Revert "fix(gemini): dereference $defs/$ref in tool response content (#19062)"

This reverts commit 84dad952a2.

litellm/litellm_core_utils/prompt_templates/factory.py

@@ -45,7 +45,6 @@ from .common_utils import (
     infer_content_type_from_url_and_content,
     is_non_content_values_set,
     parse_tool_call_arguments,
-    unpack_defs,
 )
 from .image_handling import convert_url_to_base64
 
@@ -1463,56 +1462,6 @@ def convert_to_gemini_tool_call_invoke(
         )
 
 
-def _clean_refs_for_gemini(obj: Any) -> None:
-    """
-    Recursively clean $defs, $ref, and definitions from a dict for Gemini compatibility.
-    
-    Gemini rejects:
-    - $defs sections (even after $ref has been inlined)
-    - Any remaining $ref (circular refs, external URLs)
-    
-    This function:
-    1. Removes all $defs/definitions keys
-    2. Replaces any remaining $ref with a placeholder object
-    """
-    if isinstance(obj, dict):
-        # Remove $defs and definitions at this level
-        obj.pop("$defs", None)
-        obj.pop("definitions", None)
-        
-        # Check for and handle remaining $ref (circular or external)
-        if "$ref" in obj:
-            ref_value = obj.pop("$ref")
-            # Replace with a generic object type as placeholder
-            obj["type"] = "object"
-            obj["description"] = f"(schema reference: {ref_value})"
-        
-        # Recurse into values
-        for value in obj.values():
-            _clean_refs_for_gemini(value)
-    elif isinstance(obj, list):
-        for item in obj:
-            _clean_refs_for_gemini(item)
-
-
-def _prepare_response_for_gemini(response_data: dict) -> dict:
-    """
-    Prepare a tool response dict for Gemini by inlining $ref and removing $defs.
-    
-    Gemini rejects JSON schemas with $defs/$ref in function_response content.
-    This function applies unpack_defs to inline references, then cleans up
-    any remaining $defs sections and unresolved $refs (circular or external).
-    
-    Returns a new dict (does not mutate the input).
-    """
-    import copy
-
-    result = copy.deepcopy(response_data)
-    unpack_defs(result, {})
-    _clean_refs_for_gemini(result)
-    return result
-
-
 def convert_to_gemini_tool_call_result(
     message: Union[ChatCompletionToolMessage, ChatCompletionFunctionMessage],
     last_message_with_tool_calls: Optional[dict],
@@ -1621,11 +1570,6 @@ def convert_to_gemini_tool_call_result(
         # Not valid JSON, wrap in content field
         response_data = {"content": content_str}
 
-    # Gemini rejects JSON schemas with $defs/$ref in function_response content.
-    # Inline $refs and clean up for Gemini compatibility.
-    if isinstance(response_data, dict):
-        response_data = _prepare_response_for_gemini(response_data)
-
     # We can't determine from openai message format whether it's a successful or
     # error call result so default to the successful result template
     _function_response = VertexFunctionResponse(