fix(websearch): preserve user-defined web_search tools

litellm/integrations/websearch_interception/tools.py

@@ -161,7 +161,9 @@ def is_web_search_tool_chat_completion(tool: dict[str, Any]) -> bool:
 
     Detects ONLY:
     - LiteLLM standard: name == "litellm_web_search" (Anthropic format)
-    - OpenAI format: type == "function" with function.name == "litellm_web_search" or "web_search"
+    - OpenAI format: type == "function" with function.name == "litellm_web_search"
+      or a bare function definition whose name is "web_search"
+      or a bare function definition whose name is "web_search"
 
     Args:
         tool: Tool dictionary to check
@@ -185,8 +187,15 @@ def is_web_search_tool_chat_completion(tool: dict[str, Any]) -> bool:
     # Check for OpenAI format: {"type": "function", "function": {"name": "litellm_web_search"}}
     if tool_type == "function" and "function" in tool:
         function_def: Final = tool.get("function", {})
+        if not isinstance(function_def, dict):
+            return False
         function_name: Final = function_def.get("name", "")
-        if function_name in (LITELLM_WEB_SEARCH_TOOL_NAME, "web_search"):
+        if function_name == LITELLM_WEB_SEARCH_TOOL_NAME:
+            return True
+        # The conventional name is only recognized for the name-only shape.
+        # A user-defined function may also be named ``web_search``; preserving
+        # any additional definition fields lets that tool pass through intact.
+        if function_name == "web_search" and set(function_def) == {"name"}:
             return True
 
     # Check for LiteLLM standard tool (Anthropic format)
@@ -269,8 +278,14 @@ def is_web_search_tool(tool: dict[str, Any]) -> bool:
     # Check for OpenAI format: {"type": "function", "function": {"name": "..."}}
     if tool_type == "function" and "function" in tool:
         function_def: Final = tool.get("function", {})
+        if not isinstance(function_def, dict):
+            return False
         function_name: Final = function_def.get("name", "")
-        if function_name in (LITELLM_WEB_SEARCH_TOOL_NAME, "web_search"):
+        if function_name == LITELLM_WEB_SEARCH_TOOL_NAME:
+            return True
+        # Do not hijack a user-defined function that happens to use the
+        # conventional name and carries its own schema or description.
+        if function_name == "web_search" and set(function_def) == {"name"}:
             return True
 
     # Check for LiteLLM standard tool (Anthropic format)

tests/test_litellm/integrations/websearch_interception/test_websearch_tools.py

@@ -1,5 +1,7 @@
 """Unit tests for web search tool shape detection."""
 
+from typing import Any
+
 import pytest
 
 from litellm.integrations.websearch_interception.tools import (
@@ -15,7 +17,7 @@ from litellm.integrations.websearch_interception.tools import (
         {"type": "function", "function": {"name": "web_search"}},
     ],
 )
-def test_openai_function_web_search_shapes_are_detected(tool):
+def test_openai_function_web_search_shapes_are_detected(tool: dict[str, Any]):
     """Recognize both LiteLLM and conventional web_search function names."""
     assert is_web_search_tool(tool) is True
     assert is_web_search_tool_chat_completion(tool) is True
@@ -28,7 +30,26 @@ def test_openai_function_web_search_shapes_are_detected(tool):
         {"type": "function", "function": {"name": "search"}},
     ],
 )
-def test_unrelated_openai_function_tools_are_not_detected(tool):
+def test_unrelated_openai_function_tools_are_not_detected(tool: dict[str, Any]):
     """Do not classify similarly named user tools as web search."""
     assert is_web_search_tool(tool) is False
     assert is_web_search_tool_chat_completion(tool) is False
+
+
+@pytest.mark.parametrize(
+    "tool",
+    [
+        {
+            "type": "function",
+            "function": {
+                "name": "web_search",
+                "description": "Search a private index",
+                "parameters": {"type": "object", "properties": {}},
+            },
+        },
+    ],
+)
+def test_user_defined_web_search_functions_are_not_detected(tool: dict[str, Any]):
+    """Preserve user-defined schemas even when their name is web_search."""
+    assert is_web_search_tool(tool) is False
+    assert is_web_search_tool_chat_completion(tool) is False