fix(gemini): preserve search tools when include_server_side_tool_invocations is set

litellm/constants.py

@@ -744,6 +744,7 @@
     "store": None,
     "metadata": None,
     "context_management": None,
+    "include_server_side_tool_invocations": None,
 }
 
 openai_compatible_endpoints: List = [

litellm/llms/gemini/chat/transformation.py

@@ -92,6 +92,7 @@ def get_supported_openai_params(self, model: str) -> List[str]:
             "parallel_tool_calls",
             "web_search_options",
             "service_tier",
+            "include_server_side_tool_invocations",
         ]
         if supports_reasoning(model, custom_llm_provider="gemini"):
             supported_params.append("reasoning_effort")

litellm/llms/vertex_ai/gemini/vertex_and_google_ai_studio_gemini.py

@@ -1077,6 +1077,8 @@ def map_openai_params(  # noqa: PLR0915
         model: str,
         drop_params: bool,
     ) -> Dict:
+        if non_default_params.get("include_server_side_tool_invocations") is True:
+            optional_params["include_server_side_tool_invocations"] = True
         for param, value in non_default_params.items():
             if param == "temperature":
                 if VertexGeminiConfig._is_gemini_3_or_newer(model):

tests/test_litellm/llms/vertex_ai/gemini/test_vertex_and_google_ai_studio_gemini.py

@@ -3499,7 +3499,12 @@ def test_video_metadata_supported_for_all_gemini_models():
         }
     ]
 
-    for model in ["gemini-1.5-pro", "gemini-2.5-flash", "gemini-2.5-pro", "gemini-3-pro-preview"]:
+    for model in [
+        "gemini-1.5-pro",
+        "gemini-2.5-flash",
+        "gemini-2.5-pro",
+        "gemini-3-pro-preview",
+    ]:
         contents = _gemini_convert_messages_with_history(messages=messages, model=model)
 
         file_part = None
@@ -3509,19 +3514,25 @@ def test_video_metadata_supported_for_all_gemini_models():
                 break
 
         assert file_part is not None, f"{model}: file part should exist"
-        assert "video_metadata" in file_part, f"{model}: video_metadata should be present"
+        assert (
+            "video_metadata" in file_part
+        ), f"{model}: video_metadata should be present"
         assert file_part["video_metadata"]["fps"] == 5, f"{model}: fps should be 5"
 
     # Per-part media_resolution is Gemini 3+ only; 2.x uses generation_config global
     for model in ["gemini-3-pro-preview"]:
         contents = _gemini_convert_messages_with_history(messages=messages, model=model)
         file_part = next(p for p in contents[0]["parts"] if "file_data" in p)
-        assert "media_resolution" in file_part, f"{model}: media_resolution should be present"
+        assert (
+            "media_resolution" in file_part
+        ), f"{model}: media_resolution should be present"
 
     for model in ["gemini-1.5-pro", "gemini-2.5-flash", "gemini-2.5-pro"]:
         contents = _gemini_convert_messages_with_history(messages=messages, model=model)
         file_part = next(p for p in contents[0]["parts"] if "file_data" in p)
-        assert "media_resolution" not in file_part, f"{model}: per-part media_resolution should not be set"
+        assert (
+            "media_resolution" not in file_part
+        ), f"{model}: per-part media_resolution should not be set"
 
 
 def test_chunk_parser_handles_prompt_feedback_block():
@@ -4154,8 +4165,9 @@ def test_vertex_ai_usage_metadata_with_document_tokens_in_prompt():
 
     # DOCUMENT tokens should be included in text_tokens: 8 (TEXT) + 774 (DOCUMENT) = 782
     assert result.prompt_tokens_details is not None
-    assert result.prompt_tokens_details.text_tokens == 782, \
-        "DOCUMENT modality tokens should be added to text_tokens (8 TEXT + 774 DOCUMENT = 782)"
+    assert (
+        result.prompt_tokens_details.text_tokens == 782
+    ), "DOCUMENT modality tokens should be added to text_tokens (8 TEXT + 774 DOCUMENT = 782)"
 
     # Verify completion token details
     assert result.completion_tokens_details is not None
@@ -4190,8 +4202,9 @@ def test_vertex_ai_usage_metadata_with_document_tokens_cached():
 
     # DOCUMENT cached tokens map to cached_text_tokens, so:
     # text_tokens = (8 TEXT + 774 DOCUMENT) - 400 cached = 382
-    assert result.prompt_tokens_details.text_tokens == 382, \
-        "text_tokens should be (8 + 774) - 400 cached = 382"
+    assert (
+        result.prompt_tokens_details.text_tokens == 382
+    ), "text_tokens should be (8 + 774) - 400 cached = 382"
     assert result.prompt_tokens_details.cached_tokens == 400
 
 
@@ -4290,3 +4303,91 @@ def test_transform_response_does_not_leak_body_on_parse_failure():
     msg = str(exc_info.value)
     assert "secret content" not in msg
     assert "Error converting to valid response block" in msg
+
+
+class TestServerSideToolInvocationsSearchToolPreservation:
+    """
+    Regression tests for https://github.com/BerriAI/litellm/issues/27479
+
+    When include_server_side_tool_invocations=True is passed alongside
+    mixed function + search tools, the search tool must NOT be dropped.
+    """
+
+    def test_search_tool_preserved_with_server_side_invocations(self):
+        """map_openai_params must preserve googleSearch when the flag is set,
+        even though tools iterates before the flag handler."""
+        v = VertexGeminiConfig()
+        result = v.map_openai_params(
+            non_default_params={
+                "tools": [
+                    {"google_search": {}},
+                    {
+                        "type": "function",
+                        "function": {
+                            "name": "send_message",
+                            "description": "Send a message",
+                            "parameters": {
+                                "type": "object",
+                                "properties": {"message": {"type": "string"}},
+                                "required": ["message"],
+                            },
+                        },
+                    },
+                ],
+                "include_server_side_tool_invocations": True,
+            },
+            optional_params={},
+            model="gemini-3.1-pro-preview",
+            drop_params=False,
+        )
+        tools = result["tools"]
+        has_google_search = any("googleSearch" in t for t in tools)
+        has_func_declarations = any("function_declarations" in t for t in tools)
+        assert has_google_search, "googleSearch should be preserved"
+        assert has_func_declarations, "function declarations should be preserved"
+
+    def test_search_tool_dropped_without_server_side_invocations(self):
+        """Without include_server_side_tool_invocations, mixed tools should
+        still drop search tools (existing behavior)."""
+        v = VertexGeminiConfig()
+        result = v.map_openai_params(
+            non_default_params={
+                "tools": [
+                    {"google_search": {}},
+                    {
+                        "type": "function",
+                        "function": {
+                            "name": "send_message",
+                            "description": "Send a message",
+                            "parameters": {
+                                "type": "object",
+                                "properties": {"message": {"type": "string"}},
+                                "required": ["message"],
+                            },
+                        },
+                    },
+                ],
+            },
+            optional_params={},
+            model="gemini-3.1-pro-preview",
+            drop_params=False,
+        )
+        tools = result["tools"]
+        has_google_search = any("googleSearch" in t for t in tools)
+        assert not has_google_search, "googleSearch should be dropped"
+
+    def test_google_ai_studio_supports_server_side_invocations(self):
+        """GoogleAIStudioGeminiConfig must list the flag in supported params."""
+        cfg = GoogleAIStudioGeminiConfig()
+        params = cfg.get_supported_openai_params(model="gemini-3.1-pro-preview")
+        assert "include_server_side_tool_invocations" in params
+
+    def test_flag_in_default_chat_completion_params(self):
+        """include_server_side_tool_invocations must be in DEFAULT_CHAT_COMPLETION_PARAM_VALUES
+        so get_non_default_params does not strip it."""
+        from litellm.constants import DEFAULT_CHAT_COMPLETION_PARAM_VALUES
+
+        assert (
+            "include_server_side_tool_invocations"
+            in DEFAULT_CHAT_COMPLETION_PARAM_VALUES
+        )