diff --git a/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/__init__.py b/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/__init__.py
index 1a138b29fe0..d38b851680a 100644
--- a/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/__init__.py
+++ b/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/__init__.py
@@ -1,5 +1,6 @@
 """Built-in Sensitive Data Routing guardrail: reroutes sensitive prompts to an on-premise model."""
 
+from collections.abc import Sequence
 from typing import TYPE_CHECKING, Final
 
 from litellm.types.guardrails import GuardrailEventHooks, Mode, SupportedGuardrailIntegrations
@@ -14,8 +15,8 @@ if TYPE_CHECKING:
 
 
 def _to_event_hook(
-    mode: str | list[str] | Mode | None,
-) -> GuardrailEventHooks | list[GuardrailEventHooks] | Mode | None:
+    mode: str | Sequence[str] | Mode | None,
+) -> GuardrailEventHooks | list[GuardrailEventHooks] | Mode | None:  # mutable-ok: base type
     if mode is None or isinstance(mode, Mode):
         return mode
     if isinstance(mode, str):
diff --git a/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/sensitive_data_routing.py b/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/sensitive_data_routing.py
index 7a6c7ee09e1..4f2aa2c1e0e 100644
--- a/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/sensitive_data_routing.py
+++ b/litellm/proxy/guardrails/guardrail_hooks/sensitive_data_routing/sensitive_data_routing.py
@@ -80,7 +80,7 @@ class SensitiveDataRoutingGuardrail(CustomGuardrail):
         keywords: Sequence[str] | None = None,
         sticky_session: bool = True,
         session_ttl_seconds: int = DEFAULT_SESSION_TTL_SECONDS,
-        event_hook: GuardrailEventHooks | list[GuardrailEventHooks] | None = None,
+        event_hook: GuardrailEventHooks | list[GuardrailEventHooks] | None = None,  # mutable-ok: base type
         default_on: bool = False,
     ) -> None:
         if not on_premise_model:
@@ -105,7 +105,7 @@ class SensitiveDataRoutingGuardrail(CustomGuardrail):
         self.session_ttl_seconds = session_ttl_seconds
 
     @classmethod
-    def get_supported_event_hooks(cls) -> list[GuardrailEventHooks]:
+    def get_supported_event_hooks(cls) -> list[GuardrailEventHooks]:  # mutable-ok: base type
         return [GuardrailEventHooks.pre_call]
 
     @staticmethod
@@ -122,7 +122,7 @@ class SensitiveDataRoutingGuardrail(CustomGuardrail):
     async def apply_guardrail(
         self,
         inputs: GenericGuardrailAPIInputs,
-        request_data: dict,
+        request_data: dict,  # mutable-ok: proxy request body, owned by the caller
         input_type: Literal["request", "response"],
         logging_obj: Optional["LiteLLMLoggingObj"] = None,
     ) -> GenericGuardrailAPIInputs:
diff --git a/litellm/types/proxy/guardrails/guardrail_hooks/sensitive_data_routing.py b/litellm/types/proxy/guardrails/guardrail_hooks/sensitive_data_routing.py
index 65aa4c077cf..326dae595b3 100644
--- a/litellm/types/proxy/guardrails/guardrail_hooks/sensitive_data_routing.py
+++ b/litellm/types/proxy/guardrails/guardrail_hooks/sensitive_data_routing.py
@@ -1,5 +1,6 @@
 """Types for the built-in Sensitive Data Routing guardrail."""
 
+from collections.abc import Sequence
 from typing import Final
 
 from pydantic import Field
@@ -16,15 +17,15 @@ class SensitiveDataRoutingGuardrailConfigModel(GuardrailConfigModel):
         default=None,
         description="Model group (from model_list) to route the request to when sensitive data is detected.",
     )
-    prebuilt_patterns: list[str] | None = Field(
+    prebuilt_patterns: Sequence[str] | None = Field(
         default=None,
         description="Prebuilt pattern names to match (e.g. us_ssn, credit_card, email).",
     )
-    regex_patterns: list[str] | None = Field(
+    regex_patterns: Sequence[str] | None = Field(
         default=None,
         description="Custom regular expressions; a match in any message reroutes the request.",
     )
-    keywords: list[str] | None = Field(
+    keywords: Sequence[str] | None = Field(
         default=None,
         description="Case-insensitive keywords; a match in any message reroutes the request.",
     )