fix(guardrails)!: make hide-secrets honor skip_tool_message_in_guardrail (#48689)

* fix(guardrails): make hide-secrets honor skip_tool_message_in_guardrail

With the flag on, per guardrail or in litellm_settings, hide-secrets leaves
role: tool messages and Anthropic tool_result blocks as sent, as the
unified guardrails do. Tool call arguments are still masked.

* test(guardrails): type the skip-tool walker test and assert the whole request

enterprise/litellm_enterprise/enterprise_callbacks/secret_detection.py

@@ -32,6 +32,7 @@ from litellm.integrations.custom_guardrail import (
     CustomGuardrail,
     log_guardrail_information,
 )
+from litellm.llms.base_llm.guardrail_translation.utils import effective_skip_tool_message_for_guardrail
 from litellm.proxy._types import UserAPIKeyAuth
 from litellm.proxy.guardrails._content_utils import iter_tool_json_fields, map_tool_json_text, walk_user_text
 from litellm.types.guardrails import GuardrailEventHooks
@@ -753,7 +754,12 @@ class _ENTERPRISE_SecretDetection(CustomGuardrail):
         _masked_entity_count.set({})
 
         # Covers multimodal list content + Responses-API input.
-        inspected = walk_user_text(data, self.redact_text, self.redact_tool_payload) + self._redact_prompt(data)
+        inspected = walk_user_text(
+            data,
+            self.redact_text,
+            self.redact_tool_payload,
+            skip_tool_message=effective_skip_tool_message_for_guardrail(self),
+        ) + self._redact_prompt(data)
 
         if inspected == 0:
             # Image-only, empty-text, and unsupported payloads inspected

litellm/proxy/guardrails/_content_utils.py

@@ -305,6 +305,11 @@ def iter_message_text(data: Mapping[str, object]) -> Iterator[str]:
         yield from _iter_text_parts_in_content(message.get("content"))
 
 
+def _is_tool_message(message: object) -> bool:
+    fields: Final = _text_object(message)
+    return fields is not None and str(fields.get("role") or "").lower() == "tool"
+
+
 def _call_item(item: object) -> tuple[str, object] | None:
     """Return ``(field, value)`` for a Responses tool-call input item, else None."""
     fields: Final = _text_object(item)
@@ -316,11 +321,14 @@ def walk_user_text(
     data: dict[str, object],
     visit: Callable[[str], str],
     visit_tool: Callable[[JsonValue], JsonValue] | None = None,
+    *,
+    skip_tool_message: bool = False,
 ) -> int:
     """Rewrite every text fragment in place via ``visit``.
 
     Mutates ``data["messages"]`` and ``data["input"]`` (including tool payloads), ``data["system"]`` and
-    ``data["instructions"]``. Returns the number
+    ``data["instructions"]``. ``skip_tool_message`` leaves ``role: tool`` messages and ``tool_result``
+    blocks as sent. Returns the number
     of fragments visited so callers can short-circuit when nothing was
     inspected.
     """
@@ -353,6 +361,8 @@ def walk_user_text(
 
     def _rewrite_part(part: Mapping[str, object], native: bool) -> Mapping[str, object]:
         nonlocal visited
+        if skip_tool_message and part.get("type") == "tool_result":
+            return part
         text: Final = _part_text(part)
         rewritten: Final = {**part, **({"text": visit(text)} if text is not None else {})}
         if text is not None:
@@ -384,18 +394,17 @@ def walk_user_text(
         return content
 
     messages: Final = data.get("messages")
-    if isinstance(messages, list):
-        for message in messages:
-            if not isinstance(message, dict):
-                continue
-            if "content" in message:
-                message["content"] = _rewrite_content(message["content"])
-            calls = message.get("tool_calls")
-            if isinstance(calls, list):
-                for call in calls:
-                    function = call.get("function") if isinstance(call, dict) else None
-                    if isinstance(function, dict) and "arguments" in function:
-                        function["arguments"] = _rewrite_arguments(function["arguments"])
+    for message in _object_list(messages) or ():
+        if (skip_tool_message and _is_tool_message(message)) or not isinstance(message, dict):
+            continue
+        if "content" in message:
+            message["content"] = _rewrite_content(message["content"])
+        calls = message.get("tool_calls")
+        if isinstance(calls, list):
+            for call in calls:
+                function = call.get("function") if isinstance(call, dict) else None
+                if isinstance(function, dict) and "arguments" in function:
+                    function["arguments"] = _rewrite_arguments(function["arguments"])
 
     if "system" in data:
         data["system"] = _rewrite_content(data["system"])  # rebind-ok: preserve the native hook's in-place contract

tests/integration/security/test_hide_secrets_tool_traffic.py

@@ -413,3 +413,71 @@ def test_resent_tool_history_is_scanned_once(single_worker: Rig, shape: str) ->
     second: Final = timed(lambda: single_worker.proxy.request("POST", path, following))
     assert first.value.status_code == 200 and second.value.status_code == 200, (first.value.text, second.value.text)
     assert_within_factor_of_control(second.seconds, control=first.seconds, factor=0.5)
+
+
+@pytest.mark.parametrize("placement", ("guardrail", "global"))
+def test_skip_tool_message_in_guardrail_forwards_tool_results(tmp_path: Path, placement: str) -> None:
+    def configure(configuration: dict[str, JsonValue]) -> None:
+        guardrails: Final = configuration["guardrails"]
+        settings: Final = configuration["litellm_settings"]
+        assert isinstance(guardrails, list) and isinstance(guardrails[0], dict) and isinstance(settings, dict)
+        params: Final = guardrails[0]["litellm_params"]
+        assert isinstance(params, dict)
+        (params if placement == "guardrail" else settings)["skip_tool_message_in_guardrail"] = True
+
+    with tool_rig(tmp_path, configure=configure) as rig:
+        rig.wire.drain()
+        replies: Final = (
+            rig.proxy.request(
+                "POST",
+                "/v1/messages",
+                {
+                    "model": "claude",
+                    "max_tokens": 32,
+                    "cache": {"no-cache": True},
+                    "messages": [
+                        {"role": "user", "content": TEXT},
+                        {
+                            "role": "assistant",
+                            "content": [
+                                {"type": "tool_use", "id": "tool_1", "name": "read_file", "input": {"env": TEXT}}
+                            ],
+                        },
+                        {
+                            "role": "user",
+                            "content": [{"type": "tool_result", "tool_use_id": "tool_1", "content": TEXT}],
+                        },
+                    ],
+                },
+            ),
+            rig.proxy.request(
+                "POST",
+                "/v1/chat/completions",
+                {
+                    "model": "gpt",
+                    "cache": {"no-cache": True},
+                    "messages": [
+                        {"role": "user", "content": TEXT},
+                        {
+                            "role": "assistant",
+                            "content": None,
+                            "tool_calls": [
+                                {
+                                    "id": "call_1",
+                                    "type": "function",
+                                    "function": {"name": "read_file", "arguments": json.dumps({"env": TEXT})},
+                                }
+                            ],
+                        },
+                        {"role": "tool", "tool_call_id": "call_1", "content": TEXT},
+                    ],
+                },
+            ),
+        )
+        assert all(reply.status_code == 200 for reply in replies), [reply.text for reply in replies]
+        sent: Final = rig.wire.drain()
+        assert len(sent) == 2
+        for request in sent:
+            messages = json.loads(request.body)["messages"]
+            assert SECRET not in json.dumps(messages[:2])
+            assert SECRET in json.dumps(messages[2])

tests/unit/proxy/guardrails/test_content_utils.py

@@ -2,6 +2,7 @@
 
 import json
 from functools import reduce
+from typing import Final
 
 import pytest
 from pydantic import JsonValue
@@ -924,6 +925,34 @@ def test_native_writer_visits_each_tool_and_system_slot(data):
     assert "payload" not in json.dumps(data)
 
 
+def test_skip_tool_message_leaves_tool_results_and_masks_the_rest() -> None:
+    data: Final[dict[str, object]] = {
+        "messages": [
+            {"role": "user", "content": "secret"},
+            {
+                "role": "assistant",
+                "content": [{"type": "tool_use", "id": "tool", "name": "read", "input": {"env": "secret"}}],
+                "tool_calls": [{"id": "call", "function": {"name": "read", "arguments": '{"env": "secret"}'}}],
+            },
+            {"role": "user", "content": [{"type": "tool_result", "tool_use_id": "tool", "content": "secret"}]},
+            {"role": "tool", "tool_call_id": "call", "content": "secret"},
+        ]
+    }
+    assert walk_user_text(data, lambda text: text.replace("secret", "[MASKED]"), skip_tool_message=True) == 3
+    assert data == {
+        "messages": [
+            {"role": "user", "content": "[MASKED]"},
+            {
+                "role": "assistant",
+                "content": [{"type": "tool_use", "id": "tool", "name": "read", "input": {"env": "[MASKED]"}}],
+                "tool_calls": [{"id": "call", "function": {"name": "read", "arguments": '{"env": "[MASKED]"}'}}],
+            },
+            {"role": "user", "content": [{"type": "tool_result", "tool_use_id": "tool", "content": "secret"}]},
+            {"role": "tool", "tool_call_id": "call", "content": "secret"},
+        ]
+    }
+
+
 @pytest.mark.parametrize(
     "part",
     (