesToChatCompletionStreamIterator,
+    input_tool_search_tools,
     tool_call_dict_from_output_item,
+    with_namespace_members,
 )
 from litellm.litellm_core_utils.core_helpers import has_attributes
 from litellm.llms.base_llm.guardrail_translation.base_translation import (
@@ -76,6 +78,7 @@ from litellm.llms.openai.responses.guardrail_translation.tool_merge import (
     append_returned_tools,
     merge_guardrailed_tools,
 )
+from litellm.responses.additional_tools import additional_tools_in_input
 from litellm.responses.litellm_completion_transformation.compaction_items import (
     compaction_summary,
     decode_compaction_item,
@@ -953,9 +956,12 @@ class OpenAIResponsesHandler(BaseTranslation):
 
     def extract_request_tool_names(self, data: Mapping[str, object]) -> list[str]:
         """Extract tool names from Responses API request (tools[].name for function
-        and custom, tools[].server_label for mcp)."""
+        and custom, tools[].server_label for mcp), including the tools additional_tools
+        items in input[] carry, opening namespace tools into their members and adding
+        the tools a tool_search_output in input[] loads."""
         names: Final[list[str]] = []
-        for tool in list_field(data, "tools"):
+        request_tools: Final = (*list_field(data, "tools"), *additional_tools_in_input(data.get("input")))
+        for tool in (*with_namespace_members(request_tools), *input_tool_search_tools(data)):
             if not isinstance(tool, dict):
                 continue
             if tool.get("type") in ("function", "custom") and tool.get("name"):
diff --git a/litellm/responses/additional_tools.py b/litellm/responses/additional_tools.py
index 9c7a3a5f72e..9373ca334c7 100644
--- a/litellm/responses/additional_tools.py
+++ b/litellm/responses/additional_tools.py
@@ -1,11 +1,11 @@
 import json
 from collections.abc import Iterator, Mapping, Sequence
 from dataclasses import dataclass
-from itertools import groupby
+from itertools import chain, groupby
 from types import MappingProxyType
 from typing import Final, cast  # noqa: TID251  # validating the openai tool union strips vendor keys from raw tools
 
-from pydantic import ValidationError
+from pydantic import TypeAdapter, ValidationError
 
 from litellm._logging import verbose_logger
 from litellm.types.llms.base import LiteLLMBaseModel
@@ -29,6 +29,9 @@ class HoistedAdditionalTools:
     hoisted: tuple[ALL_RESPONSES_API_TOOL_PARAMS, ...]
 
 
+_INPUT_ITEMS: Final = TypeAdapter(tuple[object, ...])
+
+
 def _is_additional_tools_item(item: object) -> bool:
     try:
         return _InputItemType.model_validate(item).type == ADDITIONAL_TOOLS_INPUT_ITEM_TYPE
@@ -86,6 +89,12 @@ def _unique_tools(tools: Sequence[Mapping[str, object]]) -> tuple[Mapping[str, o
     return tuple(_merged(copies_by_identity[identity]) for identity in first_seen_order)
 
 
+def additional_tools_in_input(input: object) -> tuple[ALL_RESPONSES_API_TOOL_PARAMS, ...]:
+    """The tools that ``additional_tools`` input items carry, in input order."""
+    items: Final = _INPUT_ITEMS.validate_python(input) if isinstance(input, list) else ()
+    return tuple(chain.from_iterable(_tools_of_item(item) for item in items if _is_additional_tools_item(item)))
+
+
 def hoist_additional_tools(
     input: str | ResponseInputParam,
     tools: Sequence[ALL_RESPONSES_API_TOOL_PARAMS] | None,
diff --git a/tests/unit/proxy/test_tools_allowlist_enforcement.py b/tests/unit/proxy/test_tools_allowlist_enforcement.py
index e306f7be4f8..2bc18ec6cf8 100644
--- a/tests/unit/proxy/test_tools_allowlist_enforcement.py
+++ b/tests/unit/proxy/test_tools_allowlist_enforcement.py
@@ -86,6 +86,66 @@ class TestExtractRequestToolNames:
             "get_current_weather",
         ]
 
+    def test_openai_responses_namespace_tools(self):
+        """Codex sends MCP tools grouped in a namespace; the allowlist must see each member."""
+        data = {
+            "tools": [
+                {"type": "function", "name": "exec_command"},
+                {
+                    "type": "namespace",
+                    "name": "mcp__mock",
+                    "tools": [{"type": "function", "name": "search_issues"}, {"type": "function", "name": "get_issue"}],
+                },
+            ]
+        }
+        assert extract_request_tool_names("/v1/responses", data) == ["exec_command", "search_issues", "get_issue"]
+
+    def test_openai_responses_tool_search_output_in_input(self):
+        """With tool_search, deferred MCP tools arrive only in input[], never in tools[]."""
+        data = {
+            "tools": [{"type": "tool_search"}],
+            "input": [
+                {"role": "user", "content": "find the issue"},
+                {"type": "tool_search_call", "call_id": "ts_1", "execution": "client"},
+                {
+                    "type": "tool_search_output",
+                    "call_id": "ts_1",
+                    "tools": [
+                        {
+                            "type": "namespace",
+                            "name": "mcp__mock",
+                            "tools": [{"type": "function", "name": "search_issues", "defer_loading": True}],
+                        }
+                    ],
+                },
+            ],
+        }
+        assert extract_request_tool_names("/v1/responses", data) == ["search_issues"]
+
+    def test_openai_responses_additional_tools_in_input(self):
+        """Codex on newer models leaves tools[] empty and sends every tool in an additional_tools input item."""
+        data = {
+            "input": [
+                {
+                    "type": "additional_tools",
+                    "role": "developer",
+                    "tools": [
+                        {
+                            "type": "namespace",
+                            "name": "functions",
+                            "tools": [{"type": "custom", "name": "exec"}, {"type": "function", "name": "wait"}],
+                        },
+                        {"type": "function", "name": "search_issues"},
+                    ],
+                },
+                {"role": "user", "content": "hi"},
+            ],
+        }
+        assert extract_request_tool_names("/v1/responses", data) == ["exec", "wait", "search_issues"]
+
+    def test_openai_responses_string_input_has_no_additional_tools(self):
+        assert extract_request_tool_names("/v1/responses", {"input": "hi"}) == []
+
     def test_anthropic_tools(self):
         data = {"tools": [{"name": "get_weather"}, {"name": "run_sql"}]}
         assert extract_request_tool_names("/v1/messages", data) == [
@@ -242,6 +302,55 @@ class TestCheckToolsAllowlist:
         assert exc_info.value.type == ProxyErrorTypes.tool_access_denied
         assert "restricted_tool" in str(exc_info.value.message)
 
+    @pytest.mark.parametrize(
+        "body",
+        [
+            {
+                "tools": [
+                    {"type": "namespace", "name": "mcp__mock", "tools": [{"type": "function", "name": "run_shell"}]}
+                ]
+            },
+            {
+                "tools": [{"type": "tool_search"}],
+                "input": [
+                    {
+                        "type": "tool_search_output",
+                        "call_id": "ts_1",
+                        "tools": [
+                            {
+                                "type": "namespace",
+                                "name": "mcp__mock",
+                                "tools": [{"type": "function", "name": "run_shell", "defer_loading": True}],
+                            }
+                        ],
+                    }
+                ],
+            },
+            {
+                "input": [
+                    {
+                        "type": "additional_tools",
+                        "role": "developer",
+                        "tools": [{"type": "function", "name": "run_shell"}],
+                    }
+                ]
+            },
+        ],
+        ids=["namespace_in_tools", "tool_search_output_in_input", "additional_tools_in_input"],
+    )
+    @pytest.mark.asyncio
+    async def test_disallowed_tool_outside_top_level_tools_raises_on_responses_route(self, body):
+        token = _token(metadata={"allowed_tools": ["get_weather"]})
+        with pytest.raises(ProxyException) as exc_info:
+            await check_tools_allowlist(
+                request_body=body,
+                valid_token=token,
+                team_object=None,
+                route="/v1/responses",
+            )
+        assert exc_info.value.type == ProxyErrorTypes.tool_access_denied
+        assert "run_shell" in str(exc_info.value.message)
+
     @pytest.mark.parametrize(
         "loaded_tool",
         [