call_openai_tool on MCP client

litellm/mcp_client/tools.py

@@ -1,6 +1,8 @@
+import json
 from typing import List, Literal, Union
 
 from mcp import ClientSession
+from mcp.types import CallToolResult
 from mcp.types import Tool as MCPTool
 from openai.types.chat import ChatCompletionToolParam
 from openai.types.shared_params.function_definition import FunctionDefinition
@@ -19,6 +21,27 @@ def transform_mcp_tool_to_openai_tool(mcp_tool: MCPTool) -> ChatCompletionToolPa
     )
 
 
+def _get_function_arguments(function: FunctionDefinition) -> dict:
+    """Helper to safely get and parse function arguments."""
+    arguments = function.get("arguments", {})
+    if isinstance(arguments, str):
+        try:
+            arguments = json.loads(arguments)
+        except json.JSONDecodeError:
+            arguments = {}
+    return arguments if isinstance(arguments, dict) else {}
+
+
+def transform_openai_tool_to_mcp_tool(openai_tool: ChatCompletionToolParam) -> MCPTool:
+    """Convert an OpenAI tool to an MCP tool."""
+    function = openai_tool["function"]
+    return MCPTool(
+        name=function["name"],
+        description=function.get("description", ""),
+        inputSchema=_get_function_arguments(function),
+    )
+
+
 async def load_mcp_tools(
     session: ClientSession, format: Literal["mcp", "openai"] = "mcp"
 ) -> Union[List[MCPTool], List[ChatCompletionToolParam]]:
@@ -38,3 +61,31 @@ async def load_mcp_tools(
             transform_mcp_tool_to_openai_tool(mcp_tool=tool) for tool in tools.tools
         ]
     return tools.tools
+
+
+async def call_mcp_tool(
+    session: ClientSession,
+    name: str,
+    arguments: dict,
+) -> CallToolResult:
+    """Call an MCP tool."""
+    tool_result = await session.call_tool(
+        name=name,
+        arguments=arguments,
+    )
+    return tool_result
+
+
+async def call_openai_tool(
+    session: ClientSession,
+    openai_tool: ChatCompletionToolParam,
+) -> CallToolResult:
+    """Call an OpenAI tool using MCP client."""
+    mcp_tool = transform_openai_tool_to_mcp_tool(
+        openai_tool=openai_tool,
+    )
+    return await call_mcp_tool(
+        session=session,
+        name=mcp_tool.name,
+        arguments=mcp_tool.inputSchema,
+    )