diff --git a/litellm/mcp_client/tools.py b/litellm/mcp_client/tools.py
index 4f204b3629e..11aef794c4b 100644
--- a/litellm/mcp_client/tools.py
+++ b/litellm/mcp_client/tools.py
@@ -37,7 +37,6 @@ def transform_mcp_tool_to_openai_tool(mcp_tool: MCPTool) -> ChatCompletionToolPa
             name=mcp_tool.name,
             description=mcp_tool.description or "",
             parameters=normalized_parameters,
-            strict=False,
         ),
     )
 
diff --git a/litellm/responses/litellm_completion_transformation/transformation.py b/litellm/responses/litellm_completion_transformation/transformation.py
index bc92bc9cb3a..6512314d0e5 100644
--- a/litellm/responses/litellm_completion_transformation/transformation.py
+++ b/litellm/responses/litellm_completion_transformation/transformation.py
@@ -2708,7 +2708,7 @@ class LiteLLMCompletionResponsesConfig:
             return convert_custom_tool_to_function_tool({**namespace_tool, "description": description})
 
         raw_parameters: Final = namespace_tool.get("parameters")
-        parameters: Final = (
+        parameters: Final[Mapping[str, object]] = (
             MappingProxyType(raw_parameters) if isinstance(raw_parameters, Mapping) else MappingProxyType({})
         )
         normalized_parameters: Final = (
@@ -2716,11 +2716,16 @@ class LiteLLMCompletionResponsesConfig:
         )
         tool_name: Final = str(namespace_tool.get("name") or "")
         chat_tool_name: Final = f"{namespace}__{tool_name}" if nested else tool_name
-        function: Final = ChatCompletionToolParamFunctionChunk(
-            name=chat_tool_name,
-            description=description,
-            parameters=dict(normalized_parameters),
-            strict=bool(namespace_tool.get("strict", False)),
+        chat_parameters: Final = dict(normalized_parameters)
+        caller_strict: Final = namespace_tool.get("strict")
+        function: Final = (
+            ChatCompletionToolParamFunctionChunk(
+                name=chat_tool_name, description=description, parameters=chat_parameters, strict=caller_strict
+            )
+            if isinstance(caller_strict, bool)
+            else ChatCompletionToolParamFunctionChunk(
+                name=chat_tool_name, description=description, parameters=chat_parameters
+            )
         )
         return function_chat_tool(
             function,
@@ -2798,13 +2803,14 @@ class LiteLLMCompletionResponsesConfig:
             typed_tool: Final = cast(FunctionToolParam, tool)
             raw_parameters: Final = typed_tool.get("parameters", {}) or {}
             parameters: Final = {**raw_parameters} if "type" in raw_parameters else {**raw_parameters, "type": "object"}
+            caller_strict: Final = typed_tool.get("strict")
             chat_completion_tool: Final[dict[str, object]] = {
                 "type": "function",
                 "function": {
                     "name": typed_tool.get("name") or "",
                     "description": typed_tool.get("description") or "",
                     "parameters": parameters,
-                    "strict": typed_tool.get("strict", False) or False,
+                    **({"strict": caller_strict} if isinstance(caller_strict, bool) else {}),
                 },
             }
             if tool.get("cache_control"):
diff --git a/tests/unit/llms/hosted_vllm/chat/test_hosted_vllm_chat_transformation.py b/tests/unit/llms/hosted_vllm/chat/test_hosted_vllm_chat_transformation.py
index 2a5bb400671..9112d6ee30e 100644
--- a/tests/unit/llms/hosted_vllm/chat/test_hosted_vllm_chat_transformation.py
+++ b/tests/unit/llms/hosted_vllm/chat/test_hosted_vllm_chat_transformation.py
@@ -402,14 +402,14 @@ def test_hosted_vllm_custom_tools_use_top_level_input_schema():
     assert tools[0]["function"]["parameters"] == input_schema
 
 
-def _strict_tools() -> list[dict[str, object]]:
+def _strict_tools(strict: bool = True) -> list[dict[str, object]]:
     return [
         {
             "type": "function",
             "function": {
                 "name": "record_code",
                 "description": "Record a ten letter code",
-                "strict": True,
+                "strict": strict,
                 "parameters": {
                     "type": "object",
                     "properties": {
@@ -428,9 +428,10 @@ def _strict_tools() -> list[dict[str, object]]:
     ]
 
 
+@pytest.mark.parametrize("strict", [True, False])
 @pytest.mark.parametrize("drop_params", [True, False])
-def test_hosted_vllm_forwards_strict_tool_schema_as_sent(drop_params: bool) -> None:
-    tools: Final = _strict_tools()
+def test_hosted_vllm_forwards_strict_tool_schema_as_sent(drop_params: bool, strict: bool) -> None:
+    tools: Final = _strict_tools(strict)
     sent: Final = copy.deepcopy(tools)
 
     optional_params: Final = get_optional_params(
diff --git a/tests/unit/mcp_client/test_tools.py b/tests/unit/mcp_client/test_tools.py
index ca3cf29bd90..849df68b7f1 100644
--- a/tests/unit/mcp_client/test_tools.py
+++ b/tests/unit/mcp_client/test_tools.py
@@ -73,6 +73,7 @@ def test_transform_mcp_tool_to_openai_tool(mock_mcp_tool):
         "properties": {"test": {"type": "string"}},
         "additionalProperties": False,
     }
+    assert "strict" not in openai_tool["function"]
 
 
 def testtransform_openai_tool_call_request_to_mcp_tool_call_request(mock_mcp_tool):
diff --git a/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py b/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
index 3fd4be6f722..0d9adda3499 100644
--- a/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
+++ b/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
@@ -2001,6 +2001,29 @@ class TestToolTransformation:
         assert [tool["function"]["name"] for tool in not_deferred] == ["finance__get_stock_price", "get_weather"]
         assert all("defer_loading" not in tool for tool in not_deferred)
 
+    def test_function_tools_carry_strict_only_when_the_caller_set_it(self) -> None:
+        strict_variants: Final = {"unset": {}, "null": {"strict": None}, "on": {"strict": True}, "off": {"strict": False}}
+        function_tools: Final = [
+            {"type": "function", "name": name, "parameters": {"type": "object"}, **strict}
+            for name, strict in strict_variants.items()
+        ]
+
+        chat_tools, _ = LiteLLMCompletionResponsesConfig.transform_responses_api_tools_to_chat_completion_tools(
+            tools=[*function_tools, {"type": "namespace", "name": "ns", "tools": function_tools}]
+        )
+
+        sent_strict: Final = {tool["function"]["name"]: tool["function"].get("strict", "absent") for tool in chat_tools}
+        assert sent_strict == {
+            "unset": "absent",
+            "null": "absent",
+            "on": True,
+            "off": False,
+            "ns__unset": "absent",
+            "ns__null": "absent",
+            "ns__on": True,
+            "ns__off": False,
+        }
+
     @pytest.mark.parametrize("global_drop_params", [False, True])
     def test_malformed_tool_flags_answer_400_unless_drop_params_drops_them(
         self, monkeypatch: pytest.MonkeyPatch, global_drop_params: bool