From 1c85934231fb0e5d202cd320ec594ea1ef04fa1e Mon Sep 17 00:00:00 2001
From: moe-berri <moe@berri.ai>
Date: Tue, 27 Oct 2026 11:31:32 -0700
Subject: [PATCH] fix(responses): validate replay fields when action is missing

---
 .../transformation.py                         | 18 ++++++++---
 .../test_litellm_completion_responses.py      | 31 ++++++++++++++++++-
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/litellm/responses/litellm_completion_transformation/transformation.py b/litellm/responses/litellm_completion_transformation/transformation.py
index cf9642f2a85..3850654daf9 100644
--- a/litellm/responses/litellm_completion_transformation/transformation.py
+++ b/litellm/responses/litellm_completion_transformation/transformation.py
@@ -2062,11 +2062,19 @@ class LiteLLMCompletionResponsesConfig:
         - ItemReference
         """
         if input_item.get("type") == "web_search_call":
-            search: Final = (
-                ResponseFunctionWebSearch.model_validate(input_item)
-                if "action" in input_item
-                else ResponseFunctionWebSearch.model_construct(None, **input_item)
-            )
+            try:
+                search: Final = ResponseFunctionWebSearch.model_validate(input_item)
+            except ValidationError as exc:
+                errors: Final = exc.errors(include_url=False, include_input=False)
+                if len(errors) != 1 or errors[0]["type"] != "missing" or errors[0]["loc"] != ("action",):
+                    raise
+                replay: Final = ResponseFunctionWebSearch.model_construct(None, **input_item)
+                return [
+                    GenericChatCompletionMessage(
+                        role="assistant",
+                        content="Hosted web search: " + replay.model_dump_json(exclude_none=True),
+                    )
+                ]
             return [
                 GenericChatCompletionMessage(
                     role="assistant",
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 4f3b7e45825..63c98b571cb 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
@@ -14,7 +14,7 @@ from openai.types.responses.response_function_web_search import (
     ActionSearchSource,
     ResponseFunctionWebSearch,
 )
-from pydantic import TypeAdapter
+from pydantic import TypeAdapter, ValidationError
 
 import litellm
 from litellm.constants import CALLER_SESSION_ID_METADATA_KEY
@@ -5077,6 +5077,35 @@ class TestHostedWebSearchReplay:
         assert isinstance(content, str)
         assert json.loads(content[content.index("{") :]) == input_item
 
+    @pytest.mark.parametrize(
+        "fields",
+        (
+            {"status": "completed"},
+            {"id": "ws_invalid"},
+            {"id": 42, "status": "completed"},
+            {"id": "ws_invalid", "status": "invalid"},
+            {"id": "ws_invalid", "status": "completed", "action": None},
+            {"id": "ws_invalid", "status": "completed", "action": 42},
+            {"id": "ws_invalid", "status": "completed", "action": {"type": "invalid"}},
+            {"id": "ws_invalid", "status": "completed", "action": {"type": "find_in_page"}},
+        ),
+        ids=(
+            "missing-id",
+            "missing-status",
+            "invalid-id",
+            "invalid-status",
+            "null-action",
+            "invalid-action-type",
+            "unknown-action",
+            "incomplete-action",
+        ),
+    )
+    def test_rejects_search_with_other_invalid_fields(self, fields: Mapping[str, object]) -> None:
+        with pytest.raises(ValidationError):
+            LiteLLMCompletionResponsesConfig.transform_responses_api_input_to_messages(
+                input=[{"type": "web_search_call", **fields}], responses_api_request={}
+            )
+
     @pytest.mark.parametrize("order", ((0, 1, 2, 3), (1, 0, 3, 2), (1, 3, 0, 2)))
     @pytest.mark.parametrize("modify_params", (False, True))
     @pytest.mark.parametrize("structured_content", (False, True))