Agent BUilder MCP problem

Have you been able to figure out how to pass the input from the AGENT to the MCP Server? Im doing a basic add_numbers(a, b) MCP call, and I receive the same error as you. Ive tried many options in defining the output scheme from the agent without any luck: AGENT → Json output schema with a and b → MCP SERVER add_numbers(a, b) function.

I also noticed that only 1 function can be assigned:

The MCP Server works with the Chat (Responses), so I know its an Agent Builder (ChatKit) problem only…