from typing import Annotated from mcp_types import ElicitRequestParams, ElicitResult from pydantic import BaseModel from mcp import Client from mcp.client import ClientRequestContext from mcp.server import MCPServer from mcp.server.mcpserver import AcceptedElicitation, Elicit, ElicitationResult, Resolve mcp = MCPServer("Bookshop") class Quantity(BaseModel): copies: int async def ask_quantity() -> Elicit[Quantity]: """Resolver: ask the user how many copies to put aside.""" return Elicit("How many copies?", Quantity) @mcp.tool() async def reserve(title: str, quantity: Annotated[ElicitationResult[Quantity], Resolve(ask_quantity)]) -> str: """Reserve copies of a book, asking the user how many.""" if isinstance(quantity, AcceptedElicitation): return f"Reserved {quantity.data.copies} of {title!r}." return "Nothing reserved." async def answer(context: ClientRequestContext, params: ElicitRequestParams) -> ElicitResult: return ElicitResult(action="accept", content={"copies": 2}) async def main() -> None: async with ( Client(mcp, mode="legacy", elicitation_callback=answer) as legacy, Client(mcp, elicitation_callback=answer) as modern, ): for client in (legacy, modern): result = await client.call_tool("reserve", {"title": "Dune"}) print(client.protocol_version, result.structured_content)