diff --git a/src/crewai/llm.py b/src/crewai/llm.py
index 6b0ce8ac0..ef904fffd 100644
--- a/src/crewai/llm.py
+++ b/src/crewai/llm.py
@@ -305,8 +305,6 @@ class LLM:
         Args:
             messages: Input messages for the LLM
             tools: Optional list of tool schemas
-            callbacks: Optional list of callback functions
-            available_functions: Optional dict of available functions
 
         Returns:
             Dict[str, Any]: Parameters for the completion call
@@ -317,16 +315,53 @@ class LLM:
         formatted_messages = self._format_messages_for_provider(messages)
 
         # --- 2) If using Gemini, ensure additionalProperties is not in tool schemas
-        if tools and "gemini" in self.model.lower():
-            for i, tool in enumerate(tools):
-                if (
-                    isinstance(tool, dict) 
-                    and "function" in tool 
-                    and "parameters" in tool["function"]
-                ):
-                    params = tool["function"]["parameters"]
-                    if "additionalProperties" in params:
-                        del params["additionalProperties"]
+        self._clean_gemini_tool_parameters(tools)
+        
+        # --- 3) Prepare the parameters for the completion call
+        params = {
+            "model": self.model,
+            "messages": formatted_messages,
+            "timeout": self.timeout,
+            "temperature": self.temperature,
+            "top_p": self.top_p,
+            "n": self.n,
+            "stop": self.stop,
+            "max_tokens": self.max_tokens or self.max_completion_tokens,
+            "presence_penalty": self.presence_penalty,
+            "frequency_penalty": self.frequency_penalty,
+            "logit_bias": self.logit_bias,
+            "response_format": self.response_format,
+            "seed": self.seed,
+            "logprobs": self.logprobs,
+            "top_logprobs": self.top_logprobs,
+            "api_base": self.api_base,
+            "base_url": self.base_url,
+            "api_version": self.api_version,
+            "api_key": self.api_key,
+            "stream": self.stream,
+            "tools": tools,
+            "reasoning_effort": self.reasoning_effort,
+            **self.additional_params,
+        }
+
+        # Remove None values from params
+        return {k: v for k, v in params.items() if v is not None}
+        
+    def _clean_gemini_tool_parameters(
+        self, tools: Optional[List[dict]]
+    ) -> None:
+        """Remove additionalProperties from tool parameters for Gemini compatibility.
+        
+        Args:
+            tools: List of tool dictionaries that may contain function schemas
+        """
+        if not tools or "gemini" not in self.model.lower():
+            return
+            
+        for tool in tools:
+            if isinstance(tool, dict) and "function" in tool:
+                params = tool["function"].get("parameters", {})
+                params.pop("additionalProperties", None)
 
         # --- 3) Prepare the parameters for the completion call
         params = {
diff --git a/src/crewai/tools/structured_tool.py b/src/crewai/tools/structured_tool.py
index 200a4ee4a..2697a3212 100644
--- a/src/crewai/tools/structured_tool.py
+++ b/src/crewai/tools/structured_tool.py
@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import inspect
 import textwrap
-from typing import Any, Callable, Optional, Union, get_type_hints
+from typing import Any, Callable, Dict, List, Optional, Type, Union, get_type_hints
 
 from pydantic import BaseModel, Field, create_model
 
@@ -240,25 +240,36 @@ class CrewStructuredTool:
         """Get the tool's input arguments schema."""
         return self.args_schema.model_json_schema()["properties"]
         
-    def to_openai_function(self) -> dict:
+    def to_openai_function(self) -> Dict[str, Any]:
         """Convert the tool to an OpenAI function format.
         
         Returns:
-            dict: A dictionary in the OpenAI function format.
+            Dict[str, Any]: A dictionary in the OpenAI function format.
+            
+        Example:
+            ```python
+            tool = CrewStructuredTool(...)
+            function_dict = tool.to_openai_function()
+            # Use with OpenAI or compatible APIs
+            ```
+            
+        Raises:
+            ValueError: If the schema conversion fails
         """
-        schema = self.args_schema.model_json_schema()
-        # Remove additionalProperties field to prevent Gemini API errors
-        if "additionalProperties" in schema:
-            del schema["additionalProperties"]
-        
-        return {
-            "type": "function",
-            "function": {
-                "name": self.name,
-                "description": self.description,
-                "parameters": schema
+        try:
+            schema = self.args_schema.model_json_schema()
+            schema.pop("additionalProperties", None)
+            
+            return {
+                "type": "function",
+                "function": {
+                    "name": self.name,
+                    "description": self.description,
+                    "parameters": schema
+                }
             }
-        }
+        except Exception as e:
+            raise ValueError(f"Failed to convert tool to OpenAI function format: {str(e)}")
 
     def __repr__(self) -> str:
         return (
diff --git a/tests/tools/test_structured_tool.py b/tests/tools/test_structured_tool.py
index de4a5ee64..47b5b91dc 100644
--- a/tests/tools/test_structured_tool.py
+++ b/tests/tools/test_structured_tool.py
@@ -171,3 +171,28 @@ class TestInternalCrewStructuredTool:
         assert function_dict["function"]["description"] == "A test tool"
         assert "properties" in function_dict["function"]["parameters"]
         assert "test_field" in function_dict["function"]["parameters"]["properties"]
+        
+    def test_to_openai_function_edge_cases(self):
+        """Test edge cases for to_openai_function conversion."""
+        class EmptySchema(BaseModel):
+            pass
+            
+        def empty_func() -> None:
+            pass
+            
+        tool = CrewStructuredTool(
+            name="empty_tool",
+            description="A tool with empty schema",
+            args_schema=EmptySchema,
+            func=empty_func
+        )
+        
+        function_dict = tool.to_openai_function()
+        assert function_dict["type"] == "function"
+        assert function_dict["function"]["name"] == "empty_tool"
+        
+        # Check that parameters contains the expected fields
+        params = function_dict["function"]["parameters"]
+        assert params["title"] == "EmptySchema"
+        assert params["type"] == "object"
+        assert "properties" in params  # Empty schema still has a properties field