"""Rendezvous tool on the lowlevel `Server`, proving concurrent dispatch without `MCPServer`.""" from collections import defaultdict from typing import Any import anyio import mcp_types as types from mcp.server.context import ServerRequestContext from mcp.server.lowlevel import Server from stories._hosting import run_server_from_args MEET_INPUT_SCHEMA: dict[str, Any] = { "type": "object", "properties": { "tag": {"type": "string"}, "party": {"type": "array", "items": {"type": "string"}}, }, "required": ["tag", "party"], } def build_server() -> Server[Any]: arrivals: dict[str, anyio.Event] = defaultdict(anyio.Event) async def list_tools( ctx: ServerRequestContext[Any], params: types.PaginatedRequestParams | None ) -> types.ListToolsResult: return types.ListToolsResult( tools=[types.Tool(name="meet", description="Rendezvous with peers.", input_schema=MEET_INPUT_SCHEMA)] ) async def call_tool(ctx: ServerRequestContext[Any], params: types.CallToolRequestParams) -> types.CallToolResult: assert params.name == "meet" assert params.arguments is not None tag = params.arguments["tag"] assert isinstance(tag, str) arrivals[tag].set() for peer in params.arguments["party"]: await arrivals[peer].wait() await ctx.session.report_progress(1.0, total=1.0, message=tag) return types.CallToolResult(content=[types.TextContent(text=tag)]) return Server("parallel-calls-example", on_list_tools=list_tools, on_call_tool=call_tool) if __name__ == "__main__": run_server_from_args(build_server)