diff --git a/litellm/proxy/guardrails/guardrail_hooks/ztds.py b/litellm/proxy/guardrails/guardrail_hooks/ztds.py
index 3522d070dfb..69b1f29d486 100644
--- a/litellm/proxy/guardrails/guardrail_hooks/ztds.py
+++ b/litellm/proxy/guardrails/guardrail_hooks/ztds.py
@@ -17,14 +17,14 @@ from __future__ import annotations
 import re
 import uuid
 from collections.abc import AsyncGenerator
-from typing import Any, ClassVar
+from typing import ClassVar
 
 try:
     from litellm.integrations.custom_guardrail import CustomGuardrail
 except ImportError:
     # Standalone fallback when running outside full LiteLLM package
     class CustomGuardrail:
-        def __init__(self, **kwargs: Any) -> None:
+        def __init__(self, **kwargs: object) -> None:
             for k, v in kwargs.items():
                 setattr(self, k, v)
 
@@ -55,8 +55,8 @@ class ZTDSGuardrail(CustomGuardrail):
         reverse_on_output: bool = True,
         enforce_zero_egress: bool = True,
         guardrail_name: str | None = "ztds",
-        **kwargs: Any,
-    ):
+        **kwargs: object,
+    ) -> None:
         super().__init__(guardrail_name=guardrail_name, **kwargs)
         self.enabled_entities = enabled_entities or list(self.PATTERNS.keys())
         self.reverse_on_output = reverse_on_output
@@ -156,11 +156,11 @@ class ZTDSGuardrail(CustomGuardrail):
 
     async def async_pre_call_hook(
         self,
-        user_api_key_dict: Any,
-        cache: Any,
-        data: dict[str, Any],
+        user_api_key_dict: object,
+        cache: object,
+        data: dict[str, object],
         call_type: str,
-    ) -> dict[str, Any]:
+    ) -> dict[str, object]:
         """
         LiteLLM pre-call hook: intercepts outgoing messages, prompts, and inputs and sanitizes all content.
         Generates an internal random nonce to prevent cross-tenant ID collisions.
@@ -223,16 +223,16 @@ class ZTDSGuardrail(CustomGuardrail):
 
     async def async_post_call_success_hook(
         self,
-        data: dict[str, Any],
-        user_api_key_dict: Any,
-        response: Any,
-    ) -> Any:
+        data: dict[str, object],
+        user_api_key_dict: object,
+        response: object,
+    ) -> object:
         """
         LiteLLM post-call success hook: restores cleartext entities in volatile RAM and zeroizes session map.
         Guarantees Theorem 2 cleanup in finally block regardless of reverse_on_output configuration.
         """
         session_id = data.get("_ztds_session_id")
-        if not session_id:
+        if not session_id or not isinstance(session_id, str):
             return response
 
         try:
@@ -259,51 +259,52 @@ class ZTDSGuardrail(CustomGuardrail):
 
     async def async_post_call_failure_hook(
         self,
-        data: dict[str, Any],
-        user_api_key_dict: Any,
+        data: dict[str, object],
+        user_api_key_dict: object,
         error: Exception,
     ) -> None:
         """
         LiteLLM post-call failure hook: ensures volatile RAM zeroization when upstream provider calls fail.
         """
         session_id = data.get("_ztds_session_id") if isinstance(data, dict) else None
-        if session_id:
+        if session_id and isinstance(session_id, str):
             self.zeroize_session(session_id)
 
     async def async_post_call_streaming_iterator_hook(
         self,
-        user_api_key_dict: Any,
-        response: Any,
-        request_data: dict,
-    ) -> AsyncGenerator[Any, None]:
+        user_api_key_dict: object,
+        response: object,
+        request_data: dict[str, object],
+    ) -> AsyncGenerator[object, None]:
         """
         LiteLLM streaming iterator hook: restores tokens across streaming response chunks in volatile RAM
         and guarantees Theorem 2 zeroization upon stream completion or error.
         """
         session_id = request_data.get("_ztds_session_id") if isinstance(request_data, dict) else None
         try:
-            async for chunk in response:
-                if session_id and self.reverse_on_output:
-                    if hasattr(chunk, "choices") and chunk.choices:
-                        for choice in chunk.choices:
-                            delta = getattr(choice, "delta", None)
-                            if delta and hasattr(delta, "content") and isinstance(delta.content, str):
-                                delta.content = self.restore_text(delta.content, session_id)
-                    elif isinstance(chunk, dict) and "choices" in chunk:
-                        for choice in chunk["choices"]:
-                            delta = choice.get("delta") if isinstance(choice, dict) else None
-                            if delta and isinstance(delta, dict) and isinstance(delta.get("content"), str):
-                                delta["content"] = self.restore_text(delta["content"], session_id)
-                yield chunk
+            if hasattr(response, "__aiter__"):
+                async for chunk in response:  # type: ignore[union-attr]
+                    if session_id and isinstance(session_id, str) and self.reverse_on_output:
+                        if hasattr(chunk, "choices") and chunk.choices:
+                            for choice in chunk.choices:
+                                delta = getattr(choice, "delta", None)
+                                if delta and hasattr(delta, "content") and isinstance(delta.content, str):
+                                    delta.content = self.restore_text(delta.content, session_id)
+                        elif isinstance(chunk, dict) and "choices" in chunk:
+                            for choice in chunk["choices"]:
+                                delta = choice.get("delta") if isinstance(choice, dict) else None
+                                if delta and isinstance(delta, dict) and isinstance(delta.get("content"), str):
+                                    delta["content"] = self.restore_text(delta["content"], session_id)
+                    yield chunk
         finally:
-            if session_id:
+            if session_id and isinstance(session_id, str):
                 self.zeroize_session(session_id)
 
     async def async_post_call_streaming_hook(
         self,
-        user_api_key_dict: Any,
+        user_api_key_dict: object,
         response: str,
-    ) -> Any:
+    ) -> object:
         """
         LiteLLM post-call streaming hook fallback.
         """