fix(vertex_httpx.py): Fix tool calling with empty param list

Fixes https://github.com/BerriAI/litellm/issues/5055

litellm/llms/vertex_httpx.py

@@ -205,8 +205,9 @@ class GoogleAIStudioGeminiConfig:  # key diff from VertexAI - 'frequency_penalty
                     gtool_func_declaration = FunctionDeclaration(
                         name=tool["function"]["name"],
                         description=tool["function"].get("description", ""),
-                        parameters=_parameters,
                     )
+                    if len(_parameters.keys()) > 0:
+                        gtool_func_declaration["parameters"] = _parameters
                     gtool_func_declarations.append(gtool_func_declaration)
                 optional_params["tools"] = [
                     Tools(function_declarations=gtool_func_declarations)

litellm/model_prices_and_context_window_backup.json

@@ -2796,6 +2796,18 @@
         "tool_use_system_prompt_tokens": 159,
         "supports_assistant_prefill": true
     },
+    "openrouter/anthropic/claude-3.5-sonnet:beta": {
+        "max_tokens": 4096,
+        "max_input_tokens": 200000,
+        "max_output_tokens": 4096,
+        "input_cost_per_token": 0.000003,
+        "output_cost_per_token": 0.000015,
+        "litellm_provider": "openrouter",
+        "mode": "chat",
+        "supports_function_calling": true,
+        "supports_vision": true,
+        "tool_use_system_prompt_tokens": 159
+    },
     "openrouter/anthropic/claude-3-sonnet": {
         "max_tokens": 200000,
         "input_cost_per_token": 0.000003,

litellm/tests/test_function_calling.py

@@ -337,3 +337,27 @@ def test_groq_parallel_function_call():
                 print("second response\n", second_response)
     except Exception as e:
         pytest.fail(f"Error occurred: {e}")
+
+
+@pytest.mark.parametrize("model", ["gemini/gemini-1.5-pro"])
+def test_simple_function_call_function_param(model):
+    try:
+        litellm.set_verbose = True
+        messages = [{"role": "user", "content": "What is the weather like in Boston?"}]
+        response = completion(
+            model=model,
+            messages=messages,
+            tools=[
+                {
+                    "type": "function",
+                    "function": {
+                        "name": "plot",
+                        "description": "Generate plots",
+                    },
+                }
+            ],
+            tool_choice="auto",
+        )
+        print(f"response: {response}")
+    except Exception as e:
+        raise e