add _is_bedrock_tool_block

litellm/litellm_core_utils/prompt_templates/factory.py

@@ -4395,6 +4395,32 @@ def add_cache_point_tool_block(tool: dict) -> Optional[BedrockToolBlock]:
     return None
 
 
+def _is_bedrock_tool_block(tool: dict) -> bool:
+    """
+    Check if a tool is already a BedrockToolBlock.
+    
+    BedrockToolBlock has one of: systemTool, toolSpec, or cachePoint.
+    This is used to detect tools that are already in Bedrock format
+    (e.g., systemTool for Nova grounding) vs OpenAI-style function tools
+    that need transformation.
+    
+    Args:
+        tool: The tool dict to check
+        
+    Returns:
+        True if the tool is already a BedrockToolBlock, False otherwise
+        
+    Examples:
+        >>> _is_bedrock_tool_block({"systemTool": {"name": "nova_grounding"}})
+        True
+        >>> _is_bedrock_tool_block({"type": "function", "function": {...}})
+        False
+    """
+    return isinstance(tool, dict) and (
+        "systemTool" in tool or "toolSpec" in tool or "cachePoint" in tool
+    )
+
+
 def _bedrock_tools_pt(tools: List) -> List[BedrockToolBlock]:
     """
     OpenAI tools looks like:
@@ -4448,7 +4474,13 @@ def _bedrock_tools_pt(tools: List) -> List[BedrockToolBlock]:
 
     tool_block_list: List[BedrockToolBlock] = []
     for tool in tools:
-        # Handle regular function tools
+        # Check if tool is already a BedrockToolBlock (e.g., systemTool for Nova grounding)
+        if _is_bedrock_tool_block(tool):
+            # Already a BedrockToolBlock, pass it through
+            tool_block_list.append(tool)  # type: ignore
+            continue
+
+        # Handle regular OpenAI-style function tools
         parameters = tool.get("function", {}).get(
             "parameters", {"type": "object", "properties": {}}
         )